1. Issue description

RH-SSO standalone mode does also contains embedded caches.
here is the 7.6.6 standalone.xml

~~~
<local-cache name="sessions"/>
<local-cache name="authenticationSessions"/>
<local-cache name="offlineSessions"/>
<local-cache name="clientSessions"/>
<local-cache name="offlineClientSessions"/>
<local-cache name="loginFailures"/>
~~~

There is a memory leak issue with local embedded caches

2. Similar existing (fixed in SSO 7.6.1 for standalone-HA mode)

There was in issue with distributed caches which has been fixed since:
-KEYCLOAK-18518 - (fixed in KC 15) - Expired cache objects in infinispan cache are never garbage collected and lead to out of memory [1]

-RHSSO-2169 - fixed in RH-SSO 7.6.1 - Expired cache objects in infinispan cache are never garbage collected in standalone configuration [2].

For further information, see also KCS article:

-SSO 7.6 OOME due to org.infinispan.container.impl.DefaultSegmentedDataContainer [3]

3. Existing Work-around
The issue faced (standalone mode) is similar to RH-SSO-2169, which has been fixed in RH-SSO 7.6.1 for standalone-ha mode, but not for the standalone mode.

In standalone mode, you should apply the same work-around/solution that is indicated within the KCS to circumvent this issue:

You need to add expiration and eviction for cache container keycloak. Add expiration in all locals cache as it is shown below.

here is the 7.6.6 standalone.xml

~~~
<local-cache name="sessions"/>
<local-cache name="authenticationSessions"/>
<local-cache name="offlineSessions"/>
<local-cache name="clientSessions"/>
<local-cache name="offlineClientSessions"/>
<local-cache name="loginFailures"/>
~~~

It needs to be updated as follows using jboss cli:

~~~
/subsystem=infinispan/cache-container=keycloak/local-cache=sessions/component=expiration/:write-attribute(name=lifespan,value=2000000000)
/subsystem=infinispan/cache-container=keycloak/local-cache=clientSessions/component=expiration/:write-attribute(name=lifespan,value=2000000000)
/subsystem=infinispan/cache-container=keycloak/local-cache=offlineSessions/component=expiration/:write-attribute(name=lifespan,value=2000000000)
/subsystem=infinispan/cache-container=keycloak/local-cache=offlineClientSessions/component=expiration/:write-attribute(name=lifespan,value=2000000000)
/subsystem=infinispan/cache-container=keycloak/local-cache=authenticationSessions/component=expiration/:write-attribute(name=lifespan,value=2000000000)
/subsystem=infinispan/cache-container=keycloak/local-cache=loginFailures/component=expiration/:write-attribute(name=lifespan,value=2000000000)
/subsystem=infinispan/cache-container=keycloak/local-cache=actionTokens/component=expiration/:write-attribute(name=lifespan,value=2000000000)
~~~
 

[1] https://issues.redhat.com/browse/KEYCLOAK-18518

[2] https://issues.redhat.com/browse/RHSSO-2169

[3] https://access.redhat.com/solutions/7011043