PH11895: APAR PI81056 DID NOT FULLY RESOLVE THE ISSUE RESULTING IN MSG CWWKO0224E (HOSTNAME RESOLUTION ERROR) DURING SERVER STARTUP

APAR status

• Closed as program error.

Error description

• When the Liberty server is started shortly after TCPIP is
  up, there is a timing window where there may not be routes
  to the DNS causing a the server's host name to fail to be
  resolved (since the DNS cannot be contacted). In a case like
  this, if the server tries to resolve the host name at a
  later time, the host name will resolve successfully. So, the
  server should retry starting the TCP Channel, versus needing
  to be restarted. The messages.log will show these errors:
  CWWKO0224E: TCP Channel defaultHttpEndpoint-ssl
  initialization failed. The host server_hostname and port
  server_port could not be resolved.
  

Local fix

• start the Liberty Server after TCPIP and other network
  applications like OMPROUTE are fully up
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All Users of IBM WebSphere Application      *
  *                  Server Liberty - Channel Framework          *
  ****************************************************************
  * PROBLEM DESCRIPTION: Rarely, a port may not open during      *
  *                      server startup                          *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When a Liberty server is started shortly after TCPIP has
  finished starting, there is a timing window where the server's
  host name cannot be resolved due to failure to contact DNS, and
  the server fails to open up one or more ports.
  
  When this happens, the following error will be seen in
  messages.log:
  
  CWWKO0224E: TCP Channel defaultHttpEndpoint-ssl initialization
  failed. The host server_hostname and port server_port could not
  be resolved.
  
  In such a case, the server would eventually be able to resolve
  the hostname and open the ports if it tried again later, but
  there currently does not exist any code to attempt a retry.
  

Problem conclusion

• Port opening retry logic was added to Liberty.  Each retry
  attempt will be tried 1 second after the previous one, up until
  the port opens successfully or the number of retries has been
  reached.  To activate this logic add the portOpenRetries option
  to the tcpOptions under the httpEndpoint element in server.xml.
  The fix for this APAR is currently targeted for inclusion in fix
  pack 20.0.0.2.  Please refer to the Recommended Updates page for
  delivery information:
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

Temporary fix

• Ensure the subsystem which provides port access is ready to have
  the port opened.
  

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  LIBERTY PROF -

• Fixed component ID

  5655W6514

Applicable component levels