Add check that kube-master, kube-node and etcd groups are not empty.

[mgsergio]

This can save a lot of time debugging silly mistakes.

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[woopstar]

Please commit with github user and if so, sign the cla.

[mgsergio]

Please commit with github user and if so, sign the cla.

Done.

[woopstar]

Will this create any issues when you run playbooks like upgrade / scale and you limit to either masters, nodes or etcd's ?

[mgsergio]

Good question. I didn't think of it.
I'll check...

[mgsergio]

It works like a charm. ansible is clever enough to keep groups and other settings intact while using --limit. If to thing carefully it should behave this way because while limiting to some hosts you may still need group and host vars from others. Or you may need to delegate a task to another host. So ansible can't touch your inventory.

2018-09-20 16:52:08 mgserjio: tmp$ cat i.ini
[kube-master]
master1 ansible_host=127.0.0.1

[etcd]
etcd1 ansible_host=127.0.0.1

[kube-node]
node1 ansible_host=127.0.0.1
node2 ansible_host=127.0.0.1
node3 ansible_host=127.0.0.1
node4 ansible_host=127.0.0.1
node5 ansible_host=127.0.0.1

[k8s-cluster:children]
kube-master
kube-node
2018-09-20 16:52:21 mgserjio: tmp$ cat task.yml
- hosts: k8s-cluster
  connection: local

  tasks:
    - name: Stop if either kube-master, kube-node, etcd is empty
      assert:
        that: groups.get('{{ item }}')
      with_items:
        - kube-master
        - kube-node
        - etcd

- hosts: kube-node
  connection: local

  tasks:
    - name: Stop if either kube-master, kube-node, etcd is empty
      assert:
        that: groups.get('{{ item }}')
      with_items:
        - kube-master
        - kube-node
        - etcd
2018-09-20 16:52:27 mgserjio: tmp$ ansible-playbook -i i.ini task.yml --limit master1

PLAY [k8s-cluster] **********************************************************************************************************************************************************************

TASK [Gathering Facts] ******************************************************************************************************************************************************************
ok: [master1]

TASK [Stop if either kube-master, kube-node, etcd is empty] *****************************************************************************************************************************
ok: [master1] => (item=kube-master) => {
    "changed": false,
    "item": "kube-master",
    "msg": "All assertions passed"
}
ok: [master1] => (item=kube-node) => {
    "changed": false,
    "item": "kube-node",
    "msg": "All assertions passed"
}
ok: [master1] => (item=etcd) => {
    "changed": false,
    "item": "etcd",
    "msg": "All assertions passed"
}

PLAY [kube-node] ************************************************************************************************************************************************************************
skipping: no hosts matched

PLAY RECAP ******************************************************************************************************************************************************************************
master1                    : ok=2    changed=0    unreachable=0    failed=0

[mgsergio]

Would it be better to move some checks to earlier stages and perform on localhost?

[mgsergio]

PTAL

[Atoms]

ci check this

[Atoms]

/lgtm
/approve

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