tl;dr: Get vmdebootstrap replacement from
http://git.liw.fi/vmdb2 and
run it from the source tree. Tell me if something doesn't work. Send
patches.
Many years ago I wrote
vmdebootstrap, a tool for installing Debian
on a disk image for virtual machines. I had a clear personal need: I
was setting up a CI system and it needed six workers: one each for
Debian oldstable, stable, and unstable, on two architectures (i386,
amd64). Installing Debian six times in the same way is a lot of work,
so I figured how difficult can it be to automate it. Turns out that
not difficult at all, except to install a bootloader.
(Don't ask me why I didn't use any of the other tools for this. It was
long ago, and while some of the tools that now exist probably did
exist then, I like writing code and learning things while doing it.)
After a while I was happy with what the program did, but didn't want
to upload it to Debian, and didn't want to add the kinds of things
other people wanted, so I turned vmdebootstrap over to Neil Williams,
who added a ton of new features. Unfortunately, it turned out that my
initial architecture was not scaleable, and also the code I wrote
wasn't very good, and there weren't any tests.
Neil did heroic work forcing my crappy software into doing things I never
envisioned. Last year he needed a break and asked me to take
vmdebootstrap back. I did, and have been hiding from the public eye
ever since, since I was so ashamed of the code. (I created a new
identity and pretended to be an international assassin and backup
specialist, travelling the world forcing people to have at least one
tested backup of their system. If you've noticed reports in the press
about people reporting near-death experiences while holding a shiny
new USB drive, that would've been my fault.)
Pop quiz: if you have a program with ten boolean options ("do this,
except if that option is given, do the other thing"), how many black
box tests do you need to test all the functionality? If one run of the
program takes half an hour, how long will a full test suite run?
I did some hard thinking about vmdebootstrap, and came to the sad
conclusion that it had reached the end of its useful life as a living
software project. There was no reasonable way to add most of the
additional functionality people were asking for, and even maintaining
the current code was too tedious a task to consider seriously. It was
time to make a clean break of the past and start over, without caring
about backwards compatibility. After all, the old code wasn't going
anywhere so anyone who needed it could still use it. There was no need
to burden a new program with my past mistakes. All new mistakes were
called for.
At the Cambridge mini-Debconf of November, 2016, I gave a short
presentation of what I was going to do. I also posted about my
plans to the debian-cloud list. In short, I would write a new, more
flexible and cleaner replacement to be called vmdb2. For various
personal reasons, I've not been able to spend as much time on vmdb2
as I'd like to, but I've now reached the point where I'd like to
announce the first alpha version publically.
The source code is hosted here: http://git.liw.fi/vmdb2 . There are
.deb packages at my personal public APT repo (http://liw.fi/code/),
but vmdb2 is easy enough to run directly from a git checkout:
sudo ./vmdb2 foo.vmdb --output foo.img
There's no need to install it to try it.
What works:
- vmdb2 can build a disk image with Debian installed, for amd64 only
at this time
- the boot loader is GRUB, either for UEFI or BIOS
- the image boots under Qemu / KVM and also on actual hardware
What doesn't work:
- other architecures, including building for a foreign archiecture
- live CD building (no squashfs support)
I'm not opposed to adding support for those, but they're not directly
interesting to me. For example, I only have amd64 machines. The best
way to get support for additional features is to tell me how,
preferably in the form of patches. (If I have to read tons of docs, or
other people's code, and then write code and iterate while other
people tell me it doesn't work, it's probably not happening.)
Why would you be interested in vmdb2? There's a lot of other tools to
do what it does, so perhaps you shouldn't care. That's fine. I like
writing tools for myself. But if this kind of tool is of interest to
you, please do have a look.
A short tutorial: vmdb2 wants you to give it a "specification file"
(conventionally suffixed .vmdb, because someone stole the .spec
suffix, but vmdb2 doesn't care about the name). Below is an example.
vmdb2 image specification files are in YAML, since I like YAML, and
specify a sequence of steps to take to build the image. Each step is a
tiny piece of self-contained functionality provided by a plugin.
steps:
- mkimg: " output "
size: 4G
- mklabel: msdos
device: " output "
- mkpart: primary
device: " output "
start: 0%
end: 100%
part-tag: root-part
The above create an image (name is specified with the --output
option), which is four gigabytes in size, and create a partitition
table and a single partition that fills the whole disk. The "tag" is
given so that later steps can easily refer to the partition.
If you prefer another way to partition the disk, you can achieve that
by adding more "mkpart" steps. For example, for UEFI you'll want to
have an EFI partition.
- mkfs: ext4
partition: root-part
- mount: root-part
fs-tag: root-fs
The above formats the partition with the ext4 filesystem, and then
mounts it. The mount point will be a temporary directory created by vmdb2,
and a tag is again given to the mount point so it can be referred to.
- unpack-rootfs: root-fs
The above unpacks a tar archive to put content into the filesystem, if
the tar archive exists. The tar archive is specified with the
--rootfs-tarball command line option.
- debootstrap: stretch
mirror: http://http.debian.net/debian
target: root-fs
unless: rootfs_unpacked
- apt: linux-image-amd64
fs-tag: root-fs
unless: rootfs_unpacked
- cache-rootfs: root-fs
unless: rootfs_unpacked
The above will run debootstrap and install a kernel into the
filesystem, but skip doing that if the rootfs tarball was used. Also,
the tarball is created if it didn't exist. This way the tarball is
used by all but the first run, which saves a bit of time. On my laptop
and with a local mirror, debootstrap and kernel installation takes on the
order of nine minutes (500 to 600 seconds), whereas unpacking the tar
archive is a bit faster (takes around 30 seconds). When iterating over
things other than debootstrap, this speeds things up something
wonderful, and seems worth the complexity.
The "unless:" mechanism is generic. All the steps share some state,
and the unpack-rootfs step sets the "rootfs_unpacked" flag in the
shared state. The "unless:" field tells vmdb2 to check for the flag
and if it is not set, or if it is set to false ("unless it is set to
true"), vmdb2 will execute the step. vmdb2 may get more such flags in
the future, if there's need.
- chroot: root-fs
shell:
sed -i '/^root:[^:]*:/s//root::/' /etc/passwd
echo pc-vmdb2 > /etc/hostname
The above executes a couple of shell commands in a chroot of the root
filesystem we've just created. In this case they remove a login
password from root, and set the hostname. This is a replacement of the
vmdebootstrap "customize" script, but it can be inserted anywhere into
the sequence of steps. There's boot chroot and non-chroot variants of
the step.
This is a good point to mention that writing customize scripts gets
quite repetitive and tedious after a while, so vmdb2 has a plugin to
run Ansible instead. You can customize your image with that instead,
while the image is being built and not have to wait until you boot the
image and running Ansible over ssh.
- grub: bios
root-fs: root-fs
root-part: root-part
device: " output "
console: serial
Finally, install a boot loader, grub. This shows the BIOS variant,
UEFI is also supported. This also configures grub and the kernel to use a
serial console. There's a "yarn" (test suite) to build and smoke test
an image with vmdb2 to make sure at least the basic functionality
works. The smoke test boots the image under Qemu, logs in as root, and
tells the VM to power off. Very, very basic, but has already found
actual bugs in vmdb2. The smoke test needs the serial console to work.
As with vmdebootstrap originally, I don't particularly want to
maintain the package in Debian. I've added Debian packaging (so that I
can install it on my own machines), but I already have enough packages
to maintain, so I'm hoping someone else will volunteer to take on the
Debian maintainership and bug handling duties.
If you would like vmdb2 to do more things to suit you better, I'm
happy to explain how to write plugins to provide more types of steps.
If you are currently using vmdebootstrap, either directly or as part
of another tool, I encourage you to have a look at vmdb2. In the long
term, I would like to retire vmdebootstrap entirely, once vmdb2 can do
everything vmdebootstrap can do, and few people use vmdebootstrap.
This may take a while.
In any case, whether you want a new image building tool or not, happy
hacking.
In May, I got selected as a 
Float/String Conversion in Picolibc
Exact conversion between strings and floats seems like a fairly
straightforward problem. There are two related problems:
The following contributors got their Debian Developer accounts in the last two months:
The 
Is it possible to do software development, mathematical or not, as mathematician in academics? This is a question I was asking myself recently a lot, seeing my own development from logician at a state university getting rid of foreigners to software developer. And then, a friend pointed me to this very depressing document: 
My monthly report covers a large part of what I have been doing in the free software world. I write it for 
Apologies the first blog post got sent out by mistake.
Weather comparisons between the two countries
Last year, I had come to know that this year s debconf is happening in Canada, a cold country. Hence, few weeks/month back, I started trying to find information online when I stumbled across few discussion boards where people were discussing about Innerwear and Outerwear and I couldn t understand what that was all about. Then somehow stumbled across this Video, which is of a game called the Long Dark and just seeing couple of episodes it became pretty clear to me why the people there were obsessing with getting the right clothes and everything about it. Couple of Debconf people were talking about the weather in Montreal, and surprise, surprise it was 
Population Density
As well in the game and whatever I could find on the web, Canada seems to be on the lower side as far as population is concerned. 
Rail
This is one thing that is similar in both the great countries. India has Indian Railways and while the Canadians have their own mountain railway called 
Business houses, Political Families
This is again something that is similar in both the countries, it seems (from afar) that its only few business houses and more importantly political families which have governed for years. From what little I could understand, both India and Canada have first past the post system which as shared by its critics is unfair to new and small parties. It would be interesting to see if Canada does a re-think. For India, it would need a massive public education outreach policy and implementation. We just had elections in 5 states of India with U.P. (with respect to area-size and population density) and from the last several years, the EVM s (Electronic Voting Machines) tries to make sure that nobody could know which area which party got the most votes. This is to make sure the winning party is not able to take revenge on people or areas which did not vote for them. Instead you have general region counting of votes with probably even the Election Commission not knowing which EVM went to what area and what results are there in sort of double-blind methodology.
As far as Business houses are concerned, I am guessing it s the same world-over, only certain people hold the wealth while majority of us are in hard-working, non-wealthy status.
Northern Lights, Aurora Borealis
Apart from all the social activities that Montreal is famous for, somebody told/shared with me that it is possible to see the Northern Lights, Aurora Borealis can be seen in Canada. I dunno how true or not it is, while probably in Montreal it isn t possible to see due to light pollution, but maybe around 40-50 kms. from the city ? Can people see it from Canada ? IF yes, how far would you have to go ? Are there any companies or people who take people to see the Northern Lights.
While I still have to apply for bursary, and if that gets ok, then try getting the visa, but if that goes through, apart from debconf and social activities happening in and around Montreal, Museums, Music etc. , this would be something I would like to experience if it s possible. While I certainly would have to be prepared for the cold that would be, if it s possible, no offence to debconf or anybody else but it probably would be the highlight of the entire trip if its possible. This should be called/labelled as the greatest show on earth TM. 
For people who are visually differently-abled, the above reads
To learn who rules over you, simply find out who you are not allowed to criticize Voltaire wrote this either in late 16th century or early 17th century and those words were as apt in those times, as it is in these turbulent times as well.
Update 05/03 According to @bla these words are attributable to a neo-nazi and apparently a child abuser. While I don t know the context in which it was shared, it describes the environment in which we are perfectly. Please see his comment for a link and better understanding.
The below topic requires a bit of maturity, so if you are easily offended, feel free not to read further.
While this week-end I was supposed to share about the recent Science Day celebrations that we did last week
Would explore it probably next week.
This week the attempt is to share thoughts which had been simmering at the back of my mind for more than 2 weeks or more and whose answers are not clear to me.
My buttons were pressed when Martin f. Kraft 
From the little sharings and interactions I have been part of, I find people take offence at the most innocuous things. For instance, one of the easy routes of not offending anyone is to use self-deprecating humour (or so I thought) either of my race, caste, class or even my issues with weight and each of the above would offend somebody. Charlie Chaplin didn t have those problems. If somebody is from my caste, I m portraying the caste in a certain light, a certain slant. If I m talking about weight issues, then anybody who is like me (fat) feels that the world is laughing at them rather than at me or they will be discriminated against. While I find the last point a bit valid, it leaves with me no tools and no humour. I neither have the observational powers or the skills that 
