{"id":370,"date":"2026-10-13T22:51:34","date_gmt":"2026-10-13T22:51:34","guid":{"rendered":"http:\/\/www.scmgalaxy.com\/tutorials\/2014\/08\/20\/interview-questions-and-answers-of-jenkins\/"},"modified":"2026-10-13T22:51:35","modified_gmt":"2026-10-13T22:51:35","slug":"interview-questions-and-answers-of-jenkins","status":"publish","type":"post","link":"https:\/\/www.devopsschool.com\/blog\/interview-questions-and-answers-of-jenkins\/","title":{"rendered":"Jenkins Interview Questions, Answered: CI, APIs, Installation, Backups, and Essential Plugins"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">If you are preparing for a DevOps interview, this guide turns common Jenkins questions into practical, interview-ready answers with commands and examples you can discuss confidently.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Originally published on August 20, 2014; fully revised and updated.<\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full aligncenter\" src=\"https:\/\/www.devopsschool.com\/blog\/wp-content\/uploads\/2014\/08\/jenkins-interview-questions.png\" alt=\"jenkins interview questions\" width=\"600\" height=\"400\" \/><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Core Jenkins interview topics at a glance<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Most Jenkins interviews test whether you understand <strong>how CI works in practice<\/strong>, not just definitions. You should be ready to explain workflow, setup, plugins, and operational safety.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Continuous Integration and delivery flow<\/li><li>Jenkins API and automation capabilities<\/li><li>Advantages and trade-offs of Jenkins<\/li><li>System requirements and architecture basics<\/li><li>Installation on Ubuntu and RHEL-like systems<\/li><li>Backup, restore, and migration of Jenkins data<\/li><li>Frequently used plugins and when to use them<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">What continuous integration means in Jenkins<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Continuous Integration (CI)<\/strong> means developers merge code frequently, and each change triggers automated build and test steps. In Jenkins, this is typically implemented with webhooks from source control and a Pipeline job.<\/p>\n\n\n\n<pre class=\"mermaid\">\nflowchart LR\n    A[Developer commit] --> B[SCM webhook]\n    B --> C[Jenkins controller]\n    C --> D[Checkout stage]\n    D --> E[Build stage]\n    E --> F[Test stage]\n    F --> G{Quality gate pass}\n    G -- No --> H[Fail build and notify]\n    G -- Yes --> I[Package artifact]\n    I --> J[Deploy to target]\n<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">A basic Pipeline-as-Code example:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-1\" data-shcb-language-name=\"JavaScript\" data-shcb-language-slug=\"javascript\"><span><code class=\"hljs language-javascript language-groovy\">pipeline {\n  agent any\n\n  stages {\n    stage(<span class=\"hljs-string\">'Checkout'<\/span>) {\n      steps { checkout scm }\n    }\n    stage(<span class=\"hljs-string\">'Build'<\/span>) {\n      steps { sh <span class=\"hljs-string\">'mvn -B package'<\/span> }\n    }\n    stage(<span class=\"hljs-string\">'Test'<\/span>) {\n      steps { sh <span class=\"hljs-string\">'mvn test'<\/span> }\n    }\n  }\n\n  post {\n    always {\n      junit <span class=\"hljs-string\">'target\/surefire-reports\/*.xml'<\/span>\n    }\n  }\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">JavaScript<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">javascript<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\">Jenkins API and automation features interviewers ask about<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Jenkins exposes a Remote Access API (JSON\/XML), CLI options, and web UI actions. Interviewers often ask how you would trigger builds, fetch status, and integrate external systems.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Trigger jobs remotely<\/li><li>Read job\/build metadata via API<\/li><li>Integrate with scripts, release tooling, and chat systems<\/li><li>Use API token-based authentication for automation<\/li><\/ul>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-2\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php language-bash\">JENKINS_URL=http:<span class=\"hljs-comment\">\/\/jenkins.example.com<\/span>\nUSER=interviewer-demo\nTOKEN=api_token_here\nJOB=sample-pipeline\n\ncurl -s -u $USER:$TOKEN $JENKINS_URL\/job\/$JOB\/api\/json\nCRUMB=$(curl -s -u $USER:$TOKEN $JENKINS_URL\/crumbIssuer\/api\/json | jq -r .crumb)\ncurl -X POST -u $USER:$TOKEN -H Jenkins-Crumb:$CRUMB $JENKINS_URL\/job\/$JOB\/build<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-2\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\">Jenkins job types you should compare in interviews<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Job type<\/th><th>Best for<\/th><th>Interview talking point<\/th><\/tr><\/thead><tbody><tr><td>Freestyle<\/td><td>Simple, UI-driven automation<\/td><td>Fast to start, harder to standardize at scale<\/td><\/tr><tr><td>Pipeline<\/td><td>Versioned CI\/CD as code<\/td><td>Supports review, reuse, and controlled change management<\/td><\/tr><tr><td>Multibranch Pipeline<\/td><td>Repository with many branches\/PRs<\/td><td>Automatically discovers branch pipelines and reduces manual job creation<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Requirements for using Jenkins<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">At minimum, you need a server (or container host), Java runtime, network access to your SCM and build targets, and storage for Jenkins home data.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Supported OS (Linux is most common in production)<\/li><li>Java runtime compatible with your Jenkins release<\/li><li>Persistent storage for <code>JENKINS_HOME<\/code><\/li><li>Service account and access controls<\/li><li>SCM credentials and webhook connectivity<\/li><li>Backup destination and restore plan<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Installing Jenkins on Ubuntu and RHEL-like systems<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Package names and repository keys can change over time, so validate against current Jenkins documentation before production rollout.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Aspect<\/th><th>Ubuntu or Debian<\/th><th>RHEL, CentOS Stream, Rocky, AlmaLinux<\/th><\/tr><\/thead><tbody><tr><td>Package manager<\/td><td>apt<\/td><td>dnf or yum<\/td><\/tr><tr><td>Repo setup<\/td><td>Jenkins Debian repo + keyring<\/td><td>Jenkins RPM repo + imported key<\/td><\/tr><tr><td>Java example<\/td><td>openjdk-17-jre<\/td><td>java-17-openjdk<\/td><\/tr><tr><td>Service control<\/td><td>systemctl<\/td><td>systemctl<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-3\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php language-bash\"><span class=\"hljs-comment\"># Ubuntu or Debian example<\/span>\nsudo apt update\nsudo apt install -y fontconfig openjdk<span class=\"hljs-number\">-17<\/span>-jre\nsudo wget -O \/usr\/share\/keyrings\/jenkins-keyring.asc https:<span class=\"hljs-comment\">\/\/pkg.jenkins.io\/debian-stable\/jenkins.io-2023.key<\/span>\n<span class=\"hljs-keyword\">echo<\/span> <span class=\"hljs-string\">'deb &#91;signed-by=\/usr\/share\/keyrings\/jenkins-keyring.asc] https:\/\/pkg.jenkins.io\/debian-stable binary\/'<\/span> | sudo tee \/etc\/apt\/sources.<span class=\"hljs-keyword\">list<\/span>.d\/jenkins.<span class=\"hljs-keyword\">list<\/span> &gt; \/dev\/<span class=\"hljs-keyword\">null<\/span>\nsudo apt update\nsudo apt install -y jenkins\nsudo systemctl enable --now jenkins\nsudo systemctl status jenkins<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-3\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-4\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php language-bash\"><span class=\"hljs-comment\"># RHEL-like example<\/span>\nsudo dnf install -y fontconfig java<span class=\"hljs-number\">-17<\/span>-openjdk\nsudo wget -O \/etc\/yum.repos.d\/jenkins.repo https:<span class=\"hljs-comment\">\/\/pkg.jenkins.io\/redhat-stable\/jenkins.repo<\/span>\nsudo rpm --import https:<span class=\"hljs-comment\">\/\/pkg.jenkins.io\/redhat-stable\/jenkins.io-2023.key<\/span>\nsudo dnf install -y jenkins\nsudo systemctl enable --now jenkins\nsudo systemctl status jenkins<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-4\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-5\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php language-bash\"><span class=\"hljs-comment\"># Get initial admin password after first start<\/span>\nsudo cat \/<span class=\"hljs-keyword\">var<\/span>\/lib\/jenkins\/secrets\/initialAdminPassword<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-5\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\">Process to back up Jenkins and copy files safely<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">For reliable recovery, prioritize backing up <code>JENKINS_HOME<\/code> (commonly <code>\/var\/lib\/jenkins<\/code>). This includes job configuration, build history, plugins, and critical secrets.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><code>\/var\/lib\/jenkins\/jobs\/<\/code> for job definitions and build metadata<\/li><li><code>\/var\/lib\/jenkins\/plugins\/<\/code> for installed plugins<\/li><li><code>\/var\/lib\/jenkins\/secrets\/<\/code> and related credential files for encrypted credentials<\/li><li>Global config files in <code>\/var\/lib\/jenkins\/<\/code><\/li><\/ul>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-6\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php language-bash\"><span class=\"hljs-comment\"># Consistent backup example<\/span>\nsudo systemctl stop jenkins\nsudo tar -czf \/srv\/backups\/jenkins_home_$(date +%F).tar.gz \/<span class=\"hljs-keyword\">var<\/span>\/lib\/jenkins\nsudo systemctl start jenkins\n\n<span class=\"hljs-comment\"># Copy backup to another server<\/span>\nrsync -avz \/srv\/backups\/jenkins_home_$(date +%F).tar.gz backup@backuphost:\/data\/jenkins\/<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-6\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-7\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php language-bash\"><span class=\"hljs-comment\"># Restore example<\/span>\nsudo systemctl stop jenkins\nsudo tar -xzf \/srv\/backups\/jenkins_home_YYYY-MM-DD.tar.gz -C \/\nsudo chown -R jenkins:jenkins \/<span class=\"hljs-keyword\">var<\/span>\/lib\/jenkins\nsudo systemctl start jenkins<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-7\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h2 class=\"wp-block-heading\">20 commonly used Jenkins plugins and what they are for<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Plugin<\/th><th>Typical use in CI\/CD<\/th><\/tr><\/thead><tbody><tr><td>Pipeline<\/td><td>Define CI\/CD logic as code<\/td><\/tr><tr><td>Git<\/td><td>Integrate Git repositories with jobs<\/td><\/tr><tr><td>GitHub<\/td><td>GitHub webhooks and metadata integration<\/td><\/tr><tr><td>GitLab<\/td><td>GitLab project and webhook integration<\/td><\/tr><tr><td>Credentials Binding<\/td><td>Inject secrets into build steps safely<\/td><\/tr><tr><td>SSH Agent<\/td><td>Use SSH keys during pipeline execution<\/td><\/tr><tr><td>Docker<\/td><td>Build and publish container images<\/td><\/tr><tr><td>Kubernetes<\/td><td>Dynamic Jenkins agents on Kubernetes<\/td><\/tr><tr><td>Blue Ocean<\/td><td>Visual pipeline interface<\/td><\/tr><tr><td>Job DSL<\/td><td>Create jobs programmatically<\/td><\/tr><tr><td>Configuration as Code<\/td><td>Manage Jenkins configuration declaratively<\/td><\/tr><tr><td>Email Extension<\/td><td>Customizable email notifications<\/td><\/tr><tr><td>Slack Notification<\/td><td>Send build and deployment events to Slack<\/td><\/tr><tr><td>JUnit<\/td><td>Publish and trend unit test reports<\/td><\/tr><tr><td>HTML Publisher<\/td><td>Publish generated HTML reports<\/td><\/tr><tr><td>Warnings Next Generation<\/td><td>Aggregate static analysis warnings<\/td><\/tr><tr><td>SonarQube Scanner<\/td><td>Run code quality scans from Jenkins<\/td><\/tr><tr><td>OWASP Dependency-Check<\/td><td>Dependency vulnerability scanning<\/td><\/tr><tr><td>Artifactory<\/td><td>Publish and consume build artifacts<\/td><\/tr><tr><td>Copy Artifact<\/td><td>Reuse artifacts from upstream jobs<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Best practices for interview answers<\/h2>\n\n\n\n<ul class=\"wp-block-list\"><li>Give concise definitions first, then explain with one real project example.<\/li><li>Prefer Pipeline-as-Code examples over only UI descriptions.<\/li><li>Mention security controls: credentials handling, RBAC, and audited changes.<\/li><li>When discussing backups, always include restore testing, not just backup creation.<\/li><li>Avoid claiming Jenkins is &#8220;best&#8221; universally; explain when managed CI may be a better fit.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Reference link retained from the original post: <a href=\"https:\/\/www.youtube.com\/watch?v=ZCfrNvu6nMc\">YouTube video<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>This revised guide turns common Jenkins interview prompts into practical answers you can explain with confidence. It covers CI fundamentals, API usage, setup on Ubuntu and RHEL-like systems, backup strategy, and key plugins.<\/p>\n","protected":false},"author":1,"featured_media":3399,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_joinchat":[],"footnotes":""},"categories":[52],"tags":[641,766,1558,1557,145,1554,1560,1555,1559,507,1556,1553,482,637],"class_list":["post-370","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-interview-questions-answers","tag-answers","tag-interview","tag-interview-questions-and-answers-of-jenkins","tag-interview-questions-of-jenkins","tag-jenkins","tag-jenkins-interview","tag-jenkins-interview-qa","tag-jenkins-interview-questions","tag-jenkins-interview-questions-and-answers","tag-list","tag-list-of-jenkins-interview-questions","tag-most-asked","tag-questions","tag-top"],"_links":{"self":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/370","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/comments?post=370"}],"version-history":[{"count":4,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/370\/revisions"}],"predecessor-version":[{"id":79245,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/370\/revisions\/79245"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/media\/3399"}],"wp:attachment":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/media?parent=370"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/categories?post=370"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/tags?post=370"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}