Complex host patterns

[Gonzalo Servat]

Hi All

When working with host patterns, is it possible to craft one that says "must be in group X *and* must be in either group Y, W and Z"?

e.g. host must be in group "webserver" but it *must* also be in either group dc1, dc2 or dc3.

I can see how to check that webserver is part of dc1 (webserver,&dc1) but not sure how to build it with multiple "OR" on the "AND" (something like "webserver,&(dc1,dc2,dc3)" is what I'm looking for but it doesn't work)

Cheers

Gonz

[Vladimir Botka]

There is an example in the doc (you posted the link).

    webservers:dbservers:&staging

    The above configuration means “all machines in the groups ‘webservers’ and ‘dbservers’ are to be managed if they are in the group ‘staging’ also, ...

[Gonzalo Servat]

Not quite. How about "all machines in the groups webservers and dbservers are to be managed only if they are part of staging OR qa"?

--
You received this message because you are subscribed to the Google Groups "Ansible Project" group.
To unsubscribe from this group and stop receiving emails from it, send an email to ansible-proje...@googlegroups.com.
To post to this group, send email to ansible...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/ansible-project/fd716817-e0a0-49f3-9be1-59a07fbf1887%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Kai Stian Olstad]

On Tuesday, 23 October 2018 08:24:37 CEST Gonzalo Servat wrote:
> Hi All
>
> When working with host patterns

> <https://docs.ansible.com/ansible/2.7/user_guide/intro_patterns.html>, is

> it possible to craft one that says "must be in group X *and* must be in
> either group Y, W and Z"?
>
> e.g. host must be in group "webserver" but it *must* also be in either
> group dc1, dc2 or dc3.
>
> I can see how to check that webserver is part of dc1 (webserver,&dc1) but
> not sure how to build it with multiple "OR" on the "AND" (something like
> "webserver,&(dc1,dc2,dc3)" is what I'm looking for but it doesn't work)

Put the dc1, dc2 and dc3 group in a group called dc and then you can use

webserver:&dc

--
Kai Stian Olstad

[flowerysong]

You're trying to do it backwards. Build the union of your other groups and do the intersection with webserver.

&webserver,dc1,dc2,dc3

[Gonzalo Servat]

Thanks, good suggestion. I suppose there's no way to say "must be webserver OR dbserver AND in (dc1 OR dc2 OR dc3)"?

- Gonz

[Gonzalo Servat]

On Wed, Oct 24, 2018 at 1:13 AM Kai Stian Olstad <ansible-pr...@olstad.com> wrote:

[..snip..] 

 
> I can see how to check that webserver is part of dc1 (webserver,&dc1) but
> not sure how to build it with multiple "OR" on the "AND" (something like
> "webserver,&(dc1,dc2,dc3)" is what I'm looking for but it doesn't work)

Put the dc1, dc2 and dc3 group in a group called dc and then you can use

  webserver:&dc

I'd like to be able to do this on the fly so creating a custom group like that is not ideal.

- Gonz

[flowerysong]

Not in a host pattern. no. If you can't do it in the inventory, you can do it with a dynamic group:

- hosts: localhost

  gather_facts: false

  tasks:

    - add_host:

        name: "{{ item }}"

        groups: target_hosts

      when: hostvars[item].group_names | intersect(['dc1', 'dc2', 'dc3'])

      loop: "{{ groups.webserver | union(groups.dbserver) }}"

- hosts: target_hosts

  tasks:

    - command: /bin/true

[Gonzalo Servat]

On Wed, Oct 24, 2018 at 12:17 PM flowerysong <ezek...@umich.edu> wrote:

Not in a host pattern. no. If you can't do it in the inventory, you can do it with a dynamic group:

- hosts: localhost

  gather_facts: false

  tasks:

    - add_host:

        name: "{{ item }}"

        groups: target_hosts

      when: hostvars[item].group_names | intersect(['dc1', 'dc2', 'dc3'])

      loop: "{{ groups.webserver | union(groups.dbserver) }}"

- hosts: target_hosts

  tasks:

    - command: /bin/true

Thanks for that! Very useful.

- Gonz