finding a specific port on a list of servers

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1

HI,
I have a list of servers that only part of them are running port 9090.
I need to create two tasks, each should loop the server’s hostnames. the first task should define inside a register the first server hostname that was found running port 9090 , the second task should define in a register all server’s hostnames that are running port 9090. If no server is running port 9090 the tasks should fail

I have nc installed on the server and i thought about using a shell with the command "nc -zv {{ item}} 9090

But I don’t know how to filter the relevant answers

For example:
server1
server2

server3 running 9090

server4

server5 running 9090

  • The first task should include in a register server 3 or server 5 hostname
  • The second task should include in a register server 3 and server 5 hostname
2

Let’s assume (ha!) you’ve got a shell task that loops over a list of servers, and for any server with port 9090 open it prints “{{item}} running 9090” to its stdout. And that you register that to “fake” to match the code below.

---
- name: Working with registered data
  hosts: localhost
  gather_facts: no
  vars:
    fake:
      results:
        - item: server1
          stdout: ""
        - item: server2
          stdout: ""
        - item: server3
          stdout: "server3 running 9090\n"
        - item: server4
          stdout: ""
        - item: server5
          stdout: "server5 running 9090\n"
  tasks:
    - name: task1 pick the first server running 9090
      debug:
        msg: "{{ fake.results | selectattr('stdout', 'search', 'running 9090') | first }}"

    - name: task2 pick all servers running 9090
      debug:
        msg: "{{ fake.results | selectattr('stdout', 'search', 'running 9090') | map(attribute='item') }}"

That produces the following output:

TASK [task1 pick the first server running 9090] ********************************
task path: /home/utoddl/ansible/register-games.yml:19
ok: [localhost] => {
    "msg": "server3"
}

TASK [task2 pick all servers running 9090] *************************************
task path: /home/utoddl/ansible/register-games.yml:25
ok: [localhost] => {
    "msg": [
        "server3",
        "server5"
    ]
}
3

…except that first task should be

  • name: task1 pick the first server running 9090
    debug:
    msg: “{{ item.item }}”
    vars:
    item: “{{ fake.results | selectattr(‘stdout’, ‘search’, ‘running 9090’) | first }}”
4

… or

  • name: task1 pick the first server running 9090
    debug:
    msg: “{{ (fake.results | selectattr(‘stdout’, ‘search’, ‘running 9090’) | first).item }}”
5

The wait_for module can test for a given port.

  • name: Check if port 9090 is listening (times out in 3 secs per host)
    wait_for:
    port: 9090
    timeout: 3
    msg: “Timeout waiting for 9090 to respond”
    register: port_check
    ignore_errors: yes

Then you can look in port_check to see whether it succeeded.

Walter