¿How to configure an Agent jenkins/inbound-agent with docker installed?

@Miguel_Angel have you considered using kubernetes agent which launches a pod (with jnlp embedded into it as a container in addition to actual job container).

Here is a sample Jenkinsfile (created from my existing pipeline, not tested)

FIle: Jenkinsfile

pipeline {

  agent {
    kubernetes {
      yamlFile 'build-agent.yaml'
      defaultContainer 'alpine'
      idleMinutes 1
    }
  }
  stages {
    stage('Sample Stage') {
      parallel {
        stage('this runs in a pod') {
          steps {
            container('alpine') {
              sh 'uptime'
            }
          }
        }
      }
    }
    }
}

If you use configure above you would also have to add build agent config in its own file. For example,

file : build-agent.yaml

apiVersion: v1
kind: Pod
metadata:
  labels:
    app: xyz
spec:
  containers:
    - name: alpine
      image: alpine
      command:
        - cat
      tty: true

Let me know if this could help.