Dynamically selecting the docker image for a downstream Pipeline using Kubernetes Pod Templates

Issue

I would like to trigger a downstream Pipeline build, and I would like to pass a parameter to that build to specify which Docker image to use in the Kubernetes Pod Template for the agent.
One use case for this would be when I build and push a new tag of a Docker image in an upstream build, and I want to use that new image in a downstream Pipeline.

Environment

Resolution

In your upstream Pipeline, trigger the downstream Pipeline using the build step:

build job: 'downstream', parameters: [string(name: 'IMAGE', value: 'ubuntu:18.04')]

In the Jenkinsfile of your ‘downstream’ Pipeline job, use code similar to:

pipeline {
    parameters {
        string defaultValue: 'ubuntu:latest', description: 'Docker image and tag to use', name: 'IMAGE', trim: true
    }
    agent {
        kubernetes {
            yaml """
apiVersion: v1
kind: Pod
spec:
  containers:
  - name: shell
    image: $IMAGE
    command:
    - sleep
    args:
    - infinity
"""
            defaultContainer 'shell'
        }
    }
    stages {
        stage('Main') {
            steps {
                sh 'cat /etc/os-release'
            }
        }
    }
}

The important points in this code are:

If the ‘downstream’ build is run with the default parameters, you would see:

...
Pipeline] {
[Pipeline] container
[Pipeline] {
[Pipeline] stage
[Pipeline] { (Main)
[Pipeline] sh
+ cat /etc/os-release
NAME="Ubuntu"
VERSION="20.04.1 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.1 LTS"
VERSION_ID="20.04"
...

If the ‘downstream’ build is triggered with build job: 'downstream', parameters: [string(name: 'IMAGE', value: 'ubuntu:18.04')] you would see this in the console output of the build:

...
[Pipeline] {
[Pipeline] container
[Pipeline] {
[Pipeline] stage
[Pipeline] { (Main)
[Pipeline] sh
+ cat /etc/os-release
NAME="Ubuntu"
VERSION="18.04.5 LTS (Bionic Beaver)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 18.04.5 LTS"
VERSION_ID="18.04"
...

Tested product/plugin versions

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