This test-kitchen plugin provides a driver, transport, and provisioner for rapid cookbook testing and container development using Docker and Chef.
Add the following to your ~/.bash_profile
export KITCHEN_YAML=.kitchen.yml
export KITCHEN_LOCAL_YAML=.kitchen.dokken.yml
- Behold
.kitchen.yml
laptop:~/src/chef-cookbooks/hello_dokken$ cat .kitchen.yml
---
driver:
name: dokken
chef_version: latest
transport:
name: dokken
provisioner:
name: dokken
verifier:
name: inspec
platforms:
- name: centos-7
driver:
image: centos:7
suites:
- name: default
run_list:
- recipe[hello_dokken::default]- List kitchen suites
laptop:~/src/chef-cookbooks/hello_dokken$ kitchen list
Instance Driver Provisioner Verifier Transport Last Action Last Error
- List containers
laptop:~/src/chef-cookbooks/hello_dokken$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
- List images
laptop:~/src/chef-cookbooks/hello_dokken$ docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
laptop:~/src/chef-cookbooks/hello_dokken$ kitchen create
-----> Starting Kitchen (v1.15.0)
-----> Creating <default-centos-7>...
Creating local sandbox at /Users/someara/.dokken/sandbox/6e1b03ab46-default-centos-7
Building work image..
Finished creating <default-centos-7> (0m21.04s).
-----> Kitchen is finished. (0m21.95s)
The kitchen create phase of the kitchen run pulls (if missing)
the chef/chef image from the Docker hub, then creates a volume
container named chef-<version>. This makes /opt/chef available for
mounting by other containers.
When talking to a local Docker host (over a socket), The driver
creates and bind mounts a sandbox directory to /opt/kitchen. This
prevents us from having to "upload" the test data.
When talking to a remote Docker host (tcp://somewhere.else), dokken
starts a container named <suite-name>-data. It makes /opt/kitchen and
/opt/verifier available for mounting by the runner. The data
container is the "trick" to the whole thing. It comes with rsync, runs
an openssh daemon, and uses an insecure, authorized_key ala
Vagrant. This is later used to upload cookbook test data.
The venerable /tmp directory is avoided, due to the popularity of
tmpfs clobbering by inits.
Finally, the driver pulls the image specified by the suite's platform
section and creates a runner container named
<unique_prefix>-<suitename>. This container bind-mounts the volumes
from chef-<version> and <suite-name>-data, giving access to Chef
and the test data. By default, the pid_one_command of the runner
container is a script that sleeps in a loop, letting us exec our
provisioner in the next phase. It can be overridden with init systems
like Upstart and systemd, for testing recipes with service resources
as needed.
- List containers
laptop:~/src/chef-cookbooks/hello_dokken$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
3489588d4470 6e1b03ab46-default-centos-7:latest "sh -c 'trap exit ..." About a minute ago Up About a minute 6e1b03ab46-default-centos-7
f678882b1575 chef/chef:current "true" About a minute ago Created chef-current
- List images
laptop:~/src/chef-cookbooks/hello_dokken$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
6e1b03ab46-default-centos-7 latest 2ea1040b9c10 About a minute ago 192 MB
chef/chef current 01ec788610e2 6 days ago 124 MB
centos 7 67591570dd29 7 weeks ago 192 MB
- Converge suite
laptop:~/src/chef-cookbooks/hello_dokken$ time kitchen converge
-----> Starting Kitchen (v1.15.0)
-----> Converging <default-centos-7>...
Creating local sandbox in /Users/someara/.dokken/sandbox/6e1b03ab46-default-centos-7
Preparing dna.json
Preparing current project directory as a cookbook
Removing non-cookbook files before transfer
Preparing validation.pem
Preparing client.rb
Starting Chef Client, version 12.19.5
[2017-02-08T04:23:00+00:00] WARN: unable to detect ipaddress
Creating a new client identity for default-centos-7 using the validator key.
resolving cookbooks for run list: ["hello_dokken::default"]
Synchronizing Cookbooks:
- hello_dokken (0.1.0)
Installing Cookbook Gems:
Compiling Cookbooks...
Converging 1 resources
Recipe: hello_dokken::default
* file[/hello] action create
- create new file /hello
- update content in file /hello from none to 2d6944
--- /hello 2017-02-08 04:23:01.780659287 +0000
+++ /.chef-hello20170208-41-105f1ha 2017-02-08 04:23:01.780659287 +0000
@@ -1 +1,2 @@
+hello\n
- change mode from '' to '0644'
- change owner from '' to 'root'
- change group from '' to 'root'
Running handlers:
Running handlers complete
Chef Client finished, 1/1 resources updated in 01 seconds
Finished converging <default-centos-7> (0m2.61s).
-----> Kitchen is finished. (0m3.46s)
real 0m3.887s
user 0m1.080s
sys 0m0.210s
The kitchen-converge phase of the kitchen run uses the provisioner
to upload cookbooks through the data container, then execs
chef-client in the runner container. It does NOT install Chef, as it
is has already mounted by the driver. The transport then commits the
runner container, creating an image that only contains the changes
made by Chef.
- List containers
laptop:~/src/chef-cookbooks/hello_dokken$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c153dfd8e53d e9fa5d3a0d0e "sh -c 'trap exit 0 S" 9 minutes ago Up 9 minutes default-centos-7
32c42fba4a8c someara/kitchen-cache:latest "/usr/sbin/sshd -D -p" 9 minutes ago Up 9 minutes 0.0.0.0:32846->22/tcp default-centos-7-data
7e327add6bf2 chef/chef:12.5.1 "true" 17 minutes ago Created chef-12.5.1
- List images
laptop:~/src/chef-cookbooks/hello_dokken$ docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
default-centos-7 latest ec1d208d77cd 8 minutes ago 172.3 MB
someara/kitchen-cache latest abbdb063dff1 2 weeks ago 300.8 MB
chef/chef 12.5.1 86245605bbe3 4 weeks ago 168.1 MB
centos 7 e9fa5d3a0d0e 6 weeks ago 172.3 MB
- Diff container
laptop:~/src/chef-cookbooks/hello_dokken$ docker diff default-centos-7
A /hello
C /opt
A /opt/chef
A /opt/kitchen
C /run
A /run/mount
A /run/mount/utab
C /tmp
C /var/lib/rpm/.dbenv.lock
C /var/lib/rpm/__db.001
C /var/lib/rpm/__db.002
C /var/lib/rpm/__db.003
- Verify suite
laptop:~/src/chef-cookbooks/hello_dokken$ time kitchen verify
-----> Starting Kitchen (v1.15.0)
-----> Setting up <default-centos-7>...
Finished setting up <default-centos-7> (0m0.00s).
-----> Verifying <default-centos-7>...
Loaded
Target: docker://84def4c49ce3703e42ac2be8a95c672d561c052520ca90788d42bbdb94e7cc6f
File /hello
✔ should be file
✔ should be mode 420
✔ should be owned by "root"
✔ should be grouped into "root"
Test Summary: 4 successful, 0 failures, 0 skipped
Finished verifying <default-centos-7> (0m0.80s).
-----> Kitchen is finished. (0m1.99s)
real 0m2.695s
user 0m1.310s
sys 0m0.365s
The kitchen-verify phase uses the transport to run acceptance tests, verifying image state.
- List containers
laptop:~/src/chef-cookbooks/hello_dokken$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
84def4c49ce3 6e1b03ab46-default-centos-7:latest "sh -c 'trap exit ..." 6 minutes ago Up 6 minutes 6e1b03ab46-default-centos-7
f678882b1575 chef/chef:current "true" 9 minutes ago Created chef-current
- List images
laptop:~/src/chef-cookbooks/hello_dokken$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
6e1b03ab46-default-centos-7 latest fec1a50470ed 6 minutes ago 192 MB
chef/chef current 01ec788610e2 6 days ago 124 MB
centos 7 67591570dd29 7 weeks ago 192 MB
laptop:~/src/chef-cookbooks/hello_dokken$ kitchen destroy
-----> Starting Kitchen (v1.15.0)
-----> Destroying <default-centos-7>...
Deleting local sandbox at /Users/someara/.dokken/sandbox/6e1b03ab46-default-centos-7
Finished destroying <default-centos-7> (0m0.83s).
-----> Kitchen is finished. (0m1.81s)
- List containers
laptop:~/src/chef-cookbooks/hello_dokken$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
f678882b1575 chef/chef:current "true" 10 minutes ago Created chef-current
- List images
laptop:~/src/chef-cookbooks/hello_dokken$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
chef/chef current 01ec788610e2 6 days ago 124 MB
centos 7 67591570dd29 7 weeks ago 192 MB
Due to the nature of Docker, a handful of considerations need to be addressed.
A complete example of a non-trivial kitchen.yml is found in the docker cookbook, at
https://github.com/chef-cookbooks/docker/blob/master/.kitchen.yml
The Distros (debian, centos, etc) will typically manage an official image on the Docker Hub. They are really pushing the boundaries of minimalist images, well beyond what is typically laid to disk as part of a "base installation".
Very often, an image will come with a package manager, GNU coreutils, and that's about it. This can differ greatly from what is found in typical Vagrant and IaaS images.
Because of this, it is often necessary to "cheat" and install prerequisites into the image before running Chef, Serverspec, or your own programs.
To help with this, the Dokken driver provides an intermediate_instructions
directive. Here is an example from httpd
platforms:
- name: debian-7
driver:
image: debian:7
intermediate_instructions:
- RUN /usr/bin/apt-get update
- RUN /usr/bin/apt-get install -y apt-transport-https net-tools
If present, an intermediate image is built, using a Dockerfile rendered from lines
provided. Any valid instruction will work, including MAINTAINER,
ENTRYPOINT, VOLUMES, etc. Knowledge of Docker is assumed.
This should be used as little as possible.
Docker containers are process oriented rather than machine oriented. This makes life
interesting when testing things not necessarily destined to run in Docker. Specifically,
Chef recipes that utilize the service resource present a problem. To overcome this,
we run the container in a way that mimics a machine.
As mentioned previously, we use an infinite loop to keep the container process from exiting.
This allows us to do multiple kitchen converge and kitchen login operations without
needing to commit a layer and start a new container. This is fine until we need to start
testing recipes that use the service resource.
The default pid_one_command is 'sh -c "trap exit 0 SIGTERM; while :; do sleep 1; done"'
If you need to use the service resource to drive Upstart or systemd, you'll need to
specify the path to init. Here are more examples from httpd
- systemd for RHEL-7 based platforms
platforms:
- name: centos-7
driver:
image: centos:7
privileged: true
pid_one_command: /usr/lib/systemd/systemd
volumes:
- /sys/fs/cgroup:/sys/fs/cgroup:ro # required by systemd
You can combine intermediate_instructions and pid_one_command as needed.
- Upstart for Ubuntu 12.04
- name: ubuntu-12.04
driver:
image: ubuntu-upstart:12.04
pid_one_command: /sbin/init
intermediate_instructions:
- RUN /usr/bin/apt-get update
- RUN /usr/bin/apt-get install apt-transport-https
When starting a container with an init system, it will often mount a tmpfs into /tmp.
When this happens, it is necessary to specify a root_path for the verifier if using
traditional Bats or Serverspec. This is due to Docker bind mounting the kitchen data
before running init. This is not necessary when using Inspec.
verifier:
root_path: '/opt/verifier'
sudo: false
Chef publishes all functioning builds to the Docker Hub,
including those from the "current" channel. If you wish to use pre-release versions of Chef, set
your chef_version value to "current".
It is possible to pass several extra configs to configure the chef binary and options, for example to use older versions that do not have the "-z" switch or to get some debug logging.
provisioner:
chef_binary: /opt/chef/bin/chef-solo
chef_options: ""
chef_log_level: debug
chef_output_format: minimal
Containers that supply a no-op binary which returns a successful exit status can be tested without requiring Chef to actually converge.
verifier:
name: inspec
platforms:
- name: alpine
driver:
image: alpine:latest
provisioner:
chef_binary: /bin/true
We already had a thing that drives Docker, why did you make this instead of modifying that?
The current kitchen-docker driver ends up baking SSH, Chef, and the kitchen data
into the image. This does not. To make this work, I had to create a Driver, a Transport,
and a Provisioner that blur the traditional duties of each. The current Docker driver
can be used with Puppet, Ansible, CFEngine provisioners. This (for the time being) requires
Chef.
Right now there is no kitchen publish mechanism. See this issue.
You can, however, do it manually.
cd my_cookbook ;
kitchen verify suite_name
docker stop suite_name
docker tag suite_name:latest my.computers.biz:5043/something/whatever
docker push my.computers.biz:5043/something/whatever
kitchen destroy