Question 179243 in Nginx Question posted in
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Can Nginx & ansible-playbook use jinja2 for hosts?

ansible-playbook hosts can not use jinja2 for matching more hosts

when i need to install more same service in one host in test env, i write a group like this

[nginx]
demo-region-nginx-1:22 ansible_ssh_host=10.0.0.1 port=80
demo-region-nginx-2:22 ansible_ssh_host=10.0.0.1 port=81
demo-region-nginx-3:22 ansible_ssh_host=10.0.0.1 port=82

my playbook like this

- hosts: "demo-region-nginx-{{ num }}"
  remote_user: root
  roles:
    - role: upgrade_nginx

amosttime just setup a "num" when i want to upgrade one nginx, this is easy, if i upgrade nginx-1 and nginx-3, i must be execute multiple times playbook.

In the future, i will have many such service, I must by setup more variable
,so i use jinja2 to filter the hosts, i think jinja2 can fix my problem, but it seems like error, the playbook like this

- hosts: "{% for num in {{ awx_num }} %}demo-region-nginx-{{ num }}{% endfor %}"
  remote_user: root
  roles:
    - role: upgrade_nginx

this is error log

ERROR! template error while templating string: expected token ':', got '}'. String: {% for num in {{ awx_num }} %}demo-region-nginx-{{ num }}{% endfor %}. expected token ':', got '}'

someone know how to fix this error?

Tags:

2

Answers


  1. 0

    You dont need to set variables between brackets inside jinja expression on the for:

    - hosts: "{% for num in awx_num %}demo-region-nginx-{{ num }}{% endfor %}"
  remote_user: root
  roles:
    - role: upgrade_nginx
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  2. 0

    You are reinventing the wheel and making your life complicated. ansible(-playbook) has a limit option that does exactly what you want.

    Given your above inventory and the dummy playbook:

    - name: Dummy PB to illustrate limit
  hosts: nginx
  gather_facts: false
  
  tasks:
    - ansible.builtin.debug:
        var: inventory_hostname

    Here are some example commands making use of patterns for the limit argument and their results:

    $ ansible-playbook -i inventory.ini dummy.yml

PLAY [Dummy PB to illustrate limit] *****************************************************************************************************************************************

TASK [ansible.builtin.debug] ************************************************************************************************************************************************
ok: [demo-region-nginx-1] => {
    "inventory_hostname": "demo-region-nginx-1"
}
ok: [demo-region-nginx-2] => {
    "inventory_hostname": "demo-region-nginx-2"
}
ok: [demo-region-nginx-3] => {
    "inventory_hostname": "demo-region-nginx-3"
}

PLAY RECAP ******************************************************************************************************************************************************************
demo-region-nginx-1        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
demo-region-nginx-2        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
demo-region-nginx-3        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   


$ ansible-playbook -i inventory.ini dummy.yml -l demo-region-nginx-1

PLAY [Dummy PB to illustrate limit] *****************************************************************************************************************************************

TASK [ansible.builtin.debug] ************************************************************************************************************************************************
ok: [demo-region-nginx-1] => {
    "inventory_hostname": "demo-region-nginx-1"
}

PLAY RECAP ******************************************************************************************************************************************************************
demo-region-nginx-1        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   


$ ansible-playbook -i inventory.ini dummy.yml -l '!demo-region-nginx-1'

PLAY [Dummy PB to illustrate limit] *****************************************************************************************************************************************

TASK [ansible.builtin.debug] ************************************************************************************************************************************************
ok: [demo-region-nginx-2] => {
    "inventory_hostname": "demo-region-nginx-2"
}
ok: [demo-region-nginx-3] => {
    "inventory_hostname": "demo-region-nginx-3"
}

PLAY RECAP ******************************************************************************************************************************************************************
demo-region-nginx-2        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
demo-region-nginx-3        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   


$ ansible-playbook -i inventory.ini dummy.yml -l 'nginx[0]'

PLAY [Dummy PB to illustrate limit] *****************************************************************************************************************************************

TASK [ansible.builtin.debug] ************************************************************************************************************************************************
ok: [demo-region-nginx-1] => {
    "inventory_hostname": "demo-region-nginx-1"
}

PLAY RECAP ******************************************************************************************************************************************************************
demo-region-nginx-1        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   


$ ansible-playbook -i inventory.ini dummy.yml -l '!nginx[0]'

PLAY [Dummy PB to illustrate limit] *****************************************************************************************************************************************

TASK [ansible.builtin.debug] ************************************************************************************************************************************************
ok: [demo-region-nginx-2] => {
    "inventory_hostname": "demo-region-nginx-2"
}
ok: [demo-region-nginx-3] => {
    "inventory_hostname": "demo-region-nginx-3"
}

PLAY RECAP ******************************************************************************************************************************************************************
demo-region-nginx-2        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
demo-region-nginx-3        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   


$ ansible-playbook -i inventory.ini dummy.yml -l 'nginx[1:]'

PLAY [Dummy PB to illustrate limit] *****************************************************************************************************************************************

TASK [ansible.builtin.debug] ************************************************************************************************************************************************
ok: [demo-region-nginx-2] => {
    "inventory_hostname": "demo-region-nginx-2"
}
ok: [demo-region-nginx-3] => {
    "inventory_hostname": "demo-region-nginx-3"
}

PLAY RECAP ******************************************************************************************************************************************************************
demo-region-nginx-2        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
demo-region-nginx-3        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   


$ ansible-playbook -i inventory.ini dummy.yml -l '!nginx[1:]'

PLAY [Dummy PB to illustrate limit] *****************************************************************************************************************************************

TASK [ansible.builtin.debug] ************************************************************************************************************************************************
ok: [demo-region-nginx-1] => {
    "inventory_hostname": "demo-region-nginx-1"
}

PLAY RECAP ******************************************************************************************************************************************************************
demo-region-nginx-1        : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
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