Update Jenkins core and plugins (2023Q4 edition)

Last time: #18019 (closed)

Preparation

• Go through the changelog, paying attention to changes on how agents connect to controller, config changes that may need update, important changes in plugins, etc.
  • Current version: 2.414.2
  • Available version: 2.426.2

Deployment

• Deploy Jenkins upgrade to latest version available
• Use the Groovy and Python3 scripts to generate a list of up-to-date plugins
• Deploy plugin upgrades
• Restart all agents.
• Manually run the Update jobs script (may be needed so XML is valid with current Jenkins):

  sudo -u jenkins /usr/local/sbin/deploy_jenkins_jobs update

• Go through warnings in Jenkins interface.
• Manually uninstall removed plugins via Jenkins interface.
• Manually delete removed plugins from /var/lib/jenkins/plugins.

Wrap up

• Restart builds that were interrupted by Jenkins restart.
• Schedule next update.