Auto Upgrade fails for MID servers on Linux hosts: ERROR *** Error or exception in monitor: java.long.NoClassDefFoundErrorIssue MID server Auto Upgrade fails with error: AutoUpgrade.3600 SEVERE *** ERROR *** Error or exception in monitor: java.long.NoClassDefFoundError. Agent logs also show below error: StatusMonitor.600 SEVERE *** ERROR *** ip-192-168-220-6: ip-192-168-220-6: Name or service not known ReleaseMID servers installed on Linux/Unix hostsCauseBoth errors seen in the agent and wrapper logs come down to the following parts of the code: For startup: com.glide.util.HostUtil.getHostname(HostUtil.java:47) Or for upgrade: shade.distupgrade.com.glide.util.HostUtil.getHostname(HostUtil.java:52) This calls regular java class: java.net.InetAddress.getLocalHost(); This only checks the hostname in /etc/hosts and ignores /etc/resolv.conf of Linux hostsResolution Putty into the hostAttempt to restart the MID cd /servicenow/MIDSERVER1/agentRun the command ./stop.shRun the command ./start.sh At this point the MID should come UP and then quickly change to UPGRADING stateIf not.... Check the agent log for the errors below(You can use VI editor or "less" command): MIDServer SEVERE *** ERROR *** MIDSERVER1: MIDSERVER1: System errorjava.net.UnknownHostException: MIDSERVER: MISERVER: System errorat java.net.InetAddress.getLocalHost(InetAddress.java:1505) Or AutoUpgrade.3600 SEVERE *** ERROR *** Error or exception in monitorjava.lang.NoClassDefFoundError: shade/distupgrade/org/xml/sax/SAXExceptionat shade.distupgrade.com.glide.util.Log.isIgnoredException(Log.java:482) To resolve this you can do the following: Run the command "hostname" to find the name of the hostRun "ifconfig" to find the IP address of the hostUse VI (editor) and edit the /etc/hosts file by adding a line to reflect the localhost 192.168.220.6 MIDSERVER1 localhost Restart the MID by doing the following: Change directory by running "cd /servicenow/MIDSERVER1/agent"Run the command ./stop.shRun the command ./start.sh