Caching of images in Openstack glance in a multinode set up [closed]

asked 2020-05-29 02:55:26 -0500

Taslim gravatar image

Hi everyone!

I just want to understand/setup caching of glance images in a multinode environment,where there are 
multiple  controller and compute nodes 

1.Where should the image caching be done,whether it is on the control/compute node?
2.If it is on the compute node, How should I enable the caching of Images on the compute node?
and how should I manage it?
3.how images are selected for caching? how they are updated? And where are they stored?

My Openstack set up:

Openstack version:5.2.0
Deployed as openstack-helm(Openstack deployed on K8S nodes)-All the services are running as PODS on controller 
node.
There is one Controller node-glance api and glance-registry is running as K8s POD here, and there are two compute 
nodes and there are no glance service running on compute nodes.


According to glance documentation http://docs.openstack.org/developer/glance/cache.html (here). , the selection 
of cached images for example is done manually by the administrator of the system, Using this I can configure 
manually,but I am looking on how to enable caching on all compute nodes while deploying.

Thank you!
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Closed for the following reason the question is answered, right answer was accepted by Taslim
close date 2020-06-02 15:02:15.814524

Comments

1

The page you reference starts with

The Glance API server may be configured to have an optional local image cache.

This means that this cache is on the controller where glance-api runs.

AFAIK Nova caches images on compute nodes anyway, and without operator intervention.

Bernd Bausch gravatar imageBernd Bausch ( 2020-05-29 04:40:51 -0500 )edit

But What I did see is Image is getting cached in the glance-api pod itself in the same dir as image_cache_dir and this is running in controller node.

Taslim gravatar imageTaslim ( 2020-05-29 06:36:26 -0500 )edit

As I said. This cache is on the controller where glance-api runs.

And: Nova caches images on compute nodes anyway, and without operator intervention. Nova. Not Glance.

Bernd Bausch gravatar imageBernd Bausch ( 2020-05-29 07:50:09 -0500 )edit

If I have to follow the Instance creation steps as mentioned in the diagram: https://maestropandy.wordpress.com/2016/05/26/openstack-instance-creation-request-work-flow/ (https://maestropandy.wordpress.com/20...) With Cache configured ,Instance creation flow is Nova-Compute-->Glance Api-->Picks Cached Image instead of Hitting Img store?

Taslim gravatar imageTaslim ( 2020-05-29 08:55:09 -0500 )edit

The fact that this page includes references to Quantum doesn't inspire a lot of confidence. Quantum was renamed Neutron around 2013, I think. There is a chance this is outdated.

But yes, instead of accessing the store, Glance uses the image cache. Much faster.

Bernd Bausch gravatar imageBernd Bausch ( 2020-05-29 10:03:42 -0500 )edit