Unexpected application redeploys on Tomcat

Environment

• JBoss Web Server (JWS) 5.x
  • Tomcat 9.0.x

Issue

• We occasionally see applications are unexpectedly redeploy on Tomcat and user's lose their session state as a result.

Resolution

• Set autoDeploy to false in the Host element of your Tomcat conf/server.xml to disable the automatic redeployments from file modifications:

      <Host name="localhost"  appBase="webapps"
            unpackWARs="true" autoDeploy="false">

• Or identify the source of and stop any unwanted application file modifications prompting the redeployments

Root Cause

• Files monitored under /webappsor conf/Catalina/ are being modified to trigger a redeployment

Diagnostic Steps

• Set the following in your tomcat conf/logging.properties for additional logging:

org.apache.catalina.startup.HostConfig.level = FINEST

• This will log messages like below indicating the files being monitored for modifications

12-Jul-2022 10:00:29.441 FINE [Catalina-utility-2] org.apache.catalina.startup.HostConfig.checkResources Checking context[/docs] redeploy resource /jboss/jws-5.6/tomcat/webapps/docs.war
12-Jul-2022 10:00:29.442 FINE [Catalina-utility-2] org.apache.catalina.startup.HostConfig.checkResources Checking context[/docs] redeploy resource /jboss/jws-5.6/tomcat/webapps/docs
12-Jul-2022 10:00:29.442 FINE [Catalina-utility-2] org.apache.catalina.startup.HostConfig.checkResources Checking context[/docs] redeploy resource /jboss/jws-5.6/tomcat/conf/Catalina/localhost/docs.xml
12-Jul-2022 10:00:29.442 FINE [Catalina-utility-2] org.apache.catalina.startup.HostConfig.checkResources Checking context[/docs] redeploy resource /jboss/jws-5.6/tomcat/webapps/docs/META-INF/context.xml
12-Jul-2022 10:00:29.442 FINE [Catalina-utility-2] org.apache.catalina.startup.HostConfig.checkResources Checking context[/docs] redeploy resource /jboss/jws-5.6/tomcat/conf/context.xml
12-Jul-2022 10:00:29.442 FINE [Catalina-utility-2] org.apache.catalina.startup.HostConfig.checkResources Checking context[/docs] reload resource /jboss/jws-5.6/tomcat/conf/web.xml
12-Jul-2022 10:00:29.442 FINE [Catalina-utility-2] org.apache.catalina.startup.HostConfig.checkResources Checking context[/docs] reload resource /jboss/jws-5.6/tomcat/webapps/docs/WEB-INF/tomcat-web.xml
12-Jul-2022 10:00:29.442 FINE [Catalina-utility-2] org.apache.catalina.startup.HostConfig.checkResources Checking context[/docs] reload resource /jboss/jws-5.6/tomcat/webapps/docs/WEB-INF/web.xml

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