Docker Compose Demo Environment for CloudBees Jenkins Platform

A great way to run CloudBees Jenkins on your laptop, with support for "Docker stuff"!

Feel free to clone/fork/extend this repo to meet your specific needs, and shoot me a PR if I missed anything!

My goal for this repo is to help people learn about CloudBees Jenkins and Docker while journeying through the README below.

DISCLAIMER: Not officially suppported by CloudBees. A very cool, pre-configured Docker trial is available here on the CloudBees website.

What does this include?

Nginx reverse proxy at http://cjp.local
CloudBees Jenkins Operations Center (CJOC) at http://cjp.local/cjoc
CloudBees Jenkins Enterprise (CJE) "prod" at http://cjp.local/cje-prod
CloudBees Jenkins Enterprise (CJE) "test" at http://cjp.local/cje-test
A shared SSH agent based on jenkinsci/ssh-slave
A shared Cloud with one JNLP agent based on cloudbees/jnlp-slave-with-java-build-tools
Support for Docker on Docker

NOTE: All services are intended to run on the same host in this example.

Prerequisites

Go get Docker for Mac Beta.

NOTE: Docker on Docker support has not been tested on other platforms.

Increase CPU/Memory limits in Docker preferences to as much as you can spare (e.g. CPU: 4, Memory: 6GB).
Open terminal and type:
```
 sudo vi /etc/hosts
```
then add (or append) this entry:
```
 127.0.0.1 cjp.local
```
Create a file called .env in the project directory (alongside docker-compose.yml) and copy everything into it from the provided .env.sample. Update the MAVEN_CACHE so that it's specific to your environment. If you don't have a Maven cache, or want to use additional/other caches, then update the ssh-slave: volumes: in docker-compose.yml accordingly. For now this is the only change needed in .env.

How to run

Simply,

docker-compose up

..from the project directory, and wait a little while :)

Important directories like JENKINS_HOME(s), Nginx logs, etc. are volume mapped (persisted) to the working project directory. Treat JENKINS_HOME directories with care, and consider backups.

Post-Startup Tasks

Connect Client Masters

Go to http://cjp.local/cjoc
Activate
Click Manage Jenkins > Configure System and set the Jenkins URL to http://cjp.local/cjoc (or just save if it's already correct)
Add a Client Master item named e.g. cje-prod with URL http://cjp.local/cje-prod.
Add a Client Master item named e.g. cje-test with URL http://cjp.local/cje-test.

Connect SSH Shared Agent

exec into the CJOC container and generate a key pair:
```
 docker exec -it cjoc bash

 ssh-keygen
```
Stick with the defaults and choose a password (or leave blank).

Copy your public key to a text editor:

 cd /var/jenkins_home/.ssh

 cat id_rsa.pub

In CJOC, click "Credentials", "System", "Global credentials (unrestricted)", "Add Credentials", select SSH Username with private key. Enter jenkins as the username and select From the Jenkins master ~/.ssh for the Private key option.
In .env, replace SSH_SLAVE_COMMAND with the public key that was just generated, save, and restart the container:
```
 docker-compose restart ssh-slave
```
Create a Shared Slave item in CJOC (named e.g. shared-ssh-agent), using the credentials above, host: ssh-slave, and a Remote FS root of /home/jenkins. Give it some labels, like shared, ssh, docker, docker-cloud.

Connect JNLP Shared Agent

Add a Shared Cloud item in CJOC (named e.g. shared-cloud). Remote FS root is /home/jenkins. Give it some labels, like shared, jnlp, java-build-tools, docker, docker-cloud and click Save. You should now be taken to a screen that displays the slave command to run.
In .env, replace JNLP_SLAVE_COMMAND with the -secret you see in the Jenkins UI, then save.
Start the JNLP agent (and watch it add itself to the shared-cloud):
```
 docker-compose restart jnlp-slave
```

Note: The JNLP agent bombs on initial startup because the CJOC shared-cloud is not available and ready to accept clients - remember: JNLP agents connect to the master, not the other way around. Add it to the shared-cloud pool (via restart) after CJOC is up and running.

What Next?

Automate all the things!

Consider the following plugins

Mock Security Realm
CloudBees Docker Build and Publish
CloudBees Docker Custom Build Environment
CloudBees Docker Pipeline
Docker Slaves Plugin (use in tandem with docker-service)

Miscellaneous

Docker on Docker (a.k.a "Docker inception")

Is supported by the following services:

cje-test
ssh-slave
jnlp-slave
docker-service (tcp://docker-service:2375)

When executing a docker command from within these containers, the Docker client installed inside the container communicates with the Docker server outside the container. This magic is provided by Docker socket volume mapping; see -v /var/run/docker.sock:/var/run/docker.sock in docker-compose.yml. For more information, read this famous blog post.

Pro tips

Use ⌃ + C to stop the environment, or better, use:
```
  docker-compose down
```
Clean your environment often (free disk space, fix "strange" issues) with:
```
  ./docker-clean.sh
```
Open an interactive terminal on a container (service) with:
```
  docker exec -it <containerName/serviceName> bash
```
Or run a command within a container immediately, e.g. to ping another container (thank you Docker 1.12 :)
```
  docker exec -it <containerName/serviceName> ping cjp.proxy
```

cloudbees/cjp-demo-environment