Ceph CRUSH map editing script

If you're working with Ceph, you'll find yourself updating the CRUSH map sooner or later. For that, you regularly need to get the current map, decompile it, edit it, comile it and upload it again. Here's a little script that makes this easier.


set -e
set -u

ceph osd getcrushmap -o /tmp/crushmap
crushtool -d /tmp/crushmap -o /tmp/crushmap.txt
cp /tmp/crushmap.txt /tmp/crushmap.txt.orig
${EDITOR:-vi} /tmp/crushmap.txt

# diff returns 0 if the file stayed the same
if ! diff /tmp/crushmap.txt.orig /tmp/crushmap.txt > /dev/null; then
        crushtool -c /tmp/crushmap.txt -o /tmp/crushmap
        ceph osd setcrushmap -i /tmp/crushmap
        echo "Updated crush map. Tree is now:"
        ceph osd tree
        echo "Crushmap not changed, not updating ceph"

Save as /usr/local/sbin/vicrushmap or something, chmod +x it and edit away!