Hello, I tried to centralize logging in our docker environment by using logback as default logging framework. The idea is to use logback in our core application which compiles to a *.war file which is deployed in an Apache Tomcat v8.5. We now use Docker and I want to get a logging setup in our swarm like that: Our own *.war file is already successfully logging to STDOUT with logback and the logstash-logback-encoder. After I deployed the war to Tomcat running within a Docker container I realized that more information coming from Tomcat is logged via STDOUT and this is not in JSON format. I also read about logback-access and how to use it in Tomcat so I first added logback-access to the classpath of Tomcat and added a logback-access.xml config file as well. In the server.xml I added <Valve className="ch.qos.logback.access.tomcat.LogbackValve"/>. The server.xml looks like: <?xml version="1.0" encoding="UTF-8"?> <Server port="8005" shutdown="SHUTDOWN">     <!--<Listener className="org.apache.catalina.startup.VersionLoggerListener"/>-->     <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on"/>     <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener"/>     <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener"/>     <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener"/>     <GlobalNamingResources>         <Resource name="UserDatabase" auth="Container"                   type="org.apache.catalina.UserDatabase"                   description="User database that can be updated and saved" factory="org.apache.catalina.users.MemoryUserDatabaseFactory"                   pathname="conf/tomcat-users.xml"/>     </GlobalNamingResources>     <Service name="Catalina">         <Connector port="8080" protocol="HTTP/1.1"                    connectionTimeout="20000"                    redirectPort="8443"/>         <Connector port="8009" protocol="AJP/1.3" redirectPort="8443"/>         <Engine name="Catalina" defaultHost="localhost">             <Realm className="org.apache.catalina.realm.LockOutRealm">                 <Realm className="org.apache.catalina.realm.UserDatabaseRealm" resourceName="UserDatabase"/>             </Realm>             <Host name="localhost" appBase="webapps" unpackWARs="true" autoDeploy="true">                 <Valve className="ch.qos.logback.access.tomcat.LogbackValve" />             </Host>         </Engine>     </Service> </Server> Running our war like this works. Now I wanted to make Tomcat to use logback as default logging framework as well and integrated ADD logback-core-1.2.3.jar /usr/local/tomcat/lib/ ADD logback-classic-1.2.3.jar /usr/local/tomcat/lib/ ADD logstash-logback-encoder-5.3.jar /usr/local/tomcat/lib/ ADD jackson-databind-2.9.8.jar /usr/local/tomcat/lib/ ADD jul-to-slf4j-1.7.26.jar /usr/local/tomcat/lib/ ADD slf4j-api-1.7.26.jar /usr/local/tomcat/lib/ ADD jackson-core-2.9.8.jar /usr/local/tomcat/lib/ ADD jackson-annotations-2.9.8.jar /usr/local/tomcat/lib/ to the lib folder as well as to the classpath via setenv.sh: export CLASSPATH="$CATALINA_HOME/lib/jul-to-slf4j-1.7.26.jar:$CATALINA_HOME/lib/slf4j-api-1.7.26.jar:$CATALINA_HOME/lib/logback-classic-1.2.3.jar:$CATALINA_HOME/lib/logstash-logback-encoder-5.3.jar:$CATALINA_HOME/lib/jackson-databind-2.9.8.jar:$CATALINA_HOME/lib/jackson-core-2.9.8.jar:$CATALINA_HOME/lib/jackson-annotations-2.9.8.jar:$CATALINA_HOME/lib/logback-access-1.2.3.jar:$CATALINA_HOME/lib/logback-core-1.2.3.jar:$CATALINA_HOME/conf/logback/" I also added a proper logback.xml for Tomcat. Unfortunately in this situation the Tomcat server process is not starting up correctly as the following error occurs: java.lang.NoClassDefFoundError: org/apache/catalina/Lifecycle         at java.lang.ClassLoader.defineClass1(Native Method)         at java.lang.ClassLoader.defineClass(ClassLoader.java:763)         at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)         at java.net.URLClassLoader.defineClass(URLClassLoader.java:468)         at java.net.URLClassLoader.access$100(URLClassLoader.java:74)         at java.net.URLClassLoader$1.run(URLClassLoader.java:369)         at java.net.URLClassLoader$1.run(URLClassLoader.java:363)         at java.security.AccessController.doPrivileged(Native Method)         at java.net.URLClassLoader.findClass(URLClassLoader.java:362)         at java.lang.ClassLoader.loadClass(ClassLoader.java:424)         at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)         at java.lang.ClassLoader.loadClass(ClassLoader.java:411)         at java.lang.ClassLoader.loadClass(ClassLoader.java:357)         at org.apache.tomcat.util.digester.ObjectCreateRule.begin(ObjectCreateRule.java:116)         at org.apache.tomcat.util.digester.Digester.startElement(Digester.java:1250)         at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:509)         at com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:182)         at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1339)         at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2784)         at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:602)         at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:505)         at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:842)         at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:771)         at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)         at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1213)         at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:643)         at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1518)         at org.apache.catalina.startup.Catalina.load(Catalina.java:611)         at org.apache.catalina.startup.Catalina.load(Catalina.java:662)         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.apache.catalina.startup.Bootstrap.load(Bootstrap.java:309)         at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:492) Caused by: java.lang.ClassNotFoundException: org.apache.catalina.Lifecycle         at java.net.URLClassLoader.findClass(URLClassLoader.java:382)         at java.lang.ClassLoader.loadClass(ClassLoader.java:424)         at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)         at java.lang.ClassLoader.loadClass(ClassLoader.java:357)         ... 35 common frames omitted java.lang.NoClassDefFoundError: org/apache/catalina/Lifecycle         at java.lang.ClassLoader.defineClass1(Native Method)         at java.lang.ClassLoader.defineClass(ClassLoader.java:763)         at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)         at java.net.URLClassLoader.defineClass(URLClassLoader.java:468)         at java.net.URLClassLoader.access$100(URLClassLoader.java:74)         at java.net.URLClassLoader$1.run(URLClassLoader.java:369)         at java.net.URLClassLoader$1.run(URLClassLoader.java:363)         at java.security.AccessController.doPrivileged(Native Method)         at java.net.URLClassLoader.findClass(URLClassLoader.java:362)         at java.lang.ClassLoader.loadClass(ClassLoader.java:424)         at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)         at java.lang.ClassLoader.loadClass(ClassLoader.java:411)         at java.lang.ClassLoader.loadClass(ClassLoader.java:357)         at org.apache.tomcat.util.digester.ObjectCreateRule.begin(ObjectCreateRule.java:116)         at org.apache.tomcat.util.digester.Digester.startElement(Digester.java:1250)         at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:509)         at com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:182)         at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1339)         at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2784)         at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:602)         at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:505)         at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:842)         at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:771)         at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)         at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1213)         at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:643)         at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1518)         at org.apache.catalina.startup.Catalina.load(Catalina.java:611)         at org.apache.catalina.startup.Catalina.load(Catalina.java:662)         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.apache.catalina.startup.Bootstrap.load(Bootstrap.java:309)         at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:492) Caused by: java.lang.ClassNotFoundException: org.apache.catalina.Lifecycle         at java.net.URLClassLoader.findClass(URLClassLoader.java:382)         at java.lang.ClassLoader.loadClass(ClassLoader.java:424)         at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)         at java.lang.ClassLoader.loadClass(ClassLoader.java:357)         ... 35 more Now if I commend out the line <Valve className="ch.qos.logback.access.tomcat.LogbackValve" /> from the server.xml the startup is running fine and Tomcat logs via logback-classic - but logback-access is not used. I found a question on stackoverflow.com where people seem to have the same problem but no solution is provided: https://stackoverflow.com/questions/32134974/added-logback-to-tomcat-got-jav... Does anyone has a hint for me what is going wrong? Best Simon