Add note re nova and cinder for migrating to ceph-mon

Closes-Bug: #1776780

Change-Id: Ib97a1c81c09c69c501c3c999726fea8eff34e60d
This commit is contained in:
Peter Matulis 2019-11-08 18:02:57 -05:00
parent c74ce0fbdf
commit c6b135270d
1 changed files with 16 additions and 0 deletions

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@ -22,6 +22,21 @@ guidance.
Deploy ceph-mon
~~~~~~~~~~~~~~~
.. warning::
Every new ceph-mon unit introduced will result in a Ceph monitor receiving a
new IP address. However, due to an issue in Nova, this fact is not
propagated completely throughout the cloud under certain circumstances,
thereby affecting Ceph RBD volume reachability.
Any instances previously deployed using Cinder to interface with Ceph, or
using Nova's ``libvirt-image-backend=rbd`` setting will require a manual
database update to change to the new addresses. For Cinder, its stale data
will also need to be updated in the 'block_device_mapping' table.
Failure to do this can result in instances being unable to start as their
volumes cannot be reached. See bug `LP #1452641`_.
First deploy the ceph-mon charm; if the existing ceph charm is deployed to machines
0, 1 and 2, you can place the ceph-mon units in LXD containers on these machines:
@ -111,3 +126,4 @@ owned by the ceph-osd units deployed alongside ceph.
<!-- LINKS -->
.. _Charm upgrades: app-upgrade-openstack#charm-upgrades
.. _LP #1452641: https://bugs.launchpad.net/nova/+bug/1452641