Strato VServer + Docker + Keycloak: Probleme nach längerer Laufzeit

Hallo zusammen,

Ich habe mir bei Strato einen VServer Linux V30 gemietet. Drauf laufen verschiedene Anwendung in Docker Container und nativ:

Plesk
Wordpress
Flarum
MySQL
Wiki.js (in Docker)
Keycloak (in Docker)
MariaDB (in Docker)

Keycloak nutze ich als SSO für Wordpress, Wiki.js und Flarum. Nun habe ich das Problem, dass mir Keycloak nach einer Weile einfach abschmiert und ich es nicht mehr in Docker neu gestartet bekomme. Erst nach kompletten neu aufsetzen von Keycloak funktioniert es wieder. Folgende Fehlermeldung erhalte ich (Log-File stark eingekürzt):

keycloak_1  | 17:22:06,447 DEBUG [org.jboss.as.config] (MSC service thread 1-3) VM Arguments: -D[Standalone] -Xms512m -Xmx2048m -XX:MetaspaceSize=96M -XX:MaxMetaspaceSize=256m -XX:+UseAdaptiveSizePolicy -XX:MaxMetaspaceSize=1024m -Djboss.modules.system.pkgs=org.jboss.byteman -Djava.awt.headless=true-Djava.net.preferIPv4Stack=true --add-exports=java.base/sun.nio.ch=ALL-UNNAMED --add-exports=jdk.unsupported/sun.misc=ALL-UNNAMED --add-exports=jdk.unsupported/sun.reflect=ALL-UNNAMED -Dorg.jboss.boot.log.file=/opt/jboss/keycloak/standalone/log/server.log -Dlogging.configuration=file:/opt/jboss/keycloak/standalone/configuration/logging.properties
keycloak_1  | 17:22:19,493 ERROR [org.jboss.as.controller.management-operation] (Controller Boot Thread) WFLYCTL0013: Operation ("add") failed - address: ([  
keycloak_1  |     ("subsystem" => "infinispan"),  
keycloak_1  |     ("cache-container" => "keycloak"),  
keycloak_1  |     ("thread-pool" => "transport")  
keycloak_1  | ]) - failure description: {"WFLYCTL0080: Failed services" => {"org.wildfly.clustering.infinispan.cache-container.keycloak" => "org.infinispan.manager.EmbeddedCacheManagerStartupException: org.infinispan.commons.CacheException: java.lang.OutOfMemoryError: unable to create native thread: possibly out of memory or process/resource limits reached  
keycloak_1  |     Caused by: org.infinispan.manager.EmbeddedCacheManagerStartupException: org.infinispan.commons.CacheException: java.lang.OutOfMemoryError: unable to create native thread: possibly out of memory or process/resource limits reached
keycloak_1  |     Caused by: org.infinispan.commons.CacheException: java.lang.OutOfMemoryError: unable to create native thread: possibly out of memory or process/resource limits reached
keycloak_1  |     Caused by: java.lang.OutOfMemoryError: unable to create native thread: possibly out of memory or process/resource limits reached"}}  
keycloak_1  | 17:22:19,505 INFO  [org.jboss.as.server] (ServerService Thread Pool -- 46) WFLYSRV0010: Deployed "keycloak-server.war" (runtime-name : "keycloak-server.war")  
keycloak_1  | 17:22:19,507 INFO  [org.jboss.as.controller] (Controller Boot Thread) WFLYCTL0183: Service status report
keycloak_1  | WFLYCTL0186:   Services which failed to start:      service org.wildfly.clustering.infinispan.cache.ejb.http-remoting-connector: org.infinispan.commons.CacheConfigurationException: Error starting component org.infinispan.expiration.impl.InternalExpirationManager
keycloak_1  |       service org.wildfly.clustering.infinispan.cache-container.keycloak: org.infinispan.manager.EmbeddedCacheManagerStartupException: org.infinispan.commons.CacheException: java.lang.OutOfMemoryError: unable to create native thread: possibly out of memory or process/resource limits reached
keycloak_1  | WFLYCTL0448: 32 additional services are down due to their dependencies being missing or failed
keycloak_1  | 17:22:19,599 INFO  [org.jboss.as.server] (Controller Boot Thread) WFLYSRV0212: Resuming server
keycloak_1  | 17:22:19,606 ERROR [org.jboss.as] (Controller Boot Thread) WFLYSRV0026: Keycloak 12.0.4 (WildFly Core 13.0.3.Final) started (with errors) in 15455ms - Started 558 of 926 services (44 services failed or missing dependencies, 684 services are lazy, passive or on-demand)
keycloak_1  | 17:22:19,614 INFO  [org.jboss.as] (Controller Boot Thread) WFLYSRV0060: Http management interface listening on http://127.0.0.1:9990/management
keycloak_1  | 17:22:19,614 INFO  [org.jboss.as] (Controller Boot Thread) WFLYSRV0051: Admin console listening on http://127.0.0.1:9990

Der entscheidende Fehler sollte folgender sein:

Caused by: java.lang.OutOfMemoryError: unable to create native thread: possibly out of memory or process/resource limits reached"  

keycloak_1  | 17:48:15,196 ERROR [org.jboss.msc.service.fail] (ServerService Thread Pool -- 60) MSC000001: Failed to start service org.wildfly.clustering.infinispan.cache-container.keycloak: org.jboss.msc.service.StartException in service org.wildfly.clustering.infinispan.cache-container.keycloak: org.infinispan.manager.EmbeddedCacheManagerStartupException: org.infinispan.commons.CacheException: java.lang.OutOfMemoryError: unable to create native thread: possibly out of memory or process/resource limits reached

Im ersten Moment dachte ich, dass Keycloak in Verbindung mit Docker sich irgendwo voll "frisst" und ich dem einfach mehr Speicher zuweisen muss. Leider hat das nicht den gewünschten Erfolg gebracht. Nach längerer Recherche habe ich gelesen, dass es immer wieder Probleme mit den nativen Threads bei den VServern von Strato gibt. Leider kenne ich mich auf dem Feld nicht so gut aus. Ich komme aus der Frontend-Entwicklung.

Kann mir jemand weiterhelfen oder hatte sogar ein ähnliches Problem?

Anbei noch meine docker-compose File:

version: '3'  

services:

  mariadb:
    image: mariadb:latest
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: ******
      MYSQL_DATABASE: app_keycloak
      MYSQL_USER: ******
      MYSQL_PASSWORD: ******
    ports:
      - 3308:3306
    # Copy-pasted from https:{{comment_single_line_double_slash:0}}
    healthcheck:
      test: ["CMD", "mysqladmin", "ping", "--silent"]  

  keycloak:
    image: jboss/keycloak:latest
    restart: always
    environment:
      DB_VENDOR: mariadb
      DB_ADDR: mariadb
      DB_DATABASE: ******
      DB_USER: ******
      DB_PASSWORD: ******
      KEYCLOAK_USER: ******
      KEYCLOAK_PASSWORD: ******
      JGROUPS_DISCOVERY_PROTOCOL: JDBC_PING
      JAVA_OPTS: "-server -Xms512m -Xmx2048m -XX:MetaspaceSize=96M -XX:MaxMetaspaceSize=256m -XX:+UseAdaptiveSizePolicy -XX:MaxMetaspaceSize=1024m -Djboss.modules.system.pkgs=org.jboss.byteman -Djava.awt.head$t.headless=true-Djava.net.preferIPv4Stack=true"  
    ports:
      - 8080:8080
    depends_on:
      - mariadb