Getting Ansible hosts from debug stdout

Hello people,
Please I am working on a ansible playbook to patch Linux cluster machines. The machines have hashicorp vault installed on them. So I am trying to do a micropatching such that only one node is patched and then rebooted rebooted at a time.
The playbook continues to the next machine only when the first node has been fully up, and the vault application status is validated.

Challenge I am having is that in vault cluster, one server is selected as the “leader” while others are followers. I need to patch the followers first, one after the other. Then patch the leader last.

To determine which is the leader or followers, I will run a command on one of the vault servers which will print all the machine in the cluster and their roles. as follows:
vault operator raft list-peers
Node Address State Voter

vault-001 vault-001.internal:8201 follower true
vault-002 vault-002.internal:8201 follower true
vault-003 vault-003.internal:8201 leader true

I can use grep command with shell module in the ansible playbook to filter out the workers but I don’t know how I can then pass the worker to the next play that will do the patching.
Please see my code below:

- name: Check Seal Status
  shell: vault status |grep Sealed
  become: yes
  become_user: ec2-user
  register: vault_status
- debug: msg="{{ vault_status.stdout_lines }}"
- debug: msg="Vault sealed"
  when: vault_status|regex_search("false")

# Checking the Vault followers
- name: Get followers
  shell: vault operator raft list-peers | grep follower|awk '{print $1}'
  become: yes
  become_user: ec2-user
  register: followers
- debug: msg="{{ followers.stdout_lines }}"

- set_fact:
    vault_followers: "{{followers.stdout}}"

- name: Patch the worker nodes
  hosts: "{{vault_followers}}"
    name: "*"
    state: latest
  register: follower_patched

The “Get followers” task provide the following result as expected:

TASK [vault_leader_check : Get followers] ********************************************************************changed: [vault-001]

TASK [vault_leader_check : debug] ****************************************************************************ok: [vault-001] => {
    "msg": [

Please note that I also have those two hosts in the ansible inventory. but I can not tell which is followers or leader that is why I had to run the command to first grep the followers then patch each of them one at a time first before the leader.

Please help to understand how I can then use the given hosts from the debug message “vault-001” and “vault-002” in the "patch worker

Hi @ollyonearth,

Since Ansible 2.2 you can use ansible_play_hosts or ansible_play_batch and sort it:

- hosts: "{{ ansible_play_hosts | sort() }}"

From ansible doc:

ansible_play_hosts is the full list of all hosts still active in the current play.

ansible_play_batch is available as a list of hostnames that are in scope for the current ‘batch’ of the play. The batch size is defined by serial , when not set it is equivalent to the whole play (making it the same as ansible_play_hosts ).

KodeKloud Support