I am trying to create sample jenkins pipeline to build maven/gradle based application on internal kubernetes cluster. I have setup proxy through environment variable, on addition I have inserted proxy parameters in gradle.properties file too. Whenever I tries to build an application through gradle build It fails with an error Java: READ ONLY FILE SYSTEM . I searched online and found that due to different UID on jnlp and gradle container, Gradle fails to access /home/jenkins/ workspace. I inserted Pod Security Policy parameter on the pod and tried to executed all the container with same UID 1000, still It fails. I am still not sure exact root cause of this weird issue.

Reference Link: https://akomljen.com/set-up-a-jenkins-ci-cd-pipeline-with-kubernetes/

I am using Jenkins official helm chart to deploy jenkins on the cluster.

def label = "maven-${UUID.randomUUID().toString()}"

podTemplate(label: label, containers: [
  containerTemplate(name: 'gradle', image: 'gradle:latest', ttyEnabled: true, command: 'cat',
  envVars: [
    envVar(key: 'http_proxy',value: 'www.xxx:8080'),
    envVar(key: 'https_proxy',value: 'www.xxx:8080')
    ])
  ]) {

  node(label) {
    stage('Build a Gradle project') {
      git 'SOME GRADLE PROJECT REPO.'
      container('gradle') {
          sh 'gradle build --stacktrace'
      }
    }
  }
}

Consider the above sample example (assume jenkinsci/jnlp-slave:latest will be provisioned by Jenkins Default Pod template and will be attached to this pod)

Gradle Daemon will start and later fails with the following error.

Error resolving plugin [id: 'org.springframework.boot', version: '2.1.4.RELEASE']
18:24:47.119 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter] > Could not resolve all dependencies for configuration 'detachedConfiguration1'.
18:24:47.119 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]    > java.io.IOException: Read-only file system