Hello, While deploying Keycloak 4.5.0.Final in an Openshift environment, using Mariadb (Galera) as a database produces several exceptions in the logs, all of them being related to the communication between the Keycloak server and the database. The access to the Galera server (3 instances) is performed via a Maxscale proxy. The Galera server, Maxscale (deployment of 3 pods) and Keycloak (deployment of 2 replicas) are all deployed inside Openshift, on AWS (1master + 3 workers). I am hoping you guys can help with fixing these issues. The errors look like below: 08:40:46,603 WARN [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (ConnectionValidator) IJ030027: Destroying connection that is not valid, due to the following exception: org.mariadb.jdbc.MariaDbConnection@76883993: java.sql.SQLNonTransientConnectionException: (conn=24) unexpected end of stream, read 0 bytes from 4 (socket was closed by server) at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.get(ExceptionMapper.java:175) at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.getException(ExceptionMapper.java:110) at org.mariadb.jdbc.MariaDbStatement.executeExceptionEpilogue(MariaDbStatement.java:228) at org.mariadb.jdbc.MariaDbStatement.executeInternal(MariaDbStatement.java:334) at org.mariadb.jdbc.MariaDbStatement.execute(MariaDbStatement.java:386) at org.jboss.jca.adapters.jdbc.CheckValidConnectionSQL.isValidConnection(CheckValidConnectionSQL.java:74) at org.jboss.jca.adapters.jdbc.BaseWrapperManagedConnectionFactory.isValidConnection(BaseWrapperManagedConnectionFactory.java:1273) at org.jboss.jca.adapters.jdbc.BaseWrapperManagedConnectionFactory.getInvalidConnections(BaseWrapperManagedConnectionFactory.java:1086) at org.jboss.jca.core.connectionmanager.pool.mcp.SemaphoreConcurrentLinkedDequeManagedConnectionPool.validateConnections(SemaphoreConcurrentLinkedDequeManagedConnectionPool.java:1442) at org.jboss.jca.core.connectionmanager.pool.validator.ConnectionValidator$ConnectionValidatorRunner.run(ConnectionValidator.java:277) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Caused by: java.sql.SQLException: unexpected end of stream, read 0 bytes from 4 (socket was closed by server) Query is: SELECT 1 at org.mariadb.jdbc.internal.util.LogQueryTool.exceptionWithQuery(LogQueryTool.java:119) at org.mariadb.jdbc.internal.protocol.AbstractQueryProtocol.executeQuery(AbstractQueryProtocol.java:199) at org.mariadb.jdbc.MariaDbStatement.executeInternal(MariaDbStatement.java:328) ... 9 more Caused by: java.io.EOFException: unexpected end of stream, read 0 bytes from 4 (socket was closed by server) at org.mariadb.jdbc.internal.io.input.StandardPacketInputStream.getPacketArray(StandardPacketInputStream.java:239) at org.mariadb.jdbc.internal.io.input.StandardPacketInputStream.getPacket(StandardPacketInputStream.java:207) at org.mariadb.jdbc.internal.protocol.AbstractQueryProtocol.readPacket(AbstractQueryProtocol.java:1347) at org.mariadb.jdbc.internal.protocol.AbstractQueryProtocol.getResult(AbstractQueryProtocol.java:1328) at org.mariadb.jdbc.internal.protocol.AbstractQueryProtocol.executeQuery(AbstractQueryProtocol.java:196) ... 10 more I suspect that the errors come from the way the jdbc data source is configured. The mariadb configurations related to connections and wait timeouts are like below: max_connections=1000 wait_timeout=180 The second issue I noticed was the following: one of the pods in the deployments (we deploy 2 replicas of Keycloak) sometimes does not start correctly because of the following exception, which is still related to the database connection: 08:13:03,409 ERROR [org.jboss.msc.service.fail] (ServerService Thread Pool -- 52) MSC000001: Failed to start service jboss.undertow.deployment.default-server.default-host./auth: org.jboss.msc.service.StartException in service jboss.undertow.deployment.default-server.default-host./auth: java.lang.RuntimeException: RESTEASY003325: Failed to construct public org.keycloak.services.resources.KeycloakApplication(javax.servlet.ServletContext,org.jboss.resteasy.core.Dispatcher) at org.wildfly.extension.undertow.deployment.UndertowDeploymentService$1.run(UndertowDeploymentService.java:81) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35) at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1985) at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1487) at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1378) at java.lang.Thread.run(Thread.java:748) at org.jboss.threads.JBossThread.run(JBossThread.java:485) Caused by: java.lang.RuntimeException: RESTEASY003325: Failed to construct public org.keycloak.services.resources.KeycloakApplication(javax.servlet.ServletContext,org.jboss.resteasy.core.Dispatcher) at org.jboss.resteasy.core.ConstructorInjectorImpl.construct(ConstructorInjectorImpl.java:162) at org.jboss.resteasy.spi.ResteasyProviderFactory.createProviderInstance(ResteasyProviderFactory.java:2676) at org.jboss.resteasy.spi.ResteasyDeployment.createApplication(ResteasyDeployment.java:361) at org.jboss.resteasy.spi.ResteasyDeployment.startInternal(ResteasyDeployment.java:274) at org.jboss.resteasy.spi.ResteasyDeployment.start(ResteasyDeployment.java:86) at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.init(ServletContainerDispatcher.java:119) at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.init(HttpServletDispatcher.java:36) at io.undertow.servlet.core.LifecyleInterceptorInvocation.proceed(LifecyleInterceptorInvocation.java:117) at org.wildfly.extension.undertow.security.RunAsLifecycleInterceptor.init(RunAsLifecycleInterceptor.java:78) at io.undertow.servlet.core.LifecyleInterceptorInvocation.proceed(LifecyleInterceptorInvocation.java:103) at io.undertow.servlet.core.ManagedServlet$DefaultInstanceStrategy.start(ManagedServlet.java:300) at io.undertow.servlet.core.ManagedServlet.createServlet(ManagedServlet.java:140) at io.undertow.servlet.core.DeploymentManagerImpl$2.call(DeploymentManagerImpl.java:584) at io.undertow.servlet.core.DeploymentManagerImpl$2.call(DeploymentManagerImpl.java:555) at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:42) at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43) at org.wildfly.extension.undertow.security.SecurityContextThreadSetupAction.lambda$create$0(SecurityContextThreadSetupAction.java:105) at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1514) at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1514) at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1514) at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1514) at io.undertow.servlet.core.DeploymentManagerImpl.start(DeploymentManagerImpl.java:597) at org.wildfly.extension.undertow.deployment.UndertowDeploymentService.startContext(UndertowDeploymentService.java:97) at org.wildfly.extension.undertow.deployment.UndertowDeploymentService$1.run(UndertowDeploymentService.java:78) ... 8 more Caused by: java.lang.RuntimeException: Failed to connect to database at org.keycloak.connections.jpa.DefaultJpaConnectionProviderFactory.getConnection(DefaultJpaConnectionProviderFactory.java:373) at org.keycloak.connections.jpa.updater.liquibase.lock.LiquibaseDBLockProvider.lazyInit(LiquibaseDBLockProvider.java:65) at org.keycloak.connections.jpa.updater.liquibase.lock.LiquibaseDBLockProvider.lambda$waitForLock$0(LiquibaseDBLockProvider.java:97) at org.keycloak.models.utils.KeycloakModelUtils.suspendJtaTransaction(KeycloakModelUtils.java:611) at org.keycloak.connections.jpa.updater.liquibase.lock.LiquibaseDBLockProvider.waitForLock(LiquibaseDBLockProvider.java:95) at org.keycloak.services.resources.KeycloakApplication$1.run(KeycloakApplication.java:143) at org.keycloak.models.utils.KeycloakModelUtils.runJobInTransaction(KeycloakModelUtils.java:227) at org.keycloak.services.resources.KeycloakApplication.<init>(KeycloakApplication.java:136) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:423) at org.jboss.resteasy.core.ConstructorInjectorImpl.construct(ConstructorInjectorImpl.java:150) ... 31 more Caused by: java.sql.SQLException: javax.resource.ResourceException: IJ000453: Unable to get managed connection for java:jboss/datasources/KeycloakDS at org.jboss.jca.adapters.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:146) at org.jboss.as.connector.subsystems.datasources.WildFlyDataSource.getConnection(WildFlyDataSource.java:64) at org.keycloak.connections.jpa.DefaultJpaConnectionProviderFactory.getConnection(DefaultJpaConnectionProviderFactory.java:367) ... 43 more Caused by: javax.resource.ResourceException: IJ000453: Unable to get managed connection for java:jboss/datasources/KeycloakDS at org.jboss.jca.core.connectionmanager.AbstractConnectionManager.getManagedConnection(AbstractConnectionManager.java:690) at org.jboss.jca.core.connectionmanager.tx.TxConnectionManagerImpl.getManagedConnection(TxConnectionManagerImpl.java:430) at org.jboss.jca.core.connectionmanager.AbstractConnectionManager.allocateConnection(AbstractConnectionManager.java:789) at org.jboss.jca.adapters.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:138) ... 45 more Caused by: javax.resource.ResourceException: IJ031084: Unable to create connection at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.createLocalManagedConnection(LocalManagedConnectionFactory.java:345) at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.getLocalManagedConnection(LocalManagedConnectionFactory.java:352) at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.createManagedConnection(LocalManagedConnectionFactory.java:287) at org.jboss.jca.core.connectionmanager.pool.mcp.SemaphoreConcurrentLinkedDequeManagedConnectionPool.createConnectionEventListener(SemaphoreConcurrentLinkedDequeManagedConnectionPool.java:1326) at org.jboss.jca.core.connectionmanager.pool.mcp.SemaphoreConcurrentLinkedDequeManagedConnectionPool.getConnection(SemaphoreConcurrentLinkedDequeManagedConnectionPool.java:499) at org.jboss.jca.core.connectionmanager.pool.AbstractPool.getSimpleConnection(AbstractPool.java:632) at org.jboss.jca.core.connectionmanager.pool.AbstractPool.getConnection(AbstractPool.java:604) at org.jboss.jca.core.connectionmanager.AbstractConnectionManager.getManagedConnection(AbstractConnectionManager.java:624) ... 48 more Caused by: java.sql.SQLNonTransientConnectionException: could not load system variables at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.get(ExceptionMapper.java:175) at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.getException(ExceptionMapper.java:110) at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.connectWithoutProxy(AbstractConnectProtocol.java:1093) at org.mariadb.jdbc.internal.util.Utils.retrieveProxy(Utils.java:494) at org.mariadb.jdbc.MariaDbConnection.newConnection(MariaDbConnection.java:150) at org.mariadb.jdbc.Driver.connect(Driver.java:86) at org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory.createLocalManagedConnection(LocalManagedConnectionFactory.java:321) ... 55 more Caused by: java.sql.SQLNonTransientConnectionException: could not load system variables at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.get(ExceptionMapper.java:175) at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.connException(ExceptionMapper.java:83) at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.readPipelineAdditionalData(AbstractConnectProtocol.java:606) at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.connect(AbstractConnectProtocol.java:477) at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.connectWithoutProxy(AbstractConnectProtocol.java:1089) ... 59 more Caused by: java.sql.SQLException: Error reading SessionVariables results. Socket is connected ? true at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.readRequestSessionVariables(AbstractConnectProtocol.java:572) at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.readPipelineAdditionalData(AbstractConnectProtocol.java:603) ... 61 more The pod is in state running, but it is not ready, as it can be seen below: oc describe pod keycloak-787795bbcb-qng6j Name: keycloak-787795bbcb-qng6j Namespace: frame-2900 Start Time: Thu, 25 Oct 2018 10:03:30 +0200 Labels: application=keycloak pod-template-hash=3433516676 Annotations: openshift.io/scc=restricted Status: *Running* IP: 10.131.0.12 Controlled By: ReplicaSet/keycloak-787795bbcb Containers: keycloak: Container ID: docker://b703c13a70ffa24f696e08996590b972ec65e6b6041f8d08f50a44372b9e4760 Image: jboss/keycloak Image ID: docker-pullable:// docker.io/jboss/keycloak@sha256:cb5c24d06f22c51ca193e6d1e930d206ef0b841a745f8e475a08e33f10b38ad4 Ports: 8080/TCP, 8443/TCP *State: Waiting* * Reason: CrashLoopBackOff* Last State: Terminated Reason: Error Exit Code: 1 Started: Thu, 25 Oct 2018 10:12:43 +0200 Finished: Thu, 25 Oct 2018 10:13:03 +0200 Ready: False * Restart Count: 6* Liveness: http-get http://:8080/auth/realms/master delay=60s timeout=1s period=10s #success=1 #failure=3 Readiness: http-get http://:8080/auth/realms/master delay=30s timeout=1s period=10s #success=1 #failure=10 Environment: KEYCLOAK_USER: BokIm2Kl KEYCLOAK_PASSWORD: o8QobI0D PROXY_ADDRESS_FORWARDING: true DB_VENDOR: MARIADB JGROUPS_DISCOVERY_PROTOCOL: dns.DNS_PING JGROUPS_DISCOVERY_PROPERTIES: dns_query=keycloak.default.svc.cluster.local DB_ADDR: max-scale DB_DATABASE: keycloak DB_PORT: 4408 DB_USER: <set to the key 'keycloakDatabaseUserName' in secret 'qa-complex-secret'> Optional: false DB_PASSWORD: <set to the key 'keycloakDatabaseUserPassword' in secret 'qa-complex-secret'> Optional: false Mounts: /var/run/secrets/kubernetes.io/serviceaccount from frame-2900-token-k8cwj (ro) Conditions: Type Status Initialized True Ready False PodScheduled True Volumes: frame-2900-token-k8cwj: Type: Secret (a volume populated by a Secret) SecretName: frame-2900-token-k8cwj Optional: false QoS Class: BestEffort Node-Selectors: node-role.kubernetes.io/compute=true Tolerations: <none> Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Scheduled 11m default-scheduler Successfully assigned keycloak-787795bbcb-qng6j to ip-10-0-141-24.eu-west-1.compute.internal Normal SuccessfulMountVolume 11m kubelet, ip-10-0-141-24.eu-west-1.compute.internal MountVolume.SetUp succeeded for volume "frame-2900-token-k8cwj" Normal Pulled 7m (x4 over 9m) kubelet, ip-10-0-141-24.eu-west-1.compute.internal Successfully pulled image "jboss/keycloak" Normal Created 7m (x4 over 9m) kubelet, ip-10-0-141-24.eu-west-1.compute.internal Created container Normal Started 7m (x4 over 9m) kubelet, ip-10-0-141-24.eu-west-1.compute.internal Started container Normal Pulling 6m (x5 over 10m) kubelet, ip-10-0-141-24.eu-west-1.compute.internal pulling image "jboss/keycloak" Warning BackOff 53s (x31 over 8m) kubelet, ip-10-0-141-24.eu-west-1.compute.internal Back-off restarting failed container The pod is restarted several times it seems, but it does not start correctly. I deleted the pod and it was recreated automatically by Openshift and the new pod started correctly. Then, there is a third issue that I've encountered while trying to login into the deployed application. While entering some wrong credentials I got an error page and noticed in the logs that there is still a database connection error: 08:18:12,405 WARN [org.keycloak.services] (default task-2) KC-SERVICES0013: Failed authentication: javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: could not extract ResultSet at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1692) at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1602) at org.hibernate.jpa.internal.QueryImpl.getResultList(QueryImpl.java:492) at org.keycloak.models.jpa.JpaUserProvider.getUserByUsername(JpaUserProvider.java:526) at org.keycloak.storage.UserStorageManager.getUserByUsername(UserStorageManager.java:390) at org.keycloak.models.cache.infinispan.UserCacheSession.getUserByUsername(UserCacheSession.java:253) at org.keycloak.models.utils.KeycloakModelUtils.findUserByNameOrEmail(KeycloakModelUtils.java:213) at org.keycloak.authentication.authenticators.browser.AbstractUsernameFormAuthenticator.validateUserAndPassword(AbstractUsernameFormAuthenticator.java:153) at org.keycloak.authentication.authenticators.browser.UsernamePasswordForm.validateForm(UsernamePasswordForm.java:55) at org.keycloak.authentication.authenticators.browser.UsernamePasswordForm.action(UsernamePasswordForm.java:48) at org.keycloak.authentication.DefaultAuthenticationFlow.processAction(DefaultAuthenticationFlow.java:113) at org.keycloak.authentication.DefaultAuthenticationFlow.processAction(DefaultAuthenticationFlow.java:97) at org.keycloak.authentication.AuthenticationProcessor.authenticationAction(AuthenticationProcessor.java:873) at org.keycloak.services.resources.LoginActionsService.processFlow(LoginActionsService.java:292) at org.keycloak.services.resources.LoginActionsService.processAuthentication(LoginActionsService.java:263) at org.keycloak.services.resources.LoginActionsService.authenticate(LoginActionsService.java:259) at org.keycloak.services.resources.LoginActionsService.authenticateForm(LoginActionsService.java:320) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:140) at org.jboss.resteasy.core.ResourceMethodInvoker.internalInvokeOnTarget(ResourceMethodInvoker.java:510) at org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTargetAfterFilter(ResourceMethodInvoker.java:401) at org.jboss.resteasy.core.ResourceMethodInvoker.lambda$invokeOnTarget$0(ResourceMethodInvoker.java:365) at org.jboss.resteasy.core.interception.PreMatchContainerRequestContext.filter(PreMatchContainerRequestContext.java:361) at org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTarget(ResourceMethodInvoker.java:367) at org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:339) at org.jboss.resteasy.core.ResourceLocatorInvoker.invokeOnTargetObject(ResourceLocatorInvoker.java:137) at org.jboss.resteasy.core.ResourceLocatorInvoker.invoke(ResourceLocatorInvoker.java:100) at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:441) at org.jboss.resteasy.core.SynchronousDispatcher.lambda$invoke$4(SynchronousDispatcher.java:231) at org.jboss.resteasy.core.SynchronousDispatcher.lambda$preprocess$0(SynchronousDispatcher.java:137) at org.jboss.resteasy.core.interception.PreMatchContainerRequestContext.filter(PreMatchContainerRequestContext.java:361) at org.jboss.resteasy.core.SynchronousDispatcher.preprocess(SynchronousDispatcher.java:140) at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:217) at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:227) at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:56) at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:51) at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74) at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129) at org.keycloak.services.filters.KeycloakSessionServletFilter.doFilter(KeycloakSessionServletFilter.java:90) at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84) at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62) at io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68) at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36) at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:132) at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46) at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64) at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60) at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77) at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50) at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at org.wildfly.extension.undertow.deployment.GlobalRequestControllerHandler.handleRequest(GlobalRequestControllerHandler.java:68) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:292) at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:81) at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:138) at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:135) at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48) at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43) at org.wildfly.extension.undertow.security.SecurityContextThreadSetupAction.lambda$create$0(SecurityContextThreadSetupAction.java:105) at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1514) at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1514) at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1514) at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1514) at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:272) at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81) at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:104) at io.undertow.server.Connectors.executeRootHandler(Connectors.java:360) at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:830) at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35) at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1985) at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1487) at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1378) at java.lang.Thread.run(Thread.java:748) Caused by: org.hibernate.exception.JDBCConnectionException: could not extract ResultSet at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:48) at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:111) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:97) at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:79) at org.hibernate.loader.Loader.getResultSet(Loader.java:2122) at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1905) at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1881) at org.hibernate.loader.Loader.doQuery(Loader.java:925) at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:342) at org.hibernate.loader.Loader.doList(Loader.java:2622) at org.hibernate.loader.Loader.doList(Loader.java:2605) at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2434) at org.hibernate.loader.Loader.list(Loader.java:2429) at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:501) at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:370) at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:216) at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1339) at org.hibernate.internal.QueryImpl.list(QueryImpl.java:87) at org.hibernate.jpa.internal.QueryImpl.list(QueryImpl.java:606) at org.hibernate.jpa.internal.QueryImpl.getResultList(QueryImpl.java:483) ... 83 more Caused by: java.sql.SQLNonTransientConnectionException: (conn=476) Connection is closed at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.get(ExceptionMapper.java:175) at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.getException(ExceptionMapper.java:110) at org.mariadb.jdbc.MariaDbStatement.executeExceptionEpilogue(MariaDbStatement.java:228) at org.mariadb.jdbc.MariaDbPreparedStatementClient.executeInternal(MariaDbPreparedStatementClient.java:216) at org.mariadb.jdbc.MariaDbPreparedStatementClient.execute(MariaDbPreparedStatementClient.java:150) at org.mariadb.jdb c.MariaDbPreparedStatementClient.executeQuery(MariaDbPreparedStatementClient.java:164) at org.jboss.jca.adapters.jdbc.WrappedPreparedStatement.executeQuery(WrappedPreparedStatement.java:504) at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:70) ... 99 more Caused by: java.sql.SQLException: Connection is closed at org.mariadb.jdbc.internal.protocol.AbstractQueryProtocol.cmdPrologue(AbstractQueryProtocol.java:1711) at org.mariadb.jdbc.internal.protocol.AbstractQueryProtocol.executeQuery(AbstractQueryProtocol.java:237) at org.mariadb.jdbc.MariaDbPreparedStatementClient.executeInternal(MariaDbPreparedStatementClient.java:209) ... 103 more After a couple of seconds, the issue dissapeared, probably because Keycloak was able to get a valid connection from the connection pool. Thanks in advance for your help. Greetings, Cristi