https://codeleading.com/article/11015806881/.

Remeber sshCommand remote, remote infos have identityFile. identityFile need be at insdie identity.

Don’t understand identity be keep. Only can be used inside identity

def getRemoteHost(ip, user) {
    def remote = [:]
    remote.name = ip
    remote.host = ip
    remote.user = user
    remote.identityFile = identity
    remote.port = 22
    remote.allowAnyHosts = true

    return remote
}

pipeline {
    agent any

    environment {
        ssh_ip = 'ooo.xxx.ooo.xxx'
        ssh_user = 'ubuntu'
        ssh_jenkins_key_uid = 'oooooooo-xxxx-xxxx-xxxx-oooooooooooo'
        
        // SSH_CREDS = credentials('oooooooo-xxxx-xxxx-xxxx-oooooooooooo')
    }
    
    stages {
        stage('ssh Command'){
            steps {
                withCredentials([sshUserPrivateKey(credentialsId: "${ssh_jenkins_key_uid}", keyFileVariable: 'identity')]) {
                    sshCommand remote: getRemoteHost(ssh_ip, ssh_user), command: "echo"  //在远程服务器执行echo命令
                }
                
            }
        }
        
        
    }
}

def runCommand(cmd) {
    def remote = [:]
    remote.name = "${ssh_ip}"
    remote.host = "${ssh_ip}"
    remote.user = "${ssh_user}"
    // remote.identityFile = identity
    remote.port = 22
    remote.allowAnyHosts = true
    
    withCredentials([sshUserPrivateKey(
        credentialsId: "${ssh_jenkins_key_uid}", 
        keyFileVariable: 'identity')]) 
    {
        remote.identityFile = identity
        sshCommand remote: remote, command: cmd
    }
}

pipeline {
    agent any

    environment {
        ssh_ip = 'ooo.xxx.ooo.xxx'
        ssh_user = 'ubuntu'
        ssh_jenkins_key_uid = 'oooooooo-xxxx-xxxx-xxxx-oooooooooooo'
        
        // SSH_CREDS = credentials('oooooooo-xxxx-xxxx-xxxx-oooooooooooo')
    }
    
    stages {
        stage('ssh Command') {
            steps {
                echo 'whoami start...'
                runCommand('whoami') 
                echo 'whoami success'
    		}
        }
    }
}