First off let me start by saying that the new Cinder logo is wonderful. Nothing helps me think of backend storage better than the backend of a horse.
In an environment I am working in, we have a large number of cinder volumes that are in error state, due to the backend storage being ripped out. The volumes were not deleted, nor were they detached from the VMs.
End result, you cannot delete the zombie VM (at it has an attached volume) and you cannot delete the zombie/orphaned volume (as it is attached to a VM).
The following process allows you to work around the chicken-and-egg scenario above.
First we get a list of all volumes in error state.
# openstack volume list –all | grep -i error
Then we take a closer look at the volume to see if it exists/existed on the backend that was removed.
# openstack volume show 05b372ef-ee45-499b-9676-72cc4170e1b3
First we check the backend to ensure it is the affected backend – in this case it is.
The PackStack installer for OpenStack is largely considered an installer for Test and Proof-of-Concept OpenStack environments. Being such, the PackStack Installer can automatically create a loopback device for use with Cinder if you allow it to. In my lab, I would actually rather create a separate volume for Cinder to use. Below are the steps needed to do so.
First you need to ensure that the PackStack installer is not going to try to create its loopback device. To accomplish this you must modify the Packstack Answers file. The example below shows where I have specified that PackStack should not create a volume on its own. Note that the default size for this volume would be 20gb. Keep this in mind should you want PackStack to create the Cinder Volume, as you are going to need a bit of free space.
# Create Cinder’s volumes group. This should only be done for testing
# on a proof-of-concept installation of Cinder. This will create a
# file-backed volume group and is not suitable for production usage.
CONFIG_CINDER_VOLUMES_CREATE=n
# Cinder’s volumes group size. Note that actual volume size will be
# extended with 3% more space for VG metadata.
CONFIG_CINDER_VOLUMES_SIZE=20G
In my lab environment I have attached a secondary disk to RHEL 7 vm. This disk has been named /dev/sdb by the OS.
Note that other instructions that I have seen on this topic do not show or even recommend creating a partition on your Cinder volume disk before running pvcreate. I find that its best practice to always create a partition on a disk as this helps indicate to other root users that this disk is in use.
Next partition the disk and create one partition, type LVM
[root@rhelosp ~]# fdisk /dev/sdb
Device Boot Start End Blocks Id System
/dev/sdb1 2048 41943039 20970496 8e Linux LVM
Then run pvcreate to put your disk under the control of LVM
[root@rhelosp ~]# pvcreate /dev/sdb1
Physical volume “/dev/sdb1” successfully created
Now create the volume group as shown below. Note that the volume name must be “cinder-volumes”
[root@rhelosp ~]# vgcreate cinder-volumes /dev/sdb1
Volume group “cinder-volumes” successfully created
On this standalone host we have just added an additional disk, which has been enumerated as “/dev/vdc”. First lets go ahead and create a partition on this disk and label it with the type “lvm”.
Now lets view the partition that we created. Note that our new disk is approx 21gb in size. Since we are working in our lab, we are not working with large disks.
Now lets make sure that cinder services are up and running.
[root@packstack cinder(keystone_admin)]# systemctl | grep cinder | awk ‘{print $1}’| xargs -tn1 systemctl status | grep Active
systemctl status openstack-cinder-api.service
Active: active (running) since Tue 2015-04-28 17:02:29 EDT; 1min 21s ago
systemctl status openstack-cinder-backup.service
Active: active (running) since Tue 2015-04-28 17:02:29 EDT; 1min 21s ago
systemctl status openstack-cinder-scheduler.service
Active: active (running) since Tue 2015-04-28 17:02:29 EDT; 1min 21s ago
systemctl status openstack-cinder-volume.service
Active: active (running) since Tue 2015-04-28 17:02:30 EDT; 1min 20s ago
Now we must declare the new volume as block storage using the commands below.
[root@packstack cinder(keystone_admin)]# cinder type-create lvm1
+————————————–+——+
| ID | Name |
+————————————–+——+
| 082fc208-9d38-4ad4-ab48-110d056a2856 | lvm1 |
+————————————–+——+
Now lets link the backend volume to the newly created type-key.
[root@packstack cinder(keystone_admin)]# cinder type-key lvm1 set volume_backend_name=cinder-volumes-1
Below you can see our new cinder backend volume, and its backend name.
