81 lines
2.6 KiB
Markdown
81 lines
2.6 KiB
Markdown
# Jenkins Controller + Docker Agent (Docker Compose)
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This directory contains a minimal Jenkins setup running as Docker containers:
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- `jenkins-controller`: Jenkins UI + configuration (no builds should run here).
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- `jenkins-agent-docker`: inbound agent used for Docker-based pipelines (label: `docker-agent`).
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The goal is to keep the controller responsible for orchestration/configuration while all CI jobs run on the dedicated agent.
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## Prerequisites
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- Docker Engine installed on the host.
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- Docker Compose available as `docker compose`.
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- A host directory `/opt/shagram` (used by pipelines as a shared location for source code and deployment files).
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## Start Jenkins
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From the repository root:
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```bash
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cd infra/jenkins
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docker compose up -d
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docker compose ps
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```
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Jenkins UI will be available at:
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```text
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http://<server-ip>:8080
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```
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## Initial admin password
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Retrieve the initial password:
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```bash
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docker exec -it jenkins-controller \
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cat /var/jenkins_home/secrets/initialAdminPassword
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```
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## Disable builds on the controller
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To ensure builds do not run on the controller:
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1. Open Jenkins UI.
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2. Go to: `Manage Jenkins` → `Manage Nodes and Clouds`.
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3. Open: `Built-In Node` → `Configure`.
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4. Set **Number of executors** to `0`.
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5. Save.
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## Configure the inbound agent node
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Create a dedicated node for running pipelines:
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1. `Manage Jenkins` → `Manage Nodes and Clouds` → `New Node`.
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2. Set:
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- Node name: `docker-agent`
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- Type: `Permanent Agent`
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- Remote root directory: `/home/jenkins/agent`
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- Labels: `docker-agent` (must match your Jenkinsfile `agent { label ... }`)
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- Usage: “Only build jobs with label expressions matching this node”
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3. Save.
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After saving, open the agent page:
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- `Manage Nodes and Clouds` → `docker-agent`
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On that page Jenkins will show the inbound connection details, including the **secret** required by the inbound agent container.
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## Set agent secret in Compose
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Edit `infra/jenkins/compose.yaml` and replace the placeholder with the real secret value shown on the `docker-agent` node page:
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- `JENKINS_SECRET=PASTE_ME`
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Then restart only the agent container:
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```bash
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docker compose up -d --force-recreate jenkins-agent-docker
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docker logs -f jenkins-agent-docker
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```
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Verification:
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- In Jenkins UI, the node `docker-agent` should become **Online**.
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- Any pipeline using `agent { label 'docker-agent' }` should execute on this agent.
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## Security note
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The Docker agent mounts `/var/run/docker.sock`, which effectively grants high-level control over the Docker host.
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Use this setup only in trusted environments and limit access to Jenkins accordingly.
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