48 lines
1.8 KiB
ReStructuredText
48 lines
1.8 KiB
ReStructuredText
.. _quiesce_cephstorage:
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Quiescing a CephStorage Node
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============================
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The process of quiescing a cephstorage node means to inform the Ceph
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cluster that one or multiple OSDs will be permanently removed so that
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the node can be shut down without affecting the data availability.
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Take the OSDs out of the cluster
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--------------------------------
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Before you remove an OSD, you need to take it out of the cluster so that Ceph
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can begin rebalancing and copying its data to other OSDs. Running the following
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commands on a given cephstorage node will take all data out of the OSDs hosted
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on it::
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OSD_IDS=$(ls /var/lib/ceph/osd | awk 'BEGIN { FS = "-" } ; { print $2 }')
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for OSD_ID in $OSD_IDS; do ceph crush reweight osd.$OSD_ID 0.0; done
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Ceph will begin rebalancing the cluster by migrating placement groups out of
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the OSDs. You can observe this process with the ceph tool::
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ceph -w
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You should see the placement group states change from active+clean to active,
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some degraded objects, and finally active+clean when migration completes.
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Removing the OSDs
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-----------------
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After the rebalancing, the OSDs will still be running. Running the following on
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that same cephstorage node will stop all OSDs hosted on it, remove them from the
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CRUSH map, from the OSDs map and delete the authentication keys::
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OSD_IDS=$(ls /var/lib/ceph/osd | awk 'BEGIN { FS = "-" } ; { print $2 }')
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for OSD_ID in $OSD_IDS; do
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ceph osd out $OSD_ID
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systemctl stop ceph-osd@$OSD_ID
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ceph osd crush remove osd.$OSD_ID
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ceph auth del osd.$OSD_ID
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ceph osd rm $OSD_ID
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done
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You are now free to reboot or shut down the node (using the Ironic API), or
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even remove it from the overcloud altogether by scaling down the overcloud
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deployment, see :ref:`delete_nodes`.
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