Hi,

Yes, you are right. I have deploied a ceph as the backend storage of glance, cinder and nova. And it can resolve this question.

But I wonder why it's designed this way. It doesn't fit my perception of OpenStack.

As currently designed, local storage of glance must not be used in the cluster. Why not record the host where the image resides? Just like the local storage of the nova-compute node, if a Glance node breaks down, the image on the host cannot be accessed.

Sorry that maybe this idea is unreasonable and stupid. Could anyone tell me the reason or what's the problem with that

best wishes to you, love you.

Thank you, Han Guangyu

Eugen Block eblock@nde.ag 于2022年1月6日周四 17:03写道：

Hi,

if you really aim towards a highly available cluster you'll also need a ha storage solution like ceph. Having glance images or VMs on local storage can make it easier to deploy, maybe for testing and getting involved with openstack, but it's not really recommended for production use. You'll probably have the same issue with cinder volumes, I believe. Or do you have a different backend for cinder?

Regards, Eugen

Zitat von 韩光宇 hanguangyu2@gmail.com:

...

Deal all,

Sorry that maybe I ask a stupid question. But I'm really confused with it and didn't find discuss in glance document(https://docs.openstack.org/glance/latest/).

I have a OpenStack Victoria cluster with three all-in-one node in centos8. I implemented it with reference to https://docs.openstack.org/ha-guide/. So this cluster use Pacemaker, HAproxy and Galera. "To implement high availability, run an instance of the database on each controller node and use Galera Cluster to provide replication between them."

I found that I will encounter an error If I configure Glance backend to use local storage driver to store image files on the local disk. If I upload a image, this image only will be storaged in one node. But the database only storage the file path of image such as "/v2/images/aa3cbee0-717f-4699-8cca-61243302d693/file", don't have the host information. The database data is same in three node.

If I upload a image in node1, image only is storaged in node1. The database of three node stores the local filesystem path of image. And If The create Instance task is assigned to node2, It will find image in node2, but image can't be found in node2. So we get the "Image has no associated data" error.

So I want to ask:

1. Wheter glance does not support using local filesystem storage in

a cluster? 2. If 1 was right, why do we do this design instead of storing information about the host on which images is located, as nova does with instance.

I would appreciate any kind of guidance or help.

Thank you, Han Guangyu

We've done something similar insofar as we've installed gluster with replica X on our controllers to share out the glace images volume between nodes. Saves you having to rsync between nodes and supports proper HA. ________________________________ From: Thomas Goirand zigo@debian.org Sent: 06 January 2022 12:44 To: 韩光宇 hanguangyu2@gmail.com; openstack-discuss openstack-discuss@lists.openstack.org Cc: hanguangyu@uniontech.com hanguangyu@uniontech.com; wangleic@uniontech.com wangleic@uniontech.com Subject: Re: [glance] Does glance not support using local filesystem storage in a cluster

CAUTION: This email originates from outside THG

On 1/6/22 03:33, 韩光宇 wrote:

Deal all,

Sorry that maybe I ask a stupid question. But I'm really confused with it and didn't find discuss in glance document(https://docs.openstack.org/glance/latest/https://docs.openstack.org/glance/latest).

I have a OpenStack Victoria cluster with three all-in-one node in centos8. I implemented it with reference to https://docs.openstack.org/ha-guide/https://docs.openstack.org/ha-guide. So this cluster use Pacemaker, HAproxy and Galera. "To implement high availability, run an instance of the database on each controller node and use Galera Cluster to provide replication between them."

I found that I will encounter an error If I configure Glance backend to use local storage driver to store image files on the local disk. If I upload a image, this image only will be storaged in one node. But the database only storage the file path of image such as "/v2/images/aa3cbee0-717f-4699-8cca-61243302d693/file", don't have the host information. The database data is same in three node.

If I upload a image in node1, image only is storaged in node1. The database of three node stores the local filesystem path of image. And If The create Instance task is assigned to node2, It will find image in node2, but image can't be found in node2. So we get the "Image has no associated data" error.

So I want to ask:

1. Wheter glance does not support using local filesystem storage in a cluster?
2. If 1 was right, why do we do this design instead of storing

information about the host on which images is located, as nova does with instance.

I would appreciate any kind of guidance or help.

Thank you, Han Guangyu

Hi 光宇,

It is possible to setup Glance with a local storage in a HA way.

The way to do this, is simply to get your HAproxy to use one node, always, and the other as backups. Then have a cron job that does the rsync from the first node to the other 2. A simple command as Glance user like this is enough (to be run as Glance user, and having the ssh host keys thingy fixed (we sign host keys, so we don't have this problem)):

rsync -e ssh -avz --delete /var/lib/glance/images/ \ <dest-host>:/var/lib/glance/images/ >/dev/null 2>&1

We have some internal logic to iterate through all the backup nodes and replace dest-host accordingly...

This way, if the first node fails, yes, you do have a problem because there wont be the primary node that is up, so saving new Glance image will be a problem as it wont be replicated to other nodes. But existing image will be there already, so it ok until you repair the first node.

I hope this helps, Cheers,

Thomas Goirand (zigo)

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