Docker Jenkins Blue Ocean can not run ssh scp in Pipeline

For me the key to understanding was that the Build-Executor named "Master" is the runtime "Agent" context for the blueocean jenkinsci FROM jenkinsci/blueocean image

In the Jenkinsfile saying agent { label 'master' } means run steps on Master, agent { label 'Dockerfile' } means run steps in the projects docker container.

You need a multi agent pipeline, so start with agent none and add an agent in each stage targeting its agent enviroment. in this case agent { label 'master' } to run ssh from the jenkinsci/blueocean container

Too obvious for anyone to explain ... !

You'll need the SSH Agent Plugin to create a credential, and copy in a private ssh key. It will give you an ID to use in your Jenkinsfile DSL script

pipeline {  agent none  stages {    stage('Hello Docker') {      agent { dockerfile {filename 'Dockerfile'}}      steps {        echo 'Hello Docker'      }    } stage('Make useful SSH connections') {        agent { label 'master' }        steps{             //Your in the in Master Container             sh 'hostname'             //In this working directory             sh 'pwd'             //You provide SSH credentails via the SSHagent              sshagent(credentials : ['<ID OF THE SSH AGENT CREDENTIAL>']) {             //Connect to hostip/s with ssh, run scripts, go wild!             sh 'ssh -o StrictHostKeyChecking=no user@hostip uptime'             //and SCP              sh 'scp ./source/filename user@hostip:/remotehost/target             }      }}

Jenkins nodes are controlled by the agent label, cool :)