[Python] Ansible code fails when NVMe drive changes name after reboot or reinstallation

I am setting up my Proxmox cluster via Ansible, but I have a big problem with my NVMe drives changing names during reboot. So far I have lived with them changing names when I reinstall Proxmox, but having them also do so after reboot doesn't work, as my machines reboots after a kernel update. The problem occurs when setting up my Ceph cluster, which fails if the NVMe drive has changed its name. As far as I can read, I need to use the drive's UUID to ensure persistent naming, but I have no idea how to do that via Ansible.

Here is my Ansible code used to create Ceph OSDs.

Snippet from /inventory/host_vars/pxenode1/variables.yml:

# Configure Ceph OSDs
pve_ceph_osd_device: /dev/nvme0n1 # Device for the Ceph OSD.


Snippet from /inventory/group_vars/ceph/variables.yml:

pve_ceph_osds: # List of Ceph OSDs to create.
- device: "{{ pve_ceph_osd_device }}"
crush.device.class: NVMe


The following Ansible code is executed on all machines that are members of the Ceph inventory group.

- name: Create Ceph OSDs
block:
- name: Query for existing Ceph volumes
pve_ceph_volume:
check_mode: no
register: _ceph_volume_data

- name: Generate a list of active OSDs
ansible.builtin.set_fact:
_existing_ceph_osds: "{{ _ceph_volume_data.stdout | from_json | json_query('*[].devices[]') | default([]) }}"

- name: Generate list of unprovisioned OSDs
ansible.builtin.set_fact:
_ceph_osds_diff: "{{ _ceph_osds_diff | default([]) + [item] }}"
loop: "{{ pve_ceph_osds }}"
when: item.device not in _existing_ceph_osds

- name: Create Ceph OSDs
ansible.builtin.command: >-
pveceph osd create {{ item.device }}
{% if "crush.device.class" in item %}--crush-device-class {{ item["crush.device.class"] }}{% endif %}
{% if "encrypted" in item and item["encrypted"] | bool %}--encrypted 1{% endif %}
{% if "block.db" in item %}--db_dev {{ item["block.db"] }}{% endif %}
{% if "block.wal" in item %}--wal_dev {{ item["block.wal"] }}{% endif %}
loop: '{{ _ceph_osds_diff | default([]) }}'
when: _ceph_osds_diff | length > 0
register: _ceph_osd_create


From Ansible, a Python script is called which comes here:

#!/usr/bin/python

from ansible.module_utils.basic import AnsibleModule
import datetime

ANSIBLE_METADATA = {
'metadata_version': '1.0',
'status': ['preview'],
'supported_by': 'community'
}

DOCUMENTATION = '''
---
module: ceph_volume

short_description: Query ceph OSDs with ceph-volume

description:
- Using the ceph-volume utility available in Ceph this module
can be used to query ceph OSDs that are backed by logical volumes.
- Only available in ceph versions luminous or greater.

options:
cluster:
description:
- The ceph cluster name.
required: false
default: ceph
data:
description:
- The logical volume name or device to use for the OSD data.
required: true
data_vg:
description:
- If data is a lv, this must be the name of the volume group it belongs to.
required: false

author:
- Andrew Schoen (@andrewschoen)
- Sebastien Han <seb@redhat.com>
'''

EXAMPLES = '''
- name: query all osds
ceph_volume:

- name: query single osd on test cluster
ceph_volume:
cluster: test
data: /dev/sdc
'''

def exec_command(module, cmd, stdin=None):
'''
Execute command(s)
'''
binary_data = False
if stdin:
binary_data = True
rc, out, err = module.run_command(cmd, data=stdin, binary_data=binary_data)
return rc, cmd, out, err

def get_data(data, data_vg):
if data_vg:
data = '{0}/{1}'.format(data_vg, data)
return data


def list_osd(module):
'''
List will detect whether or not a device has Ceph LVM Metadata
'''

# get module variables
cluster = module.params['cluster']
data = module.params.get('data', None)
data_vg = module.params.get('data_vg', None)
data = get_data(data, data_vg)

# Build the CLI
action = ['lvm', 'list']
cmd = ['ceph-volume', '--cluster', cluster]
cmd.extend(action)
if data:
cmd.append(data)
cmd.append('--format=json')

return cmd


def run_module():
module_args = dict(
cluster=dict(type='str', required=False, default='ceph'),
data=dict(type='str', required=False),
data_vg=dict(type='str', required=False),
)

module = AnsibleModule(
argument_spec=module_args,
supports_check_mode=True,
)

result = dict(
changed=False,
stdout='',
stderr='',
rc=0,
start='',
end='',
delta='',
)

if module.check_mode:
module.exit_json(**result)

# start execution
startd = datetime.datetime.now()

# List Ceph LVM Metadata on a device
rc, cmd, out, err = exec_command(module, list_osd(module))

endd = datetime.datetime.now()
delta = endd - startd

result = dict(
cmd=cmd,
start=str(startd),
end=str(endd),
delta=str(delta),
rc=rc,
stdout=out.rstrip('\r\n'),
stderr=err.rstrip('\r\n'),
changed=False,
)

if rc != 0:
module.fail_json(msg='non-zero return code', **result)

module.exit_json(**result)


def main():
run_module()


if __name__ == '__main__':
main()


I haven't programmed the Python script nor the Ansible code myself and I have no idea about Python programming. I hope someone can help me, as this is really a showstopper in my project.

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