Migrate from jenkins-agent ConfigMap to agent-injection

2 minute read
As of the CloudBees CI 2.462.3.3 release, the jenkins-agent ConfigMap has been deprecated. The jenkins-agent ConfigMap will be removed from the Helm chart in late 2025.

This guide shows you how to migrate from the deprecated jenkins-agent ConfigMap to agent-injection.

If you have pod templates that leverage the jenkins-agent ConfigMap, you need to migrate its configuration to the new agent-injection option provided by the Kubernetes plugin as follows:

  1. Select the Inject Jenkins agent in agent container option or add agentInjection: true to the pod template step or add agentInjection: true in the declarative pipelines.

  2. Remove the volume mounting in the jenkins-agent ConfigMap and the associated command (the new option injects the required command and arguments automatically).

The following example uses agentInjection: true in the pod template step.

// Build a Maven project using the standard image and Scripted syntax.
// Rather than inline YAML, you could use: yaml: readTrusted('jenkins-pod.yaml')
// Or, to avoid YAML: containers: [containerTemplate(name: 'maven', image: 'maven:3.6.3-jdk-8', command: 'sleep', args: 'infinity')]
podTemplate(
    agentContainer: 'maven',
    agentInjection: true,
    yaml: '''
apiVersion: v1
kind: Pod
spec:
  containers:
  - name: maven
    # In a real Jenkinsfile, it is recommended to pin to a specific version and use Dependabot or Renovate to bump it.
    image: maven:latest
    resources:
      requests:
        memory: "256Mi"
      limits:
        memory: "512Mi"
    command:
    - sleep
    args:
    - infinity
    securityContext:
      # maven runs as root by default, it is recommended or even mandatory in some environments (such as pod security admission "restricted") to run as a non-root user.
      runAsUser: 1000
''') {
    retry(count: 2, conditions: [kubernetesAgent(), nonresumable()]) {
        node(POD_LABEL) {
            // some steps...
        }
    }
}
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The following example adds agentInjection: true in a declarative pipeline and also uses agentContainer. You can use this to provide the name of the container that will run the agent. This container must have a JDK installed and available in PATH.

pipeline {
  agent {
    kubernetes {
      agentInjection true
      agentContainer 'maven'
      yaml '''
apiVersion: v1
kind: Pod
spec:
  containers:
  - name: maven
    # In a real Jenkinsfile, it is recommended to pin to a specific version and use Dependabot or Renovate to bump it.
    image: maven:latest
    resources:
      requests:
        memory: "256Mi"
      limits:
        memory: "512Mi"
    command:
    - sleep
    args:
    - infinity
    securityContext:
      # maven runs as root by default, it is recommended or even mandatory in some environments (such as pod security admission "restricted") to run as a non-root user.
      runAsUser: 1000
'''
    }
  }
  stages {
    stage('Stage 1') {
      steps {
        // Some steps
      }
    }
  }
}
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