I'm trying to find if we have any options in setup or any combination of ansible modules to find the LVM / VG name if we give the mount point name as input to the playbook, please suggest if you have any options, as of now I can only see the only option in setup is to fetch the device name "device": "/dev/mapper/rhel-root", using the ansible_mounts.device. But to split the LV and VG name from the "/dev/mapper/rhel-root" is another challenge. Kindly suggest if any options.
2 Answers
This is actually possible since 2015 through the ansible_lvm facts returned by setup and part of the hardware subset.
To get a result, you need to run setup as root and the lvm utilities must be installed on the target.
You can make a quick test on your local machine (if relevant, adapt to whatever target where you have privilege escalation rights):
ansible localhost -b -m setup \
-a 'gather_subset=!all,!min,hardware' -a 'filter=ansible_lvm'
Here is an example output from the first test vm I could connect to:
localhost | SUCCESS => {
"ansible_facts": {
"ansible_lvm": {
"lvs": {
"docker_data": {
"size_g": "80.00",
"vg": "docker"
},
"root": {
"size_g": "16.45",
"vg": "system"
},
"swap": {
"size_g": "3.00",
"vg": "system"
}
},
"pvs": {
"/dev/sda2": {
"free_g": "0.05",
"size_g": "19.50",
"vg": "system"
},
"/dev/sdb": {
"free_g": "0",
"size_g": "80.00",
"vg": "docker"
}
},
"vgs": {
"docker": {
"free_g": "0",
"num_lvs": "1",
"num_pvs": "1",
"size_g": "80.00"
},
"system": {
"free_g": "0.05",
"num_lvs": "2",
"num_pvs": "1",
"size_g": "19.50"
}
}
}
},
"changed": false
}
This would be a very simple .yaml file, doing the same as what @Zeitounator suggested:
---
- name: detect lvm setup
setup:
filter: "ansible_lvm"
gather_subset: "!all,!min,hardware"
register: lvm_facts
- debug: var=lvm_facts
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