How to convert existing Openstack clouds into Cells?

asked 2014-12-15 04:04:19 -0600

DaveJ gravatar image


I currently have 3 independent Openstack installations running in a lab. They each live on their own networks, although the public endpoints of each deployment are rotatable.

Is it possible to convert these three existing deployments into cells, so I can use a single horizon/keystone/glance across all 3? I've had a look at the Openstack documentation, but it isn't overly clear in the deployment architecture or what is required.

Also in terms of HA - is each child cell considered a full deployment in it's own right, i.e. would you still expect it to have 3 controller nodes (with everything except glance, horizon etc). Is it possible to spread the HA across cells, so if services in one cell fail, they can fail over to another cell?

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answered 2014-12-16 19:26:34 -0600

fifieldt gravatar image

Basically, yes - you should be able to convert deployments into child cells of a parent (call if "API") cell.

Set up the new "API" cell, configure the child cells with the right keystone things and nova-cells configuration, then point your horizon at the new API cell. It won't be a pretty conversion process, but it should be possible to hack it through.

Each cell does indeed have its own database, queue, scheduler etc, so they're fairly independent. A failure on one cell should not kill the other cells.

At time of writing, you cannot live migrate between cells. However, if you add in appropriate availability zones (which are shown to users) it enables your users to have apps that can work across multiple availability zones (map 1:1 with cells, perhaps) and allow them to work around the failure this way.

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Asked: 2014-12-15 04:04:19 -0600

Seen: 177 times

Last updated: Dec 16 '14