CODEWITHSUNDEEP
ansibleansible-2.x
cscan
cscan

Reputation: 3840

Ansible: removing hosts

I know that one can add host with the following task:

- name: Add new instance to host group
  add_host:
    hostname: '{{ item.public_ip }}'
    groupname: "tag_Name_api_production"
  with_items: ec2.instances

But I can't seem to find a way to remove a host from inventory. Is there any way to do this?

Upvotes: 15

Views: 17475

Answers (5)

Jack
Jack

Reputation: 6158

You can just stop the play for those hosts:

- name: Remove unwanted hosts from play_hosts
  meta: end_host
  when: unwanted

This assumes, of course, that the unwanted variable exists on all the hosts and is set properly.

Upvotes: 5

George Shuklin
George Shuklin

Reputation: 7867

I just got the same problem. I have tests which run converge for a given playbook (which I can't modify), and then I need to run the same playbook with smaller set of hosts in the group.

My solution is:

Let's say you have group target you want to make smaller.

  1. Put smallest number of hosts in the target group.
  2. Put additional hosts into target_addon group.
- hosts: target_addon
  tasks:
    - add_host:
        name: '{{ inventory_hostname }}'
        groups: [target]

- import_playbook: converge.yaml  # uses group `target` with added hosts

# Removing hosts added from target_addon group from group target by reloading inventory
- hosts: localhost
  tasks:
    - meta: refresh_inventory

- import_playbook: converge.yaml  # uses group `target` without added hosts

Upvotes: 0

wener
wener

Reputation: 7740

Can not removing hosts, but can choose to run on the new created group.

- name: kubectl
  hosts: localhost
  gather_facts: false

  tasks:
  - add_host:
      name: nextcloud
      ansible_connection: kubectl
      ansible_kubectl_context: cluster
      ansible_kubectl_namespace: default
      ansible_kubectl_pod: nextcloud-75fc7f5c6f-hxrq6
      groupname: "pods"

# only run on pods
- hosts: pods
  gather_facts: false
  tasks:
  - raw: pwd
    register: raw_result
  - debug:
      msg: "{{raw_result.stdout_lines[0]}}"

Upvotes: 2

slm
slm

Reputation: 16406

We typically do it like this in a playbook using multiple hosts: sections.

- hosts: auth:!ocp
  roles:
    - ntp-server

- hosts: all:!auth:!ocp
  roles:
    - ntp-client

This will remove the groups of hosts from consideration via the !group mechanism. Specifically here in the 1st block we're removing the !ocp group and in the 2nd we're removing both the !auth and !ocp groups.

References

Upvotes: 1

Nick Roz
Nick Roz

Reputation: 4230

Unfortunately, it seems, that you can't do this using Ansible 2. There is no such a module called remove_host or another one.

However, using Ansible 2 you can refresh your inventory mid-play:

- meta: refresh_inventory

Have a look at this question

Another idea might be to filter hosts beforehand. Try adding them to group, and then excluding this group in a play lately, e.g. :

- hosts: '!databases'

Upvotes: 9

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