Jenkins declarative pipeline ssh agent plugin

As noted, you should select a credential which does reference the right remote username, as seen in the SSH Agent Jenkins plugin:

node {  sshagent (credentials: ['deploy-dev']) {    sh 'ssh -o StrictHostKeyChecking=no -l cloudbees 192.168.1.106 uname -a'  }}

Plus, I would execute only one script which would have the all sequence of commands you want to execute remotely.

Well, so far this is the best way to do so, in-spite of repetition!

pipeline {  agent any  stages {      stage('Deploy') {          steps {             sshagent(['nginx-ec2']) {                 // some block                 sh "ssh -o StrictHostKeyChecking=no -l ubuntu <remote_ip> 'whoami'"                 sh "ssh -o StrictHostKeyChecking=no -l ubuntu <remote_ip> 'sudo apt update  && sudo apt install -y docker.io'"                 sh "ssh -o StrictHostKeyChecking=no -l ubuntu <remote_ip> 'sudo usermod -aG docker ubuntu'"                 sh "ssh -o StrictHostKeyChecking=no -l ubuntu <remote_ip> 'source .bashrc'"                 sh "ssh -o StrictHostKeyChecking=no -l ubuntu <remote_ip> 'docker run -d -nginx'"             }         }      }   }}