Hypervisor Plus cephX

Still missing is the cephX configuration on the hypervisor systems. You can use a trick to integrate them by giving each hypervisor a ceph-secret.xml file, which you populate with the contents of Listing 4. Then, run the

virsh define secret-ceph-secret.xml

command to create the entry for the password in the internal Libvirt database. However, this is just a blank entry without a password. The latter consists of the user's cephX client.cinder key; the command

ceph-authtool --id client.cinder--print- key/etc/ceph/ceph.client.cinder.keyring

outputs it on the screen. Finally, you assign the actual password to the empty space you create – in this example:

virsh secret-set-value 2a5b08e4-3dca-4ff9-9a1d-40389758d081AQA5jhZRwGPhBBAAa3t78yY/0+1QB5Z/9iFK2Q==

The workflow from creating ceph-secret.xml to inputting the virsh command needs to be repeated on each host. Libvirt at least remembers the password after the first entry. The reward for all of this effort is a number of VMs that access Ceph directly, without any detours.

High-Speed Storage

One possible way to tease more performance from the Cinder and Ceph team is for users to configure multiple volumes on their virtual machines and then combine them on the VM to create a virtual RAID 0. You could thus bundle the performance of each object storage device, which would allow write speeds of 500MBps and more within the VMs.

Conclusions

OpenStack and the Ceph object store are certainly not just a flash in the pan. The cloud storage solution that admins generate by teaming distributed object storage with the computing components of OpenStack impresses with its stability, redundancy, and performance: It significantly outperforms conventional virtualization systems.

If you are planning to build an open cloud in the near future and want to tackle the topic of storage the right way, right from the start, you will want to try teaming OpenStack and Ceph.

The Author

Martin Gerhard Loschwitz is the principal consultant with Hastexo, where he focuses on high-availability solutions. In his leisure time, he maintains the Linux Cluster stack for Debian GNU/Linux.