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.

What does this include?

Nginx reverse proxy at http://cjp.local (404 means it's running, home page is TODO)
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 Docker-enabled, shared SSH agent based on jenkinsci/ssh-slave
The ability to spawn Docker-enabled, shared JNLP agents based on cloudbees/jnlp-slave-with-java-build-tools

NOTE: All services are intended to run on the same host in this example, but similar practices can be applied to e.g. Docker Swarm (multi host) setups.

Prerequisites

Go get Docker for Mac.

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

so that your host file will look like the following example:

 ##
 # Host Database
 #
 # localhost is used to configure the loopback interface
 # when the system is booting.  Do not change this entry.
 ##
 127.0.0.1       localhost
 127.0.0.1       cjp.local
 255.255.255.255 broadcasthost
 ::1             localhost

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 (or remove) the ssh-slave: volumes: in docker-compose.yml accordingly. For now this is the only change needed in .env.
Create a Docker network by running this from the project directory:
```
 make network
```

How to run (and restart after shutting down)

Simply type the following command

docker-compose up -d

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

You can view logs (and safely ctrl+c out of them) via:

docker-compose logs -t -f

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

Post-Startup Checklist

Connect Client Masters (one time)

Activate CJOC at http://cjp.local/cjoc using the recommended settings
Follow the same process for http://cjp.local/cje-prod and http://cjp.local/cje-test, again with recommended settings
In CJOC, create Client Master items for cje-prod and cje-test, and use the URLs from step 2 to make the connection

Connect ssh-slave as a Shared Slave (one time)

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.

Add JNLP Agent(s) to a Shared Cloud (config once, then repeat step 4)

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 SHARED_CLOUD_NAME if needed, and replace JNLP_SLAVE_COMMAND with the -secret you find the Jenkins UI, then save your changes.
Build the JNLP agent:
```
 make build-jnlp-slave
```
Launch a JNLP agent into the Shared Cloud, repeatedly if desired:
```
 make jnlp-slave
```
Finally, destroy all JNLP slaves:
```
 make destroy-jnlp
```

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 in docker-compose.yml)

Miscellaneous

Upgrades

Please refer to the Releases Page for upgrade instructions.

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

See what's running:
```
  docker ps
```

Shutdown command(s):

  docker-compose down

  make destroy-jnlp

Clean Docker after shutting down:
```
  make clean
```
Tail the logs for a running container:
```
  docker logs -f $CONTAINER_NAME_OR_ID
```
Open an interactive terminal on a running container:
```
  docker exec -it $CONTAINER_NAME_OR_ID sh
```
Run a command within a container immediately, e.g. to test networking
```
  docker exec -it $CONTAINER_NAME_OR_ID ping cjp.proxy
```

RoCry / cjp-demo-environment