Jenkins : Foreman Node Sharing Plugin

Essentials

• This plugin provides a means to automatically coordinate the sharing of bare metal resources as nodes among multiple masters.
• It connects to single Foreman instance and multiple Jenkins masters reserve it communicating via the Foreman Reserve Plugin API.
  • Ensure the Foreman Reserve Plugin is installed. See https://github.com/david-caro/foreman_reserve
• Once configured, Jenkins is able to reserve hosts based on labels attached to them and the labels builds require.
  • It will behave just any other Jenkins Cloud.
• Nodes are connected over SSH using the same credential.
• To ensure fairness, hosts will be utilized for a single build only and returned back to pool for other masters to reserve.

Set Up

Cloud in Jenkins(es)

• Once the plugin is installed, a cloud type called Foreman Shared Node is made available.
• Navigate to Manage Jenkins / Configure Jenkins / Cloud
• Click on Add a new cloud
• Select Foreman Shared Node

• Enter the Foreman connection details

• Click Test Connection to verify the Foreman connection details.
  • The plugin will report the version of Foreman.

• Click Save.

Hosts in Foreman

Automatically

TODO: Document new inventory population tool.

There is a script that can be used to populate many resources in Foreman. See https://raw.githubusercontent.com/scoheb/acceptance-test-harness/f1f426b171538373d92e69afa278a0288bf9b017/src/test/resources/foreman_node_sharing_plugin/setup.sh

Usage: setup.sh URL HOSTNAME IP LABEL

Manually

• Login to the Foreman instance
• Navigate to Hosts / New Host
• Populate the following properties
  • Name
  • Domain
  • IP Address
• Add the following properties:
  • JENKINS_LABEL
  • JENKINS_SLAVE_REMOTEFS_ROOT
  • RESERVED
• Set the JENKINS_LABEL property to be the set of labels that this resources provides. Separate mulitple labels by a space.
• Set the JENKINS_SLAVE_REMOTEFS_ROOT property to be the value of the REMOTEFS_ROOT for this shared node.

Internal workings

• Plugin uses
  • SSH Slaves plugin to connect to machines.
  • Cloud Statistics Plugin to report foreman reservation progress.
  • Resource Disposer Plugin to tear down resources reliably.

Build sequence

• A job with label myLabel is triggered and placed in Jenkins queue.
• Jenkins Cloud API checks to see if a slave exists with label myLabel
• If not, all defined Clouds are checked to see which one can provision label myLabel
• The plugin is requested to provision and performs:
  • Foreman query to search for an UN-RESERVED host where JENKINS_LABEL matches myLabel
  • Foreman API call to reserve host
    • The Jenkins URL will be added as the RESERVED property value.
  • Foreman query to obtain Jenkins RemoteFS Root for the host
• Node is created and SSH Connection established using defined Cloud credentials.
• Build is performed on newly provisioned slave.
• The plugin immediately attempts to terminate the node and calls Foreman API to release the resource.

Important Notes

• Freestyle, Maven and Matrix jobs are supported.
• In the event that the Foreman connection is lost while a build is running, the plugin will attempt to release the resource in the background
• Should you need to forcefully release a resource, simply set the RESERVED property in Foreman to be false
  • Only string value 'false' put into RESERVED property makes a node free and available for further reservation, nothing else
• You may also use the Audit feature in Foreman for debugging purposes.

Change Log

Version 1.2.9

• Removed PendingDelete behavior
• Bug fixed release

Version 1.2.2

• JENKINS-41693 Added timeouts to web client connection
• Javadoc fixes.
• Handle initialization properly when no hosts are reserved.

Version 1.2.1

• JENKINS-39148 Implemented basic cleanup on startup
• Show compatible hosts on dedicated page instead of configure page
• JENKINS-40030 Re-defined delays defined in hudson.slaves.NodeProvisioner.NodeProvisionerInvoker
• JENKINS-38899 ForemanSharedNodeCloud.provision(Label) iterates over the whole collection
• JENKINS-39140 Node termination is performed by periodic task
• Override AbstractCloudComputer.doDoDelete()

Version 1.2.0

• Initial release