Http: server gave HTTP response to HTTPS client

Using Jenkins
1

Hello,

I’m using Jenkins 2.466.
I’m trying to use Docker inside Pipeline with below code.

pipeline {
    agent any
	
    stages {
        stage ('build') {
            when {
                anyOf {
                    branch 'preprod'
                }
            }

            agent {
                docker {
                    image 'maven:3.9.8-eclipse-temurin-8'

                    // caching data on the agent between Pipeline runs.
                    args '-v $HOME/.m2:/root/.m2'

                    // Run the container on the node specified at the
                    // top-level of the Pipeline, in the same workspace,
                    // rather than on a new node entirely:
                    reuseNode true
                }
            }

            steps {
                sh 'mvn clean package'
            }
        }
	}
}

Jenkins setup:

In my company, Jenkins has not been set up as per the documentation, like, running a docker:dind image and referring that in the Jenkins’ container’s Envrionment variable.
--env DOCKER_HOST=tcp://docker:2376.

Instead, the Host Docker’s Unix socket is exposed. Like,

docker run -d --restart=always \
    -p 127.0.0.1:2376:2375 \
    -v /var/run/docker.sock:/var/run/docker.sock \
    alpine/socat \
    tcp-listen:2375,fork,reuseaddr unix-connect:/var/run/docker.sock

So, I tried to do the same setup in my local machine to do R&D and when running the Jenkins container, the only difference is, I added DOCKER_HOST environment variable --env DOCKER_HOST=tcp://172.17.0.2:2375 , where, “172.17.0.2” is the IP address of the “alpine/socat” container.

So final run command is,

docker run \
  --name jenkins-blueocean-2 \
  --restart=on-failure \
  --detach \
  --env DOCKER_HOST=tcp://172.17.0.2:2375 \
  --env DOCKER_CERT_PATH=/certs/client \
  --env DOCKER_TLS_VERIFY=1 \
  --publish 8088:8080 \
  --volume jenkins-data-2:/var/jenkins_home \
  --volume jenkins-docker-certs:/certs/client:ro \
  myjenkins-blueocean

This setup is only working fine when using “Docker Agent Templates” (Manage Jenkins → Clouds → New Cloud).and referring to those templates inside “label” in the pipeline.

But when I try to make use of Pipeline’s integrated Docker feature, with the above Pipeline code, I’m getting above mentioned error.

Please let me know how do I get this to working.

Thank you.