Randonly getting 503 response

techteam
Participant I

We are getting the randomly 503 response in our proxy. This is very frequent sometimes. This is our the response we are getting.


HTTP/1.1 503 Service Unavailable

Date: Mon, 12 Mar 2018 05:18:13 GMT
Content-Length: 139
Connection: keep-alive
Content-Type: application/json

{"fault":{"faultstring":"The Service is temporarily unavailable","detail":{"errorcode":"messaging.adaptors.http.flow.ServiceUnavailable"}}

This behavior is random. In our all the cases, the request which was returning 503 on the second attempt it is returning response 200.

0 4 710
4 REPLIES 4

There are a couple of different things that could be causing a 503 error. The one that comes to mind immediately is a Spike Arrest -- you may want to check to make sure your Spike Arrest parameters are set correctly.

Another common issue is if the backing service really isn't responding in a timely fashion. Perhaps the first call takes much longer than expected to return, exceeding the timeout period. The second call to the backing service then queries the now loaded cache. You can check this by looking at the trace and seeing if the response from the backing service (the "factory" in the trace) is 503.

If it's neither of these things, you'll need to post your configuration and/or trace for review.

Thanks, Paul. I will look into the Spike Arrest.

Regarding the backing service, it is running fine. Interesting thing here happening is none of the 503 calls are appearing in trace.

Do a tcpdump on target endpoint on mp servers if it is on-prem.

Usually you would get this error if MP is not able tor each backend server.(Could be one MP is not responding/not able tor each backend). TCPDump will help clear out where the issue is..

You might look at some of the steps in this related question, to see if the troubleshooting steps yield any interesting insights.

https://community.apigee.com/questions/28966/why-are-we-seeing-intermittent-503-errors.html