====== [HOWTO] Completely remove OSD from cluster ======

^  Documentation  ^|
^Name:| [HOWTO] Completely remove OSD from cluster |
^Description:|  HOW TO Completely remove OSD from cluster (hardcore edition) |
^Modification date :|07/06/2018|
^Owner:|dodger|
^Notify changes to:|Owner |
^Tags:|ceph, object storage |
^Scalate to:|The_fucking_bofh|


====== Official documentation  ======

  * [[https://access.redhat.com/solutions/1979363|RH support link]] (you'll need rhnetwork user/pass)

====== Instructions ======
<WRAP center round info 60%>
Instructions are copy/paste
</WRAP>


===== What are the steps to remove an OSD from an RHCS cluster? =====

There can be various reasons to remove an OSD from an RHCS cluster, and the following steps show how to do it:\\
==== 1. Stop the OSD process ====

<code bash>
sudo /etc/init.d/ceph stop osd.{X} # where {X} is the OSD number
</code>
or:
<code bash>
sudo systemctl stop ceph-osd@{X} # where {X} is the OSD number
</code>
\\
==== 2.Mark the OSD out ====

<code bash>
ceph osd out {X} # where {X} is the OSD number
</code>
\\
==== 3.Confirm if the OSD is indeed marked out with ====
<code bash>
ceph -w
</code>
<WRAP center round important 60%>
Important: Wait for data rebalance to complete and all the PG's to come back active+clean, before moving to next steps.
</WRAP>
\\



==== 4. [OPTIONAL] Remove the OSD from the crush map ====
<WRAP center round info 60%>
Step 4 is only needed if OSD is getting permanently removed from the cluster and will not be redeployed
</WRAP>
<code bash>
ceph osd crush remove osd.{X}
</code>
If OSD is being redeployed and because of that need removal then skip step 4 it will keep OSD in the CRUSH map as DNE and will not cause data rebalance because of CRUSH map update. Only addition of OSD will cause data movement.
\\
==== 5.Remove the authentication key for the OSD ====
<code bash>
ceph auth del osd.{X}
</code>
\\
==== 6.Confirm that the keys for OSD.{X} are not listed ====
<code bash>
ceph auth list
</code>
\\
==== 7.Remove the OSD from the OSD map ====
<code bash>
ceph osd rm {X}
</code>
\\
==== 8.If the procedure is used for replacing the OSD disk then please unmount this osd disk which you want to replace ====
<code bash>
umount /var/lib/ceph/osd/ceph-{x}
</code>