# Gerrit CI Docker Image

This is a Docker image based on the Jenkins Docker image that allows users
to build and test the Gerrit CI jobs automatically, based on the configuration
at https://gerrit.googlesource.com/gerrit-ci-scripts/

In turn, these CI scripts are based on
http://docs.openstack.org/infra/jenkins-job-builder/ -- which builds Jenkins
jobs based on YAML configurations.

In this particular image, the YAML configurations are updated and jobs
reloaded every 5 minutes via the Jenkins SCM trigger.  These jobs are fetched
from the gerrit-ci-scripts repository and automatically reloaded.

It is also possible to run the gerrit-ci-scripts-manual job and provide the
legacy Change ID number and a particular revision to build: Jenkins will fetch
this particular change and load any job configurations changed in this revision.
Note that it will not inhibit the main gerrit-ci-scripts trigger from polling.

## Notes for users of boot2docker

If you're using boot2docker, the stock drive image and memory will not be enough.
I would recommend growing your boot2docker volume to at least 40GB, and perhaps
adding an extra 2-4GB swap space at the end of the volume.  Additionally, you
may wish to increase the amount of memory allocated to your boot2docker VM to
at least 3GB (4GB+ preferred).  Failing to do this may result in unusual
failures of the VM or build errors.

For more information on enlarging the boot2docker volume, please see:
https://docs.docker.com/articles/b2d_volume_resize/

## Building all the images with one command

make build

## Images

Images available are:

* gerritforge/gerrit-ci-agent: Base Jenkins agent with OS and prerequisites.

* gerritforge/gerrit-ci-agent-debian: Base Jenkins agent with OS and prerequisites.

* gerritforge/gerrit-ci-agent-bazel: Bazel build for gerrit 2.14+.

* gerritforge/gerrit-ci-agent-bazel-sbt: Setups scala for plugins that use scala.

* gerritforge/gerrit-ci-agent-mvn - Setups maven for plugins that use maven.

## Running the container

* docker run --privileged -it <image_name> bash

If your not familar with docker please follow https://docs.docker.com/get-started/

## Contributing agent to Gerrit Code Review verification

* Set up root server with running docker service.
* Generate ecdsa SSH key and send public key to CI maintainer:

----
  $ ssh-keygen -t ecdsa -b 521
----

* Ask CI maintainer to generate for you unique agent id.

* Run `cat /proc/cpuinfo` and report CI maintainer the number of CPUs, so
that your agent would not get overloaded.

* Clone gerrit-ci-scripts repository:

----
  $ git clone https://gerrit.googlesource.com/gerrit-ci-scripts
----

* Make sure `ppp` package is installed, e.g. on Ubuntu run:

----
  $ apt-get install ppp
----

* Activate Docker's remote API. On Ubuntu, add this option to systemd script:

----
  $ cat /lib/systemd/system/docker.service
  [...]
  ExecStart=/usr/bin/dockerd -H tcp://10.0.9.1:2375 -H fd://
----

Caution: Don't expose generic interface: `-H tcp://0.0.0.0:2375`,
otherwise, your Docker container could be hijacked.

* Reload systemd and restart docker service:

----
  $ systemctl daemon-reload
  $ systemctl restart docker.service
----

* Add this line to crontab job (replace <your_agent_id>):

----
*/5 * * * * /root/gerrit-ci-scripts/worker/tunnel.sh <your_agent_id>
----

* In case your server is behind a Firewall, open tcp/2375 port for
incoming requests.

* Check on https://gerrit-ci.gerritforge.com and running `docker ps`
that your agent is up and running and build jobs are scheduled. If all
went well and when jobs have arrived you should see something like:

----
  $ docker ps
  CONTAINER ID        IMAGE                                    COMMAND                  CREATED             STATUS              PORTS
  d9ff4b6a8b1c        gerritforge/jenkins-agent-bazel:debian   "bash -x /bin/star..."   6 minutes ago       Up 6 minutes        0.0.0.0:32792->22/tcp
----