How to detect UNREACHABLE HOSTS in Ansible

Question

Below is my playbook

- name: Play 1.5 - Check each target
  hosts: all_hosts
  ignore_unreachable: yes
  ignore_errors: yes
  gather_facts: true

  tasks:

   - raw: "echo {{ inventory_hostname }} is UNREACHABLE"
     delegate_to: localhost
     when: <Need help with the when condition here>

I need help with the when condition in the above playbook.

When i run the play against unreachable hosts the debug output clearly shows that the output is in JSON format and there must a variable that captures inventory_host connection status

Please see the output below:

TASK [Gathering Facts] *************************************************************************************************************************************************
task path: /app/Ansible/playbook/check/check.yml:55
<10.9.80.111> Attempting python interpreter discovery
<10.9.80.111> ESTABLISH SSH CONNECTION FOR USER: root
<10.9.80.111> SSH: EXEC ssh -o 'IdentityFile="/app/automation/ssh_keys/id_rsa"' -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o 'User="root"' -o ConnectTimeout=10 -o StrictHostKeyChecking=no 10.9.80.111 '/bin/sh -c '"'"'echo PLATFORM; uname; echo FOUND; command -v '"'"'"'"'"'"'"'"'/usr/bin/python'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python3.7'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python3.6'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python3.5'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python2.7'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python2.6'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'/usr/libexec/platform-python'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'/usr/bin/python3'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python'"'"'"'"'"'"'"'"'; echo ENDFOUND && sleep 0'"'"''
<10.9.80.111> (255, '', 'ssh: connect to host 10.9.80.111 port 22: Connection timed out\r\n')
[WARNING]: Unhandled error in Python interpreter discovery for host 10.9.80.111: Failed to connect to the host via ssh: ssh: connect to host 10.9.80.111 port 22:
Connection timed out

Using module file /usr/lib/python2.7/site-packages/ansible/modules/system/setup.py
Pipelining is enabled.
<10.9.80.111> ESTABLISH SSH CONNECTION FOR USER: root
<10.9.80.111> SSH: EXEC ssh -o 'IdentityFile="/app/axmw/misc_automation/ssh_keys/axmw_id_rsa"' -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o 'User="root"' -o ConnectTimeout=10 -o StrictHostKeyChecking=no 10.9.80.111 '/bin/sh -c '"'"'/usr/bin/python && sleep 0'"'"''
fatal: [10.9.80.111]: UNREACHABLE! => {
    "changed": false,
    "msg": "Data could not be sent to remote host \"10.9.80.111\". Make sure this host can be reached over ssh: ssh: connect to host 10.9.80.111 port 22: Connection timed out\r\n",
    "skip_reason": "Host 10.9.80.111 is unreachable",
    "unreachable": true
}
META: ran handlers 

From the output above i want to get the variable that has the below values:

fatal: [10.9.80.111]: UNREACHABLE! => {
    "changed": false,
    "msg": "Data could not be sent to remote host \"10.9.80.111\". Make sure this host can be reached over ssh: ssh: connect to host 10.9.80.111 port 22: Connection timed out\r\n",
    "skip_reason": "Host 10.9.80.111 is unreachable",
    "unreachable": true

Thus, I wish to capture the unreachable": true status from there.

Can someone please guide ?

Answer 1

you can use changed_when , when the changed is false, get the unreachable host

- name: Test connection and gather facts
  hosts: all
  serial: 1
  gather_facts: true
  ignore_unreachable: yes
  become: false
  tasks:

  - name: Test connection
    shell: hostname
    register: connection_output
    ignore_unreachable: yes

  - debug: var=connection_output.changed
    ignore_errors: yes



  - name: print the list of unreachable servers
    lineinfile:
      line: "{{ connection_output.msg }}"
      dest: "/tmp/AnsibleConnectionCheck.txt"
      insertafter: EOF
    become: false
    delegate_to: 127.0.0.1
    run_once: true
    ignore_errors: yes
    changed_when: False

Today I just finished this playbook :) Hope it will helpful for you!

Answer 2

Thank you so much Yvette Lau! I've been looking for this everywhere. Here is my implementation of the same logic with win_ping:

---

- hosts: all
  gather_facts: no
  become: yes

  tasks:

  - name: Win_Ping
    win_ping:
    register: WinPingResult
    ignore_unreachable: yes

  - debug: var=WinPingResult.changed
    ignore_errors: yes

  - name: Printing errors
    debug:
      msg: "{{ WinPingResult.msg }}"
    run_once: yes
    changed_when: False