1. 503 - Servlet Temporarily Unavailable.
If the Servlet is destroyed or application is stopped when the
request is in service method for longer than 60sec, then the
servlet becomes unavailable.
PROBLEM DESCRIPTION: Servlets return 503 return code after an application has been restarted.
RECOMMENDATION: When stopping an application, the WebContainer waits for any
active servlet requests to finish before destroying the associated servlet wrapper. If the WebContainer times out waiting for the service method to complete, it will destroy
the wrapper anyway and when the currently serviced request Finishes it will add the wrapper back to the cache.
Conclusion
Updated the WebContainer to prevent servlet wrappers from being added for web applications that are being stopped. The fix for this APAR is currently targeted for inclusion in fix pack 6.1.0.19. Please refer to the Recommended Updates page for delivery information:
2. ERROR : During a rolling restart of the appservers, the server will respond to requests with a 503 "Service temporarily unavailable" response. When plugin receives a 503 response, it will retry the request to try to obtain a good response. If the request has affinity, it will go back to the same server thus resulting in a failure because the server is being restarted.
PROBLEM DESCRIPTION: When the server provides a 503 *
response, if the request has affinity, all retries will go to the same server.
RECOMMENDATION:Requests are retried to the same server if the request has
affintiy and the server responds with a 503 reponse code.
Problem conclusion
A custom property has been added to allow for a failover to occur if the server responds with a 503. The property MarkBusyDown is set at Servers > Web Servers > Web_server_name > Plug-in properties > Custom propertie. If the value is true, then plugin will temporarily mark the server down to give it a chance to complete the restart. The duration of the markdown depends on the RetryInterval specified in the plugin configuration.
If the Servlet is destroyed or application is stopped when the
request is in service method for longer than 60sec, then the
servlet becomes unavailable.
PROBLEM DESCRIPTION: Servlets return 503 return code after an application has been restarted.
RECOMMENDATION: When stopping an application, the WebContainer waits for any
active servlet requests to finish before destroying the associated servlet wrapper. If the WebContainer times out waiting for the service method to complete, it will destroy
the wrapper anyway and when the currently serviced request Finishes it will add the wrapper back to the cache.
Conclusion
Updated the WebContainer to prevent servlet wrappers from being added for web applications that are being stopped. The fix for this APAR is currently targeted for inclusion in fix pack 6.1.0.19. Please refer to the Recommended Updates page for delivery information:
2. ERROR : During a rolling restart of the appservers, the server will respond to requests with a 503 "Service temporarily unavailable" response. When plugin receives a 503 response, it will retry the request to try to obtain a good response. If the request has affinity, it will go back to the same server thus resulting in a failure because the server is being restarted.
PROBLEM DESCRIPTION: When the server provides a 503 *
response, if the request has affinity, all retries will go to the same server.
RECOMMENDATION:Requests are retried to the same server if the request has
affintiy and the server responds with a 503 reponse code.
Problem conclusion
A custom property has been added to allow for a failover to occur if the server responds with a 503. The property MarkBusyDown is set at Servers > Web Servers > Web_server_name > Plug-in properties > Custom propertie. If the value is true, then plugin will temporarily mark the server down to give it a chance to complete the restart. The duration of the markdown depends on the RetryInterval specified in the plugin configuration.
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