Re: Different apps clustering on the same Tomcat?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 John, On 1/20/2010 10:28 PM, John Tangney wrote: We use a cluster to do seamless deploys. We use Nginx on the front end to direct traffic to one or other of the nodes in the cluster. To deploy, we bring up the new version of the app in a one node, tell Nginx to send traffic to that node, then bring down the other node. Because sessions are propagated, users never notice that one node has been exchanged for another. Careful: if you change the definition of any of the classes whose objects are in the session, you'll get a nasty replication error (because de-serialization will fail). Be careful with anything you modify that might be lurking in a user's session. We need to add two more nodes that run on Windows (we have platform-specific code, and Nginx sends windows traffic to one of the windows nodes based on URL) but we only have one Windows box. We thought that perhaps we could just run a second instance of the app on the Windows node. From what you said previously, this does not appear to be possible. So we'll be looking new hardware. Oh, you can certainly do it. Knowing why you want to do it certainly helps clear things up. I'm still as confused as Chuck is, though :) - -chris -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAktYcQ0ACgkQ9CaO5/Lv0PDZCgCdF4KSG28DNwocB2nYQyuX6gHU Me0AniApCDjAYyRRM+kAGI/nkBIv6+Oc =rdu1 -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
RE: Different apps clustering on the same Tomcat?
Thanks, Chuck. Caldarale, Charles R chuck.caldar...@unisys.com wrote .. From: John Tangney [mailto:jo...@jdtangney.com] Is it possible to get two apps in the same Tomcat instance to exchange session info, in a cluster? If so, how? Not sure what you're asking. Apologies if I was not clear. We have two machines, each with a Tomcat, forming a cluster. An app named gh runs on each cluster node. We want to add a second app to one of the Tomcats (call it gh2 it's just a clone of gh) that synchronizes sessions with gh on all of the nodes. Multiple apps in one Tomcat cannot share a session, since that's prohibited by the servlet spec. I think you've answered my question. So gh2 cannot synchronize sessions with gh on the same cluster node or not. You can create a bean from a class in a shared library to hold data needed by both apps. Ah, this sounds promising! Where would this shared library live so that both apps can talk to it? Just for background... In an ideal world, we'd just buy another server and add it to the (existing) cluster. But we are looking for ways to get the benefit of another cluster node without new hardware. Thanks! --johnt - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: Different apps clustering on the same Tomcat?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 John, On 1/20/2010 12:37 PM, John Tangney wrote: Just for background... In an ideal world, we'd just buy another server and add it to the (existing) cluster. But we are looking for ways to get the benefit of another cluster node without new hardware. Is this need for a new server related to your desire to add a shadow copy of the webapp? If so, I don't see the point: deploying another instance of the webapp into an existing Tomcat isn't going to help you serve any more users... which would be the point of bringing another server online. Maybe I don't understand. - -chris -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAktXUHIACgkQ9CaO5/Lv0PDl+ACfQri+1/l/fY4JAB2WkMqTl/E/ xWQAnAz4//+Mwqb+ovDnH3sWCsQRjwxi =GrHE -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
RE: Different apps clustering on the same Tomcat?
From: John Tangney [mailto:jo...@jdtangney.com] Subject: RE: Different apps clustering on the same Tomcat? We have two machines, each with a Tomcat, forming a cluster. An app named gh runs on each cluster node. We want to add a second app to one of the Tomcats (call it gh2 ? it's just a clone of gh) that synchronizes sessions with gh on all of the nodes. Like Chris, I still don't really understand what you're trying to achieve. You can create a bean from a class in a shared library to hold data needed by both apps. Ah, this sounds promising! Where would this shared library live so that both apps can talk to it? In Tomcat 6, $CATALINA_HOME/lib; in 5.5, $CATALINA_HOME/shared/lib (or classes). You also have the option of modifying conf/catalina.properties and defining your own location for classloaders to examine. - Chuck THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: Different apps clustering on the same Tomcat?
On Jan 20, 2010, at 10:57 AM, Caldarale, Charles R wrote: From: John Tangney [mailto:jo...@jdtangney.com] Subject: RE: Different apps clustering on the same Tomcat? We have two machines, each with a Tomcat, forming a cluster. An app named gh runs on each cluster node. We want to add a second app to one of the Tomcats (call it gh2 ? it's just a clone of gh) that synchronizes sessions with gh on all of the nodes. Like Chris, I still don't really understand what you're trying to achieve. We use a cluster to do seamless deploys. We use Nginx on the front end to direct traffic to one or other of the nodes in the cluster. To deploy, we bring up the new version of the app in a one node, tell Nginx to send traffic to that node, then bring down the other node. Because sessions are propagated, users never notice that one node has been exchanged for another. We need to add two more nodes that run on Windows (we have platform- specific code, and Nginx sends windows traffic to one of the windows nodes based on URL) but we only have one Windows box. We thought that perhaps we could just run a second instance of the app on the Windows node. From what you said previously, this does not appear to be possible. So we'll be looking new hardware. Thanks for all your help! --johnt - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
RE: Different apps clustering on the same Tomcat?
From: John Tangney [mailto:jo...@jdtangney.com] Subject: Re: Different apps clustering on the same Tomcat? We use a cluster to do seamless deploys. We use Nginx on the front end to direct traffic to one or other of the nodes in the cluster. To deploy, we bring up the new version of the app in a one node, tell Nginx to send traffic to that node, then bring down the other node. Because sessions are propagated, users never notice that one node has been exchanged for another. This is fairly typical. We need to add two more nodes that run on Windows (we have platform- specific code, and Nginx sends windows traffic to one of the windows nodes based on URL) but we only have one Windows box. We thought that perhaps we could just run a second instance of the app on the Windows node. This is the part that I can't make sense of. You talk about two more Windows nodes, which I take to mean two more OS/JVM/Tomcat instances. Then you talk about *one* additional instance of your existing webapp running in the same Tomcat, but using a different name. Your numbers don't match up. You can run multiple instances of Tomcat on the same box, and each could have a copy of the app deployed, and each Tomcat could be a separate node in the cluster. You would need to give each Tomcat instance a unique IP address or set of ports, of course, and make sure you have enough RAM to handle all instances without provoking paging. - Chuck THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: Different apps clustering on the same Tomcat?
On Jan 20, 2010, at 7:38 PM, Caldarale, Charles R wrote: You can run multiple instances of Tomcat on the same box, and each could have a copy of the app deployed, and each Tomcat could be a separate node in the cluster. That's exactly what we do on Linux, but it fails on Windows due to a bug I have already logged. --johnt - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
RE: Different apps clustering on the same Tomcat?
From: John Tangney [mailto:jo...@jdtangney.com] Subject: Re: Different apps clustering on the same Tomcat? That's exactly what we do on Linux, but it fails on Windows due to a bug I have already logged. What bug is that? I run multiple Tomcats concurrently on Vista 64 without a problem. - Chuck THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
RE: Different apps clustering on the same Tomcat?
From: John Tangney [mailto:jo...@jdtangney.com] Subject: Different apps clustering on the same Tomcat? Is it possible to get two apps in the same Tomcat instance to exchange session info, in a cluster? If so, how? Not sure what you're asking. If there's only one Tomcat instance, there's no cluster. Multiple apps in one Tomcat cannot share a session, since that's prohibited by the servlet spec. You can create a bean from a class in a shared library to hold data needed by both apps. If you really do have a cluster of multiple Tomcat instances, you can choose to replicate session information across them by any of several means. Consult the documentation for details: http://tomcat.apache.org/tomcat-6.0-doc/cluster-howto.html - Chuck THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
