etc_hosts

This role is used in a rootless and possibly dns void world to ensure any endpoints your deployment depends on resolve on the host. The resolution can be either /etc/hosts or via DNS. If the FQDN is unable to resolve, the task will fail. If the FQDN resolves, then the IPv4 will be checked to ensure it matches. If the match fails, the task will fail.

Requirements

This role is designed to be included with other roles.

Role Variables

Variable structure looks more complex then it needs to be, however this role was designed to work within a deployment framework and is following a general standard.

Variable Name	Variable TYPE	Location to define or override
etc_hosts	DICTIONARY	group_vars
etc_hosts_dep	LIST	playbook

group_vars/group_name

etc_hosts:
  ws-sips:
    fqdn: ws-sips.cluster.local
    ipv4: 192.68.241.207
  ws-coffee:
    fqdn: ws-coffee.cluster.local
    ipv4: 192.68.241.173

label Required, and is the key your etc_hosts_deps list from playbook vars will reference

fqdn Required, and is the fqdn portion of the endpoint you depend on

ipv4 Required, and is the ipv4 portion of the endpoint you depend on

Dependencies

None

Example Playbook

ansible-playbook -i <inventory file> <playbook name> -e "targets=<deploy targets>"

- hosts: "{{ targets }}"

  vars:
    etc_hosts_deps:
      - ws-sips
      - ws-coffee

  roles:
    - etc_hosts

Sample Task Outputs

Task where entries are found and match the expected IP

TASK [etc_hosts : check for any etc hosts dependencies] *********************************************************
ok: [localhost] => (item=ws-sips)
ok: [localhost] => (item=ws-coffee)

TASK [etc_hosts : validate ipv4 matches expected value] *********************************************************
skipping: [localhost] => (item=None) 
skipping: [localhost] => (item=None) 

Task where an entry does not resolve at all

TASK [etc_hosts : check for any etc hosts dependencies] *********************************************************
failed: [localhost] (item=ws-sips) => {
    "changed": false, 
    "item": "ws-sips"
}

MSG:

One or more supplied key could not be found in the database.

Task where entry resolves, but to a non-matching IP

TASK [etc_hosts : check for any etc hosts dependencies] *********************************************************
ok: [localhost] => (item=ws-sips)
ok: [localhost] => (item=ws-coffee)

TASK [etc_hosts : validate ipv4 matches expected value] *********************************************************
failed: [localhost] (item={'_ansible_parsed': True, 'changed': False, '_ansible_no_log': False, 'item': u'ws-sips', '_ansible_item_result': True, 'failed': False, u'invocation': {u'module_args': {u'fail_key': True, u'split': None, u'key': u'ws-sips.cluster.local', u'database': u'hosts'}}, u'ansible_facts': {u'getent_hosts': {u'192.68.241.208': [u'ws-sips.cluster.local']}}, '_ansible_ignore_errors': None}) => {
    "changed": false, 
    "item": {
        "ansible_facts": {
            "getent_hosts": {
                "192.68.241.208": [
                    "ws-sips.cluster.local"
                ]
            }
        }, 
        "changed": false, 
        "failed": false, 
        "invocation": {
            "module_args": {
                "database": "hosts", 
                "fail_key": true, 
                "key": "ws-sips.cluster.local", 
                "split": null
            }
        }, 
        "item": "ws-sips"
    }
}

MSG:

Entry IP mismatch ws-sips.cluster.local Expected 192.68.241.207 Received [u'192.68.241.208']

License

GNU General Public License v3.0

Author Information

Bob Boldin