Ask Your Question

remove image caching on nova-compute? [closed]

asked 2014-09-02 11:58:03 -0500

capsali gravatar image


Following my last post i have a question.

Is there a way to make nova not use the _base subfolder? When booting from image, a copy of the image is downloaded on the compute node and stored under /var/lib/nova/instances/_base . It is converted to qcow and held there as copy on write image for the future instances.

The problem is that i use ceph for all storage. When i boot an instance, the image is copied from the ceph cluster to the compute-node and then uploaded into ceph again. It takes a lot of time and it uses network.

edit retag flag offensive reopen merge delete

Closed for the following reason the question is answered, right answer was accepted by SamYaple
close date 2014-09-02 13:43:25.489055

1 answer

Sort by ยป oldest newest most voted

answered 2014-09-02 12:59:16 -0500

SamYaple gravatar image

updated 2014-09-02 13:44:15 -0500


What you are talking about, we have talked about previously from a different angle.

The answer is No unfortuantely. Even though you can prevent the cache in a few ways, it will still download the image and upload it. It just won't keep it around afterward.

For cloning from ceph-backed glance to ceph-backed ephemeral you have two options.

I have looked at the patch and it isn't messing with much code, just adding some. It should be able to be patched for what you are using it for without much more than some fuzzing.

edit flag offensive delete link more


HI, Sry for double post-ish! I saw the patch but unfortunatly i don;t know how to apply a patch. Can you point me in the right direction? Or better yet, can you tell me how to apply the patch?

Thank you!

capsali gravatar imagecapsali ( 2014-09-02 13:02:09 -0500 )edit

If you are unfamiliar with the patching process this may be difficult for you. Unless this is for testing purposes I would advise waiting until the branch with this commit is stable.

On the other hand, it is as simple as taking your nova/virt/libvirt/* files and making them look like the b side.

SamYaple gravatar imageSamYaple ( 2014-09-02 13:42:39 -0500 )edit

Just to update this topic, setting cache_images = none in /etc/nova/nova.conf on compute node(s) disables local cache on the compute nodes. It saved my day!

eblock gravatar imageeblock ( 2019-02-01 08:37:45 -0500 )edit

Get to know Ask OpenStack

Resources for moderators

Question Tools

1 follower


Asked: 2014-09-02 11:58:03 -0500

Seen: 1,621 times

Last updated: Sep 02 '14