Some useful tips for running ansible playbook

[masharma]

This tips are more useful when developing the ansible code. Also if we use roles, many of them will work easily with import_role rather then include_role.

Skip to step 5 , if you are well versed on tags,always,never.

1) We can use tags to run a specific task from the playbook

$ cat example1.yaml

- name: Tags example
  hosts: localhost
  connection: local
  tasks:
   - name: tag example task1
     ansible.builtin.debug:
       msg: "Hello from task1"
     tags: task1
  
   - name: tag example task2
     ansible.builtin.debug:
       msg: "Hello from task2"
     tags: task2

Running only task1:

$ ansible-playbook example1.yaml -t task1

PLAY [Tags example] **********************************************************************************************************

TASK [Gathering Facts] *******************************************************************************************************
ok: [localhost.example.com]

TASK [tag example task1] *****************************************************************************************************
ok: [localhost.example.com] => {
"msg": "Hello from task1"
}

PLAY RECAP *******************************************************************************************************************
localhost.example.com : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0

Similarly we can run task2, by just calling the tag of task2

2) If we want to run any task always , even if we call other tags then we need to use always tag

$ cat example1.yaml

- name: Tags example
  hosts: localhost
  connection: local
  tasks:
   - name: tag example task1
     ansible.builtin.debug:
       msg: "Hello from task1"
     tags: [always,task1]
  
   - name: tag example task2
     ansible.builtin.debug:
       msg: "Hello from task2"
     tags: task2

I am calling task2 yet it will run task1 :

$ ansible-playbook example1.yaml -t task2

PLAY [Tags example] **********************************************************************************************************

TASK [Gathering Facts] *******************************************************************************************************
ok: [localhost.example.com]

TASK [tag example task1] *****************************************************************************************************
ok: [localhost.example.com] => {
    "msg": "Hello from task1"
}

TASK [tag example task2] *****************************************************************************************************
ok: [localhost.example.com] => {
    "msg": "Hello from task2"
}

PLAY RECAP *******************************************************************************************************************
localhost.example.com : ok=3    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   

3) If we don't want any task to run until we call it, then we can use never tag

$ cat example1.yaml

- name: Tags example
  hosts: localhost
  connection: local
  tasks:
   - name: tag example task1
     ansible.builtin.debug:
       msg: "Hello from task1"
     tags: [never,task1]
  
   - name: tag example task2
     ansible.builtin.debug:
       msg: "Hello from task2"
     tags: task2

Only task2 runs as task1 is not called:

$ ansible-playbook example1.yaml 

PLAY [Tags example] **********************************************************************************************************

TASK [Gathering Facts] *******************************************************************************************************
ok: [localhost.example.com]

TASK [tag example task2] *****************************************************************************************************
ok: [localhost.example.com] => {
    "msg": "Hello from task2"
}

PLAY RECAP *******************************************************************************************************************
localhost.example.com : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   

task1 runs as it is called

$ ansible-playbook example1.yaml -t task1

PLAY [Tags example] **********************************************************************************************************

TASK [Gathering Facts] *******************************************************************************************************
ok: [localhost.example.com]

TASK [tag example task1] *****************************************************************************************************
ok: [localhost.example.com] => {
    "msg": "Hello from task1"
}

PLAY RECAP *******************************************************************************************************************
localhost.example.com : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
 

4) If we want to skip any task during run then we can use "--skip-tags" option

$ cat example1.yaml

- name: Tags example
  hosts: localhost
  connection: local
  tasks:
   - name: tag example task1
     ansible.builtin.debug:
       msg: "Hello from task1"
     tags: [never,task1]
  
   - name: tag example task2
     ansible.builtin.debug:
       msg: "Hello from task2"
     tags: task2

Here it will not run anything as we are not calling never tag and also telling playbook to skip task2

$ ansible-playbook example1.yaml --skip-tags task2

PLAY [Tags example] **********************************************************************************************************

TASK [Gathering Facts] *******************************************************************************************************
ok: [localhost.example.com]

PLAY RECAP *******************************************************************************************************************
localhost.example.com : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   

You can explore more on this.

5) If we want to run the playbook for checking and not allow it to do any changes , sort of dry run, we can use "--check" option

$ cat example1.yaml

- name: More examples
  hosts: localhost
  connection: local
  become: true
  gather_facts: False
  tasks:
   - name: Stop a service 
     ansible.builtin.systemd_service:
       name: ollama.service
       state: stopped

Service is active:

$ systemctl is-active ollama
active

Running the playbook with "--check"

$ ansible-playbook example1.yaml -K --check
BECOME password:

PLAY [More examples] *********************************************************************************************************

TASK [Stop a service] ********************************************************************************************************
changed: [localhost.example.com]

PLAY RECAP *******************************************************************************************************************
localhost.example.com : ok=1 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0

Service is still active:

$ systemctl is-active ollama
active

Running the playbook without "--check":

$ ansible-playbook example1.yaml -K
BECOME password:

PLAY [More examples] *********************************************************************************************************

TASK [Stop a service] ********************************************************************************************************
changed: [localhost.example.com]

PLAY RECAP *******************************************************************************************************************
localhost.example.com : ok=1 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0

Service is now stopped:

$ systemctl is-active ollama
inactive

6) If we want ansible to ask us before running any task we can run the playbook with "--step" option:

$ cat example1.yaml

- name: More examples
  hosts: localhost
  connection: local
  tasks:
   - name: Print date and message
     ansible.builtin.debug:
       msg: "{{ ansible_date_time.date }} ***Merry Christmas***"

   - name: Run command
     ansible.builtin.shell: whoami

Running the playbook with "--step"

$ ansible-playbook example1.yaml --step

PLAY [More examples] *********************************************************************************************************
Perform task: TASK: Gathering Facts (N)o/(y)es/(c)ontinue: y

Perform task: TASK: Gathering Facts (N)o/(y)es/(c)ontinue: *******************************************************************

TASK [Gathering Facts] *******************************************************************************************************
ok: [localhost.example.com]
Perform task: TASK: Print date and message (N)o/(y)es/(c)ontinue: y

Perform task: TASK: Print date and message (N)o/(y)es/(c)ontinue: ************************************************************

TASK [Print date and message] ************************************************************************************************
ok: [localhost.example.com] => {
"msg": "2024-12-25 ***Merry Christmas***"
}
Perform task: TASK: Run command (N)o/(y)es/(c)ontinue: n

Perform task: TASK: Run command (N)o/(y)es/(c)ontinue: ***********************************************************************

PLAY RECAP *******************************************************************************************************************
localhost.example.com : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0

7) If we want to start at specific task of the playbook and proceed till end then we can use "--start-at-task" option

$ cat example1.yaml

- name: More examples
  hosts: localhost
  connection: local
  tasks:
   - name: Print date and message
     ansible.builtin.debug:
       msg: "{{ ansible_date_time.date }} ***Merry Christmas***"

   - name: Run command
     ansible.builtin.shell: whoami
     register: var1

   - name: Print var1
     ansible.builtin.debug:
        msg: "{{ var1.stdout_lines }}"

I want to run only the last 2 tasks:

$ ansible-playbook example1.yaml --start-at-task "Run command"

PLAY [More examples] *********************************************************************************************************

TASK [Gathering Facts] *******************************************************************************************************
ok: [localhost.example.com]

TASK [Run command] ***********************************************************************************************************
changed: [localhost.example.com]

TASK [Print var1] ************************************************************************************************************
ok: [localhost.example.com] => {
"msg": [
"masharma"
]
}

PLAY RECAP *******************************************************************************************************************
localhost.example.com : ok=3 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0

I would love to hear some more tips or suggestions on this.

Thank you!

[Trevor]

I just want to say thank you very much for these excellent tips!!!