Hi Stephen,

In our case, we end up with multiple keystone endpoints (one for each region) but going to the same auth.<blah> address.

Will try and send over a sample later.

I think it would be a good addition to the core openstack documentation to talk more about multi-region deployments and what the big operators get up to with implementing this.

It’s also worth asking the question, how does this change when SSO/Centralised AD etc authentication is put into practice?

Thanks,

Karl.

Karl Kloppenborg

Chief Technology Officer

m: +61 437 239 565
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From: Stephen Finucane <stephenfin@redhat.com>
Date: Wednesday, 16 October 2024 at 8:40 pm
To: Karl Kloppenborg <kkloppenborg@resetdata.com.au>, Artem Goncharov <artem.goncharov@gmail.com>
Cc: openstack-discuss <openstack-discuss@lists.openstack.org>
Subject: Re: [keystone] What does a multi-region service catalog look like?

That's great info. Thanks both. So to be clear, Karl, in your service catalog you see a single endpoint for Keystone and N endpoints (one per region) for Cinder, Nova etc? And tooling (OSC, SDK, etc.) is happy using one region for Keystone and potentially a different one for all other services?

I would like to document this somewhere, so I'd like to make sure said docs reflect a real world scenario. If you had a service catalog you could share (with potentially sensitive info like URLs stripped out/anonymised) that would be helpful.

Cheers,

Stephen

On Tue, 2024-10-15 at 22:19 +0000, Karl Kloppenborg wrote:

Hi Stephen,

As Artem has pointed out, we’ve seen both.

Some people also have a single keystone distributed across several regions using database replication.

There’s pros and cons to all these deployments, however we personally use a centralised keystone and multiple regions with region specific endpoints.

The downside of this is that loss of comms to the keystone makes multiple regions inaccessible however it doesn’t break customer compute workloads, so we absorb that as acceptable risk.

Some others also do an A/B keystone behind keystone, I have also seen keystone presented more cleverly utilising anycast addressing and database replication, which avoids the aforementioned situation.

Thanks,
Karl Kloppenborg.

Karl Kloppenborg

Chief Technology Officer

m: +61 437 239 565
resetdata.com

ResetData supports Mandatory Client Related Financial Disclosures – Scope 3 Emissions Reporting
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From:Artem Goncharov <artem.goncharov@gmail.com>
Date: Tuesday, 15 October 2024 at 10:36 pm
To: Stephen Finucane <stephenfin@redhat.com>
Cc: openstack-discuss <openstack-discuss@lists.openstack.org>
Subject: Re: [keystone] What does a multi-region service catalog look like?

Short answer Stephen, there can be both (and I've seen both), but typically there is single keystone for multiple non-identity regions.

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typed from mobile, auto-correct typos assumed
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On Tue, Oct 15, 2024, 13:33 Stephen Finucane <stephenfin@redhat.com> wrote:

o/

The question in $subject came up in a discussion earlier today and I neither
knew the answer nor was able to discover it by looking at a service catalogs for
a few production deployments I have access to (also, the multi-region feature is
currently broken in DevStack and likely has been for some time). Crucially, in a
"standard" multi-region deployment where there is one Keystone instances and N
Nova/Cinder/Glance/Neutron/... deployments, would I have something like the
below, where there is only one identity endpoint but multiple e.g. compute
endpoints, or would I expect there always to be as many identity endpoints as
there are e.g. compute endpoints?

    {
        "token":
        {
            ...
            "catalog":
            [
                {
                    "endpoints":
                    [
                        {
                            "id": "fb757b386a23430d8f4d636b8b45fa89",
                            "interface": "public",
                            "region_id": "RegionOne",
                            "url": "http://10.0.110.125/identity",
                            "region": "RegionOne"
                        }
                    ],
                    "id": "50c4feff9d6149b898fce20ce23904a3",
                    "type": "identity",
                    "name": "keystone"
                },
                {
                    "endpoints":
                    [
                        {
                            "id": "2ed0cb59adb0415c948f8351b6546d3e",
                            "interface": "public",
                            "region_id": "RegionOne",
                            "url": "http://10.0.110.125/compute/v2.1",
                            "region": "RegionOne"
                        },
                        {
                            "id": "2ed0cb59adb0415c948f8351b6546d3e",
                            "interface": "public",
                            "region_id": "RegionTwo",
                            "url": "http://10.0.112.232/compute/v2.1",
                            "region": "RegionOne"
                        }
                    ],
                    "id": "87322637c5ab4e7b90bea7a8c1eb9525",
                    "type": "compute",
                    "name": "nova"
                },
                ...
            ]
        }
    }

I'm guessing the latter, but I'd like to confirm this.

Stephen