Issue
- How to create Permanent Agents with Docker
Environment
- CloudBees Jenkins Enterprise - Managed Master (CJE-MM)
- CloudBees Jenkins Team (CJT)
- CloudBees Jenkins Platform - Client Master (CJP-CM)
Resolution
The best practice is using Docker for Cloud Agents (on demand).
- For CJT, CJPCM and Jenkins use Docker pipeline plugin. Or Yet Another Docker plugin in case you use freestyle jobs.
- For CJEMM Docker Agents.
Having said that, the steps are as follows, depending on the type of connector.
SSH Connection
Prerequisite: SSH key-pair.
In the Docker Server
1. Run docker run jenkinsci/ssh-slave "<my-key>.pub". Note <my-key>.pub should be passed as string (not the path).
Following, an example:
> docker run jenkins/ssh-slave "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAACAQCt5jaFU+q4An8cNxJNQSxxJ ... TQa2a9+0aSM9NtsoW8Q== user@ubuntu"
[[ '' == ssh-* ]]
+ [[ 1 -gt 0 ]]
+ [[ ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAACAQCt5jaFU+q4An8cNxJNQSxxJ ... TQa2a9+0aSM9NtsoW8Q== user@ubuntu == ssh-* ]]
+ write_key 'ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAACAQCt5jaFU+q4An8cNxJNQSxxJ ... TQa2a9+0aSM9NtsoW8Q== user@ubuntu'
+ mkdir -p /home/jenkins/.ssh
+ echo 'ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAACAQCt5jaFU+q4An8cNxJNQSxxJ ... TQa2a9+0aSM9NtsoW8Q== user@ubuntu'
+ chown -Rf jenkins:jenkins /home/jenkins/.ssh
+ chmod 0700 -R /home/jenkins/.ssh
+ shift 1
+ grep _
+ env
+ ssh-keygen -A
ssh-keygen: generating new host keys: RSA1
+ exec /usr/sbin/sshd -D -e
Server listening on 0.0.0.0 port 22.
Server listening on :: port 22.
In the Jenkins Server
2. Create a Credential type SSH username with Private Key (<my-key>), set Username as jenkins.
3. Create a new Node (<SSH_Docker_Agent>) being Launch method : Launch Agents via SSH and setting correctly the SSH port (22 in Dockerhub Jenkins - SSH agent). After saving the configuration of <SSH_Docker_Agent>, it will get connected to the Master. For host key verification settings in the Node configuration, please review the different options in this article.
JNLP Connection
Dockerhub Jenkins - JNLP agent
In Jenkins
1. Go to Manage Jenkins > Global Security, Enable TCP port for JNLP agents and select Java Web Start Agent Protocol/4 (starting from Jenkins 2.27).
2. Create a new Node (<JNLP_Docker_Agent>) being Launch method : Launch Agents via Java Web Start.
3. After saving <JNLP_Docker_Agent>, get your secrets on <JENKINS_URL>/computer/<JNLP_Docker_Agent>/.
See also: How to find agent secret key via API.
In the Docker Server
4. Run docker run jenkins/jnlp-slave -url <JENKINS_URL> <JNLP_Docker_Agent_SECRET> <JNLP_Docker_Agent_NAME> and it will get connected to the Master.
Following, an example:
> docker run jenkins/jnlp-slave -url http://jenkins.example/ 5455ab4bbafa983906f40b41e9e54599d5c8d7f070940c10f7f7a12aab5b003a docker-jnlp
Warning: JnlpProtocol3 is disabled by default, use JNLP_PROTOCOL_OPTS to alter the behavior
Sep 20, 2017 4:58:59 PM hudson.remoting.jnlp.Main createEngine
INFO: Setting up slave: docker-jnlp
Sep 20, 2017 4:59:00 PM hudson.remoting.jnlp.Main$CuiListener <init>
INFO: Jenkins agent is running in headless mode.
Sep 20, 2017 4:59:00 PM hudson.remoting.Engine startEngine
WARNING: No Working Directory. Using the legacy JAR Cache location: /home/jenkins/.jenkins/cache/jars
Sep 20, 2017 4:59:00 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Locating server among [http://jenkins.example/]
...
Sep 20, 2017 4:59:00 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Agent discovery successful
Agent address: 192.168.0.12
Agent port: 7359
Identity: 25:64:bb:7b:7b:fc:2d:16:cc:ff:d1:c2:72:f2:97:11
Sep 20, 2017 4:59:00 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Handshaking
Sep 20, 2017 4:59:00 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Connecting to 192.168.0.12:7359
Sep 20, 2017 4:59:00 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Trying protocol: JNLP4-connect
Sep 20, 2017 4:59:01 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Remote identity confirmed: 25:64:bb:7b:7b:fc:2d:16:cc:ff:d1:c2:72:f2:97:11
Sep 20, 2017 4:59:01 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Connected
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