mod_proxy_ajp with zk leading to timeout errors

asked 2017-07-26 11:53:50 +0800

saurabhz gravatar image saurabhz


We are using hybris application that internally uses ZK framework (version 8.0). Apache is the proxy server before hybris and communication between Apache and hybris is done using AJP. We are using modproxyajp module for communication.

We are seeing the following errors in the logs of Apache: [Wed Jul 19 16:32:25.898151 2017] [proxy_ajp:error] [pid 38976:tid 140482065696512] [client] AH00992: ajp_read_header: ajp_ilink_receive failed, [Wed Jul 19 16:32:25.898177 2017] [proxy_ajp:error] [pid 38976:tid 140482065696512] (70007)The timeout specified has expired: [client] AH00878: read response failed from (,

The requests are getting timed out and the request which is getting time out is as follows: |- |- |[20/Jul/2017:15:45:48 +0530] |POST /backoffice/zkcomet?dtid=z_io60 HTTP/1.1 |200 |- |67.101 |h |Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36 |- |- |[20/Jul/2017:15:45:48 +0530] |POST /backoffice/zkau HTTP/1.1 |200 |2820 |73.200 | |Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36

/zkcomet is taking 67 seconds and as a result tomcat application server responds back with 500 leading to server being unavailable to serve the request. Is this a known issue with ZK? I read zk 6.5.1 has issues with apache mod proxy but ours an upper version. Please help as we don't seem to get around with this issue.

Thanks in advance. Saurabh

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answered 2017-08-01 01:12:09 +0800

cor3000 gravatar image cor3000
6280 2 7

updated 2017-08-01 01:17:01 +0800

Hi Saurabh,

That sounds like the expected and intended behavior.

"/zkcomet" is a servlet handling long polling comet requests from the client to the server to handle server push responses. If you can't configure longer timeouts at apache level for /zkcomet, you can configure a different ajax timeout and retry limit in your zk.xml. Or configure a PollingServerPush. Which does not rely on comet requests.


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Asked: 2017-07-26 11:53:50 +0800

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Last updated: Aug 01 '17

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