When you manage a large cluster, you do not always know where your OSD are located. Sometimes you have issues with PG such as unclean or with OSDs such as slow requests. While looking at your ceph health detail you only see where the PGs are acting or on which OSD you have slow requests. Given that you might have tons of OSDs located on a lot of node, it is not straightforward to find and restart them.

You will find bellow a simple script that can do this for you. In this example, I want to restart all the down OSDs on an Ubuntu operating system.

#!/bin/bash

for down_osd in $(ceph osd tree | awk '/down/ {print $1}')
do
  host=$(ceph osd find $down_osd | awk -F\" '$2 ~ /host/ {print $4}')
  ssh $host restart ceph-osd id=$down_osd
done

Yes the awk is ugly, if someone comes out with an easier/clearer alternative ;)