Search Results: "tar"

7 August 2015

Christoph Egger: Systemd pitfalls

logind hangs If you just updated systemd and ssh to that host seems to hang, that's just a known Bug (Debian Bug). Don't panic. Wait for the logind timeout and restart logind. restart and stop;start One thing that confused me several times and still confuses people is systemctl restart doing more than systemctl stop ; systemctl start. You will notice the difference once you have a failed service. A restart will try to start the service again. Both stop and start however will just ignore it. Rumors have it this has changed post jessie however. sysvinit-wrapped services and stop While there are certainly bugs with sysvinit services in general (I found myself several times without a local resolver as unbound failed to be started, haven't managed to debug further), the stop behavior of wrapped services is just broken. systemctl stop will block until the sysv initscript finished. It will even note the result of the action in its state. However systemctl will return with exitcode 0 and not output anything on stdout/stderr. This has been reported as Debian Bug. zsh helper I found the following zshrc snipped quite helpful in dealing with non-reported systemctl failures. On root shells it will display a list of failed services as part of the prompt. This will give proper feedback whether your systemctl stop failed, it will give feedback if you still have type=simple services and if the sysv-init script or wrapper is broken. 
precmd ()  
    if [[ $UID == 0 && $+commands[systemctl] != 0 ]]
    then
      use_systemd=true
      systemd_failed=" systemctl --state=failed   grep failed   cut -d \  -f 2   tr '\n' ' ' "
    fi
 
if [[ $UID == 0 && $+commands[systemctl] != 0 ]]
then
  PROMPT=$'% $fg[red]>>  $systemd_failed$reset_color% \n'
else
  PROMPT=""
fi
PROMPT+=whateveryourpromptis
zsh completion Speaking of zsh, there's one problem that bothers me a lot and I don't have any solution for. Tab-completing the service name for service is blazing fast. Tab-completing the service name for systemctl restart takes ages. People traced down to truckloads of dbus communication for the completion but no further fix is known (to me). type=simple services As described in length by Lucas Nussbaum type=simple services are actively harmful. Proper type=forking daemons are strictly superior (they provide feedback of finished initialization and success thereof) and type=notify services are so simple there's no excuse for not using them even for private one-off hacks. Even if you're language doesn't provide libsystemd-daemon bindings: 
(defun sd-notify (event-string)
  (let ((socket (make-instance 'sb-bsd-sockets:local-socket :type :datagram))
        (name (posix-getenv "NOTIFY_SOCKET"))
        (bufferlen (length event-string)))
    (when name
      (sb-bsd-sockets:socket-connect socket name)
      (sb-bsd-sockets:socket-send socket event-string bufferlen))))
This is a stable API guaranteed to not break in the future and implemented in less than ten lines of code with just basic socket functions. And if your language has support it becomes actually trivial: 
    try:
        import systemd
        systemd.daemon.notify("READY=1")
    except ImportError:
        pass
Note that in both cases there is no drawback at all on systemd-free setups. It has the overhead of checking the process' environment for NOTIFY_SOCKET or for the systemd package and behaves like a simple service otherwise. Actually the idea of separating the technical aspect (daemonizing) from the semantic aspect of signalizing "initialization finished, everything's fine" is a pretty good idea and hopefully has the potential to reduce the number of services signalizing the "everything's fine" too early. It could even be ported to non-systemd init systems easily given the API.

Christoph Egger: Systemd pitfalls

logind hangs If you just updated systemd and ssh to that host seems to hang, that's just a known Bug (Debian Bug #770135). Don't panic. Wait for the logind timeout and restart logind. restart and stop;start One thing that confused me several times and still confuses people is systemctl restart doing more than systemctl stop ; systemctl start. You will notice the difference once you have a failed service. A restart will try to start the service again. Both stop and start however will just ignore it. Rumors have it this has changed post jessie however. sysvinit-wrapped services and stop While there are certainly bugs with sysvinit services in general (I found myself several times without a local resolver as unbound failed to be started, haven't managed to debug further), the stop behavior of wrapped services is just broken. systemctl stop will block until the sysv initscript finished. It will even note the result of the action in its state. However systemctl will return with exitcode 0 and not output anything on stdout/stderr. This has been reported as Debian Bug #792045. zsh helper I found the following zshrc snipped quite helpful in dealing with non-reported systemctl failures. On root shells it will display a list of failed services as part of the prompt. This will give proper feedback whether your systemctl stop failed, it will give feedback if you still have type=simple services and if the sysv-init script or wrapper is broken. 
precmd ()  
    if [[ $UID == 0 && $+commands[systemctl] != 0 ]]
    then
      use_systemd=true
      systemd_failed=" systemctl --state=failed   grep failed   cut -d \  -f 2   tr '\n' ' ' "
    fi
 
if [[ $UID == 0 && $+commands[systemctl] != 0 ]]
then
  PROMPT=$'% $fg[red]>>  $systemd_failed$reset_color% \n'
else
  PROMPT=""
fi
PROMPT+=whateveryourpromptis
zsh completion Speaking of zsh, there's one problem that bothers me a lot and I don't have any solution for. Tab-completing the service name for service is blazing fast. Tab-completing the service name for systemctl restart takes ages. People traced down to truckloads of dbus communication for the completion but no further fix is known (to me). type=simple services As described in length by Lucas Nussbaum type=simple services are actively harmful. Proper type=forking daemons are strictly superior (they provide feedback of finished initialization and success thereof) and type=notify services are so simple there's no excuse for not using them even for private one-off hacks. Even if you're language doesn't provide libsystemd-daemon bindings: 
(defun sd-notify (event-string)
  (let ((socket (make-instance 'sb-bsd-sockets:local-socket :type :datagram))
        (name (posix-getenv "NOTIFY_SOCKET"))
        (bufferlen (length event-string)))
    (when name
      (sb-bsd-sockets:socket-connect socket name)
      (sb-bsd-sockets:socket-send socket event-string bufferlen))))
This is a stable API guaranteed to not break in the future and implemented in less than ten lines of code with just basic socket functions. And if your language has support it becomes actually trivial: 
    try:
        import systemd
        systemd.daemon.notify("READY=1")
    except ImportError:
        pass
Note that in both cases there is no drawback at all on systemd-free setups. It has the overhead of checking the process' environment for NOTIFY_SOCKET or for the systemd package and behaves like a simple service otherwise. Actually the idea of separating the technical aspect (daemonizing) from the semantic aspect of signalizing "initialization finished, everything's fine" is a pretty good idea and hopefully has the potential to reduce the number of services signalizing the "everything's fine" too early. It could even be ported to non-systemd init systems easily given the API.

Neil McGovern: Forty five hours

IMG_0330As some may know, since October 2013, I ve been studying to gain my Private Pilot Licence, and I finally achieved this goal. It s actually taken quite a bit more than 45 hours a total of around 60, but that does include a day trip to France (Le Touquet) and getting my night rating as well. This basically means I can fly single engine piston aeroplanes on my own, with passengers, as soon as my paperwork gets processed by the Civil Aviation Authority anyway. I ve been flying Cessna 172s from Cambridge Aero Club, where they have four of them, G-SHWK, G-UFCB, G-HERC and G-MEGS, as well as a Extra 200, G-GLOC. It s a great club, with fantastically maintained planes and great instructors, and Cambridge Airport has a full ATC service as well, so it s been useful to get that experience, especially as the UK s airspace is fairly contended with a lot of controlled and military airspace which needs permission to enter. As for what next, I need to work that out. When you get your licence, it s often described as a license to learn, so that s what I intend to do. Apart from popping over to France for lunch every now and again, I m probably going to have a go at aerobatics and farm strip flying, then probably look at my IMC rating. So, if it s a nice day, and you re around in Cambridge, let me know if you want a trip up in the skies!

Mike Gabriel: My FLOSS activities in July 2015

July 2015 has been mainly dedicated to these five fields of endeavour: Debian Edu rollout at a grammar school (Gymnasium) in L beck, Germany In spring 2015, we got contacted by the IT coordinator of a grammar school (Gymnasium) in L beck, Germany. He asked for some consultancy on the existing school network based on Debian and Linux Mint. The school has been running on Linux all-over for the past 5 years (at least, IIRC). After several phone calls and a personal meeting, the decision was reached to switch over the educational segment of their school IT completely to Debian Edu / Skolelinux. GOsa and Debian Edu testing and fixing This new customer gave us the opportunity of intensively testing Debian Edu jessie. Diverting from previous rollouts, we dropped LibVirt as virtualization technology and switched over to Ganeti. The Debian Edu machines all run in KVM virtual machines. Our Diskless Workstations and diskfull workstations have been running on Debian Edu jessie plus MATE desktop environment for a while already. But the main servers at other customers' are still on Debian Edu squeeze. read more

Ben Hutchings: Debian LTS work, July 2015

This was my eighth month working on Debian LTS. I was assigned 14.75 hours of work by Freexian's Debian LTS initiative. linux-2.6 I didn't upload any new version of the kernel this month, but I did send all the recent security fixes to Willy Tarreau who maintains the 2.6.32.y branch at kernel.org. I also spent more time working on a fix for bug #770492 aka CVE-2015-1350, which is not yet fixed upstream. I now have a candidate patch for 2.6.32.y/squeeze, and automated tests covering many of the affected filesystems. Front desk The LTS 'front desk' role is now assigned on a rota, and I was my first turn in the third week of July. I investigated which new CVEs affected LTS-supported packages in squeeze, recorded this in the secure-testing repository, and mailed the package maintainers to give them a chance to handle the updates. groovy Groovy had a single issue (CVE-2015-3253) with a simple fix that I could apply to the version in squeeze. Unfortunately the previous version in squeeze had not been properly updated during the squeeze release cycle and could no longer be built from source. I eventually worked out what the build-dependencies should be, uploaded the fix and issued DLA-274-1. ruby1.9.1 Ruby 1.9.1 also had a single issue (CVE-2014-6438), though the fixes were more complicated and hard to find. (The original bug report for this is still not public in the upstream bug tracker.) I also had to find an earlier upstream change that they depended on. As I've mentioned before, Ruby has an extensive test suite so I could be quite confident in my backported changes. I uploaded and issued DLA-275-1. libidn The GNU library for Internationalized Domain Names, libidn, required applications to pass only valid UTF-8 strings as domain names. The Jabber instant messaging server turned out not to be validating untrusted domain names, leading to a security issue there (CVE-2015-2059). As there are likely to be other applications with similar bugs, this was resolved by adding UTF-8 validation to libidn. The fix for this involved importing additional functions from the GNU portability library, gnulib, and there my difficulties began. Confusingly, libidn has two separate sets of functions imported from gnulib, and due to interdependencies it turned out that I would have to update both of these wholesale rather than just importing the new functions that were wanted. This resulted in a 35,000 line patch. Following that I needed to autoreconf the package (and debug that process when it failed), ending up with another 26,000 line patch. Finally, it turned out that the new gnulib code needed gperf to build a header file for Solaris (when building for Linux? huh?). I ended up adding that with another patch instead. libidn has a decent test suite, so I could at least be confident in the result of my changes. I uploaded and issued DLA-277-1. Dear upstream developers, please use sane libraries instead of gnulib.

John Goerzen: Detailed Smart Card Cryptographic Token Security Guide

After my first post about smartcards under Linux, I thought I would share some information I ve been gathering. This post is already huge, so I am not going to dive into much specific commands, but I am linking to many sources with detailed instructions. I ve reviewed several types of cards. For this review, I will focus on the OpenPGP card and the Yubikey NEO, since the Cardomatic Smartcard-HSM is not supported by the gpg version in Jessie. Both cards are produced by people with strong support for the Free Software ecosystem and have strong cross-platform support with source code. OpenPGP card: Basics with GnuPG The OpenPGP card is well-known as one of the first smart cards to work well on Linux. It is a single-application card focused on use with GPG. Generally speaking, by the way, you want GPG2 for use with smartcards. Basically, this card contains three slots: decryption, signing, and authentication slots. The concept is that the private key portions of the keys used for these items are stored only on the card, can never be extracted from the card, and the cryptographic operations are performed on the card. There is more information in my original post. In a fairly rare move for smartcards, this card supports 4096-byte RSA keys; most are restricted to 2048-byte keys. The FSF Europe hands these out to people and has a lot of good information about them online, including some HOWTOs. The official GnuPG smart card howto is 10 years old, and although it has some good background, I d suggest using the FSFE instructions instead. As you ll see in a bit, most of this information also pertains to the OpenPGP mode of the Yubikey Neo. OpenPGP card: Other uses Of course, this is already pretty great to enhance your GPG security, but there s a lot more that you can do with this card to add two-factor authentication (2FA) to a lot of other areas. Here are some pointers: OpenPGP card: remote authentication with ssh You can store the private part of your ssh key on the card. Traditionally, this was only done by using the ssh agent emulation mode of gnupg-agent. This is still possible, of course. Now, however, the OpenSC project now supports the OpenPGP card as a PKCS#11 and PKCS#15 card, which means it works natively with ssh-agent as well. Try just ssh-add -s /usr/lib/x86_64-linux-gnu/pkcs11/opensc-pkcs11.so if you ve put a key in the auth slot with GPG. ssh-add -L will list its fingerprint for insertion into authorized_keys. Very simple! As an aside: Comments that you need scute for PKCS#11 support are now outdated. I do not recommend scute. It is quite buggy. OpenPGP card: local authentication with PAM You can authenticate logins to a local machine by using the card with libpam-poldi here are some instructions. Between the use with ssh and the use with PAM, we have now covered 2FA for both local and remote use in Unix environments. OpenPGP card: use on Windows Let s move on to Windows environments. The standard suggestion here seems to be the mysmartlogon OpenPGP mini-driver. It works with some sort of Windows CA system, or the local accounts using EIDAuthenticate. I have not yet tried this. OpenPGP card: Use with X.509 or Windows Active Directory You can use the card in X.509 mode via these gpgsm instructions, which apparently also work with Windows Active Directory in some fashion. You can also use it with web browsers to present a certificate from a client for client authentication. For example, here are OpenSC instructions for Firefox. OpenPGP card: Use with OpenVPN Via the PKCS#11 mode, this card should be usable to authenticate a client to OpenVPN. See the official OpenVPN HOWTO or these other instructions for more. OpenPGP card: a note on PKCS#11 and PKCS#15 support You ll want to install the opensc-pkcs11 package, and then give the path /usr/lib/x86_64-linux-gnu/pkcs11/opensc-pkcs11.so whenever something needs the PKCS#11 library. There seem to be some locking/contention issues between GPG2 and OpenSC, however. Usually killing pcscd and scdaemon will resolve this. I would recommend doing manipulation operations (setting PINs, generating or uploading keys, etc.) via GPG2 only. Use the PKCS#11 tools only to access. OpenPGP card: further reading Kernel Concepts also has some nice readers; you can get this card in a small USB form-factor by getting the mini-card and the Gemalto reader. Yubikey Neo Introduction The Yubikey Neo is a fascinating device. It is a small USB and NFC device, a little smaller than your average USB drive. It is a multi-application device that actually has six distinct modes: There is a ton to digest with this device. Yubikey Neo Basics By default, the Yubikey Neo is locked to only a subset of its features. Using the yubikey-personalization tool (you ll need the version in stretch; jessie is too old), you can use ykpersonalize -m86 to unlock the full possibilities of the card. Run that command, then unplug and replug the device. It will present itself as a USB keyboard as well as a PC/SC-compatible card reader. It has a capacitive button, which is used to have it generate keystrokes to input validation information for HOTP or HMAC validation. It has two slots that can be configured with HMAC and HOTP; a short button press selects the default slot #1 and a long press selects slot #2. But before we get into that, let s step back at some basics. opensc-tool list-algorithms claims this card supports RSA with 1024, 2048, and 3072 sizes, and EC with 256 and 384-bit sizes. I haven t personally verified anything other than RSA-2048 though. Yubikey Neo: OpenPGP support In this mode, the card is mostly compatible with the physical OpenPGP card. I say mostly because there are a few protocol differences I ll get into later. It is also limited to 2048-byte keys. Support for this is built into GnuPG and the GnuPG features described above all work fine. In this mode, it uses firmware from the Yubico fork of the JavaCard OpenPGP Card applet. There are Yubico-specific tutorials available, but again, most of the general GPG stuff applies. You can use gnupg-agent to use the card with SSH as before. However, due to some incompatibilities, the OpenPGP applet on this card cannot be used as a PKCS#11 card with either scute or OpenSC. That is not exactly a huge problem, however, as the card has another applet (PIV) that is compatible with OpenSC and so this still provides an avenue for SSH, OpenVPN, Mozilla, etc. It should be noted that the OpenPGP applet on this card can also be used with NFC on Android with the OpenKeychain app. Together with pass (or its Windows, Mac, or phone ports), this makes a nicely secure system for storing passwords. Yubikey Neo: PKCS#11 with the PIV applet There is also support for the PIV standard on the Yubikey Neo. This is supported by default on Linux (via OpenSC) and Windows and provides a PKCS#11-compabible store. It should, therefore, be compatible with ssh-agent, OpenVPN, Active Directory, and all the other OpenPGP card features described above. The only difference is that it uses storage separate from the OpenPGP applet. You will need one of the Yubico PIV tools to configure the key for it; in Debian, the yubico-piv-tool from stretch does this. Here are some instructions on using the Yubikey Neo in PIV mode: A final note: for security, it s important to change the management key and PINs before deploying the PIV mode. I couldn t get this to work with Firefox, but it worked pretty much everywhere else. Yubikey Neo: HOTP authentication This is the default mode for your Yubikey; all other modes require enabling with ykpersonalize. In this mode, a 128-bit AES key stored on the Yubikey is used to generate one-time passwords (OTP). (This key was shared in advance with the authentication server.) A typical pattern would be for three prompts: username, password, and Yubikey HOTP. The user clicks in the Yubikey HOTP field, touches the Yubikey, and their one-time token is pasted in. In the background, the service being authenticated to contacts an authentication server. This authentication server can be either your own (there are several open source implementations in Debian) or the free Yubicloud. Either way, the server decrypts the encrypted part of the OTP, performs validity checks (making sure that the counter is larger than any counter it s seen before, etc) and returns success or failure back to the service demanding authentication. The first few characters of the posted auth contain the unencrypted key ID, and thus it can also be used to provide username if desired. Yubico has provided quite a few integrations and libraries for this mode. A few highlights: You can also find some details on the OTP mode. Here s another writeup. This mode is simple to implement, but it has a few downsides. One is that it is specific to the Yubico line of products, and thus has a vendor lock-in factor. Another is the dependence on the authentication server; this creates a potential single point of failure and can be undesireable in some circumtances. Yubikey Neo: OATH and HOTP and TOTP First, a quick note: OATH and OAuth are not the same. OATH is an authentication protocol, and OAuth is an authorization protocol. Now then Like Yubikey HOTP, OATH (both HOTP and TOTP) modes rely on a pre-shared key. (See details in the Yubico article.) Let s talk about TOTP first. With TOTP, there is a pre-shared secret with each service. Each time you authenticate to that service, your TOTP generator combines the timestamp with the shared secret using a HMAC algorithm and produces a OTP that changes every 30 seconds. Google Authenticator is a common example of this protocol, and this is a drop-in replacement for it. Gandi has a nice description of it that includes links to software-only solutions on various platforms as well. With the Yubikey, the shared secrets are stored on the card and processed within it. You cannot extract the shared secret from the Yubikey. Of course, if someone obtains physical access to your Yubikey they could use the shared secret stored on it, but there is no way they can steal the shared secret via software, even by compromising your PC or phone. Since the Yubikey does not have a built-in clock, TOTP operations cannot be completed solely on the card. You can use a PC-based app or the Android application (Play store link) with NFC to store secrets on the device and generate your TOTP codes. Command-line users can also use the yubikey-totp tool in the python-yubico package. OATH can also use HOTP. With HOTP, an authentication counter is used instead of a clock. This means that HOTP passwords can be generated entirely within the Yubikey. You can use ykpersonalize to configure either slot 1 or 2 for this mode, but one downside is that it can really only be used with one service per slot. OATH support is all over the place; for instance, there s libpam-oath from the OATH toolkit for Linux platforms. (Some more instructions on this exist.) Note: There is another tool from Yubico (not in Debian) that can apparently store multiple TOTP and HOTP codes in the Yubikey, although ykpersonalize and other documentation cannot. It is therefore unclear to me if multiple HOTP codes are supported, and how.. Yubikey Neo: Challenge-Response Mode This can be useful for doing offline authentication, and is similar to OATH-HOTP in a sense. There is a shared secret to start with, and the service trying to authenticate sends a challenge to the token, which must supply an appropriate response. This makes it only suitable for local authentication, but means it can be done fairly automatically and optionally does not even require a button press. To muddy the waters a bit, it supports both Yubikey OTP and HMAC-SHA1 challenge-response modes. I do not really know the difference. However, it is worth noting that libpam-yubico works with HMAC-SHA1 mode. This makes it suitable, for instance, for logon passwords. Yubikey Neo: U2F U2F is a new protocol for web-based apps. Yubico has some information, but since it is only supported in Chrome, it is not of interest to me right now. Yubikey Neo: Further resources Yubico has a lot of documentation, and in particular a technical manual that is actually fairly detailed. Closing comments Do not think a hardware security token is a panacea. It is best used as part of a multi-factor authentication system; you don t want a lost token itself to lead to a breach, just as you don t want a compromised password due to a keylogger to lead to a breach. These things won t prevent someone that has compromised your PC from abusing your existing ssh session (or even from establishing new ssh sessions from your PC, once you ve unlocked the token with the passphrase). What it will do is prevent them from stealing your ssh private key and using it on a different PC. It won t prevent someone from obtaining a copy of things you decrypt on a PC using the Yubikey, but it will prevent them from decrypting other things that used that private key. Hopefully that makes sense. One also has to consider the security of the hardware. On that point, I am pretty well satisfied with the Yubikey; large parts of it are open source, and they have put a lot of effort into hardening the hardware. It seems pretty much impervious to non-government actors, which is about the best guarantee a person can get about anything these days. I hope this guide has been helpful.

6 August 2015

Eduard Sanou: Reproducible builds on Debian for GSoC 2015, 1st update

This is the second blog post I m writing about my experiences contributing to Debian for Google Summer of Code 2015 (check my first post)

Status update

First month It s been two months and a few days since the GSoC started. During the first month I worked on fixing specific packages, mainly concerning issues with timestamps, which is a very common source of unreproducibility. In many cases, during the build process files are compressed into gzip or zip archives, which store the creation time of files in the metadata. This can lead to unreproducible results when there is timezone variation between builds (easily fixed setting the timezone to UTC before the compression happens). In some cases the compressed files are generated during the build, and thus add build times in the metadata of compressed files (in this case the creation date of the files needs to be normalized somehow). As explained in my application, I finished exams on the end of June, that s why I chose to work on small fixes first, so that I could make the most out of my time between studying and finishing university projects and reports. I m happy with my first month, as I have worked as originally planned. Actually, my estimation of the number of bugs I could submit every week was surpassed in reality!

Second month Once the university was over, I started dedicating myself fully to the project. This allowed me to start working on toolchain fixes, following my original plan on working with timestamp related issues. In particular I have been working a lot in implementing a proposal for deterministic timestamps that appeared in the reproducible builds project. The idea is to define an environment variable called SOURCE_DATE_EPOCH that contains a known timestamp in Unix epoch format. With this variable exported, tools that would embed the localtime in their generated or processed files, can use this externally supplied date. This would happen only if SOURCE_DATE_EPOCH is exported, so the behaviour of the tool wouldn t change if the variable is not set. The first package I patched to implement this behaviour was gcc. The reason behind this is that there are about 420 unreproducible packages due to using the __DATE__, __TIME__ and __TIMESTAMP__ C macros. My patch changes the behavior of the macros __DATE__ and __TIME__ if SOURCE_DATE_EPOCH is exported. I submitted this patch to the gcc-patches list. Even though there was some interesting discussions in the list, the patch has not been accepted yet. Seeing how the reproducible builds idea is gaining momentum and becoming widespread, I m positive that at some point the gcc people will be more receptive for such patch. The second work with SOURCE_DATE_EPOCH was in debhelper; I patched this building tool to export the variable with the latest debian/changelog entry timestamp. With this patch, all the tools that run under dh will be able to use it to embed deterministic timestamps. Unfortunately some parts of the build process of some packages don t happen under debhelper, so the variable needs to be exported in a different way. Having submitted the debhelper patch allowed many packages to become reproducible after the tools that embedded timestamps were patched to honour SOURCE_DATE_EPOCH. As of today, the toolchain packages I have patched to do that are: gcc, libxslt, gettext, ghostscript and qt4-x11 (qhelpgenerator). I have also continued working on fixing individual packages affected by timestamps, random orderings (such as the ones from listing hash keys) and locale depending orderings; I have tagged packages in our infrastructure to note what kind of issue makes them unreproducible; I have updated some parts of the Reproducible Builds Wiki.

Impressions about reproducible builds The work I did during the first month felt a bit tedious sometimes: it didn t require much creativity or thinking as most of the fixes where quite mechanical, following a recipe. After I became free from university duties, I started looking into less trivial issues, which require more deep investigation and feel more rewarding once they are fixed. I also worked on toolchain fixes, which need more work and need more care. Fixing toolchain packages feels particularly rewarding because they can cause many packages to become reproducible at once. There is a very active community in the reproducible builds project! It s great to see so many people contributing to this project spending so many hours and putting so much effort. I ve felt very welcome from the beginning and I have gotten kind replies and helpful answers to all the questions and doubts I ve had, both from my mentor and from the other people in the project. I want to add that I m still amazed by the awesome infrastructure set up for the reproducible builds project. The team is using a Jenkins machine to continuously build packages to check for reproducibility, with irc notifications for changes, and also with a really useful web interface to list all the packages organized by issues that allows exploring them individually with all the available information. Also not only the infrastructure is used to build Debian amd64 packages, but also FreeBSD, NetBSD, OpenWRT, coreboot and lately Debian armhf with the help of a few new arm nodes.

Impressions about working on a free software project This was my first time working on a community driven free software project and I ve learned so many things. Something I learned during the first days, which is even more present in such wide project like the reproducible builds, is that contributing is not just writing patches for the features you want; you also need to convince the maintainer of the package to accept the patch! I was a bit surprised at the beginning because even if this is a Debian project, that aims to make changes to the whole distribution, decisions are not absolute for the whole Debian project. After taking decisions within the reproducible builds teams on how to approach things, we need to convince the rest of the Debian developers (mainly maintainers) to follow them, as they are allowed to disagree. So it is required to work together for solutions that makes everyone comfortable, usually with discussions on mailing lists or irc. There is another fact that I wasn t expecting before getting involved in this project. The kind of teamwork I have done previously involves having a leader who decides how stuff is done, who takes decisions when needed and oversees the whole project. There seems to be a different philosophy in Debian. Instead of having a leader, everyone tries their best, trying to convince the others that their solution is good, often by showing an implementation of the solution and providing proof that it works, rather than trying to get the solution accepted before coding it. Also, solutions and ideas are valued for their quality rather than by the position of the person submitting them, and there is no hierarchy within the group: all comments and advices are taken equally, valuing their usefulness regardless of who gives them. Usually there are no votes when deciding things. Members try their best on their approaches, trying to convince others as best as they can. And even if someone disagrees they may end up accepting the solution if they don t manage to convince the original proposer of doing things differently. The idea is to spend more time working and coding than arguing and deciding on the way to do things. So far I ve seen this approach to be very efficient :) I ve been told by my mentor that for difficult cases there exist a Debian committee that helps mediate on disagreements, but that is only used as a last option, probably when the discussion gets heated up.

Personal experience Overall I m very happy to finally having set my foot in the free software community, where I m able to contribute to the kind of software I have been using for years. The sense of community in Debian is really big, and everyone is invited to participate. I think that Google is doing an awesome job with the Google Summer of Code, not only because it gives a lot to free software but because it helps students to join the free software world as contributors (which is something that may be difficult to get into when you don t know how to begin, as it happened to myself for some time). I plan to continue contributing to the free software world, and I d encourage anyone to find projects to get involved and contribute as well! Happy hacking to everyone!

Christoph Egger

TinyTiny-RSS has some nice failure modes. And upstream support forums aren't really helpfull so when you search for your current problem, chances are that there is one mention of it on the web, in the forum, and the only thing happening there is people making fun of the reporter. Anyway. This installation has seen lots of error messages from the updater in the last several months: 
Warning: Fatal error, unknown preferences key: ALLOW_DUPLICATE_POSTS (owner: 3) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108
Warning: Fatal error, unknown preferences key: ALLOW_DUPLICATE_POSTS (owner: 3) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108
Warning: Fatal error, unknown preferences key: ALLOW_DUPLICATE_POSTS (owner: 3) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108
Warning: Fatal error, unknown preferences key: ALLOW_DUPLICATE_POSTS (owner: 3) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108
And, more recently, the android app stopped working with ERROR:JSON Parse failed.. Turns out both things are related. First thing I noticed was changing preferences in the web panel stopped working until you use the reset to Defaults option and then changed settings. Plugging wireshark in between showed what was going on (Note: API was displayed as enabled in Preferences/Preferences): 
HTTP/1.1 200 OK
Server: nginx/1.8.0
Date: Thu, 06 Aug 2015 11:00:31 GMT
Content-Type: text/json
Transfer-Encoding: chunked
Connection: keep-alive
X-Powered-By: PHP/5.4.43
Content-Language: auto
Set-Cookie: [...]
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Api-Content-Length: 234
ea


Warning:  Fatal error, unknown preferences key: ENABLE_API_ACCESS (owner: 2) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108

 "seq":0,"status":1,"content": "error":"API_DISABLED" 
0
Solution for fixing the Android app (and the logspam on the way as well) seems to be to reset the preferences and then configure tt-rss again (In the webapp, not in the android thing!). Also silences tt-rss update_daemon as well, yay! One last thing: someone out there who wants to explain to me how to fix 
Fatal error: Query INSERT INTO ttrss_enclosures
                                                        (content_url, content_type, title, duration, post_id, width, height) VALUES
                                                        ('https://2.gravatar.com/avatar/e6d6ceb7764252af8da058e30cd8cb5f?s=96&d=identicon&r=G', '', '', '', '0', 0, 0) failed: ERROR:  insert or update on table "ttrss_enclosures" violates foreign key constraint "ttrss_enclosures_post_id_fkey"
DETAIL:  Key (post_id)=(0) is not present in table "ttrss_entries". in /srv/www/tt-rss.faui2k9.de/root/classes/db/pgsql.php on line 46

Christoph Egger: unbreaking tt-rss

TinyTiny-RSS has some nice failure modes. And upstream support forums aren't really helpfull so when you search for your current problem, chances are that there is one mention of it on the web, in the forum, and the only thing happening there is people making fun of the reporter. Anyway. This installation has seen lots of error messages from the updater in the last several months: 
Warning: Fatal error, unknown preferences key: ALLOW_DUPLICATE_POSTS (owner: 3) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108
Warning: Fatal error, unknown preferences key: ALLOW_DUPLICATE_POSTS (owner: 3) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108
Warning: Fatal error, unknown preferences key: ALLOW_DUPLICATE_POSTS (owner: 3) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108
Warning: Fatal error, unknown preferences key: ALLOW_DUPLICATE_POSTS (owner: 3) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108
And, more recently, the android app stopped working with ERROR:JSON Parse failed.. Turns out both things are related. First thing I noticed was changing preferences in the web panel stopped working until you use the reset to Defaults option and then changed settings. Plugging wireshark in between showed what was going on (Note: API was displayed as enabled in Preferences/Preferences): 
HTTP/1.1 200 OK
Server: nginx/1.8.0
Date: Thu, 06 Aug 2015 11:00:31 GMT
Content-Type: text/json
Transfer-Encoding: chunked
Connection: keep-alive
X-Powered-By: PHP/5.4.43
Content-Language: auto
Set-Cookie: [...]
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Api-Content-Length: 234
ea


Warning:  Fatal error, unknown preferences key: ENABLE_API_ACCESS (owner: 2) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108

 "seq":0,"status":1,"content": "error":"API_DISABLED" 
0
Solution for fixing the Android app (and the logspam on the way as well) seems to be to reset the preferences and then configure tt-rss again (In the webapp, not in the android thing!). Also silences tt-rss update_daemon as well, yay! One last thing: someone out there who wants to explain to me how to fix 
Fatal error: Query INSERT INTO ttrss_enclosures
                                                        (content_url, content_type, title, duration, post_id, width, height) VALUES
                                                        ('https://2.gravatar.com/avatar/e6d6ceb7764252af8da058e30cd8cb5f?s=96&d=identicon&r=G', '', '', '', '0', 0, 0) failed: ERROR:  insert or update on table "ttrss_enclosures" violates foreign key constraint "ttrss_enclosures_post_id_fkey"
DETAIL:  Key (post_id)=(0) is not present in table "ttrss_entries". in /srv/www/tt-rss.faui2k9.de/root/classes/db/pgsql.php on line 46

Christoph Egger: unbreaking tt-rss

TinyTiny-RSS has some nice failure modes. And upstream support forums aren't really helpfull so when you search for your current problem, chances are that there is one mention of it on the web, in the forum, and the only thing happening there is people making fun of the reporter. Anyway. This installation has seen lots of error messages from the updater in the last several months: 
Warning: Fatal error, unknown preferences key: ALLOW_DUPLICATE_POSTS (owner: 3) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108
Warning: Fatal error, unknown preferences key: ALLOW_DUPLICATE_POSTS (owner: 3) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108
Warning: Fatal error, unknown preferences key: ALLOW_DUPLICATE_POSTS (owner: 3) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108
Warning: Fatal error, unknown preferences key: ALLOW_DUPLICATE_POSTS (owner: 3) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108
And, more recently, the android app stopped working with ERROR:JSON Parse failed.. Turns out both things are related. First thing I noticed was changing preferences in the web panel stopped working until you use the reset to Defaults option and then changed settings. Plugging wireshark in between showed what was going on (Note: API was displayed as enabled in Preferences/Preferences): 
HTTP/1.1 200 OK
Server: nginx/1.8.0
Date: Thu, 06 Aug 2015 11:00:31 GMT
Content-Type: text/json
Transfer-Encoding: chunked
Connection: keep-alive
X-Powered-By: PHP/5.4.43
Content-Language: auto
Set-Cookie: [...]
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Api-Content-Length: 234
ea


Warning:  Fatal error, unknown preferences key: ENABLE_API_ACCESS (owner: 2) in /srv/www/tt-rss.faui2k9.de/root/classes/db/prefs.php on line 108

 "seq":0,"status":1,"content": "error":"API_DISABLED" 
0
Solution for fixing the Android app (and the logspam on the way as well) seems to be to reset the preferences and then configure tt-rss again (In the webapp, not in the android thing!). Also silences tt-rss update_daemon as well, yay! One last thing: someone out there who wants to explain to me how to fix 
Fatal error: Query INSERT INTO ttrss_enclosures
                                                        (content_url, content_type, title, duration, post_id, width, height) VALUES
                                                        ('https://2.gravatar.com/avatar/e6d6ceb7764252af8da058e30cd8cb5f?s=96&d=identicon&r=G', '', '', '', '0', 0, 0) failed: ERROR:  insert or update on table "ttrss_enclosures" violates foreign key constraint "ttrss_enclosures_post_id_fkey"
DETAIL:  Key (post_id)=(0) is not present in table "ttrss_entries". in /srv/www/tt-rss.faui2k9.de/root/classes/db/pgsql.php on line 46

5 August 2015

Don Armstrong: Introducing dqsub

I've been using qsub for a while now on the cluster here at the IGB at UofI. qsub is a command line program which is used to submit jobs to a scheduler to eventually be run on one (or more) nodes of a cluster. Unfortunately, qsub's interface is horrible. It requires that you write a shell script for every single little thing you run, and doesn't do simple things like providing defaults or running multiple jobs at once with slightly different arguments. I've dealt with this for a while using some rudimentary shell scripting, but I finally had enough. So instead, I wrote a wrapper around qsub called dqsub. What used to require a complicated invocation like: 
echo -e '#!/bin/bash\nmake foo'  \
 qsub -q default -S /bin/bash -d $(pwd) \
  -l mem=8G,nodes=1:ppn=4 -;
can now be run with 
dqsub --mem 8G --ppn 4 make foo;
Want to run some command in every single directory which starts with SRX? That's easy: 
ls -1 SRX* dqsub --mem 8G --ppn 4 --array chdir make bar;
Want instead to behave like xargs but do the same thing? 
ls -1 SRX* dqsub --mem 8G --ppn 4 --array xargs make bar -C;
Now, this wrapper isn't complete yet, but it's already more than enough to do what I require, and has saved me quite a bit of time already. You can steal dqsub for yourself Feel free to request specific features, too.

DebConf team: DebConf15 registrations temporarily closed due to immense popularity (Posted by Martin Krafft)

The interest to participate in DebConf15, which will start in 10 days, has been overwhelming. Thank you so much! We planned the conference for 350 people and we now expect more than 570. This is fantastic and a wonderful support and encouragement for Debian and its contributors. But we are getting to the point where we have to prioritise considerations about the capacity of the venue and the safety of our attendees. We ve therefore had to close registrations until we have evaluated further options for accomodating even more attendees. For those of you who did not register for DebConf on time, but still want to participate, please bear with us and make sure to check back soon.

Antonio Terceiro: Elixir in Debian, MiniDebconf at FISL, and Debian CI updates

In June I started keeping track of my Debian activities, and this is my July update. Elixir in Debian Elixir is a functional language built on top of the Erlang virtual machine. If features imutable data structures, interesting concurrency primitives, and everything else that Erlang does, but with a syntax inspired by Ruby what makes it much more aproachable in my opinion. Those interested in Elixir for Debian are encouraged to hang around in #debian-elixir on the OFTC IRC servers. There are still a lot of things to figure out, for example how packaging Elixir libraries and applications is going to work. MiniDebconf at FISL, and beyond I helped organize a MiniDebconf at this year s FISL, in Porto Alegre on the 10th of July. The whole program was targetted at getting more people to participate in Debian, so there were talks about translation, packaging, and a few other more specific topics. I myself gave two talks: one about Debian basics, What is Debian, and how it works , and second one on packaging the free software web , which I will also give at Debconf15 later this month. The recordings are available (all talks in Portuguese) at the Debian video archive thanks to Holger Levsen. We are also organizing a new MiniDebconf in October as part of the Latinoware schedule. Ruby We are in the middle of a transition to switch to Ruby 2.2 as default in Debian unstable, and we are almost there. The Ruby transition is now on hold while GCC 5 one is going on, but will be picked up as soon as were are done with GCC 5. ruby-defaults has been uploaded to experimental for those that want to try having Ruby 2.2 as default before that change hits unstable. I myself have been using Ruby 2.2 as default for several weeks without any problem so far, including using vagrant on a daily basis and doing all my development on sid with it. I started taking notes about Ruby interpreter transitions work to make sure that knowledge is registered. I have uploaded minor security updates of both ruby2.1 and ruby2.2 to unstable. They both reached testing earlier today. I have also fixed another bug in redmine, which I hope to get into stable as well as soon as possible. gem2deb has seen several improvements through versions 0.19, 0.20, 0.20.1 and 0.20.2. I have updated a few packages: Two NEW packages, ruby-rack-contrib and ruby-grape-logging ,were ACCEPTED into the Debian archive. Kudos to the ftp-master team who are doing an awesome job reviewing new packages really fast. Debian Continuous Integration This month I have made good progress with the changes needed to make debci work as a distributed system with one master/scheduler node and as many worker nodes (running tests) as possible. While doing my tests, I have submitted a patch to lxc and updated autodep8 in unstable. At some point I plan to upload both autodep8 and autopkgtest to jessie-backports. Sponsoring I have sponsored a few packages:

4 August 2015

Julien Danjou: Ceilometer, Gnocchi & Aodh: Liberty progress

It's been a while since I talked about Ceilometer and its companions, so I thought I'd go ahead and write a bit about what's going on this side of OpenStack. I'm not going to cover new features and fancy stuff today, but rather a shallow overview of the new project processes we initiated. Ceilometer growing Ceilometer has grown a lot since that time when we started it 3 years ago. It has evolved from a system designed to fetch and store measurements, to a more complex system, with agents, alarms, events, databases, APIs, etc. All those features were needed and asked for by users and operators, but let's be honest, some of them should never have ended up in the Ceilometer code repository, especially not all at the same time. The reality is we picked a pragmatic approach due to the rigidity of the OpenStack Technical Committee in regards to new projects to become OpenStack integrated and, therefore, blessed projects. Ceilometer was actually the first project to be incubated and then integrated. We had to go through the very first issues of that process. Fortunately, now that time has passed, and all those constraints have been relaxed. To me, the OpenStack Foundation is turning into something that looks like the Apache Foundation, and there's, therefore, no need to tie technical solutions to political issues. Indeed, the Big Tent now allows much more flexibility to all of that. Back a year ago, we were afraid to bring Gnocchi into Ceilometer. Was the Technical Committee going to review the project? Was the project going to be in the scope of Ceilometer for the Technical Committee? Now we don't have to ask ourselves those questions, now that we have that freedom, it empowers us to actually do what we think is good in term of technical design without worrying too much about political issues.
Ceilometer development activity
Acknowledging Gnocchi The first step in this new process was to continue working on Gnocchi (a timeserie database and resource indexer designed to overcome historical Ceilometer storage issue) and to decide that it was not the right call to merge it into Ceilometer as some REST API v3, but that it was better to keep it standalone. We managed to get traction to Gnocchi, getting a few contributors and users. We're even seeing talks proposed to the next Tokyo Summit where people leverage Gnocchi, such as "Service of predictive analytics on cost and performance in OpenStack", "Suveil" and "Cutting Edge NFV On OpenStack: Healing and Scaling Distributed Applications". We are also doing some progress on pushing Gnocchi outside of the OpenStack community, as it can be a self-sufficient timeserie and resource database that can be used without any OpenStack interaction. Branching Aodh Rather than continuing to grow Ceilometer, during the last summit we all decided that it was time to reorganize and split Ceilometer into the different components it is made of, leveraging a more service-oriented architecture. The alarm subsystem of Ceilometer being mostly untied to the rest of Ceilometer, we decided it was the first and perfect candidate to do that. I personally engaged into doing the work and created a new repository with only the alarm code from Ceilometer, named Aodh.
Aodh is an Irish word meaning fire. A word picked so it also had some relation to Heat, and because we have some Irish influence around the project .
This made sense for a lot of reason. First because Aodh can now work completely standalone, using either Ceilometer or Gnocchi as a backend or any new plugin you'd write. I love the idea that OpenStack projects can work standalone like Swift does for example without implying any other OpenStack component. I think it's a proof of good design. Secondly, because it allows us to resonate on a smaller chunk of software a reason really under-estimated today in OpenStack. I believe that the size of your software should match a certain ratio to the size of your team. Aodh is, therefore, a new project under the OpenStack Telemetry program (or what remains of OpenStack programs now), alongside Ceilometer and Gnocchi, forked from the original Ceilometer alarm feature. We'll deprecate the latter with the Liberty release, and we'll remove it in the Mitaka release. Lessons learned Actually, moving that code out of Ceilometer (in the case of Aodh), or not merging it in (in the case of Gnocchi) had a few side effects that I admit I think we probably under-estimated back then. Indeed, the code size of Gnocchi or Aodh ended up being much smaller than the entire Ceilometer project Gnocchi is 7 smaller and Aodh 5x smaller than Ceilometer and therefore much more easy to manipulate and to hack on. That allowed us to merge dozens of patches in a few weeks, cleaning-up and enhancing a lot of small things in the code. Those tasks are very much harder in Ceilometer, due to the bigger size of the code base and the small size of our team. By having our small team working on smaller chunks of changes even when it meant actually doing more reviews greatly improved our general velocity and the number of bugs fixed and features implemented. On the more sociological side, I think it gave the team the sensation of finally owning the project. Ceilometer was huge, and it was impossible for people to know every side of it. Now, it's getting possible for people inside a team to cover a much larger portion of those smaller project, which gives them a greater sense of ownership and caring. Which ends up being good for the project quality overall. That also means that we technically decided to have different core teams by project (Ceilometer, Gnocchi, and Aodh) as they all serve different purposes and can all be used standalone or with each others. Meaning we could have contributors completely ignoring other projects. All of that reminds me some discussion I heard about projects such as Glance, trying to fit new features in - some that are really orthogonal to the original purpose. It's now clear to me that having different small components interacting together that can be completely owned and taken care of by a (small) team of contributors is the way to go. People that can therefore trust each others and easily bring new people in, makes a project really incredibly more powerful. Having a project covering a too wide set of features make things more difficult if you don't have enough manpower. This is clearly an issue that big projects inside OpenStack are facing now, such as Neutron or Nova.

3 August 2015

Sven Hoexter: Failing with F5: CMP - Clustered Multiprocessing

The last Whiteboard Wednesday tackled a few of the gotchas of the F5 CMP implementation. I take that as an opportunity to finish a blog post I started to write six month ago on this topic. I've run into two scenarios where CMP got in my way: All of this happened on TMOS 11.4.1+HF run on BigIP 2K systems. Since F5 is sometimes moving very quickly you might not experience those issues on other hardware or with a different software release. applying low and strict connection limits Apparently connection limits are counted on a per tmm level and are not shared between the tmm processes running on different CPUs. So if you've two CPU cores with HT you'll see four tmm processes that will all enforce the connection limit. If you have a max connection limit set to two you might still see a maximum of eight connections. That is a very bad thing if you abuse the F5 to limit your outbound connections because your counter part is not able to enforce connection limits, but forces you via a contract to not open more then two connections. Disable CMP and it will all end on the same tmm process and suddenly your connection limits work as expected. If your connection limit is big enough you can cheat, say it's twelve connections, you can configure a limit of three. With four processes that makes a max of twelve connections as required. Though due to the hashing and distribution among the tmm processes it could happen that you reject connections on one process while others are idle. Another option would be to enter the dirty land of iRules and tables to maintain your own connection count table. There are examples given in the F5 devcentral community, but the best resolution you can get, without starting to scan the whole table on every request, is X requests per minute. active health checks Active monitoring checks were added to detect the operational state of our application servers. Now imagine you have some realtime processing with over a hundred requests per minute. So in case you've issues with one instance you'd like to remove it from the pool rather sooner then later, which requires frequent checking. So here is a simple active http check: 
defaults-from http-appmon
destination *:*
interval 9
recv "^HTTP/1\\.1 200 OK"
send "GET /mon/state HTTP/1.1\\r\\nHost: MON\\r\\nConnection: Close\\r\\n\\r\\n"
time-until-up 0
timeout 2
up-interval 1
(Configuration options are described here) With an up-interval of 1 second and a timeout of 2 seconds someone naive like me expected that a fatal issue like a crashed application would be detected within three seconds and no more requests should hit the application after second 3. That turned out to be slightly longer, at least 4s for this case, often longer. Also for a regular maintenance we had to instruct our scripts to flip the application monitor to unavailable and wait for interval X tmm process count + timeout + 1s + max allowed request duration. That is not an instant off. If you use tcpdump (on the F5 where it's patched to show you the tmm that received the request) to look at the health check traffic you'll notice that the tmm threads pass around the handle to do a health check. So my guess is the threads do only sync the health check state of the application when they're due to run the health check. Makes sense performance wise but if you operate with longer timeouts and bigger intervals you will definetly loose a notable amount of requests. Even in our low end case we already loose a notable amount of requests in 4s. While you could resent them you never know exactly if a request was already processed or not. So you have to ensure that somewhere else in your stack. One option is to disable CMP but I guess that's not an option for most people that are required to scale out to handle the load and not only for the sake of redundancy. If you're running the balancer only for the sake of redundancy the choice is easy. You find a hint on this kind of issue if you lookup the documentation for the inband monitor: Note: Systems with multiple tmm processes use a per-process number to calculate failures, depending on the specified load balancing method. That case is a bit different due to the nature of the monitor but points in the same direction. The actual check is executed by bigd according to this document, so I'm pretty sure I'm still missing some pieces of the picture. Just be warned that you've to really test your outage scenarios and you should double check it if you run a transaction based service that is sensitive to lost requests.

Jamie McClelland: Docker: evil spawn or useful tool

There are plenty of criticisms of docker, the system for building a container-based virtual machine running just a single application. I've read many of them have have consistently been either in agreement or at least amused. The most relevant criticism is about the basic approach of building single-application virtual machines. To understand this criticism, let's remember - in traditional application deployment there are at least three distinct jobs: These three groups have lived in happy tension for years. Now we have containers. The problem with containers is that suddenly the system administrators are out entirely and the distribution developers' role may have been dramatically minimized or circumvented altogether. Meanwhile, the application developer is both liberated from any constraints imposed by either the system administrator or the distribution developers (hooray!) but is also sadled with the enormous responsibilities of these two roles - which may not be apparent to the application developer at first. I have practically no distribution developer experience and have considerable experience as a system administrator and an application developer. And, it took me months to sort through how to properly develop and deploy an application using docker in a way that I thought was responsible and secure. I started by learning about how docker wants you to deploy images - by downloading them from their shared regisry. As I mentioned, I have very little experience in the realm of distribution development, but I at least know enough about Debian to know that a lot of time and thought has gone into cryptographically verifying packages that I install, which apparently is not done at all with Docker images. Is that obvious to everyone using Docker?? Fortunately, you can work around this problem by creating your own base image which is trivially easy. So, now I build all images, from scratch, locally. That helps put Debian developers back into the mix. Next, I started looking at Docker Files that I could use to construct my images and discovered something else troubling. Take, for example, the official nginx Docker image. It is based on Debian Jessie (hooray - our distribution developers are in the mix!). However, it then proceeds to install nginx from the nginx repository, not the debian repository. Well, I guess if you are nginx you want to have full control, but still, the Debian developers version of nginx has been vetted to ensure it works with Debian Jessie, so you are really losing something here. So... my next break from Docker convention is to use all Debian packages in my Docker files. Once my images were built and my application was tested and running, I was done, right? Wrong. Well, I would have been done if I didn't care about upgrading my systems, backing up my data or running cron jobs. Remember those things? Those are things that distribution developers and system administrators have been perfecting for decades. And, they are not trivial. I then built a series of scripts to help alert me when a image I am using has updates (you can't just use cron-apt any more since cron isn't running in your container) and help me update the image and deploy it to all my applications (which involves restarting the application). Backing up data is a whole different can of worms - sometimes involving interacting with your container (if it's a database container, you have to launch a database dump) or simply copying files from the host, assuming you got the right Docker volume strategy (which took me days to fully understand). Lastly, I had to run a cron job from the host that then runs whatever commands are needed on each of my containers. This was complicated. In the end, was it worth it? Yes, I think so. However, not because it was simple, which seems to be the Docker mantra. I think it's worth it because I can run 100 instances of my application using significantly less resources than when I was using full virtualization and because I can more easily and flexibly adjust the resource allocation. However, check in with me in a year and I'll probably have a different opinion.

Jamie McClelland: Agents, the kinds that work for us.

I recently decided I wanted to adjust how long my gpg password cache lasts and realized I had no idea how either my ssh-agent or gpg-agent was being launched or even which programs were being used as the agent for which protocol. While I appreciate that everthing just works based on blind faith, I decided to investigate more closely. I started by reading the man pages for ssh-agent and gpg-agent and discovered that gpg-agent could be used for providing ssh-agent. Since I run openbox, I decided to dig through my ~/.config/openbox/autostart file and discovered that I was also launching gnome-keyring-daemon, which provides both an ssh-agent and a gpg-agent. This is getting confusing. I then examined the output of ps -eFH and found this: 
jamie    28499 28489  0  1082  1516   1 10:06 tty1     00:00:00     /bin/sh /usr/bin/startx
jamie    28542 28499  0  3987  1912   1 10:06 tty1     00:00:00       xinit /etc/X11/xinit/xinitrc -- /etc/X11/xinit/xserverrc :0 vt1 -auth /tmp/serverauth.gn3C5pYbPc
root     28543 28542  0 58065 25036   3 10:06 tty1     00:00:05         /usr/bin/X -nolisten tcp :0 vt1 -auth /tmp/serverauth.gn3C5pYbPc
jamie    28548 28542  0 69563 19980   0 10:06 tty1     00:00:00         /usr/bin/openbox --startup /usr/lib/x86_64-linux-gnu/openbox-autostart OPENBOX
jamie    28604 28548  0  2774   348   1 10:06 ?        00:00:00           /usr/bin/ssh-agent /usr/bin/gpg-agent --daemon --sh --write-env-file=/home/jamie/.gnupg/gpg-agent-info-animal /usr/bin/dbus-launch --exit-with-session /usr/bin/monkeysphere-validation-agent /usr/bin/im-launch /home/jamie/.xsession
jamie    28605 28548  0  4915   248   0 10:06 ?        00:00:00           /usr/bin/gpg-agent --daemon --sh --write-env-file=/home/jamie/.gnupg/gpg-agent-info-animal /usr/bin/dbus-launch --exit-with-session /usr/bin/monkeysphere-validation-agent /usr/bin/im-launch /home/jamie/.xsession
jamie    28610 28548  0 22402 34456   0 10:06 tty1     00:00:00           /usr/bin/perl -wT /usr/bin/monkeysphere-validation-agent /usr/bin/im-launch /home/jamie/.xsession
Further down (and not nested under the xinit process), I found my gnome-keyring-daemon process. I started by removing my own call to gnome-keyring-daemon and realized that everything still worked fine (both gpg and ssh). I must have added that line before things were configured system-wide to run automatically. Then, I saw that the gpg-agent was being launched without the --enable-ssh-support option (and ssh-agent was running), so looks like ssh is handled by ssh-agent and gpg is handled by gpg-agent. So far so good. Now, how do they get launched?? I start my graphical session by logging in at a console and running exec startx. In my home directory, I have ~/.xsession which contains the line exec /usr/bin/openbox-session. Therefore, I started by scouring all things openbox on my system and couldn't find any reference to these agents. Next, I turned my attention to X. Based on my ps -eFH output, I started with /etc/X11/xinit/xinitrc, which led me to /etc/X11/Xsession which led me to /etc/X11/Xsession.d and presto, I found my answer: a series of shell scripts that modify a global variable STARTUP which is executed by X. Thanks Debian developers for making it all work out of the box!

Lunar: Reproducible builds: week 14 in Stretch cycle

What happened in the reproducible builds effort this week: Toolchain fixes akira submitted a patch to make cdbs export SOURCE_DATE_EPOCH. She uploded a package with the enhancement to the experimental reproducible repository. Packages fixed The following 15 packages became reproducible due to changes in their build dependencies: dracut, editorconfig-core, elasticsearch, fish, libftdi1, liblouisxml, mk-configure, nanoc, octave-bim, octave-data-smoothing, octave-financial, octave-ga, octave-missing-functions, octave-secs1d, octave-splines, valgrind. The following packages became reproducible after getting fixed: Some uploads fixed some reproducibility issues but not all of them: In contrib, Dmitry Smirnov improved libdvd-pkg with 1.3.99-1-1. Patches submitted which have not made their way to the archive yet: reproducible.debian.net Four armhf build hosts were provided by Vagrant Cascadian and have been configured to be used by jenkins.debian.net. Work on including armhf builds in the reproducible.debian.net webpages has begun. So far the repository comparison page just shows us which armhf binary packages are currently missing in our repo. (h01ger) The scheduler has been changed to re-schedule more packages from stretch than sid, as the gcc5 transition has started This mostly affects build log age. (h01ger) A new depwait status has been introduced for packages which can't be built because of missing build dependencies. (Mattia Rizzolo) debbindiff development Finally, on August 31st, Lunar released debbindiff 27 containing a complete overhaul of the code for the comparison stage. The new architecture is more versatile and extensible while minimizing code duplication. libarchive is now used to handle cpio archives and iso9660 images through the newly packaged python-libarchive-c. This should also help support a couple other archive formats in the future. Symlinks and devices are now properly compared. Text files are compared as Unicode after being decoded, and encoding differences are reported. Support for Sqlite3 and Mono/.NET executables has been added. Thanks to Valentin Lorentz, the test suite should now run on more systems. A small defiency in unquashfs has been identified in the process. A long standing optimization is now performed on Debian package: based on the content of the md5sums control file, we skip comparing files with matching hashes. This makes debbindiff usable on packages with many files. Fuzzy-matching is now performed for files in the same container (like a tarball) to handle renames. Also, for Debian .changes, listed files are now compared without looking the embedded version number. This makes debbindiff a lot more useful when comparing different versions of the same package. Based on the rearchitecturing work has been done to allow parallel processing. The branch now seems to work most of the time. More test needs to be done before it can be merged. The current fuzzy-matching algorithm, ssdeep, has showed disappointing results. One important use case is being able to properly compare debug symbols. Their path is made using the Build ID. As this identifier is made with a checksum of the binary content, finding things like CPP macros is much easier when a diff of the debug symbols is available. Good news is that TLSH, another fuzzy-matching algorithm, has been tested with much better results. A package is waiting in NEW and the code is ready for it to become available. A follow-up release 28 was made on August 2nd fixing content label used for gzip2, bzip2 and xz files and an error on text files only differing in their encoding. It also contains a small code improvement on how comments on Difference object are handled. This is the last release name debbindiff. A new name has been chosen to better reflect that it is not a Debian specific tool. Stay tuned! Documentation update Valentin Lorentz updated the patch submission template to suggest to write the kind of issue in the bug subject. Small progress have been made on the Reproducible Builds HOWTO while preparing the related CCCamp15 talk. Package reviews 235 obsolete reviews have been removed, 47 added and 113 updated this week. 42 reports for packages failing to build from source have been made by Chris West (Faux). New issue added this week: haskell_devscripts_locale_substvars. Misc. Valentin Lorentz wrote a script to report packages tested as unreproducible installed on a system. We encourage everyone to run it on their systems and give feedback!

Sven Hoexter: mod_realdoc packages

I'm currently looking at mod_realdoc from Rasmus Lerdorf / etsy, to find out if it can scratch one of my itches at work. Since the packaging in the etsy github repository is slightly incomplete, and there are no real tarball releases I've rolled one on my own. For Debian/jessie I've dumped a test build here and for Ubuntu 14.04 I've wrestled with launchpad.net and created a ppa.

2 August 2015

Carl Chenet: My Free activities in July 2015

Follow me on Identi.ca or Twitter or Diaspora*diaspora-banner Here are the details of my Free activities in July 2015. Carl Chenet s projects: Patchs: Debian bug reports: Other bug reports: Feature requests:

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