Hetzner Cloud Plugin for Jenkins

The Hetzner cloud plugin enables Jenkins CI to schedule builds on dynamically provisioned VMs in Hetzner Cloud.

Installation

Installation from source

• Clone this git repository
• Build with maven mvn clean package
• Open your Jenkins instance in browser (as Jenkins administrator)
• Go to Manage Jenkins
• Go to Manage Plugins
• Click on Advanced tab
• Under Upload Plugin section, click on Choose file button and select target/hetzner-cloud.hpi file
• Jenkins server might require restart after plugin is installed

Configuration

Manual configuration

1. Create credentials for API token

From Dashboard => Manage Jenkins => Manage credentials => Global => Add credentials

2. Create cloud

From Dashboard => Manage Jenkins => Manage Nodes and Clouds => Configure Clouds => Add a new cloud

Choose Hetzner from dropdown menu

You can use Test Connection button to verify that token is valid and that plugin can use Hetzner API.

3. Define server templates

Scripted configuration

import cloud.dnation.jenkins.plugins.hetzner.*
import cloud.dnation.jenkins.plugins.hetzner.launcher.*

def cloudName = "hcloud-01"

def templates = [
        new HetznerServerTemplate("ubuntu20-cx21", "java", "name=ubuntu20-docker", "fsn1", "cx21"),
        new HetznerServerTemplate("ubuntu20-cx31", "java", "name=ubuntu20-docker", "fsn1", "cx31")
]

templates.each { it -> it.setConnector(new SshConnectorAsRoot("my-private-ssh-key")) }

def cloud = new HetznerCloud(cloudName, "hcloud-token", "10", templates)

def jenkins = Jenkins.get()

jenkins.clouds.remove(jenkins.clouds.getByName(cloudName))
jenkins.clouds.add(cloud)
jenkins.save()

Configuration as a code

Here is sample of CasC file

---
jenkins:
  clouds:
    - hetzner:
        name: "hcloud-01"
        credentialsId: "hcloud-api-token"
        instanceCapStr: "10"
        serverTemplates:
          - name: ubuntu2-cx21
            serverType: cx21
            remoteFs: /var/lib/jenkins
            location: fsn1
            image: name=jenkins
            labelStr: java
            numExecutors: 1
            connector:
              root:
                sshCredentialsId: 'ssh-private-key'
          - name: ubuntu2-cx31
            serverType: cx31
            remoteFs: /var/lib/jenkins
            location: fsn1
            image: name=jenkins
            labelStr: java
            numExecutors: 3
            connector:
              root:
                sshCredentialsId: 'ssh-private-key'
credentials:
  system:
    domainCredentials:
      - credentials:
          - string:
              scope: SYSTEM
              id: "hcloud-api-token"
              description: "Hetzner cloud API token"
              secret: "abcdefg12345678909876543212345678909876543234567"
          - basicSSHUserPrivateKey:
              scope: SYSTEM
              id: "ssh-private-key"
              username: "jenkins"
              privateKeySource:
                directEntry:
                  privateKey: |
                    -----BEGIN OPENSSH PRIVATE KEY-----
                    b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAABFwAAAAdzc2gtcn
                      ... truncated ...
                    baewZMKBL1QECTolAAAADHJrb3NlZ2lAbDQ4MAECAwQFBg==
                    -----END OPENSSH PRIVATE KEY-----

Server details

Plugin is able to report server details for any provisioned node

Create server image using Packer

It's possible to create images in Hetzner Cloud using Packer.

• Get Hashicorp Packer

• Create image template, see an example

• Build using packer build -force template.pkr.hcl You should see output similar to this (truncated):

   ==> Builds finished. The artifacts of successful builds are:
   --> hcloud.jenkins: A snapshot was created: 'ubuntu20-docker' (ID: 537465784)
  

Known limitations

• there is no known way of verifying SSH host keys on newly provisioned VMs
• modification of SSH credentials used to connect to VMs require manual removal of key from project's security settings. Plugin will automatically create new SSH key in project after it's removed.