troubleshooting

🔹 Real-Time Jenkins Troubleshooting Questions & Answers

1️⃣ Jenkins Job Fails Due to Git Clone Errors

❓ Issue: fatal: Authentication failed for https://github.com/repo.git ✔️ Solution:

• Verify Git credentials stored in Jenkins → Manage Credentials

• Check if GitHub access token is valid

• Use SSH keys instead of HTTPS authentication

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2️⃣ Jenkins Pipeline Stuck at "Waiting for available executors"

❓ Issue: Build is not running, shows "Waiting for available executors." ✔️ Solution:

• Check if all Jenkins agents are busy or offline

• Increase the number of executors under Manage Jenkins → Nodes

• Restart Jenkins or check for hanging jobs

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3️⃣ "No such file or directory" Error in Pipeline

❓ Issue: sh: mvn: command not found ✔️ Solution:

• Check if the required tool (e.g., Maven, Docker) is installed on the Jenkins agent

• Add the correct path to the tool in Manage Jenkins → Global Tool Configuration

• Use an absolute path in the pipeline script:

  sh '/usr/local/bin/mvn clean install'

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4️⃣ Jenkins Job Fails Due to "Permission Denied" on Script Execution

❓ Issue: Permission denied: ./deploy.sh ✔️ Solution:

• Ensure the script is executable:

  chmod +x deploy.sh

• If running in Docker, use the correct user in the Dockerfile

• If running on Linux, check Jenkins user permissions

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5️⃣ Jenkins Job Fails Due to Out of Disk Space

❓ Issue: No space left on device ✔️ Solution:

• Free space on the Jenkins server using:

  sudo du -sh /var/lib/jenkins/*
  sudo rm -rf /var/lib/jenkins/workspace/*

• Use Log Rotation under Manage Jenkins → Configure System

• Store artifacts in external storage (e.g., AWS S3, Nexus, Artifactory)

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6️⃣ Jenkins Pipeline Stuck at "Pending" in Kubernetes

❓ Issue: Jenkins pod stuck in Pending state when using Kubernetes agents. ✔️ Solution:

• Check available resources in Kubernetes using:

  kubectl get nodes
  kubectl describe pod <pod-name>

• Ensure the Jenkins agent image is correctly specified in the pod template

• Increase resource limits in Jenkins pod configuration

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7️⃣ "Invalid Pipeline Syntax" Error in Jenkinsfile

❓ Issue: Jenkinsfile execution fails due to syntax errors ✔️ Solution:

• Validate the Jenkinsfile before running:

  jenkins-linter https://github.com/user/repo/Jenkinsfile

• Use Declarative Pipeline Syntax Checker in Jenkins

• Ensure proper indentation in the Groovy script

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8️⃣ Jenkins Web UI is Slow or Unresponsive

❓ Issue: Jenkins takes too long to load or crashes frequently ✔️ Solution:

• Increase JVM memory allocation:

  export JAVA_OPTS="-Xms1024m -Xmx4096m"

• Disable unused plugins under Manage Plugins

• Set up Garbage Collection tuning for Jenkins

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9️⃣ Jenkins Job Stuck Due to Lock on Workspace

❓ Issue: Workspace is locked, waiting... ✔️ Solution:

• Manually delete the workspace lock:

  rm -rf /var/lib/jenkins/workspace/<job-name>/.git/index.lock

• Use ws directive to create a new workspace for every build

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🔟 Jenkins Job Fails Due to Incorrect Environment Variables

❓ Issue: Environment variables not loading properly ✔️ Solution:

• Check variables using echo $MY_VARIABLE in the pipeline

• Use withEnv() in scripted pipelines:

  withEnv(["MY_VAR=value"]) {
      sh "echo $MY_VAR"
  }

• Ensure variables are correctly defined in Manage Jenkins → Global Properties

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🔹 Summary

Jenkins troubleshooting requires debugging logs, permissions, network issues, and resource constraints. Always check Jenkins logs, agent status, pipeline configurations, and system resources to quickly resolve issues. 🚀