LVM SNAPSHOT CREATE FAILURE WITH LVM THIN POOL (NOT SPECIFYING SIZE)

[grtxghe]

Hi,

When trying to use the collection/role infra.lvm_snapshots.snapshot_create, it fails when there is lvm thin pool in the managed node. Snashot and rollback works fine with regular LVM but not when thin pool is used.

ANSIBLE IN USE: from RH-SAT 6.15
RH-SATELLITE: ANSIBLE JOB TEMPLATE
ANSIBLE VERSION: ansible-core-2.16.3-2.el8.x86_64
ANSIBLE COLLECTIONS :

# /etc/ansible/collections/ansible_collections
Collection                  Version
--------------------------- -------
ansible.posix               1.5.4
community.general           9.2.0
infra.lvm_snapshots         2.1.0

TASK [ansible.builtin.debug] ***************************************************
ok: [examplecustomer19.ar.custy] => {
    "msg": [
        "INFO: OPERATING PARAMETERS",
        "---------------------------------",
        "INFO: TGT CONTENT HOST RHEL OS     : '8'",
        "INFO: TGT CONTENT HOST HOSTNAME    : 'examplecustomer19'",
        "INFO: TGT CONTENT HOST FQDN        : 'examplecustomer19.ar.custy'",
        "---------------------------------",
        "INFO: TGT RHSM-ENVIRONMENT         : 'DESA/S-RHEL-8'",
        "INFO: TGT PATCHING COMMAND         : '/usr/bin/dnf install sos'",
        "---------------------------------",
        "INFO: TGT AT TASK UNIT             : 'minutes'",
        "INFO: TGT AT TASK COUNT            : '8'",
        "---------------------------------",
        "INFO: TGT LVM SNAP NAME PREFIX     : 'xcustomer_pse'",
        "INFO: TGT LVM SNAP NAME TIMESTAMP  : '2024090412'",
        "INFO: TGT LVM SNAP SET NAME        : 'xcustomer_pse2024090412'",
        "INFO: TGT LVM SNAP CREATE BOOT BKP : 'True'",
        "---------------------------------",
        "INFO: TGT LVM SNAP CREATE AUTOEXTEND PCENT  : '20'",
        "INFO: TGT LVM SNAP CREATE AUTOEXTEND TSHOLD : '70'",
        "---------------------------------",
        "INFO: TGT LVM VGs/LVs:",
        [
            {
                "lv": "lv_root",
                "vg": "vg00"
            },
            {
                "lv": "lv_var",
                "vg": "vg00"
           },
            {
                "lv": "lv_opt",
                "vg": "vg00"
            }
        ],
        "---------------------------------",
        "INFO: TGT LVM LVs COUNT : '3'"
    ]
}


```=> DEBUG ADDED TO COLLECTIONS:
TASK [infra.lvm_snapshots.snapshot_create : ansible.builtin.debug] *************
ok: [examplecustomer19.ar.custy] => {
    "msg": [
        "-------------------------",
        {
            "changed": false,
            "failed": false,
            "failed_when_result": false,
            "rc": 0,
            "stderr": "Shared connection to 166.47.102.53 closed.\r\n",
            "stderr_lines": [
                "Shared connection to 166.47.102.53 closed."
            ],
            "stdout": "[{\"vg\": \"vg00\", \"lv\": \"lv_root\", \"size\": \"0.0B\"}, {\"vg\": \"vg00\", \"lv\": \"lv_var\", \"size\": \"0.0B\"}, {\"vg\": \"vg00\", \"lv\": \"lv_opt\", \"size\": \"0.0B\"}]\r\n",
            "stdout_lines": [
                "[{\"vg\": \"vg00\", \"lv\": \"lv_root\", \"size\": \"0.0B\"}, {\"vg\": \"vg00\", \"lv\": \"lv_var\", \"size\": \"0.0B\"}, {\"vg\": \"vg00\", \"lv\": \"lv_opt\", \"size\": \"0.0B\"}]"
            ]
        },
        "-------------------------"
    ]
}

=> COLLECTIONS FAILS FOR THINPOOL LVM WITH NO SIZE:

TASK [infra.lvm_snapshots.snapshot_create : Create snapshots] ******************
failed: [examplecustomer19.ar.custy] (item={'vg': 'vg00', 'lv': 'lv_root', 'size': '0.0B'}) => {"ansible_loop_var": "item", "changed": false, "err": "  --size may not be zero.\n  Run `lvcreate --help' for more information.\n", "item": {"lv": "lv_root", "size": "0.0B", "vg": "vg00"}, "msg": "Creating logical volume 'lv_root' failed", "rc": 3}
failed: [examplecustomer19.ar.custy] (item={'vg': 'vg00', 'lv': 'lv_var', 'size': '0.0B'}) => {"ansible_loop_var": "item", "changed": false, "err": "  --size may not be zero.\n  Run `lvcreate --help' for more information.\n", "item": {"lv": "lv_var", "size": "0.0B", "vg": "vg00"}, "msg": "Creating logical volume 'lv_var' failed", "rc": 3}
failed: [examplecustomer19.ar.custy] (item={'vg': 'vg00', 'lv': 'lv_opt', 'size': '0.0B'}) => {"ansible_loop_var": "item", "changed": false, "err": "  --size may not be zero.\n  Run `lvcreate --help' for more information.\n", "item": {"lv": "lv_opt", "size": "0.0B", "vg": "vg00"}, "msg": "Creating logical volume 'lv_opt' failed", "rc": 3}
PLAY RECAP *********************************************************************
examplecustomer19.ar.custy      : ok=46   changed=8    unreachable=0    failed=1    skipped=3    rescued=0    ignored=0
Exit status: 2
StandardError: Job execution failed

ERROR: --size may not be zero.\n Run `lvcreate --help' for more information.\n"
From DOCs: https://github.com/redhat-cop/infra.lvm_snapshots/tree/main/roles/snapshot_create#size
The size of the logical volume according to the definition of the size parameter of the community.general.lvol module.
To create thin provisioned snapshot of a thin provisioned volume, omit the size parameter or set it to 0

[grtxghe]

Additional Information:

• Not specifying size for the lvol (as in documentation) results in collection error with lvol module that size is required.
• Also Not specifying size AND also patching the collection's lvol task to not include the size parameter results in collection creating the snasphots. BUT those snapshots fail to rollback due to lvs not being active.

[grtxghe]

ORIGINAL:

- name: Create snapshots
  community.general.lvol:
    vg: "{{ item.vg }}"
    lv: "{{ item.lv }}"
    snapshot: "{{ item.lv }}_{{ snapshot_create_set_name }}"
    size: "{{ item.size | default(omit) }}"
  loop: "{{ snapshot_create_volumes }}"

MODIFICATION:

- name: Create snapshots
  community.general.lvol:
    vg: "{{ item.vg }}"
    lv: "{{ item.lv }}"
    snapshot: "{{ item.lv }}_{{ snapshot_create_set_name }}"
  loop: "{{ snapshot_create_volumes }}"

[grtxghe]

If using the modified task 'Create snapshots':

TASK [infra.lvm_snapshots.snapshot_revert : Verify that the snapshot is active] ***
fatal: [lvmtest5.example.com]: FAILED! => {
    "assertion": "snapshot_revert_lv_attr[0] == 's'",
    "changed": false,
    "evaluated_to": false,
    "msg": "Assertion failed"
}

Rollback will fail.