Search Results: "ema"

31 January 2011

John Goerzen: Unix Password and Authority Management

One of the things that everyone seems to do different is managing passwords. We haven t looked at that in quite some time, despite growth both of the company and the IT department. As I look to us moving some things to the cloud, and shifting offsite backups from carrying tapes to a bank to backups via the Internet, I m aware that the potential for mischief whether intentional or not is magnified. With cloud hosting, a person could, with the press of a button, wipe out the equivalent of racks of machines in a few seconds. With disk-based local and Internet-based offsite backups, the potential for malicious behavior may be magnified; someone could pretty quickly wipe out local and remote backups. Add to that the mysterious fact that many enterprise-targeted services allow only a single username/password for an account, and make no provision for ACLs to delegate permissions to others. Even Rackspace Cloud has this problem, as do their JungleDisk backup product, and many, many other offsite backup products. Amazon AWS seems to be the only real exception to this rule, and their ACL support is more than a little complicated. So one of the questions we will have to address is the balance of who has these passwords. Too many people and the probability of trouble, intentional or not, rises. Too few and productivity is harmed, and potentially also the ability to restore. (If only one person has the password, and that person is unavailable, company data may be as well.) The company does have some storage locations, including locked vaults and safe deposit boxes, that no IT people have access to. I am thinking that putting a record of passwords in those locations may be a good first step, as putting the passwords in the control of those that can t use them seems a reasonable step. But we ve been thinking of this as it pertains to our local systems as well. We have, for a number of years now, assigned a unique root password to every server. These passwords are then stored in a password-management tool, encrypted with a master password, and stored on a shared filesystem. Everyone in the department therefore can access every password. Many places where I worked used this scheme, or some variant of it. The general idea was that if root on one machine was compromised and the attacker got root s password, it would prevent the person from being able to just try that password on the other servers on the network and achieve a greater level of intrusion. However, the drawback is that we now have more servers than anyone can really remember the passwords for. So many people are just leaving the password tool running. Moreover, while the attack described above is still possible, these days I worry more about automated intrusion attempts that most likely won t try that attack vector. A couple of ways we could go may include using a single root password everywhere, or a small set of root passwords. Another option may be to not log in to root accounts at all possibly even disabling their password and requiring the use of user accounts plus sudo. This hasn t been practical to date. We don t want to make a dependency on LDAP from a bunch of machines just to be able to use root, and we haven t been using a tool such as puppet or cfengine to manage this stuff. Using such a tool is on our roadmap and could let us manage that approach more easily. But this approach has risks too. One is that if user accounts can get to root on many machines, then we re not really more secure than a standard root password. Second is that it makes it more difficult to detect and enforce password expiration and systematic password changes. I m curious what approaches other people are taking on this.

30 January 2011

Lars Wirzenius: Python B-tree library, 0.16.2

I've just pushed out version 0.16.2 of my Python B-tree library. This should fix all remaining problems of B-tree nodes being modified in place while in the upload queue. This is done by never modifying nodes after they have been put into the node store. Performance suffers, but it's worth it for correctness. If anyone would like take a stab at making it faster again, there's instructions in the README file for getting started with hacking the code, or you can ask me. Profiling indicates that it might be quite helpful to keep the root node of a tree out of the store until the forest-of-trees gets committed. On the other hand, the performance of obnam has not been greatly affected by these changes, since it spends most of its time reading and writing the contents of files being backed up.

29 January 2011

Russell Coker: Egypt

Gunnar Wolf has written an interesting post about the current situation in Egypt, which includes references to Israel (where he lived for a few years) and Mexico (where he has spent most of his life) [1].Gunnar included a copy of Mohammed Sameer s blog post on the topic [2], which is a good idea as we can t rely on Mohammed s post remaining online.The Reid Report has an interesting summary of various news sources [3].I hope that the end result of this is a democratically elected government that respects human rights and offers fair trials to people accused of crimes and humane punishments those found guilty. It would be ideal if the transition could happen in a way that involves little violence and no interruptions to the food supply etc.Update: Chris Samuel provided some information on free PPP access in other countries for people in Egypt [4]. This will probably be of short-term use as the Egypten regime will probably cut International phone access too.Update2: Lars has written some interesting comments including links to articles about the US government wanting the power to cut off Internet access in the same way as the Egyptian government [5].

28 January 2011

Lars Wirzenius: Egypt blocks all communication: thoughts

The government of Egypt has blocked almost all Internet and mobile phone access, and, probably, every other form of communication as well. The government wants to prevent its citizens from protesting and demanding the president to resign. I wish the people of Egypt well. When the blocks are taken down, I hope the people report that the country is peaceful and that they have finally gotten some freedom. The government of Egypt claims to be democratic, but what they are doing should not be possible in a democracy. The fundamental aspect of a democracy is that every citizen should have the right to vote, but it is not the only necessary right for a democracy. Making your concerns heard to the government, and to other people, is also a fundamental right. As is hearing what other people have to say. Riots and violence are not acceptable ways to protest. Cutting everyone off is not going to prevent that, however, and it greatly harms any chance of peaceful resolution. But that's hard to see, when you're effectively a dictator, sitting at the top of a high tower, looking down at the common people. If the government is actively, and violently, hostile towards its people, the people have three choices: they can submit and accept the situation and continue suffering; they can oppose peacefully; or they can oppose violently. It requires great wisdom to oppose peacefully, and quite a lot of patience. It's easy, from my northern European point of view, to look at Egypt from afar, and think lofty thoughts. We here in the cold are not safe from such oppression, however. Evil people in the US have already tried to give the US president similar powers months ago. They're trying again. It is only a matter of time until this will be proposed in the EU, too, if it hasn't been already. In a crisis, people need timely access to reliable information, otherwise the crisis gets made worse by rumors and people making bad decisions based on bad data. Switching off communications is never the right solution, from the people's point of view. Those in power obviously think differently. See also: Information on how to bypass some of the blocks in Egypt.

Amaya Rodrigo: Indignez Vous!

If There is any sort of food for thought worth reading, this is it.
INDIGNEZ-VOUS! GET ANGRY! CRY OUT by St phane Hessel


St phane Hessel, author of Indignez-vous!
After 93 years, it is almost the final act. The end for me is not very far off any more. But it still leaves me a chance to be able to remind others of what acted as the basis of my political engagement. It was the years of resistance to the Nazi occupation -- and the program of social rights worked out 66 years ago by the National Council of the Resistance!

It is to Jean Moulin [murdered founder of the Council] that we owe, as part of this Council, the uniting of all elements of occupied France -- the movements, the parties, the labor unions -- to proclaim their membership in Fighting France, and we owe this to the only leader that it acknowledged, General de Gaulle. From London, where I had joined de Gaulle in March 1941, I learned that this Council had completed a program and adopted it on March 15th, 1944, that offered for liberated France a group of principles and values on which would rest the modern democracy of our country.

These principles and these values, we need today more than ever. It is up to us to see to it, all together, that our society becomes a society of which we are proud, not this society of immigrants without papers -- expulsions, suspicion regarding the immigrants. Not this society where they call into question social security and national retirement and health plans. Not this society where mass media are in the hands of the rich. These are things that we would have refused to give in to if we had been the true heirs of the National Council of the Resistance.









From 1945, after a dreadful drama [WWII], it was an ambitious
resurrection of society to which the remaining contingent of the Council
of the Resistance devoted itself. Let us remember them while creating
national health and pensions plans such as the Resistance wished, as its
program stipulated, "a full plan of French national health and social
security, aimed at assuring all citizens the means of existence whenever
they are unable to obtain them by a job; a retirement allowing the old
workers to finish their days with dignity."

The sources of energy, electricity, and gas, mines, the big banks, were
nationalized. Now this was as the program recommended: "... the return
to the nation of big monopolized means of production, fruits of common
labor, sources of energy, wealth from the mines, from insurance
companies and from big banks; the institution of a true economic and
social democracy involving the ousting of the big economic and financial
fiefdoms from the direction of the economy."

General interest must dominate over special interest. The just man
believes that wealth created in the realm of labor should dominate over
the power of money.

The Resistance proposed, "a rational organization of the economy
assuring the subordination of special interests to general interest, and
the emancipation of 'slaves' of the professional dictatorship that was
instituted just as in the fascist states," which had used the interim
[for two years after the war] government of the Republic as an agent.

A true democracy needs an independent press, and the Resistance
acknowledged it, demanded it, by defending "the freedom of the press,
its honor, and its independence from the State, the power of money and
foreign influence." This is what relieved restrictions on the press from
1944 on. And press freedom is definitely what is in danger today.

The Resistance called for a "real possibility for all French children to
benefit from the most advanced education," without discrimination.
Reforms offered in 2008 go contrary to this plan. Young teachers, whose
actions I support, went so far as refusing to apply them, and they saw
their salaries cut by way of punishment. They were indignant,
"disobeyed," judging these reforms too far from the ideal of the
democratic school, too much in the service of a society of commerce and
not developing the inventive and critical mind enough. 2

All the foundations of the social conquests of the Resistance are
threatened today.

The motive of the Resistance: indignation (Indignez-vous!)

Some dare to say to us that the State cannot afford the expenses of
these measures for citizens any more. But how can there be today a lack
of money to support and extend these conquests while the production of
wealth has been considerably augmented since the Liberation period when
Europe was in ruins? On the contrary, the problem is the power of money,
so much opposed by the Resistance, and of the big, boldfaced, selfish
man, with his own servants in the highest spheres of the State.

Banks, since privatized again, have proved to be concerned foremost for
their dividends and for the very high salaries of their leaders, not the
general interest. The disparity between the poorest and the richest has
never been so great, and amassing money, competition, so encouraged.

The basic motive of the Resistance was indignation!

We, the veterans of the resistance movements and combat forces of Free
France, we call on the young generation to live by, to transmit, the
legacy of the Resistance and its ideals. We say to them: Take our place,
"Indignez-vous!" [Get angry! or Cry out!].

The political, economic, intellectual leaders, and the whole society do
not have to give in, nor allow oppression by an actual international
dictatorship of the financial markets, which threatens peace and
democracy.

I wish for you all, each of you, to have your own motive for
indignation. It is precious. When something outrages you as I was
outraged by Nazism, then people become militant, strong, and engaged.
They join this current of history, and the great current of history must
continue thanks to each individual. And this current goes towards more
justice, more freedom, but not this unbridled freedom of the fox in the
henhouse. The rights contained in the UN Universal Declaration of Human
Rights of 1948 are just that, universal.

If you meet somebody who does not benefit from it, feel sorry for them
but help them to win their rights.

Two visions of history

When I try to understand what caused fascism, what made it so we were
overcome by Hitler and the Vichy [French government that collaborated
with Hitler], I tell myself that the propertied, with their selfishness,
were terrifically afraid of Bolshevik revolution. They were allowed to
lead with their fear.

But if, today as then, an active minority stands up, it will be enough;
we shall be the leavening that makes the bread rise. Certainly, the
experience of a very old person like me, born in 1917, is different from
the experience of the today's young persons. I often ask professors for
the opportunity to interact with their students, and I say to them: You
don't have the same obvious reasons to engage you. For us, to resist was
not to accept German occupation, defeat. It was comparatively simple.
Simple as what followed, decolonization. Then the war in Algeria.

It was necessary that Algeria become independent, it was obvious. As for
Stalin, we all applauded the victory of the Red Army against the Nazis
in 1943. But already we had known about the big Stalinist trials of
1935, and even if it was necessary to keep an ear open towards communism
to compensate against American capitalism, the necessity to oppose this
unbearable form of totalitarianism had established itself as an
obviousness. My long life presented a succession of reasons to outrage
me.

These reasons were born less from an emotion than a deliberate
commitment. As a young student at normal school [teachers college] I was
very influenced by Sartre, a fellow student. His "Nausea" [a novel],
"The Wall," [play], and "The Being and Nothingness" [essay] were very
important in the training of my thought. Sartre taught us, "You are
responsible as individuals." It was a libertarian message. The
responsibility of a person can not be assigned by a power or an
authority. On the contrary, it is necessary to get involved in the name
of one's responsibility as a human being.

When I entered the French Ecole Normale Superieure, Ulm Street, in Paris
in 1939, I entered it as a fervent adherent of the philosopher Hegel,
and I adhered to the thought of Maurice Merleau-Ponty. His teaching
explored concrete experience, that of the body and of its relations with
the senses, one big singular sense faced with a plurality of senses. But
my natural optimism, which wants all that is desirable to be possible,
carried me rather towards Hegel. Hegelism interprets the long history of
humanity as having a meaning: It is the freedom of man progressing step
by step. History is made of successive shocks, and the taking into
account of challenges. The history of societies thus advances; and in
the end, man having attained his full freedom, we have the democratic
state in its ideal form.

There is certainly another understanding of history. It says progress is
made by "freedom" of competition, striving for "always more"; it can be
as if living in a devastating hurricane. That's what it represented to a
friend of my father, the man who shared with him an effort to translate
into German "The Search for Time Lost" [novel] by Marcel Proust.

That was the German philosopher Walter Benjamin. He had drawn a
pessimistic view from a painting by the Swiss painter Paul Klee,
"Angelus Novus," where the face of the angel opens arms as if to contain
and push back a tempest, which he identifies with progress. For
Benjamin, who would commit suicide in September 1940 to escape Nazism,
the sense of history is the overpowering progression of disaster upon
disaster.

Indifference: the worst of attitudes

It is true the reasons to be indignant can seem today less clearly
related or the world too complex. Who's doing the ordering, who decides?
It is not always easy to differentiate between all the currents that
govern us. We are not any more dealing with a small elite whose joint
activities can be clearly seen. It is a vast world, of which we have a
feeling of interdependence.

We live in an interconnectivity as never before. But in this world there
still are intolerable things. To see them, it is well and necessary to
look, to search. I say to the young people, Search little, and that is
what you are going to find. The worst of attitudes is indifference, to
say "I can do nothing there, I'll just manage to get by." By including
yourself in that, you lose one of the essential elements that makes the
human being: the faculty of indignation and the commitment that is a
consequence of it.

They [young people] can already identify two big new challenges:

1. The huge gap which exists between the very poor and the very rich and
that does not cease increasing. It is an innovation of the 20th and 21st
centuries. The very poor in the today's world earn barely two dollars a
day. The new generation cannot let this gap become even greater. The
official reports alone should provoke a commitment.

2. Human rights and state of the planet: I had the chance after the
Liberation to join in the writing of the Universal Declaration of Human
Rights, adopted by the United Nations organization, on December 10th,
1948, in Paris at the palace of Chaillot. It was as principal private
secretary of Henry Laugier, the adjunct general-secretary of the UN, and
as and secretary of the Commission on Human Rights that I with others
was led to participate in the writing of this statement. I wouldn't know
how to forget the role in its elaboration of Ren Cassin, who was
national commissioner of justice and education in the government of Free
France in London in 1941 and won the Nobel peace prize in 1968, nor that
of Pierre Mend s-France in the Economic and Social Council, to whom the
text drafts we worked out were submitted before being considered by the
Third Committee (Social, Humanitarian and Cultural) of the General
Assembly. It was ratified by the 54 member states in session of the
United Nations, and I certified it as secretary.

It is to Ren Cassin that we owe the term "universal rights" instead of
"international rights" as offered by our American and British friends.
This [universal versus international] was key because, at the end of the
Second World War, what was at stake was to becomeereignty," which a
nation can emphasize while it devotes itself to crimes against humanity
on its own soil. Such was the case of Hitler, who felt himself supreme
and authorized to carry out a genocide. This universal statement owed
much to universal revulsion towards Nazism, fascism, and totalitarianism
-- and owes a lot, in our minds, to the spirit of the Resistance.

I had a feeling that it was necessary to move quickly so as not to be
dupes of the hypocrisy that there was in the UN membership, some whom
claimed these values already won but had no intention at all to promote
them faithfully -- claimed that we were trying to impose values on them.

I can not resist the desire to quote Article 15 of the Universal
Declaration of Human Rights (1948): "Everyone has the right to a
nationality." Article 22 says, "Everyone, as a member of society, has
the right to social security and is entitled to realization, through
national effort and international cooperation and in accordance with the
organization and resources of each State, of the economic, social and
cultural rights indispensable for his dignity and the free development
of his personality." And if this statement has a declarative scope, and
not statutory, the Declaration nevertheless has played a powerful role
since 1948. It saw colonized people take it up in their fight for
independence; it sowed minds in a battle for freedom.

I note with pleasure that in the course of last decades there has been
an increase in nongovernmental organizations (NGOs) and social movements
such as ATTAC (Association for the Taxation of Financial Transactions);

also FIDH (International Federation for Human Rights) and Amnesty
International, which are active and competitive. It is obvious that to
be effective today it is necessary to act in a network, to use all
modern means of communication.

To the young people, I say: Look around you, you will find topics that
justify your indignation facts about treatment of immigrants, of
"illegal" immigrants, of the Roma [aka Gypsies]. You will find concrete
situations that lead you to strong citizen action. Search and you shall
find!

My indignation regarding Palestine outrages by Israel [Indignez-vous!]

Today, my main indignation concerns Palestine, the Gaza Strip, and the
West Bank of Jordan. This conflict is outrageous. It is absolutely
essential to read the report by Richard Goldstone, of September 2009, on
Gaza, in which this South African, Jewish judge, who claims even to be a
Zionist, accuses the Israeli army of having committed "acts comparable
to war crimes and perhaps, in certain circumstances, crimes against
humanity" during its "Operation Cast Lead," which lasted three weeks.

I went back to Gaza in 2009 myself, when I was able to enter with my
wife thanks to our diplomatic passports, to study first-hand what this
report said. People who accompanied us were not authorized to enter the
Gaza Strip. There and in the West Bank of Jordan. We also visited the
Palestinian refugee camps set up from 1948 by the United Nations agency
UNRWA, where more than three million Palestinians expelled off their
lands by Israel wait even yet for a more and more problematical return.

As for Gaza, it is a roofless prison for one and a half million
Palestinians. A prison where people get organized just to survive.
Despite material destruction such as that of the Red Crescent hospital
by Operation Cast Lead, it is the behavior of the Gazans, their
patriotism, their love of the sea and beaches, their constant
preoccupation for the welfare of their children, who are innumerable and
cheerful, that haunt our memory. We were impressed by how ingeniously
they face up to all the scarcities that are imposed on them. We saw them
making bricks, for lack of cement, to rebuild the thousands of houses
destroyed by tanks. They confirmed to us that there had been 1400 deaths
including women, children, and oldsters in the Palestinian camp
during this Operation Cast Lead led by the Israeli army, compared to
only 50 injured men on the Israeli side. I share conclusions of the
South African judge. That Jews can, themselves, perpetrate war crimes is
unbearable. Alas, history does not give enough examples of people who
draw lessons from their own history. [The author, St phane Hessel, had
a Jewish father.]

Terrorism, or exasperation?

I know that Hamas [party of Palestine freedom fighters], which had won
the last legislative elections, could not help it that rockets were
launched on Israeli cities in response to the situation of isolation and
blockade in which Gazans exist. I think, naturally, that terrorism is
unacceptable; but it is necessary to acknowledge (from experience in
France) that when people are occupied by forces immensely superior to
their own, popular reaction cannot be altogether bloodless.

Does it serve Hamas to send rockets onto the town of Sd rot [Israeli
town across the border from Gaza]?

The answer is no. This does not serve their purpose, but they can
explain this gesture by the exasperation of Gazans. In the notion of
exasperation, it is necessary to understand violence as the regrettable
conclusion of situations not acceptable to those who are subjected them.

Thus, they can tell themselves, terrorism is a form of exasperation. And
that this "terrorism" is a misnomer. One should not have to resort to
this exasperation, but it is necessary to have hope. Exasperation is a
denial of hope. It is comprehensible, I would say almost natural, but it
still is not acceptable. Because it does not allow one to acquire
results that hope can possibly, eventually produce.

Nonviolence: the way we must learn to follow

I am persuaded that the future belongs to nonviolence, to reconciliation
of different cultures. It is by this way that humanity will have to
enter its next stage. But on this I agree with Sartre: We cannot excuse
the terrorists who throw bombs, but we can understand them. Sartre wrote
in 1947: "I recognize that violence in whatever form it may manifest
itself is a setback. But it is an inevitable setback because we are in a
world of violence. And if it is true that recourse to violence risks
perpetuating it, it is also true it is the sure means to make it stop."

To that I would add that nonviolence is a surer means of making violence
stop. One can not condone the terrorism, using Sartre or in the name of
this principle, during the war of Algeria, nor during the Munich Games
of 1972 the murder attempt made against Israeli athletes. Terrorism is
not productive, and Sartre himself would end up wondering at the end of
his life about the sense of violence and doubt its reason for being.

However, to proclaim "violence is not effective" is more important than
to know whether one must condemn or not those who devote themselves to
it. Terrorism is not effective. In the notion of effectiveness, a
bloodless hope is needed. If there is a violent hope, it is in the poem
of William Apollinaire "that hope is violent," and not in policy.

Sartre, in March 1980, within three weeks of his death, declared: "It is
necessary to try to explain why the world of today, which is horrible,
is only an instant in a long historical development, that hope always
has been one of the dominant forces in revolutions and insurrections,
and how I still feel hope as my conception of the future." [Note 5]

It is necessary to understand that violence turns its back on hope. It
is necessary to prefer to it hope, hope over violence. Nonviolence is
the way that we must learn to follow. So must the oppressors.
10

It is necessary to arrive at negotiations to remove oppression; it is
what will allow you to have no more terrorist violence. That's why you
should not let too much hate pile up.

The message of Mandela and Martin Luther King finds all its pertinence
in the world that overcame the confrontation of ideologies [e.g.,
Nazism] and conquered totalitarianism [e.g.,Hitler]. It is also a
message of hope in the capacity of modern societies to overcome
conflicts by a mutual understanding and a vigilant patience. To reach
that point is necessarily based on rights, against es, such as the
military intervention in Iraq.

We had this economic crisis, but we still did not initiate a new policy
of development. Also, the summit of Copenhagen against climatic warming
did not bring about a true policy for the preservation of the planet.

We are on a threshold between the terror of the first decade and the
possibilities of following decades. But it is necessary to hope, it is
always necessary to hope. The previous decade, that of 1990s, had been a
time of great progress. The United Nations had enough wisdom to call
conferences such as those of Rio on environment, in 1992, and that of
Beijing on women, in 1995. In September 2000, on the initiative of the
general secretary of United Nations, Kofi Annan, the 191 member
countries adopted a statement on the "eight objectives of the millennium
for development," by which they notably promised to reduce poverty in
the world by half before 2015.

My big regret is that neither Obama nor the European Union has yet
committed themselves to what should be the provision for a useful forum
bearing on the fundamental values.

Conclusion

How to conclude this call to be indignant? By saying still what, on the
occasion of the sixtieth anniversary of the program of the National
Council of the Resistance, we said on March 8th, 2004 -- we veterans of
the resistance movements and combat forces of Free France (1940-1945) --
that certainly "Nazism was conquered, thanks to the sacrifice of our
brothers and sisters of the Resistance and United Nations against
fascist barbarism. But this threat did not completely disappear, and our
anger against injustice is ever intact." [Note 6] Also, let us always be
called in "a truly peaceful insurrection against means of mass
communication that offer as a vista for our youth only the consumption
of mass trivia, contempt of the weakest and the culture, a generalized
amnesia, and the hard competition of all against all."

To those who will make the 21st century, we say with our affection:

TO CREATE IS TO RESIST; TO RESIST IS TO CREATE.

Petter Reinholdtsen: Using NVD and CPE to track CVEs in locally maintained software

The last few days I have looked at ways to track open security issues here at my work with the University of Oslo. My idea is that it should be possible to use the information about security issues available on the Internet, and check our locally maintained/distributed software against this information. It should allow us to verify that no known security issues are forgotten. The CVE database listing vulnerabilities seem like a great central point, and by using the package lists from Debian mapped to CVEs provided by the testing security team, I believed it should be possible to figure out which security holes were present in our free software collection. After reading up on the topic, it became obvious that the first building block is to be able to name software packages in a unique and consistent way across data sources. I considered several ways to do this, for example coming up with my own naming scheme like using URLs to project home pages or URLs to the Freshmeat entries, or using some existing naming scheme. And it seem like I am not the first one to come across this problem, as MITRE already proposed and implemented a solution. Enter the Common Platform Enumeration dictionary, a vocabulary for referring to software, hardware and other platform components. The CPE ids are mapped to CVEs in the National Vulnerability Database, allowing me to look up know security issues for any CPE name. With this in place, all I need to do is to locate the CPE id for the software packages we use at the university. This is fairly trivial (I google for 'cve cpe $package' and check the NVD entry if a CVE for the package exist). To give you an example. The GNU gzip source package have the CPE name cpe:/a:gnu:gzip. If the old version 1.3.3 was the package to check out, one could look up cpe:/a:gnu:gzip:1.3.3 in NVD and get a list of 6 security holes with public CVE entries. The most recent one is CVE-2010-0001, and at the bottom of the NVD page for this vulnerability the complete list of affected versions is provided. The NVD database of CVEs is also available as a XML dump, allowing for offline processing of issues. Using this dump, I've written a small script taking a list of CPEs as input and list all CVEs affecting the packages represented by these CPEs. One give it CPEs with version numbers as specified above and get a list of open security issues out. Of course for this approach to be useful, the quality of the NVD information need to be high. For that to happen, I believe as many as possible need to use and contribute to the NVD database. I notice RHEL is providing a map from CVE to CPE, indicating that they are using the CPE information. I'm not aware of Debian and Ubuntu doing the same. To get an idea about the quality for free software, I spent some time making it possible to compare the CVE database from Debian with the CVE database in NVD. The result look fairly good, but there are some inconsistencies in NVD (same software package having several CPEs), and some inaccuracies (NVD not mentioning buggy packages that Debian believe are affected by a CVE). Hope to find time to improve the quality of NVD, but that require being able to get in touch with someone maintaining it. So far my three emails with questions and corrections have not seen any reply, but I hope contact can be established soon. An interesting application for CPEs is cross platform package mapping. It would be useful to know which packages in for example RHEL, OpenSuSe and Mandriva are missing from Debian and Ubuntu, and this would be trivial if all linux distributions provided CPE entries for their packages.

Raphaël Hertzog: 3 ways to not clutter your Debian source package with autogenerated files

It s quite common that the upstream build system generates/updates some files but does not clean them up properly when you call make clean. In that case, when you rebuild the package a second time in the same tree, the generated Debian source package will contain those changes. You usually don t want those changes. They make your package harder to review because they contain unneeded modifications (either directly in the .diff.gz with the old source format, or in a new patch in debian/patches/debian-changes-<ver> with the 3.0 (quilt) source format). I ll show you 3 ways to avoid this problem. They are all workarounds, the proper fix would be to improve the upstream build system to really clean up the generated files. This is usually possible for files that are created , but it s much more cumbersome for files that are updated (you would have to keep a backup of the original file so that you can restore it). The traditional fix Instead of relying on the upstream build system to do the work, we modify the clean target in debian/rules to remove the files that are left-over. Since debian/rules clean is always called before a source package is built, those generated files are not included as changes compared to what upstream provided. A common work-around: always build from a clean state As you have noted, the problem only happens when you build (source and binaries) twice in a row in the same tree. Some VCS-helper tools always build the Debian package in a temporary tree which is exported from the VCS. This is the case of svn-buildpackage by default and of git-buildpackage if you use its --git-export-dir option. I don t like this solution because it solves the problem only for the maintainer. Anyone else who is working on top of the package without using the same VCS-helper tool would be affected by the problem. A new way to avoid the problem Since it s now possible to store dpkg-source options in the source package itself, we can conveniently have everybody use the --extend-diff-ignore option. It tells dpkg-source to ignore some files when checking whether we have made changes to upstream files. For example if you want to ignore changes made on the files config.sub , config.guess and Makefile you could put this in debian/source/options:
# Don't store changes on autogenerated files
extend-diff-ignore = "(^ /)(config\.sub config\.guess Makefile)$"
You need to know a bit about Perl regular expressions since that s what is used by dpkg-source to match the filenames to exclude. Note that this approach always works, even when you can t remove the file. So it saves you having to make a backup of the unmodified file just to be able to restore it before the next build.
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Alexander Reichle-Schmehl: Release Critical Bug report for Week 04

The bug webinterface of the Ultimate Debian Database currently knows about the following release critical bugs:
In Total:575
Affecting Squeeze:14
Squeeze only:6
Remaining to be fixed in Squeeze:8
Of these 8 bugs, the following tags are set:
Pending in Squeeze:1
Patched in Squeeze:0
Duplicates in Squeeze:0
Can be fixed in a security Update:2
Contrib or non-free in Squeeze:0
Claimed in Squeeze:0
Delayed in Squeeze:0
Otherwise fixed in Squeeze:0
Ignoring all the above (multiple tags possible) 5 bugs need to be fixed by Debian Contributors to get Debian 6.0 Squeeze released. However, with the view of the Release Managers, 9 need to be dealt with for the release to happen. Please see Interpreting the release critical bug statistics for an explanation of the different numbers.

26 January 2011

Rapha&#235;l Hertzog: My Debian related goals for 2011

Like last year, here s a list of Debian related projects that I d like to tackle this year. I might not do them all, but I like to write them down, I am more productive when I have concrete objectives.
  1. Translate my Debian book into English.
    I will run a fundraising campaign with Ulule.com and if enough people are interested, I will spend a few months with Roland Mas to translate the book. Hopefully this project can be completed until the summer.
  2. Finish multiarch support in dpkg.
    I m working on this with Guillem Jover right now, thanks to Linaro who is sponsoring my work.
  3. Make deb files use XZ compression by default.
    It s a simple change in dpkg-deb and it would literally save gigabytes of space on mirrors. It s particularly important so that single CD/DVD can have a more complete set of software. #556407 (on DAK) needs to be fixed first though and a project-wide discussion is in order. Some archs might want to have a different default.
  4. Be more reactive to review/merge dpkg patches.
    While we welcome help, we have a backlog of patches sitting in the BTS and it happened several times that we failed to review/merge submitted branches in a decent time. It s very frustrating for the contributor. I already tried to improve the situation by creating the Review/Merge Queue but nobody stepped up to help review and update the patches.
    As I am getting more familiar with the C part of dpkg, I hope to be able to jump in when Guillem doesn t have the time or the interest.
  5. Implement the rolling distribution proposed as part of the CUT project and try to improve the release process.
    I really want the new rolling distribution but it will inevitably have an impact on the release process. It can t be done as a standalone project. I would also like to see progress in the way we deal with transitions (see discussion here).
  6. Work more regularly on the developers-reference.
    Hopefully I will be able to combine this with my blog writing activities, i.e. write blog articles on the topics that the developers-reference shall cover and then adapt my articles with some docbook markup.
To the above list, I shall add a few supplementary goals related to funding my Debian work:
  1. Write a 10-lesson course called Smart Package Management .
    It will delivered by email to my newsletter subscribers.
  2. Create an information product (most likely an ebook or an online training) and sell it on my blog.
    The precise topic has not yet been defined although I have a few ideas. Is there something that you would like me to teach you? Leave your suggestions in a comment.
  3. By the end of the year, have at least 1/3 of my time funded by donations and/or earnings of my information products.
    More concretely it means 700 each month or a 9-fold increase compared to the current income level (around 80 /month mostly via Flattr).
That makes up lots of challenges for this year. You can help me reach those goals, join my Debian Supporters Guild and you ll be informed every time that I start something new or when you can help in specific ways.

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25 January 2011

John Goerzen: rdiff-backup, ZFS, and rsync scripts

rdiff-backup vs. ZFS As I ve been writing about backups, I ve gone ahead and run some tests with rdiff-backup. I have been using rdiff-backup personally for many years now probably since 2002, when I packaged it up for Debian. It s a nice, stable system, but I always like to look at other options for things every so often. rdiff-backup stores an uncompressed current mirror of the filesystem, similar to rsync. History is achieved by the use of compressed backwards binary deltas generated by rdiff (using the rsync algorithm). So, you can restore the current copy very easily a simple cp will do if you don t need to preserve permissions. rdiff-backup restores previous copies by applying all necessary binary deltas to generate the previous version. Things I like about rdiff-backup:
  1. Bandwidth-efficient
  2. Reasonably space-efficient, especially where history is concerned
  3. Easily scriptable and nice CLI
  4. Unlike tools such as duplicity, there is no need to periodically run full backups old backups can be deleted without impacting the ability to restore more current backups
Things I don t like about it:
  1. Speed. It can be really slow. Deleting 3 months worth of old history takes hours. It has to unlink vast numbers of files and that s pretty much it, but it does it really slowly. Restores, backups, etc. are all slow as well. Even just getting a list of your increment sizes so you d know how much space would be saved can take a very long time.
  2. The current backup copy is stored without any kind of compression, which is not at all space-efficient
  3. It creates vast numbers of little files that take forever to delete or summarize
So I thought I would examine how efficient ZFS would be. I wrote a script that would replay the rdiff-backup history first it would rsync the current copy onto the ZFS filesystem and make a ZFS snapshot. Then each previous version was processed by my script (rdiff-backup s files are sufficiently standard that a shell script can process them), and a ZFS snapshot created after each. This lets me directly compare the space used by rdiff-backup to that used by ZFS using actual history. I enabled gzip-3 compression and block dedup in ZFS. My backups were nearly 1TB in size and the amount of space I had available for ZFS was roughly 600GB, so I couldn t test all of them. As it happened, I tested the ones that were the worst-case scenario for ZFS: my photos, music collection, etc. These files had very little duplication and very little compressibility. Plus a backup of my regular server that was reasonably compressible. The total size of the data backed up with rdiff-backup was 583 GB. With ZFS, this came to 498GB. My dedup ratio on this was only 1.05 (meaning 5% or 25GB saved). The compression ratio was 1.12 (60GB saved). The combined ratio was 1.17 (85GB saved). Interestingly 498 + 85 = 583. Remember that the data under test here was mostly a worst-case scenario for ZFS. It would probably have done better had I had the time to throw the rest of my dataset at it (such as the 60GB backup of my iPod, which would have mostly deduplicated with the backup of my music server). One problem with ZFS is that dedup is very memory-hungry. This is common knowledge and it is advertised that you need to use roughly 2GB of RAM per TB of disk when using dedup. I don t have quite that much to dedicate to it, so ZFS got VERY slow and thrashed the disk a lot after the ARC grew to about 300MB. I found some tweakables in zfsrc and the zfs command that let me tweak the ARC cache to grow bigger. But the machine in question only has 2GB RAM, and is doing lots of other things as well, so this barely improved anything. Note that this dedup RAM requirement is not out of line with what is expected from these sorts of solutions. Even if I got absolutely stellar dedup ratio of 2:1, that would get me at most 1TB. The cost of buying a 1TB disk is less than the cost of upgrading my system to 4GB RAM, so dedup isn t worth it here. I think the lesson is: think carefully about where dedup makes sense. If you re storing a bunch of nearly-identical virtual machine images the sort of canonical use case for this go for it. A general fileserver well, maybe you should just add more disk instead of more RAM. Then that raises the question: if I don t need dedup from ZFS, do I bother with it at all, or just use ext4 and LVM snapshots? I think ZFS still makes sense, given its built-in support for compression and very fast snapshots LVM snapshots are known to cause serious degradation to write performance once enabled, which ZFS doesn t. So I plan to switch my backups to use ZFS. A few observations on this:
  1. Some testing suggests that the time to delete a few months of old snapshots will be a minute or two with ZFS compared to hours with rdiff-backup.
  2. ZFS has shown itself to be more space-efficient than rdiff-backup, even without dedup enabled.
  3. There are clear performance and convenience wins with ZFS.
  4. Backup Scripts So now comes the question of backup scripts. rsync is obviously a pretty nice choice here and if used with inplace perhaps even will play friendly with ZFS snapshots even if dedup is off. But let s say I m backing up a few machines at home, or perhaps dozens at work. There is a need to automate all of this. Specifically, there s a need to:
    1. Provide scheduling, making sure that we don t hammer the server with 30 clients all at once
    2. Provide for run before jobs to do things like snapshot databases
    3. Be silent on success and scream loudly via emails to administrators on any kind of error and keep backing up other systems when there is an error
    4. Create snapshots and provide an automated way to remove old snapshots (or mount them for reading, as ZFS-fuse doesn t support the .zfs snapshot directory yet)
    To date I haven t found anything that looks suitable. I found a shell script system called rsbackup that does a large part of this, but something about using a script whose homepage is a forum makes me less than 100% confident. On the securing the backups front, rsync comes with a good-looking rrsync script (inexplicably installed under /usr/share/doc/rsync/scripts instead of /usr/bin on Debian) that can help secure the SSH authorization. GNU rush also looks like a useful restricted shell.

24 January 2011

Julien Danjou: Emacs snapshot Ubuntu packages

Emacs snapshot packages for Ubuntu are now available, thanks to Dimitri Fontaine. Flattr this

Rapha&#235;l Hertzog: Debian is eating its own dog food more than ever

In its Fast distributions and slow servers article, Joe Zonker Brockmeier explains the difficulties that Fedora has to use its own distribution on their infrastructure and echoes some questions they faced:
Why wouldn t a Linux distribution project wish to showcase the distribution by hosting its infrastructure using its own system?
I completely share the underlying assumption. Eating its own dog food is very important if you want to build a Linux distribution and claim with some confidence that it s of quality and usable. Debian does quite well nowadays in that respect. There were times where the mailing list server was using Qmail (non-free at that time, and thus not part of Debian) but that s long gone. We have also seen our build infrastructure relying on software that was not public and not packaged in Debian, but that also is history. The Debian System Administration team (DSA) maintains more than 140 servers running Debian. They mostly run the stable version of Debian but a few test machines are already running Squeeze since a few months (qa.debian.org for example). The Debian admins want to ensure that the next stable release of Debian still has everything they need and that the software they use still work as expected. Big kudos to the DSA team for this choice! I hope we ll be able to continue to live up to those standards for a long time to come. PS: If you want to learn more about the setup that the DSA team uses, head to dsa.debian.org. You ll find all their repositories and some of their internal documentation.
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Michal &#268;iha&#345;: Gammu can read and write contacts from Symbian

First day of Hackweek 6 is almost over and my progress is quite good so far. The first step wat to make Gammu connect to the Series60 applet and retrieve basic information:
$ ./gammu/gammu identify
Device               : 5C:57:C8:xx:xx:xx
Manufacturer         : Nokia
Model                : E52 (RM-469)
Firmware             : 3.0
IMEI                 : 359000000000000
That was pretty easy. If you want to try it, you need to install Series60 applet into phone (manually for now, but autoinstallation is planned for future) and configure gammu to talk to it:
[gammu]
connection = blues60
device = 5C:57:C8:xx:xx:xx
Second thing I choose to implement was manipulation with contacts. There are some oddities in the applet (like it simply crashes when giving it wrong contact ID to retrieve), which I will try to fix in future, but for now I stick with existing applet and code functionality only in Gammu. And it works:
$ ./gammu/gammu getmemory ME 215
Memory ME, Location 215
Last name            : "Gammu"
First name           : "Test"
Mobile number        : "123456"
General number       : [home]"654321"
Email address 1      : "gammu-users@lists.sourceforge.net"
0 entries empty, 1 entries filled
Tomorrow I should be able to implement calendar, let's see how will it go. PS: All code is is available in our Git repository

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23 January 2011

Dirk Eddelbuettel: CRANberries is now tweeting

The CRANberries service (which reports on new and updated CRAN packages for the R language and environment) is now tweeting about new packages. Simply follow @CRANberriesFeed to receive theses messages. For the technically minded, adding this to the existing 200-line program which runs all of CRANberries was very easy. CRANberries relies only on R itself and a few Unix tools like diffstat as well as the simple blosxom txt-to-html/rss 'blog compiler'. The tweeting itself is now done by this new function
tweetNewBlogEntry <- function(curPkg, curVer, reposurl)  
    ## tests reveal that pipe(), cat(), close() is easiest
    ## to send multiple messages, may need --background option
    con <- pipe("bti --config bti.conf", "w")
    cat("New CRAN package", curPkg, "with initial version", curVer, " http://goo.gl/pgljT\n", file=con)
    close(con)
 
which simply pipes the message in Greg KH's bti program (which is now a new dependency). Special thanks to its Debian maintainer Gregor Herrmann for some helpful emails; I am using the newest release 0.29 which itself needs liboauth0. Once OAuth tokens are set-up (and see here for how to do that) all we need is the three-liner above. At this point I am not too sure what to do about updated packages. One message per updated package seems too noisy. To be seen---comments or suggestions welcome.

Julien Danjou: OrgCamp Paris 2011 review

Yesterday afternoon, I was at the first OrgCamp in Paris. It was my first attendance to a BarCamp, and I really liked it. It's basically the first geek event I do not find boring nor useless. There was about 18-20 persons participating, which was quite high, since we all initially though we would have been only 5. We had several presentations of various features and personal usages of Org-mode. For my part, I've quickly presented the agenda, and my BBDB replacement named org-contacts (I'll probably talk about it on this blog in another post later). The only downside was that Bastien (the new Org-mode maintainer) was not able to come and join us. On the other side, there were so much to tell for a first time, I did not have so much time to code. I only have been able to fix one bug reported during my agenda presentation. In the end, the overall atmosphere was very enthusiastic and friendly, which was extremely pleasant. The #org-mode-fr IRC channel has been created on Freenode, following this event. Feel free to join us. Since people liked it so badly, it seems there should be another barcamp in the next months. Stay tuned. Flattr this

22 January 2011

Enrico Zini: Match package names across distributions

Match package names across distributions What would happen if we had a quick and reliable way to match package names across distributions? These ideas came up at the appinstaller2011 meeting: We thought they were good ideas, so we started hacking. To try it, you need to get the code and build the index first:
git clone git://git.debian.org/users/enrico/distromatch.git
cd distromatch
# Careful: 90Mb
wget http://people.debian.org/~enrico/dist-info.tar.gz
tar zxf dist-info.tar.gz
# Takes a long time to do the indexing
./distromatch --reindex --verbose
Then you can query it this way:
./distromatch $DISTRO $PKGNAME [$PKGNAME1 ...]
This would give you, for the package $PKGNAME in $DISTRO, the corresponding package names in all other distros for which we have data. If you do not provide package names, it automatically shows output for all packages in $DISTRO. For example:
$ time ./distromatch debian libdigest-sha1-perl
debian:libdigest-sha1-perl fedora:perl-Digest-SHA1
debian:libdigest-sha1-perl mandriva:perl-Digest-SHA1
debian:libdigest-sha1-perl suse:perl-Digest-SHA1
real    0m0.073s
user    0m0.056s
sys 0m0.016s
Yes it's quick. It builds a Xapian index with the information it needs, and then it reuses it. As soon as I find a moment, I intend to deploy an instance of it on DDE. It is using a range of different heuristics: This list may get obsolete soon as more heuristics get implemented. Euristics will never cover all corner cases we surely have, but the idea is that if we can match a sizable amout of packages, the rest can be somehow fixed by hand as needed. The data it requires for a distribution should be rather straightforward to generate:
  1. a file which maps binary package names to source package names
  2. a file with the list of files in all the packages
For example:
$ ls -l dist-debian/
total 39688
-rw-r--r--  1 enrico enrico  1688249 Jan 20 17:37 binsrc
drwxr-xr-x  2 enrico enrico     4096 Jan 21 19:12 db
-rw-r--r--  1 enrico enrico 29960406 Jan 21 10:02 files.gz
-rw-r--r--  1 enrico enrico  8914771 Jan 21 18:39 interesting-files
$ head dist-debian/binsrc 
openoffice.org-dev openoffice.org
ext4-modules-2.6.32-5-4kc-malta-di linux-kernel-di-mipsel-2.6
linux-headers-2.6.30-2-common linux-2.6
libnspr4 nspr
ipfm ipfm
libforks-perl libforks-perl
med-physics debian-med
libntfs-3g-dev ntfs-3g
libguppi16 guppi
selinux selinux
$ zcat dist-debian/files.gz   head
memstat etc/memstat.conf
memstat usr/bin/memstat
memstat usr/share/doc/memstat/changelog.gz
memstat usr/share/doc/memstat/copyright
memstat usr/share/doc/memstat/memstat-tutorial.txt.gz
memstat usr/share/man/man1/memstat.1.gz
libdirectfb-dev usr/bin/directfb-config
libdirectfb-dev usr/bin/directfb-csource
libdirectfb-dev usr/include/directfb-internal/core/clipboard.h
libdirectfb-dev usr/include/directfb-internal/core/colorhash.h
interesting-files and db are generated when indexing. To prove the usefulness of the idea (but does it need proving?), you can find in the same git repo a little example app (it took me 10 minutes to write it), that uses the distromatch engine to export Debtags tags to other distributions:
$ ./exportdebtags fedora   head
memstat: admin::benchmarking, interface::commandline, role::program, use::monitor
libdirectfb-dev: devel::lang:c, devel::library, implemented-in::c, interface::framebuffer, role::devel-lib
libkonqsidebarplugin4a: implemented-in::c++, role::shared-lib, suite::kde, uitoolkit::qt
libemail-simple-perl: devel::lang:perl, devel::library, implemented-in::perl, role::devel-lib, role::shared-lib, works-with::mail
libpoe-component-pluggable-perl: devel::lang:perl, devel::library, implemented-in::perl, role::shared-lib
manpages-ja: culture::japanese, made-of::man, role::documentation
libhippocanvas-dev: devel::library, qa::low-popcon, role::devel-lib
libexpat-ocaml-dev: devel::lang:ocaml, devel::library, implemented-in::c, implemented-in::ocaml, role::devel-lib, works-with-format::xml
libgnutls-dev: devel::library, role::devel-lib, suite::gnu
Just in case this made you itch to play with Debtags in a non-Debian distribution, I've generated the full datasets for Fedora, Mandriva and OpenSUSE. Others have been working on the same matching problem. After we started writing code we started to become aware of existing work: I'd like to make use of those efforts, maybe to cross-validate results, maybe even better as yet another heuristics.

21 January 2011

Rapha&#235;l Hertzog: People behind Debian: Michael Vogt, synaptic and APT developer

Michael and his daughter Marie

Michael has been around for more than 10 years and has always contributed to the APT software family. He s the author of the first real graphical interface to APT synaptic. Since then he created software-center as part of his work for Ubuntu. Being the most experienced APT developer, he s naturally the coordinator of the APT team. Check out what he has to say about APT s possible evolutions. My questions are in bold, the rest is by Michael. Who are you? My name is Michael Vogt, I m married and have two little daughters. We live in Germany (near to Trier) and I work for Canonical as a software developer. I joined Debian as a developer in early 2000 and started to contribute to Ubuntu in 2004. What s your biggest achievement within Debian or Ubuntu? I can not decide on a single one so I will just be a bit verbose. From the very beginning I was interested in improving the package manager experience and the UI on top for our users. I m proud of the work I did with synaptic. It was one of the earliest UIs on top of apt. Because of my work on synaptic I got into apt development as well and fixed bugs there and added new features. I still do most of the uploads here, but nowadays David Kalnischkies is the most active developer. I also wrote a bunch of tools like gdebi, update-notifier, update-manager, unattended-upgrade and software-properties to make the update/install situation for the user easier to deal with. Most of the tools are written in python so I added a lot of improvements to python-apt along the way, including the initial high level apt interface and a bunch of missing low-level apt_pkg features. Julian Andres Klode made a big push in this area recently and thanks to his effort the bindings are fully complete now and have good documentation. My most recent project is software-center. Its aim is to provide a UI strongly targeted for end-users. The goal of this project is to make finding and installing software easy and beautiful. We have a fantastic collection of software to offer and software-center tries to present it well (including screenshots, instant search results and soon ratings&reviews). This builds on great foundations like aptdaemon by Sebastian Heinlein, screenshots.debian.net by Christoph Haas, ddtp.debian.org by Michael Bramer, apt-xapian-index by Enrico Zini and many others (this is what I love about free software, it usually adds , rarely takes away ). What are your plans for Debian Wheezy? For apt I would love to see a more plugable architecture for the acquire system. It would be nice to be able to make apt-get update (and the frontends that use this from libapt) be able to download additional data (like debtags or additional index file that contains more end-user targeted information). I also want to add some scripts so that apt (optionally) creates btrfs snapshots on upgrade and provide some easy way to rollback in case of problems. There is also some interesting work going on around making the apt problem resolver a more plugable part. This way we should be able to do much faster development. software-center will get ratings&reviews in the upstream branch, I really hope we can get that into Wheezy. If you could spend all your time on Debian, what would you work on? In that case I would start with a refactor of apt to make it more robust about ABI breaks. It would be possible to move much faster once this problem is solved (its not even hard, it just need to be done). Then I would add a more complete testsuite. Another important problem to tackle is to make maintainer scripts more declarative. I triaged a lot of upgrade bug reports (mostly in ubuntu though) and a lot of them are caused by maintainer script failures. Worse is that depending on the error its really hard for the user to solve the problem. There is also a lot of code duplication. Having a central place that contains well tested code to do these jobs would be more robust. Triggers help us a lot here already, but I think there is still more room for improvement. What s the biggest problem of Debian? That s a hard question :) I mostly like Debian the way it is. What frustrated me in the past were flamewars that could have been avoided. To me being respectful to each other is important, I don t like flames and insults because I like solving problems and fighting like this rarely helps that. The other attitude I don t like is to blame people and complain instead of trying to help and be positive (the difference between it sucks because it does not support $foo instead of it would be so helpful if we had $foo because it enables me to let me do $bar ). For a long time, I had the feeling you were mostly alone working on APT and were just ensuring that it keeps working. Did you also had this feeling and are things better nowadays ? I felt a bit alone sometimes :) That being said, there were great people like Eugene V. Lyubimkin and Otavio Salvador during my time who did do a lot of good work (especially at release crunch times) and helped me with the maintenance (but got interested in other area than apt later). And now we have the unstoppable David Kalnischkies and Julian Andres Klode. Apt is too big for a single person, so I m very happy that especially David is doing superb work on the day-to-day tasks and fixes (plus big project like multiarch and the important but not very thankful testsuite work). We talk about apt stuff almost daily, doing code reviews and discuss bugs. This makes the development process much more fun and healthy. Julian Andres Klode is doing interesting work around making the resolver more plugable and Christian Perrier is as tireless as always when it comes to the translations merging. I did a quick grep over the bzr log output (including all branch merges) and count around ~4300 total commits (including all revisions of branches merged). Of that there ~950 commits from me plus an additional ~500 merges. It was more than just ensuring that it keeps working but I can see where this feeling comes from as I was never very verbose. Apt also was never my only project, I am involved in other upstream work like synaptic or update-manager or python-apt etc). This naturally reduced the time available to hack on apt and spend time doing the important day-to-day bug triage, response to mailing list messages etc. One the python-apt side Julian Andres Klode did great work to improve the code and the documentation. It s a really nice interface and if you need to do anything related to packages and love python I encourage you to try it. Its as simple as:
import apt
cache = apt.Cache()
cache["update-manager"].mark_install()
cache.commit()
Of course you can do much more with it (update-manager, software-center and lots of more tools use it). With pydoc apt you can get a good overview. The apt team always welcomes contributors. We have a mailing list and a irc channel and it s a great opportunity to solve real world problems. It does not matter if you want to help triage bugs or write documentation or write code, we welcome all contributors. You re also an Ubuntu developer employed by Canonical. Are you satisfied with the level of cooperation between both projects? What can we do to get Ubuntu to package new applications developed by Canonical directly in Debian? Again a tricky question :) When it comes to cooperation there is always room for improvement. I think (with my Canonical hat on) we do a lot better than we did in the past. And it s great to see the current DPL coming to Ubuntu events and talking about ways to improve the collaboration. One area that I feel that Debian would benefit is to be more positive about NMUs and shared source repositories (collab-maint and LowThresholdNmu are good steps here). The lower the cost is to push a patch/fix (e.g. via direct commit or upload) the more there will be. When it comes to getting packages into Debian I think the best solution is to have a person in Debian as a point of contact to help with that. Usually the amount of work is pretty small as the software will have a debian/* dir already with useful stuff in it. But it helps me a lot to have someone doing the Debian uploads, responding to the bugmail etc (even if the bugmail is just forwarded as upstream bugreports :) IMO it is a great opportunity especially for new packagers as they will not have to do a lot of packaging work to get those apps into Debian. This model works very well for me for e.g. gdebi (where Luca Falavigna is really helpful on the Debian side). Is there someone in Debian that you admire for his contributions? There are many people I admire. Probably too many to mention them all. I always find it hard to single out individual people because the project as a whole can be so proud of their achievements. The first name that comes to my mind is Jason Gunthorpe (the original apt author) who I ve never met. The next is Daniel Burrows who I met and was inspired by. David Kalnischkies is doing great work on apt. From contributing his first (small) patch to being able to virtually fix any problem and adding big features like multiarch support in about a year. Sebastian Heinlein for aptdaemon. Christian Perrier has always be one of my heroes because he cares so much about i18n. Christoph Haas for screenshots.debian.net, Michael Bramer for his work on debian translated package descriptions.
Thank you to Michael for the time spent answering my questions. I hope you enjoyed reading his answers as I did. Subscribe to my newsletter to get my monthly summary of the Debian/Ubuntu news and to not miss further interviews. You can also follow along on Identi.ca, Twitter and Facebook.

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Alexander Reichle-Schmehl: Release Critical Bug report for Week 03

The bug webinterface of the Ultimate Debian Database currently knows about the following release critical bugs:
In Total:575
Affecting Squeeze:25
Squeeze only:10
Remaining to be fixed in Squeeze:15
Of these 15 bugs, the following tags are set:
Pending in Squeeze:0
Patched in Squeeze:7
Duplicates in Squeeze:2
Can be fixed in a security Update:1
Contrib or non-free in Squeeze:0
Claimed in Squeeze:0
Delayed in Squeeze:0
Otherwise fixed in Squeeze:6
Ignoring all the above (multiple tags possible) 6 bugs need to be fixed by Debian Contributors to get Debian 6.0 Squeeze released. However, with the view of the Release Managers, 21 need to be dealt with for the release to happen. Please see Interpreting the release critical bug statistics for an explanation of the different numbers.

Sandro Tosi: EuroPython 2011 @ Florence, IT - it's coming!

Just when I was looking for a contact email to ask news about EuroPython 2011 dates... I noticed they are already there!! June 19 to 26 !

Book your flights, reserve your vacations, hope to see you all there!

PS: this year, PyCon Italia joins EuroPython in a single conference - the bigger the funnier

20 January 2011

John Goerzen: Research on deduplicating disk-based and cloud backups

Yesterday, I wrote about backing up to the cloud. I specifically was looking at cloud backup services. I ve been looking into various options there, but also various options for disk-based backups. I d like to have both onsite and offsite backups, so both types of backup are needed. Also, it is useful to think about how the two types of backups can be combined with minimal overhead. For the onsite backups, I d want to see:
  1. Preservation of ownership, permissions, etc.
  2. Preservation of symlinks and hardlinks
  3. Space-efficient representation of changes ideally binary deltas or block-level deduplication
  4. Ease of restoring
  5. Support for backing up Linux and Windows machines
Deduplicating Filesystems for Local Storage Although I initially thought of block-level deduplicating file systems as something to use for offsite backups, they could also make an excellent choice for onsite disk-based backups. rsync-based dedup backups One way to use them would be to simply rsync data to them each night. Since copies are essentially free, we could do (or use some optimized version of) cp -r current snapshot/2011-01-20 or some such to save off historic backups. Moreover, we d get dedup both across and within machines. And, many of these can use filesystem-level compression. The real upshot of this is that the entire history of the backups can be browsed as a mounted filesystem. It would be fast and easy to find files, especially when users call about that file that they deleted at some point in the past but they don t remember when, exactly what it was called, or exactly where it was stored. We can do a lot more with find and grep to locate these things than we could do with tools in Bacula (or any other backup program) restore console. Since it is a real mounted filesystem, we could also do fun things like make tarballs of it at will, zip parts up, scp them back to the file server, whatever. We could potentially even give users direct access to their files to restore things they need for themselves. The downside of this approach is that rsync can t store all the permissions unless it s running as root on the system. Wrappers such as rdup around rsync could help with that. Another downside is that there isn t a central scheduling/statistics service. We wouldn t want the backup system to be hammered by 20 servers trying to send it data at once. So there d be an element of rolling our own scripts, though not too bad. I d have preferred not to authorize a backup server with root-level access to dozens of machines, but may be inescapable in this instance. Bacula and dedup The other alternative I thought of system such as Bacula with disk-based volumes . A Bacula volume is normally a tape, but Bacula can just write them to disk files. This lets us use the powerful Bacula scheduling engine, logging service, pre-backup and post-backup jobs, etc. Normally this would be an egregious waste of disk space. Bacula, like most tape-heritage programs, will write out an entire new copy of a file if even one byte changes. I had thought that I could let block-level dedupe reduce the storage size of Bacula volumes, but after looking at the Bacula block format spec, this won t be possible as each block will have timestamps and such in it. The good things about this setup revolve around using the central Bacula director. We need only install bacula-fd on each server to be backed up, and it has a fairly limited set of things it can do. Bacula already has built-in support for defining simple or complicated retention policies. Its director will email us if there is a problem with anything. And its logs and catalog are already extensive and enable us to easily find out things such as how long backups take, how much space they consume, etc. And it backs up Windows machines intelligently and comprehensively in addition to POSIX ones. The downsides are, of course, that we don t have all the features we d get from having the entire history on the filesystem all at once, and far less efficient use of space. Not only that, but recovering from a disaster would require a more extensive bootstrapping process. A hybrid option may be possible: automatically unpacking bacula backups after they ve run onto the local filesystem. Dedupe should ensure this doesn t take additional space if the Bacula blocksize aligns with the filesystem blocksize. This is certainly not a given however. It may also make sense to use Bacula for Windows and rsync/rdup for Linux systems. This seems, however, rather wasteful and useless. Evaluation of deduplicating filesystems I set up and tested three deduplicating filesystems available for Linux: S3QL, SDFS, and zfs-fuse. I did not examine lessfs. I ran a similar set of tests for each:
  1. Copy /usr/bin into the fs with tar -cpf - /usr/bin tar -xvpf - -C /mnt/testfs
  2. Run commands to sync/flush the disk cache. Evaluate time and disk used at this point.
  3. Rerun the tar command, putting the contents into a slightly different path in the test filesystem. This should consume very little additional space since the files will have already been there. This will validate that dedupe works as expected, and provide a hint about its efficiency.
  4. Make a tarball of both directories from the dedup filesystem, writing it to /dev/zero (to test read performance)
I did not attempt to flush read caches during this, but I did flush write caches. The test system has 8GB RAM, 5GB of which was free or in use by a cache. The CPU is a Core2 6420 at 2.13GHz. The filesystems which created files atop an existing filesystem had ext4 mounted noatime beneath them. ZFS was mounted on an LVM LV. I also benchmarked native performance on ext4 as a baseline. The data set consists of 3232 files and 516MB. It contains hardlinks and symlinks. Here are my results. Please note the comments below as SDFS could not accurately complete the test.
Test ext4 S3QL SDFS zfs-fuse
First copy 1.59s 6m20s 2m2s 0m25s
Sync/Flush 8.0s 1m1s 0s 0s
Second copy+sync N/A 0m48s 1m48s 0m24s
Disk usage after 1st copy 516MB 156MB 791MB 201MB
Disk usage after 2nd copy N/A 157MB 823MB 208MB
Make tarball 0.2s 1m1s 2m22s 0m54s
Max RAM usage N/A 150MB 350MB 153MB
Compression none lzma none gzip-2
It should be mentioned that these tests pretty much ruled out SDFS. SDFS doesn t appear to support local compression, and it severely bloated the data store, which was much larger than the original data. Moreover, it permitted any user to create and modify files, even if the permissions bits said that the user couldn t. tar gave many errors unpacking symlinks onto the SDFS filesystem, and du -s on the result threw up errors as well. Besides that, I noted that find found 10 fewer files than in my source data. Between the huge memory consumption, the data integrity concerns, and inefficient disk storage, SDFS is out of the running for this project. S3QL is optimized for storage to S3, though it can also store its files locally or on an sftp server a nice touch. I suspect part of its performance problem stems from being designed for network backends, and using slow compression algorithms. S3QL worked fine, however, and produced no problems. Creating a checkpoint using s3qlcp (faster than cp since it doesn t have to read the data from the store) took 16s. zfs-fuse appears to be the most-used ZFS implementation on Linux at the moment. I set up a 2GB ZFS pool for this test, and set dedupe=on and compress=gzip-2. When I evaluated compression in the past, I hadn t looked at lzjb. I found a blog post comparing lzjb to the gzip options supported by zfs and wound up using gzip-2 for this test. ZFS really shone here. Compared to S3QL, it took 25s instead of over 6 minutes to copy the data over and took only 28% more space. I suspect that if I selected gzip -9 compression it would have been closer both in time and space to S3QL. But creating a ZFS snapshot was nearly instantaneous. Although ZFS-fuse probably doesn t have as many users as ZFS on Solaris, still it is available in Debian, and has a good backing behind it. I feel safer using it than I do using S3QL. So I think ZFS wins this comparison. I spent quite some time testing ZFS snapshots, which are instantaneous. (Incidentally, ZFS-fuse can t mount them directly as documented, so you create a clone of the snapshot and mount that.) They worked out as well as could be hoped. Due to dedupe, even deleting and recreating the entire content of the original filesystem resulted in less than 1MB additional storage used. I also tested creating multiple filesystems in the zpool, and confirmed that dedupe even works between filesystems. Incidentally wow, ZFS has a ton of awesome features. I see why you OpenSolaris people kept looking at us Linux folks with a sneer now. Only our project hasn t been killed by a new corporate overlord, so guess that maybe didn t work out so well for you <grin>. The Cloud Tie-In This discussion leaves another discussion: what to do about offsite backups? Assuming for the moment that I want to back them up over the Internet to some sort of cloud storage facility, there are about 3 options:
  1. Get an Amazon EC2 instance with EBS storage and rsync files to it. Perhaps run ZFS on that thing.
  2. Use a filesystem that can efficiently store data in S3 or Cloud Files (S3QL is the only contender here)
  3. Use a third-party backup product (JungleDisk appears to be the leading option)
There is something to be said for using a different tool for offsite backups if there is some tool-level issue, that could be helpful. One of the nice things about JungleDisk is that bandwidth is free, and disk is the same $0.15/GB-mo that RackSpace normally charges. JungleDisk also does block-level dedup, and has a central management interface. This all spells nice for us. The only remaining question would be whether to just use JungleDisk to back up the backup server, or to put it on each individual machine as well. If it just backs up the backup server, then administrative burdens are lower; we can back everything there up by default and just not worry about it. On the other hand, if there is a problem with our main backups, we could be really stuck. So I d say I m leaning towards ZFS plus some sort of rsync solution and JungleDisk for offsite. I had two people suggest CrashPlan Pro on my blog. It looks interesting, but is a very closed product which makes me nervous. I like using standard tools and formats gives me more peace of mind, control, and recovery options. CrashPlan Pro supports multiple destinations and says that they do cloud hosting, but don t list pricing anywhere. So I ll probably not mess with it. I m still very interested in what comments people may have on all this. Let me know!

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