Tomcat simple tcp cluster doesn't work on switching browser

Question

I have two instances of apache-tomcat-7.0.41 running on the same server , the strange behaviour i'm observing is that a sessions are shared between the servers on multiple logins/logouts on the same browser , but when i switch browsers , the session sharing stops .

I tried finding the active sessions as mentioned in Find number of active sessions created from a given client IP by printing created & destroyed sessions

@Override  
public void sessionDestroyed(HttpSessionEvent event) {
    System.out.println("Session Destroyed::: "+event.getSession().getId());
}

@Override
public void sessionCreated(HttpSessionEvent event) {
    System.out.println("New Session ::: "+event.getSession().getId());
}

The resultant logs from this when using chrome : The tomcat through which I login:

Session Destroyed::: AC526EC82AF5E6F6F46A0BD9441EAAF0.SERVER-1
New Session ::: F87CCF46CC3318A758F3700D6437DDC4.SERVER-1
New Session ::: D0B6D84056544E7C0F425191010B1D08.SERVER-1
Session Destroyed::: F87CCF46CC3318A758F3700D6437DDC4.SERVER-1
New Session ::: 87EBFFA05489A2B22A1CD13352DC8688.SERVER-1
Session Destroyed::: 87EBFFA05489A2B22A1CD13352DC8688.SERVER-1
New Session ::: A00EC8504F9B4A93A6CD511B4EA64D0B.SERVER-1
New Session ::: 542841168FB92E17B2946EE5D194A439.SERVER-1
New Session ::: 6CAE12739B17D7C86E5596EBB3B364FD.SERVER-1
New Session ::: FE483E49AFA99D939E5C534C4E6428BF.SERVER-1
New Session ::: 3B6B21B01320EDD1A56C9A54DFAEDAB6.SERVER-1
Session Destroyed::: A00EC8504F9B4A93A6CD511B4EA64D0B.SERVER-1
New Session ::: 39BAD300FBEC2A55C770BEA3A0A78BA3.SERVER-1

The other tomcat :

New Session ::: F87CCF46CC3318A758F3700D6437DDC4.SERVER-1
New Session ::: D0B6D84056544E7C0F425191010B1D08.SERVER-1
Session Destroyed::: F87CCF46CC3318A758F3700D6437DDC4.SERVER-1
New Session ::: 87EBFFA05489A2B22A1CD13352DC8688.SERVER-1
Session Destroyed::: 87EBFFA05489A2B22A1CD13352DC8688.SERVER-1
New Session ::: A00EC8504F9B4A93A6CD511B4EA64D0B.SERVER-1
New Session ::: 542841168FB92E17B2946EE5D194A439.SERVER-1
New Session ::: 6CAE12739B17D7C86E5596EBB3B364FD.SERVER-1
New Session ::: FE483E49AFA99D939E5C534C4E6428BF.SERVER-1
New Session ::: 3B6B21B01320EDD1A56C9A54DFAEDAB6.SERVER-1
Session Destroyed::: A00EC8504F9B4A93A6CD511B4EA64D0B.SERVER-1
New Session ::: 39BAD300FBEC2A55C770BEA3A0A78BA3.SERVER-1

When i switch to firefox: The tomcat through which I login:

New Session ::: BE144AA97F9006D584D10D8FB5BB84B4.SERVER-1
Session Destroyed::: BE144AA97F9006D584D10D8FB5BB84B4.SERVER-1
New Session ::: FF0C14863E36DD748911B0209A089A87.SERVER-1
Session Destroyed::: FF0C14863E36DD748911B0209A089A87.SERVER-1
New Session ::: 6003A09956987A2035EB9BB1C5D7C157.SERVER-1
New Session ::: 2F3D59D9CD286F52C2B0C25FFEB646B5.SERVER-1
Session Destroyed::: 6003A09956987A2035EB9BB1C5D7C157.SERVER-1
New Session ::: F6DAA85FE306B0BBAAB9165216AA7290.SERVER-1
New Session ::: 2A5CBDDFB3B2A3CFBD39DDDF4679387F.SERVER-1
Session Destroyed::: F6DAA85FE306B0BBAAB9165216AA7290.SERVER-1
New Session ::: FA44460CD84449E303CF8D460DB016D4.SERVER-1
Session Destroyed::: FA44460CD84449E303CF8D460DB016D4.SERVER-1
New Session ::: 7DCF3832ABF83590543667DC4614151C.SERVER-1
New Session ::: 1066B025A7FBB295C6BD1043B9724322.SERVER-1
New Session ::: 62133E533528AD516061B09E65AFD175.SERVER-1
Session Destroyed::: 7DCF3832ABF83590543667DC4614151C.SERVER-1
New Session ::: C1FB38B4F6F0BA9AB1C43E5BD63B2ADC.SERVER-1
New Session ::: A3DFDFF36B39FE46C3074893AD312966.SERVER-1
Session Destroyed::: 62133E533528AD516061B09E65AFD175.SERVER-1
New Session ::: 16753CA90D112DE434ABA8A71F567C15.SERVER-1
Session Destroyed::: A3DFDFF36B39FE46C3074893AD312966.SERVER-1
New Session ::: F616A40375D798AB04D25B37F8FEFCF3.SERVER-1
Session Destroyed::: C1FB38B4F6F0BA9AB1C43E5BD63B2ADC.SERVER-1
New Session ::: A425ED49A28347E305B5EE0CC22A03ED.SERVER-1
Session Destroyed::: A425ED49A28347E305B5EE0CC22A03ED.SERVER-1
New Session ::: B3D9E3632685A6DEB53F753AE53145F1.SERVER-1
Session Destroyed::: D0B6D84056544E7C0F425191010B1D08.SERVER-1
Session Destroyed::: 39BAD300FBEC2A55C770BEA3A0A78BA3.SERVER-1
Session Destroyed::: 542841168FB92E17B2946EE5D194A439.SERVER-1
Session Destroyed::: 3B6B21B01320EDD1A56C9A54DFAEDAB6.SERVER-1
Session Destroyed::: 6CAE12739B17D7C86E5596EBB3B364FD.SERVER-1
Session Destroyed::: FE483E49AFA99D939E5C534C4E6428BF.SERVER-1
Session Destroyed::: 2F3D59D9CD286F52C2B0C25FFEB646B5.SERVER-1
Session Destroyed::: 2A5CBDDFB3B2A3CFBD39DDDF4679387F.SERVER-1
Session Destroyed::: 16753CA90D112DE434ABA8A71F567C15.SERVER-1
Session Destroyed::: F616A40375D798AB04D25B37F8FEFCF3.SERVER-1
Session Destroyed::: 1066B025A7FBB295C6BD1043B9724322.SERVER-1
Session Destroyed::: B3D9E3632685A6DEB53F753AE53145F1.SERVER-1
Session Destroyed::: 2F43D41620B158302343EB309D94E929.SERVER-1

The other tomcat :

New Session ::: BE144AA97F9006D584D10D8FB5BB84B4.SERVER-1
New Session ::: 1066B025A7FBB295C6BD1043B9724322.SERVER-1
New Session ::: 62133E533528AD516061B09E65AFD175.SERVER-1
Session Destroyed::: D0B6D84056544E7C0F425191010B1D08.SERVER-1
Session Destroyed::: 542841168FB92E17B2946EE5D194A439.SERVER-1
Session Destroyed::: 3B6B21B01320EDD1A56C9A54DFAEDAB6.SERVER-1
Session Destroyed::: 6CAE12739B17D7C86E5596EBB3B364FD.SERVER-1
Session Destroyed::: FE483E49AFA99D939E5C534C4E6428BF.SERVER-1
Session Destroyed::: 62133E533528AD516061B09E65AFD175.SERVER-1
Session Destroyed::: 1066B025A7FBB295C6BD1043B9724322.SERVER-1
Session Destroyed::: 39BAD300FBEC2A55C770BEA3A0A78BA3.SERVER-1
Session Destroyed::: BE144AA97F9006D584D10D8FB5BB84B4.SERVER-1

It seems from the logs that the session info is not communicated to the second server due to some reason on switching from chrome to firefox , which seems strange but i could replicate the behaviour on firefox & safari too.

I tried the solution mentioned in Tomcat's Clustering / Session Replication not replicating properly

Although it did not work , the second answer mentions using channelSendOptions="6". Tomcat docs mention channelSendOptions as

    One of the most important performance considerations is the synchronous versus
 asynchronous replication. In a synchronous replication mode the request doesn't 
return until the replicated session has been sent over the wire and reinstantiated
 on all the other cluster nodes. Synchronous vs. asynchronous is configured using 
the channelSendOptions flag and is an integer value. The default value for the 
SimpleTcpCluster/DeltaManager combo is 8, which is asynchronous. You can read more 
on the send flag(overview) or the send flag(javadoc). During async replication,
 the request is returned before the data has been replicated. async replication 
yields shorter request times, and synchronous replication guarantees the session 
to be replicated before the request returns.

Has anyone experienced such an issue before and/or could guide me to anything else I could try out ? Also could changing the channelSendOptions help ?

UPDATE

I tried to see if the connection between two tomcats is working correctly & took a netstat with the receiver port(4010) of tomcat 2 & process id(13437) of tomcat 1 which gives the following.

netstat -anp | grep 4010 | grep 192.168.x.x:4010 | grep 13437/java  
tcp        0    580 ::ffff:192.168.x.x:41140 ::ffff:192.168.x.x:4010 ESTABLISHED 13437/java          
tcp        0    578 ::ffff:192.168.x.x:41136 ::ffff:192.168.x.x:4010 ESTABLISHED 13437/java          


netstat -anp | grep 4010 | grep 192.168.x.x:4010 | grep 13437/java  
tcp        0    580 ::ffff:192.168.x.x:41146 ::ffff:192.168.x.x:4010 ESTABLISHED 13437/java          
tcp        0    826 ::ffff:192.168.x.x:41151 ::ffff:192.168.x.x:4010 ESTABLISHED 13437/java


netstat -anp | grep 4010 | grep 192.168.x.x:4010 | grep 13437/java  
tcp        0    757 ::ffff:192.168.x.x:41223 ::ffff:192.168.x.x:4010 ESTABLISHED 13437/java


netstat -anp | grep 4010 | grep 192.168.x.x:4010 | grep 13437/java  
tcp        0    580 ::ffff:192.168.x.x:41292 ::ffff:192.168.x.x:4010 ESTABLISHED 13437/java          
tcp        0    757 ::ffff:192.168.x.x:41286 ::ffff:192.168.x.x:4010 ESTABLISHED 13437/java          
tcp        0    578 ::ffff:192.168.x.x:41282 ::ffff:192.168.x.x:4010 ESTABLISHED 13437/java          
tcp        0      1 ::ffff:192.168.x.x:41293 ::ffff:192.168.x.x:4010 SYN_SENT    13437/java


netstat -anp | grep 4010 | grep 192.168.x.x:4010 | grep 13437/java

I have two observations :

a) The no of connections keeps changing form 0 to 4 .

b) When this issue occurs , the Receive queue starts filling up

Is observation 'a' normal behaviour? And are there ways to identify why the receive queue filling up ?

1. Explain, what do you mean when you say "I am switching browsers". There are several ways to interpret that English phrase. 2. Explain, what would be "expected" behaviour for you. What specifically you do not like? — Konstantin Kolinko, Nov 16 '15 at 11:37
1) As I mentioned while pasting the logs . When I established a session using chrome on tomcat 1 , I see that it is shared with tomcat 2 . But when I login again through firefox on tomcat 1 , the session is not shared with tomcat , 2) The expected behaviour is that the new session created through forefox on tomcat 1 should be shared with tomcat 2 — Amit Rawat, Nov 17 '15 at 09:42

Tomcat simple tcp cluster doesn't work on switching browser

0 Answers0