[SOLVED] application not enabled on pool '.mgr'


New Member
Sep 2, 2023
Hello everyone.

I recently set up a 3 node cluster with Ceph storage. Since the cluster was already running with local storage, I tried a 'rolling' deployment of Ceph. Meaning I reinstalled Proxmox one node at a time, then re-add that node to the cluster, install Ceph, then gradually moved VM disks over.
This worked great and my cluster is now running all my VMs with Ceph.

However, it seems Ceph has created an .mgr pool that I don't know about. It is complaining that there is no application enabled on the pool

application not enabled on pool '.mgr'
use 'ceph osd pool application enable <pool-name> <app-name>', where <app-name> is 'cephfs', 'rbd', 'rgw', or freeform for custom applications.

What is this .mgr pool? Do I need to assign an application? Which one? Should I delete it? So many questions .

I have attached two screenshots. Hope someone can shed some light on this.



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Pools have to have an associated application before they can be used [1], in the case of the `.mgr` it should associated to the `mgr` application by default.

The `.mgr` pool is an internal Ceph pool, previously called `device_health_metrics` [2].

Did you upgrade from Ceph 16 to 17? Whats the output of `ceph osd pool ls detail`? What pool do you use for storing your data?

[1] https://docs.ceph.com/en/latest/rados/operations/pools/#associating-a-pool-with-an-application
[2] https://docs.ceph.com/en/quincy/mgr/index.html
Last edited:

Here is the output of ceph osd pool ls detail
root@pve1:~# ceph osd pool ls detail
pool 8 '.mgr' replicated size 3 min_size 2 crush_rule 0 object_hash rjenkins pg_num 1 pgp_num 1 autoscale_mode on last_change 1441 flags hashpspool stripe_width 0 pg_num_max 32 pg_num_min 1
pool 11 'vmdisks' replicated size 3 min_size 2 crush_rule 0 object_hash rjenkins pg_num 512 pgp_num 512 autoscale_mode on last_change 3349 lfor 0/0/2712 flags hashpspool,selfmanaged_snaps stripe_width 0 application rbd

I store the disks of my VMs on 'vmdisks'.

I did not upgrade from Ceph 16 to 17, this is a clean installation of Proxmox 8 and Ceph 17.2.6.

Enabling the mgr application on the .mgr was easy enough. So I guess we can close this thread :)

root@pve1:~# ceph osd pool application enable .mgr mgr
enabled application 'mgr' on pool '.mgr'

Thank you Maximiliano!


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