Delegate via remote host

Archives Ansible Project
1

Is it possible to delegate a role/task to a remote hosts remote host? An example:

On a remote host (e.g. testserver) I have created a docker container. The containers IP is known on the testserver and he is accessible just from the testservers private docker network. Now I want to execute a role inside the testservers docker container. But without making the docker container public accessible. So I want to delegate the role execution via the remote testserver to the remote docker container.

Is this possible with Ansible? And if not, would that be a good feature?

Greetings - Thomas

2

Hi Thomas,

You have something called delgate_to to do this.

`

So basically if your playbook is running on a particular host (or set of hosts), above task will run on abc.server.com.

Regards,
Vikas

3

Hi Vikas,

delegate_to won’t do the trick, because it would delegate the role/tasks from the control machine to abc.server.com. Imagine abc.server.com is just visible within the private network of main.server.com which is accessible from the outside. So I want to delegate the role/tasks from my private laptop via main.server.com to the abc.server.com without delegate_to abc.server.com directly.

4

I have got the solution - port forwarding will do the trick. Here are the parts of my playbook:

`

tasks:

…

  • name: create client container
    sudo: yes
    docker:
    image: my_ssh_container
    name: test_container
    detach: False
    state: running

  • name: create connection string
    set_fact:
    connection_command: “ssh -p {{ ansible_ssh_port }} -f -N -L 3456:{{ docker_containers[0].NetworkSettings.IPAddress }}:22 {{ ansible_ssh_user}}@{{ ansible_ssh_host }}”

  • name: create local port forwarding to remote docker container
    command: “{{ connection_command }}”
    delegate_to: localhost

  • name: run roles inside the client container
    hosts: docker_container_tunnel

SET VARIABLE HERE!

roles:

  • { role: thomass.java }

  • name: quit ssh tunnel
    hosts: test.server.org
    tasks:

  • name: recreate connection string
    set_fact:
    connection_command: “ssh -p {{ ansible_ssh_port }} -f -N -L 3456:{{ docker_containers[0].NetworkSettings.IPAddress }}:22 {{ ansible_ssh_user}}@{{ ansible_ssh_host }}”

  • name: destroy local port forwarding to remote docker container
    command: “pkill -f "{{ connection_command }}"”
    delegate_to: localhost

`