Running Alpine Linux containers on LXD

2016-01-19 by saghul Leave a comment

So, more LXD! Today we are going to run some Alpine Linux containers on LXD. Why? Alpine describe themselves as a “security-oriented, lightweight Linux distribution based on musl libc and busybox.”, what’s there not to like? It has become quite popular in the Docker world due to the small yet fully functional containers one can create.

Building an Alpine container on LXD is not that straightforward, however. There are no Alpine images on the official repo, so we will have to build our own. LXD does provide some documentation on how an image should be like, lo let’s get to it!

I started by taking a look at the template for LXC. That was close enough, so I went ahead and modified it in order to create LXD images. That resulted in lxd-alpine-builder.

With that script, we can now create an image and then import it into LXD:

sudo ./build-alpine
lxc image import alpine-v3.3-x86_64-20160114_2308.tar.gz --alias alpine-v3.3

That image is 2.39MB, w00t! You can check it by listing the images:

saghul@lxd-test:~$ lxc image list
+----------------------------+--------------+--------+---------------------------------+--------+----------+-------------------------------+                                                                      
|           ALIAS            | FINGERPRINT  | PUBLIC |           DESCRIPTION           |  ARCH  |   SIZE   |          UPLOAD DATE          |                                                                      
+----------------------------+--------------+--------+---------------------------------+--------+----------+-------------------------------+                                                                      
| alpine-v3.3                | 9888dd281789 | no     | alpine v3.3 (20160114_23:08)    | x86_64 | 2.39MB   | Jan 14, 2016 at 11:10pm (CET) |                                                                      
| jessie-amd64               | 9f065ac6be10 | no     | Debian jessie (amd64)           | x86_64 | 102.66MB | Jan 12, 2016 at 4:17pm (CET)  |                                                                      
| jessie-amd64-base          | b85a1bdb5057 | no     | Debian Jessie base              | x86_64 | 87.98MB  | Jan 12, 2016 at 9:56am (CET)  |                                                                      
| jessie-amd64-base-sysvinit | 628b7f8470af | no     | Debian Jessie base (no systemd) | x86_64 | 82.91MB  | Jan 12, 2016 at 11:40am (CET) |                                                                      
| jessie-i386                | 769f90666ea8 | no     | Debian jessie (i386)            | i686   | 100.23MB | Jan 15, 2016 at 9:54am (CET)  |                                                                      
+----------------------------+--------------+--------+---------------------------------+--------+----------+-------------------------------+

Now we can launch a container and test it out!

lxc launch alpine-v3.3 alpinetest
lxc exec alpinetest /bin/ash
# cat /etc/alpine-release 
3.3.1

Happy containering!

Simple networking for your LXD containers

2016-01-18 by saghul Leave a comment

So, more LXD, here we go! Today we are going to see how to access our LXD containers from outside of the system running LXD itself.

If you are just trying out stuff (like I am), you probably installed some Ubuntu version on a VM in order to run LXD. This means that by default you have no access to your containers from your system, just from the system running LXD.

A simple solution is to add a route to the isolated network that the container get, going through the host running LXD:

ip route add addr:10.0.3.0/24 via 192.168.99.28

Here we are telling our system that the 10.0.3.0/24 network is routable through 192.168.99.28, our LXD machine.

You probably don’t want to use something like this in production, but we are exporing here! 🙂

LXD, Debian containers and systemd

2016-01-15 by saghul Leave a comment

I have been playing around with LXD the past few nights, and so far I really like it. It’s like VMs, but as a container, in contrast with Docker, which is designed around running a single application as a container.

In order to try LXD out I installed a Ubuntu 15.10 VM and added the LXD stable PPA. Then it was time to launch some containers!

lxc remote add images images.linuxcontainers.org
lxc image copy images:debian/jessie/amd64 local: --alias jessie-amd64
lxc launch jessie-amd64 jessie-test

Shortly after I hit a problem: I could not stop the container I just created! It would just hang there, so I had to stop it forcefully:

lxc stop --force jessie-test

That doesn’t look good at all. Digging around I found the issue on GitHub, which basically concludes that it’s a systemd issue, because it doesn’t seem to handle SIGPWR correctly. Oh boy. The systemd issue is still open on Launchpad, so what do we do then? Well, we get rid of systemd. Let’s prepare a base Debian Jessie image with good old SysV init, shall we?

lxc exec jessie-test /bin/bash
apt-get update && apt-get install sysvinit-core
exit
lxc stop jessie-test --force
lxc start jessie-test
lxc exec jessie-test /bin/bash
apt-get remove --purge --auto-remove systemd
rm -rf /var/lib/apt/lists/*
rm -rf /var/cache/apt/archives/*
exit
lxc stop jessie-test
lxc publish jessie-test --alias jessie-amd64-base-sysvinit

Now all containers we create with our new and shiny image will stop gracefully.

Downloading AppVeyor artifacts with a little bit of Python

2015-09-09 by saghul Leave a comment

I have recently released new versions of 3 of my Python modules (pyuv, pycares and python-fibers), which happen to be Python C extensions.

While preparing these releases, I decided to give AppVeyor a try, since it can be used for both integration testing on Windows and Python Wheels generation. I managed to do so following these instructions and checking this project example, and I was (almost) all set.

The missing part was to download all those built artifacts (the Python wheels) stored in AppVeyor and upload them to PyPI when I decided to make a release. Uploading the wheels can be easily done using twine, and for downloading the last built artifacts for a given project I created the following simple Python script using requests:

https://gist.github.com/saghul/08ef2f7495c0cf481e3b

Using it is simple:

appveyor-download --api-token 1234 --user saghul --project pyuv

I hope you find it useful!

:wq

pyuv 1.2.0 released

2015-09-08 by saghul Leave a comment

Quick heads up, I just released pyuv 1.2.0. pyuv is a Python wrapper for libuv. This time around, pyuv implements all the funcionality covering up to libuv 1.7.3.

This release was focused in 2 things: adjusting to new APIs / changes in libuv, and improving the testing, specifically on Windows.

As of this writing, pyuv is automatically tested on Linux systems thanks to Travis CI and on Windows thanks to AppVeyor. Thanks to AppVeyor, I’m now able to provide Python Wheels for pyuv, which is great because, frankly, compiling it on Windows is kind of a pain.

See the ChangeLog for a detailed outline of the changes, check the documentation, and fetch the code on GitHub. Packages have also been uploaded to PyPI.

python-fibers 1.0.0 released

2015-09-03 by saghul Leave a comment

Yeah, it must be 1.0.0 release week!

I’m happy to announce python-fibers 1.0.0! Fibers are cooperative microthreads for Python, a project I started about a couple of years ago. Head here for the initial project annoucement and rationale. (yes, I can hear you thinking “why didn’t he use greenlet?!”)

There are no API changes in this release, and since it has been stable so far I thought it it’s fair to call it a 1.0.

This release steps up the CI game by adding AppVeyor integration, and thanks to it we have binary Python wheels for Python 2.7, 3.3 and 3.4 on PyPI!

As usual, the code is available on GitHub and documentation on RTD.

:wq

pycares 1.0.0 released

2015-09-01 by saghul Leave a comment

Long time no blog!

Today I’m happy to announce pycares 1.0.0 was just released. pycares is a Python library which wrapps the c-ares C library, providing asynchronous DNS resolution capability to different applications.

The full changelog can be checked here, but these are the main highlights:

Return nametuple-like objects for all query types
Return TTL information
Dropped support for old Python versions
AppVeyor CI integration
Binary wheels available for 32 and 64 bit Windows (thanks AppVeyor!)

As usual, the code is available on GitHub and the documentation is here.

Happy querying!

:wq

Announcing the Open Household Router Contraption

2015-05-01 by saghul Leave a comment

It’s with great pleasure that today, the day when OpenBSD 5.7 was released, I can announce OpenHRC: Open Household Router Contraption.

OpenHRC is a project Iñigo and yours truly did in our spare time, in order to replace the (crappy) router our Internet provider gave us with something more robust and OpenBSD based.

We chose the PC Engines APU as our hardware platform, but any device with at least 2 network interfaces will do. OpenHRC uses Ansible to configure the basic OpenBSD installation and enable several services, configured with sane defaults:

Local NTP server
DHCP server
Firewall
Local caching DNS resolver

This is just the beginning, we will be adding more features shortly, but we couldn’t pass on making our first release the same day OpenBSD 5.7 (which we have been testing for some time) is released.

Check out the installation video below, and head over to GitHub for the source code. Happy routing!

FOSDEM: ready fuels!

2015-01-28 by saghul Leave a comment

Yes, it’s that time of the year again. The week which leads to one of my favorite conferences: FOSDEM. I’ve been attending for 4 or 5 years now and I love it. There is so much going on it even get overwhelming at times! It’s great to just hop into a random room and listen to a great talk, my brain becomes a sponge throughout the weekend 🙂

This year I’ll be giving a talk at the lightning talks track and another talk at the Python devroom. As usual, I’m super excited.

See you there?

pyuv on wheels!

2015-01-21 by saghul Leave a comment

If you are a Python user which happens to use Windows every now and then you probably also suffer when installing (or at least trying to) Python packages which need to be compiled. Python wheels really help here, as they ease the installation of binary packages, and even make the installation of non-binary packages faster.

Long time pyuv contributor Marc Schlaich has recently began to provide these wheels for both 32 and 64 Windows, for all supported Python versions: 2.7, 3.3 and 3.4. Wheels for pyuv 1.0.2 have already been uploaded to PyPI, you can check how to install Python wheels here.

Thanks a lot for your contributions Marc!