Installed Jenkins using helm

helm install --name jenkins -f values.yaml stable/jenkins

Jenkins Plugin Installed

- kubernetes:1.12.6
- workflow-job:2.31
- workflow-aggregator:2.5
- credentials-binding:1.16
- git:3.9.3
- docker:1.1.6

Defined Jenkins pipeline to build docker container

node {
    checkout scm

    def customImage = docker.build("my-image:${env.BUILD_ID}")

    customImage.inside {
        sh 'make test'
    }
}

Throws the error : docker not found