LXC & Test-Kitchen Tutorial

Transcript

1. LXC + Test-Kitchen Tutorial
   chefconf 2013, Bryan W. Berry
   

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2. Overview
   • The Setup
   • Demo
   • LXC Concepts
   • Test-Kitchen Concepts
   • Hack!
   

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3. The Setup
   • Ubuntu 12.04 or 12.10 with 2 partitions,
   1 smaller one unpartitioned
   $ sudo apt-get install -y lxc ruby1.9 ruby1.9-dev
   $ sudo gem install bundler chef -–no-ri –-no-rdoc
   $ sudo gem install test-kitchen -–pre –-no-rdoc
   $ git clone git://github.com/bryanwb/vagabond.git
   $ cd vagabond && git checkout new-lxc-cookbook
   $ sudo ln -s
   vagabond/lib/cookbooks/lxc/files/default/lxc-awesome-ephermal /
   usr/bin/lxc-awesome-ephemeral
   

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4. Vagabond
   • created by Chris Roberts
   • helps you get started with lxc and
   test-kitchen
   • has a number of awesome features
   • Totally alpha
   • Only works on ubuntu 12.*
   

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5. Demo
   • Let's create a 3-node cassandra cluster
   $ bundle exec kitchen create all –p
   ....
   $ bundle exec kitchen converge all –p
   ....
   $ bundle exec kitchen destroy all -p
   

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6. LXC is . . .
   a collection of tools to create
   an isolated environment
   Not really virtualization, just feels like it
   It's a container, not a VM
   

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7. LXC Concepts
   • All containers share the same kernel
   • We use cgroups to "namespace" or
   isolate resources per container
   • containers can sometimes see
   aspects of each other or the host
   

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8. Stuff
   • Default config file in /etc/lxc/lxc.conf
   • Templates in /usr/share/lxc/templates
   • Actual containers stored in /var/lib/lxc
   • lxcbr0 used to connect containers to the world
   • dnsmasq – lightweight dns and dhcp server
   /var/lib/misc/dnsmasq.leases
   • run-time info in
   /sys/fs/cgroup/container_name/*
   

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9. Create a Base Container
   $ sudo lxc-create –t ubuntu –n foobar
   $ sudo lxc-start –n foobar
   foobar exists at /var/lib/lxc/foobar/
   all the container-settings in
   /var/lib/lxc/foobar/config
   rootfs in /var/lib/lxc/foobar/rootfs
   

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10. Bring in the clones
    $ sudo lxc-clone -o ubuntu -n foobar
    $ sudo lxc-start –n foobar
    $ ifconfig eth0
    

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11. awesome-ephemeral
    # console 1
    $ sudo lxc-awesome-ephemeral -o
    ubuntu
    # that's faster
    # console 2
    $ sudo lxc-console attach foo..
    

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12. Let's go faster!
    $ sudo lxc-awesome-ephemeral -o
    ubuntu –I 10.0.3.100
    

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13. We've been cheating
    • lxc-awesome-ephemeral is just
    lxc-clone but stores container image
    in tmpfs by default
    • limits all your vms to the size of
    available RAM
    

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14. Modern Filesystems to the Rescue
    • We can use LVM, BTRFS, or even a Virtual
    Block Device (VBD) to run just as fast
    • Time to use that second partition
    $ sudo apt-get install –y btrfs-tools
    $ sudo parted /dev/sdx
    $ sudo mkfs.btrfs /dev/sdx1
    $ sudo mount /dev/sdx1 /var/lib/lxc
    

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15. overlay
    $ sudo lxc-awesome-ephemeral -o
    ubuntu -z /usr/lib/lxc
    Now you're cooking with butter!
    

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16. lxc-awesome-bastard-ephemeral
    $ sudo lxc-awesome-ephemeral -o
    ubuntu –n foobar –I 10.0.3.100
    -d -z /usr/lib/lxc
    $ sudo lxc-awesome-ephemeral –cleanup
    -o ubuntu –n foobar –I 10.0.3.100
    -d -z /usr/lib/lxc
    

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17. Test-Kitchen 1.0 Concepts
    • Test a cookbook against multiple distros/OS
    • Create and converge multiple distro/recipe
    combinations in parallel
    • Be easy to script
    • support different backends (drivers)
    • create & spin up clusters of nodes in parallel*
    *Proposed addition by Chris Robert
    

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18. .kitchen.yml
    • driver – currently AWS, LXC, vagrant,
    bluebox
    • platform – operating system or node
    in a cluster
    • suite – run list & set of attributes
    

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19. Why YAML?
    • easy to read
    • easy to parse
    • super flexible
    • great support for serializing data
    types
    

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20. Create a Gemfile
    Create a Gemfile
    gem'kitchen-lxc', git:
    'git://github.com/bryanwb/kitchen-lxc.git', branch:
    'awesome-ephemeral'
    gem 'berkshelf'
    gem 'kitchen', git:
    'git://github.com/opscode/test-kitchen.git', branch: 1.0
    $ bundle install
    From here on out, use
    $ bundle exec kitchen . . .
    

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21. Berkshelf
    Test-Kitchen uses Berkshelf to resolve
    cookbook dependencies and copy
    them into containers
    We won't be manually invoking it
    though for this tutorial
    

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22. My First .kitchen.yml
    $ bundle exec kitchen list
    $ bundle exec kitchen create default-ubuntu
    $ bundle exec kitchen destroy default-ubuntu
    

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23. Ideas
    • Add test-kitchen support to one of your cookbooks
    • Create a centos container and converge it
    • Use docker instead of lxc-awesome-ephemeral
    • Figure out what AUFS and how to use it
    Chris Roberts will be in later
    for your consultation/harrassment
    

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