[keycloak-user] running multiple instances without clustering

[Sam Davis]

Hi,

I understand that Keycloak supports clustering, but I am wondering if it is
possible to run multiple instances of Keycloak using the same configuration
database *without* using clustering, i.e. using the standalone
<https://keycloak.gitbooks.io/documentation/server_installation/topics/operating-mode/standalone.html>
operating mode.

It looks like the only difference between this and using the standalone
clustered mode is that the caches will not be synchronized between the
instances. I understand that it could cause some weird behaviour with user
sessions (e.g. a user logs out on one instance but is still logged in on
another, or vice versa). Would it cause any more serious problems (e.g.
corrupt configuration database) or create security vulnerabilities?

The use case is that my application bundles Keycloak and the application
and Keycloak run on the same server. If the server goes down, another
instance of the application on another server will take over, and that
instance will redirect users to another keycloak instance running on that
server. So I don't really need clustering, since normally only a single
Keycloak instance will actually be used at a time and will only be used by
a single application.

Thanks,
Sam