cinder-manage: Did you know about it ?

A tool that’s less known-about for cinder is cinder-manage. You might have run into it during upgrades. The most common use case is

cinder-manage db sync

This is normally executed during upgrades to bring the database to the latest version, or to create the schema for a new installation. But there’s actually additional usages for it. Few of them are

cinder-manage service list

the output will look like that

Binary Host Zone Status State Updated At RPC Version Object Version Cluster 
cinder-scheduler controller-server nova enabled :-) 2017-10-15 19:45:37 4.5 4.5 
cinder-volume controller-server@ceph nova enabled :-) 2017-10-15 19:45:31 4.6 4.6

The output can be used to diagnose issues when cinder-scheduler reports that the volume backend is down although cinder-volume is up. The output of the above command is the only reliable source to show how cinder-scheduler, cinder-volume and cinder-backup status is.

If you have multiple backends for cinder, or use multiple cinder-scheduler/cinder-volume on multiple controller nodes. The output will look like this

Binary Host Zone Status State Updated At RPC Version Object Version Cluster 
cinder-scheduler controller-server1 nova enabled :-) 2017-10-15 19:45:37 4.5 4.5 
cinder-volume controller-server1@ceph nova enabled :-) 2017-10-15 19:45:31 4.6 4.6
cinder-volume controller-server1@ceph2 nova enabled :-) 2017-10-15 19:45:31 4.6 4.6
cinder-scheduler controller-server2 nova enabled :-) 2017-10-15 19:45:37 4.5 4.65
cinder-volume controller-server2@ceph nova enabled XX 2017-10-15 19:45:37 4.6 4.6

As you can see above, there are multiple backends for cinder-volume on controller-server1. One of them is ceph and the other is ceph2 and both are enabled and up. It’s easy to spot that cinder-volume on the controller-server2 is showing as down, so you should expect the ceph backend to not be available. If you check the cinder-volume service using systemctl status, the service itself might be running. If that is the case you need to look deeper to why the ceph backend for cinder-volume is down

If you decide to remove a certain cinder-volume/cinder-scheduler/cinder-backup service from your deployment, you can do that by stopping the service on the controller host, and then removing it using

cinder-manage service remove cinder-scheduler controller-server2
cinder-manage service remove cinder-volume controller-server2

If this small use case got you excited, check out the following uses as well

cinder-manage logs errors
cinder-manage logs syslog
cinder-manage volume delete --> Important in the case of stuck volumes
cinder-manage host list
cinder-manage config list --> you can use it to verify what the running configuration for cinder is

The manual for cinder-manage is at

https://docs.openstack.org/cinder/latest/man/cinder-manage.html

Have fun !

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