Wrong Ceph osd disk selection

asked 2019-01-21 11:35:58 -0500

eperezf gravatar image

updated 2019-01-22 09:00:47 -0500


I'm fairly new to OpenStack so sorry If i make any beginner mistakes. I've managed to deploy a full OpenStack environment using Juju. I have 10 servers with 2 drives each. It's set up so the volumes for the VMs are stored in /dev/sdb. In Juju, ceph-osd configuration osd-devices is /dev/sdb.

My problem is that when entering into Horizon, in the admin->compute->hypervisor section, the "Local storage" indicated in each server is the one of /dev/sda, not /dev/sdb, which is used as storage for the VMs. I logged in via ssh to one of my servers and /dev/sdb has a partition called ceph--c231ecf6--6a79--4f99--99dc--01429c2cca2e-osd--block--c231ecf6--6a79--4f99--99dc--01429c2cca2e so I guess at least it initialized it.

/dev/sdb starts unmounted and without format in MAAS but shows available. Should I format it first ad xfs and mount it first before deploying?

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Although I use both OpenStack (but not Juju) and Ceph I really don't understand your setup. The partition label indicates that the device /dev/sdb will be used as an OSD within a ceph cluster. Are you trying to build VMs to create a ceph cluster? Or is /dev/sdb supposed to be used as disk for VMs?

eblock gravatar imageeblock ( 2019-01-22 05:25:59 -0500 )edit

Please help me understand what exactly you're trying to achieve and update your question.

eblock gravatar imageeblock ( 2019-01-22 05:26:46 -0500 )edit

Sorry, english is not my first language so my writing may be a bit confusing. I have updated my question.

eperezf gravatar imageeperezf ( 2019-01-22 09:02:06 -0500 )edit

A Nova instance can use the compute node's local storage, often under /var/lib/nova/instances. This is called ephemeral storage, and this is what the hypervisor section in Horizon reports.

An instance can also use a volume as root filesystem. Volumes are managed by Cinder, not Nova.

Bernd Bausch gravatar imageBernd Bausch ( 2019-01-22 18:13:12 -0500 )edit

In short, the information on the hypervisor page is correct. It is not supposed to show /dev/sdb, since /dev/sdb isn't managed by the compute service.

See also https://docs.openstack.org/nova/rocky....

I don't know if any Ceph setup is required after Juju deployment.

Bernd Bausch gravatar imageBernd Bausch ( 2019-01-22 18:19:29 -0500 )edit