Test if a server is reachable from host and has port open with Ansible

Question

I want to test if the host I am provisioning can reach a specific server and connect to a specific TCP port. If it can't the playbook should fail.

How can I do that?

Answer 1

There is wait_for module for this.
To check that target.host can access remote.host:8080:

- hosts: target.host
  tasks:
    - wait_for: host=remote.host port=8080 timeout=1
    - debug: msg=ok

There are a lot of other examples in the documentation.

Answer 2

Using wait_for is fine, however it requires the service is actually running and gives a reply.

If you just like to check whether the port is open in your firewall, you can use curl.

- name: Check if host is reachable
  shell:
    cmd: "/usr/bin/curl --connect-timeout 10 --silent --show-error remote.host:8080"
    warn: no
    executable: /bin/bash 
  register: res
  failed_when: res.rc in [28] or res.stderr is search("No route to host")

When the port is open but service does not run you get an curl: (7) Failed connect to 10.192.147.224:27019; Connection refused" which you would consider as OK.

A connection blocked by firewall will return curl: (28) Connection timed out after 10001 milliseconds