How to generate new Network UUID’s with Ansible
Okay some of you might have deployed linux vm’s from clone templates using ansible by way of the vmware_guest module.
Now everybody goes about it differently, and from what I read online…. It would seem that lots of people over complicate the generation of the UUID with over complicated code to generate the UUID.
At the end of the day all a UUID is….is JUST A “UNIQUE IDENTIFIER”. It serves no other function other than being another form of labelling the network interface on the vm. There is no need to over complicate the creation of a UUID. This is also provided you defined UUID’s on your deployments.
Why…would you want to do this? Well if you cloned from a template. The new clone with have the same network UUID on every new machine you create. Now this wont impact your infrastructure in anyway, other than you *might* get duplicate UUID warning at some point. However, it can be problematic when doing backups, restores, migrations, and monitoring in some cases.
Ansible Setup:
Role :
–
Note: This just runs the ‘uuidgen’ command on the linux vm and then registers the result into a variable that is passed to the next task.
– name: Generate new UUID
shell: uuidgen
register: new_uuid_result
– debug:
var: new_uuid_result
Note: This updates the network file on redhat and adds the UUID line with the newly generated UUID and shows a log of the new UUID that was added. This section will also be outlined in the file as managed by ansible
– name: Add New UUID to network config
blockinfile:
dest: /etc/sysconfig/network-scripts/ifcfg-ens192
insertafter: NAME=”ens192″
block: |
UUID=”{{ new_uuid_result[‘stdout‘] }}”
register: filecontents
– debug: msg=”{{ filecontents }}”
Ansible playbook run:
vi createnewUUID.yml
– hosts: all
gather_facts: no
roles:
– role: CreateNewNetworkUUID
Ansible playbook run:
Note: this run the role against all your hosts defined in inventory/DEV/hosts via ssh. You will need to know the root/pass for your ssh connection to be able to carry out the tasks.
Ansible playbook log:
SSH password:
PLAY [all] ****************************************************************************************************************************************************************************************************
TASK [CreateNewUUID : Generate new UUID] **********************************************************************************************************************************************************************
changed: [nicktestvm]
TASK [CreateNewUUID : debug] **********************************************************************************************************************************************************************************
ok: [nicktestvm] => {
“new_uuid_result“: {
“ansible_facts“: {
“discovered_interpreter_python“: “/usr/bin/python”
},
“changed”: true,
“cmd“: “uuidgen“,
“delta”: “0:00:00.010810”,
“end”: “2020-12-21 20:13:36.614154”,
“failed”: false,
“rc“: 0,
“start”: “2020-12-21 20:13:36.603344”,
“stderr”: “”,
“stderr_lines“: [],
“stdout“: “49242349-5168-4713-bcb6-a53840b2e1d6”,
“stdout_lines“: [
“49242349-5168-4713-bcb6-a53840b2e1d6”
]
}
}
TASK [CreateNewUUID : Add New UUID to network config] *********************************************************************************************************************************************************
changed: [nicktestvm]
TASK [CreateNewUUID : debug] **********************************************************************************************************************************************************************************
ok: [nicktestvm] => {
“new_uuid_result.stdout“: “49242349-5168-4713-bcb6-a53840b2e1d6”
}
PLAY RECAP ****************************************************************************************************************************************************************************************************
nicktestvm : ok=4 changed=2 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
Nicktestvm:
[root@nicktestvm ~]$ cat /etc/sysconfig/network-scripts/ifcfg-ens192
TYPE=”Ethernet”
PROXY_METHOD=”none”
BROWSER_ONLY=”no”
BOOTPROTO=”none”
DEFROUTE=”yes”
IPV4_FAILURE_FATAL=”no”
IPV6INIT=”yes”
IPV6_AUTOCONF=”yes”
IPV6_DEFROUTE=”yes”
IPV6_FAILURE_FATAL=”no”
IPV6_ADDR_GEN_MODE=”stable-privacy”
NAME=”ens192″
# BEGIN ANSIBLE MANAGED BLOCK
UUID=”49242349-5168-4713-bcb6-a53840b2e1d6″
# END ANSIBLE MANAGED BLOCK
DEVICE=”ens192″
ONBOOT=”yes”
IPADDR=”192.168.1.69″
PREFIX=”24″
GATEWAY=”192.168.1.254″
DNS1=”8.8.8.1″
DNS2=”8.8.8.2″
DOMAIN=”nicktailor.co.uk”
IPV6_PRIVACY=”no”