Jenkins pipeline exception - Docker not found - docker

Question

I have created GKE cluster and install Jenkins on that cluster. Now i am running pipeline, i have Jenkinsfile created which is used to build DockerImage but when i am running the pipeline, it throws exception that Docker not found
1) Created GKE Cluster
2) Installed Jenkins
3) Added Docker hub credentials
4) Added access key for gitlab
Jenkinsfile:
stage('Build Docker Image') {
when {
branch 'master'
}
steps {
script {
echo 'Before docker run'
sh 'docker --version'
app = docker.build("sarab321/test-pipeline")
echo 'docker run successfully'
}
}
}
Please see the exception below
apiVersion: "v1"
kind: "Pod"
metadata:
annotations: {}
labels:
jenkins: "slave"
jenkins/cd-jenkins-slave: "true"
name: "default-d7qdb"
spec:
containers:
- args:
- "59c323186a77b4be015362977ec64e4838001b6d77c0f372bec7cda7cf93f9b2"
- "default-d7qdb"
env:
- name: "JENKINS_SECRET"
value: "59c323186a77b4be015362977ec64e4838001b6d77c0f372bec7cda7cf93f9b2"
- name: "JENKINS_TUNNEL"
value: "cd-jenkins-agent:50000"
- name: "JENKINS_AGENT_NAME"
value: "default-d7qdb"
- name: "JENKINS_NAME"
value: "default-d7qdb"
- name: "JENKINS_URL"
value: "http://cd-jenkins.default.svc.cluster.local:8080"
image: "jenkins/jnlp-slave:3.27-1"
imagePullPolicy: "IfNotPresent"
name: "jnlp"
resources:
limits:
memory: "512Mi"
cpu: "1"
requests:
memory: "256Mi"
cpu: "500m"
securityContext:
privileged: false
tty: false
volumeMounts:
- mountPath: "/var/run/docker.sock"
name: "volume-0"
readOnly: false
- mountPath: "/home/jenkins"
name: "workspace-volume"
readOnly: false
workingDir: "/home/jenkins"
nodeSelector: {}
restartPolicy: "Never"
serviceAccount: "default"
volumes:
- hostPath:
path: "/var/run/docker.sock"
name: "volume-0"
- emptyDir:
medium: ""
name: "workspace-volume"
docker version
/home/jenkins/workspace/TestPipeline_master#tmp/durable-5dd73d2b/script.sh: 1: /home/jenkins/workspace/TestPipeline_master#tmp/durable-5dd73d2b/script.sh: docker: not found

Answer 1

Doesn't look like docker is installed on your build agent, that's inside the container using the "jenkins/jnlp-slave:3.27-1" image. I have examples of how I've installed the docker CLI in the jenkins LTS image at: https://github.com/sudo-bmitch/jenkins-docker
That image includes the following steps to make the docker integration portable:
installs the Docker CLI
installs gosu (needed since the entrypoint will start as root)
configures the jenkins user to be a member of the docker group
includes an entrypoint that adjusts to docker GID to match that of the /var/run/docker.sock GID
The actual docker CLI install is performed in the following lines:
RUN curl -fsSL https://download.docker.com/linux/debian/gpg | apt-key add - \
&& add-apt-repository \
"deb [arch=amd64] https://download.docker.com/linux/debian \
$(lsb_release -cs) \
stable" \
&& apt-get update \
&& DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
docker-ce-cli${DOCKER_CLI_VERSION}
You can take the entrypoint.sh and Dockerfile, modify the base image (FROM) of the Dockerfile, and the original entrypoint script inside entrypoint.sh, to point to the jnlp-slave equivalents.