mod_jk: Hot Standby and Load Balance
Due to some differences in our applications, some of them can be truly load balanced, and some of them really cannot (yet). That is, some of our applications can be (and have been) truly load balanced, and others need (and only allow) simple failover support (hot standby). I noticed that workers now support both possibilities (using disabled and redirect flags to support hot standby). What I'd like to do ultimately is have a hot standby load balancer and as well as a normal load balancer, but it doesn't seem like that's possible. From what I understand, you can really only have 1 load balanced worker per tomcat instance because it must match the jvmRoute of that instance -- having one worker that's disabled and one that's not doesn't seem possible. So if I define a load balance worker as: # traditional load balance worker worker.lb_tala_build.type=ajp13 worker.lb_tala_build.host=tala worker.lb_tala_build.port=8000 worker.lb_tala_build.lbfactor=1 worker.lb_tala_build.socket_keepalive=1 worker.lb_tala_build.recycle_timeout=300 I cannot really define a second load balanced worker like below (b/c no matching jvmRoute) # a hot standby worker based on the worker above worker.lb_tala_build2.type=ajp13 worker.lb_tala_build2.host=tala worker.lb_tala_build2.port=8000 worker.lb_tala_build2.lbfactor=1 worker.lb_tala_build2.socket_keepalive=1 worker.lb_tala_build2.recycle_timeout=300 worker.lb_tala_build2.disabled=True Is anyone familiar with this setup of have any ideas how it could be achieved? (the same problem exists for what would be the Primary server, as it would need a worker that redirects and one that doesn't) Ps - Being able to specify the jvmRoute separately would solve this problem: worker.lb_tala_build2.jvmRoute=lb_tala_build - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: mod_jk: Hot Standby and Load Balance
Well, I was thinking of using something like (truncated for clarity): # load balanced worker.lb_traditional.type=lb worker.lb_traditional.balance_workers=lb_worker1,lb_worker2 worker.lb_traditional.sticky_session=true # workers 1 and 2 are load balanced worker.lb_worker1.type=ajp13 worker.lb_worker1.host=server1 worker.lb_worker1.domain=theJRMRoute worker.lb_worker2.type=ajp13 worker.lb_worker2.host=server2 worker.lb_worker2.domain=theJRMRoute # standby setup worker.lb_standby.type=lb worker.lb_standby.balance_workers=lb_worker3,lb_worker4 worker.lb_standby.sticky_session=true # workers 4 is hot standby for worker 3 worker.lb_worker3.type=ajp13 worker.lb_worker3.host=server1 worker.lb_worker3.domain=theJRMRoute worker.lb_worker3.redirect=worker4 worker.lb_worker4.type=ajp13 worker.lb_worker4.host=server2 worker.lb_worker4.domain=theJRMRoute worker.lb_worker4.disabled=True Guernsey, Byron (GE Consumer Industrial) wrote: I believe you can specify the jvmRoute separately by using the domain attribute, but I'm not sure I see how this would help? Byron -Original Message- From: Mott Leroy [mailto:[EMAIL PROTECTED] Sent: Wednesday, August 31, 2005 11:03 AM To: Tomcat Users List Subject: mod_jk: Hot Standby and Load Balance Due to some differences in our applications, some of them can be truly load balanced, and some of them really cannot (yet). That is, some of our applications can be (and have been) truly load balanced, and others need (and only allow) simple failover support (hot standby). I noticed that workers now support both possibilities (using disabled and redirect flags to support hot standby). What I'd like to do ultimately is have a hot standby load balancer and as well as a normal load balancer, but it doesn't seem like that's possible. From what I understand, you can really only have 1 load balanced worker per tomcat instance because it must match the jvmRoute of that instance -- having one worker that's disabled and one that's not doesn't seem possible. So if I define a load balance worker as: # traditional load balance worker worker.lb_tala_build.type=ajp13 worker.lb_tala_build.host=tala worker.lb_tala_build.port=8000 worker.lb_tala_build.lbfactor=1 worker.lb_tala_build.socket_keepalive=1 worker.lb_tala_build.recycle_timeout=300 I cannot really define a second load balanced worker like below (b/c no matching jvmRoute) # a hot standby worker based on the worker above worker.lb_tala_build2.type=ajp13 worker.lb_tala_build2.host=tala worker.lb_tala_build2.port=8000 worker.lb_tala_build2.lbfactor=1 worker.lb_tala_build2.socket_keepalive=1 worker.lb_tala_build2.recycle_timeout=300 worker.lb_tala_build2.disabled=True Is anyone familiar with this setup of have any ideas how it could be achieved? (the same problem exists for what would be the Primary server, as it would need a worker that redirects and one that doesn't) Ps - Being able to specify the jvmRoute separately would solve this problem: worker.lb_tala_build2.jvmRoute=lb_tala_build - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: mod_jk: Hot Standby and Load Balance
Rainer Jung wrote: The balanced workers behind lb1, lb2 etc. are allowed to have the same name, because each load balancer has it's own list of balanced workers with associated attributes. I expect no problem from a clash of names of balanced workers in different balancing workers. I must be missing something obvious here. I am with you on the JKMount part, but I just don't see how the name clash isn't an issue for worker.properties. Simplifying again ... # as per your suggestion ... where worker1 and worker2 are jvmRoutes worker.lb1.balanced_workers=worker1,worker2 worker.lb2.balanced_workers=worker1,worker2 # the balanced workers ... which should they choose ... ? worker.worker1 (failover version) worker.worker1 (not failover version) worker.worker2 (standby version) worker.worker2 (non-standby version) - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
jar files
This probably sounds like a very newbie question, but for your own application classes, (not third party), is there any particular reason to jar them and put them into WEB-INF/lib vs compiling them as class files to WEB-INF/classes? The classloader won't blindly just load the whole jar will it? For an applet, using Jars makes some sense to avoid continually downloading class files, what are the advantages for web applications? - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: jar files
Ultimately, after a build, it's just a war file, so that's not really an issue for me. Tim Funk wrote: Personally - I prefer jar files. Its one file to keep track of. Instead of 100's of .class files. When you start building up your library - you start to get a large directory of WEB-INF/classes. It much easier to manage them as jar files. -Tim Mott Leroy wrote: This probably sounds like a very newbie question, but for your own application classes, (not third party), is there any particular reason to jar them and put them into WEB-INF/lib vs compiling them as class files to WEB-INF/classes? The classloader won't blindly just load the whole jar will it? For an applet, using Jars makes some sense to avoid continually downloading class files, what are the advantages for web applications? - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
session problems when using mod_jk (1.2.14) load balancing
Hi - I'm unable to get mod_jk load balancing working. The usual mod_jk setup works just fine, but using a load balancing worker however, is not. [Oddly, my webserver crashed during testing of this, but that could very well be unrelated] The problem is with user sessions. The instances (nodes) do not seem to recognize an already established session with the user and are creating new sessions. It's possible that is a session-stickiness issue, but it appears like the requests are hitting the same instance, just not getting the previously established session. As a result, I can't even reliably login to my application. I created a session listener for debugging purposes and it reports -no- destroyed sessions, but plenty of newly created sessions on both instances that make up the cluster. The session IDs, I noticed, have the jvmRoute name attached to them, which should be a good sign. I have a webserver running Apache (1.3.33), mod_jk (1.2.14), and an application server running the cluster -- 2 instances tomcat (5.0.28) on different ports. I added a unique jvmRoute to both instances in the server.xml: Engine name=Catalina defaultHost=localhost jvmRoute=dev_alexis Engine name=Catalina defaultHost=localhost jvmRoute=noah_alexis My worker.properties loadbalancer settings: worker.list=load_balancer_test worker.load_balancer_test.type=lb worker.load_balancer_test.balance_workers=bl_worker_dev,bl_worker_noah worker.load_balancer_test.sticky_session=true worker.load_balancer_test.sticky_session_force=false worker.bl_worker_dev.type=ajp13 worker.bl_worker_dev.host=alexis worker.bl_worker_dev.port=9003 worker.bl_worker_dev.lbfactor=1 worker.bl_worker_dev.socket_keepalive=1 worker.bl_worker_dev.recycle_timeout=300 worker.bl_worker_noah.type=ajp13 worker.bl_worker_noah.host=alexis worker.bl_worker_noah.port=8063 worker.bl_worker_noah.lbfactor=3 worker.bl_worker_noah.socket_keepalive=1 worker.bl_worker_noah.recycle_timeout=300 Any ideas, things I could try would be much appreciated. - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: session problems when using mod_jk (1.2.14) load balancing
Beautiful - worked like a charm. That might take the cake as far as longest question to quickest, shortest answer goes. ha. Thanks a bunch. I might have to gripe about doucmentation in a second (nother thread).. Noah Edgar Alves wrote: Try adding these two lines to worker.properties: worker.bl_worker_dev.domain=dev_alexis worker.bl_worker_noah.domain=noah_alexis -- Edgar Alves Mott Leroy wrote: Hi - I'm unable to get mod_jk load balancing working. The usual mod_jk setup works just fine, but using a load balancing worker however, is not. [Oddly, my webserver crashed during testing of this, but that could very well be unrelated] The problem is with user sessions. The instances (nodes) do not seem to recognize an already established session with the user and are creating new sessions. It's possible that is a session-stickiness issue, but it appears like the requests are hitting the same instance, just not getting the previously established session. As a result, I can't even reliably login to my application. I created a session listener for debugging purposes and it reports -no- destroyed sessions, but plenty of newly created sessions on both instances that make up the cluster. The session IDs, I noticed, have the jvmRoute name attached to them, which should be a good sign. I have a webserver running Apache (1.3.33), mod_jk (1.2.14), and an application server running the cluster -- 2 instances tomcat (5.0.28) on different ports. I added a unique jvmRoute to both instances in the server.xml: Engine name=Catalina defaultHost=localhost jvmRoute=dev_alexis Engine name=Catalina defaultHost=localhost jvmRoute=noah_alexis My worker.properties loadbalancer settings: worker.list=load_balancer_test worker.load_balancer_test.type=lb worker.load_balancer_test.balance_workers=bl_worker_dev,bl_worker_noah worker.load_balancer_test.sticky_session=true worker.load_balancer_test.sticky_session_force=false worker.bl_worker_dev.type=ajp13 worker.bl_worker_dev.host=alexis worker.bl_worker_dev.port=9003 worker.bl_worker_dev.lbfactor=1 worker.bl_worker_dev.socket_keepalive=1 worker.bl_worker_dev.recycle_timeout=300 worker.bl_worker_noah.type=ajp13 worker.bl_worker_noah.host=alexis worker.bl_worker_noah.port=8063 worker.bl_worker_noah.lbfactor=3 worker.bl_worker_noah.socket_keepalive=1 worker.bl_worker_noah.recycle_timeout=300 Any ideas, things I could try would be much appreciated. - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
mod_jk documentation
Before I go gripe too, too much, let me just say that the mod_jk documentation has improved immensely since I start looking into it. Some of it might be simplied by the fact that I no longer consider jk2 in the picture which seemed to be adding some confusion. I don't know who is responsible for updating the documentation, so thought I'd post here. The documentation that I'm referring to is at: http://jakarta.apache.org/tomcat/connectors-doc/index.html load balancing page: Well, the load balancing page is empty, which is ok, but a link to the majority of load balancing explanation on the worker.properties page would be nice. domain property for a worker. I had to use the domain property on a worker to get load balancing working, which corresponds to the jvmRoute. I didn't see any mention of jvmRoute or domain anywhere however in either the load balancing section or the general worker properties. finally, and this may have annoyed me more than anything else - all throughout the load balancing documentation there are red, bolded lines like These workers should not appear in the worker.list property! in reference to balance_workers. But then in the example, they do exactly what they said should NOT be done: (bottom of this page) http://jakarta.apache.org/tomcat/connectors-doc/howto/workers.html - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: session problems when using mod_jk (1.2.14) load balancing
Ok - noted. I changed it. It works without the domain as you noted. Thanks. Rainer Jung wrote: That should not work! The correct way to configure session stickyness is to use jvmRoute (which you already did) and then giving the workers the same names as the jvmRoute. That is instead of bl_worker_dev use dev_alexis and instead of bl_worker_noah use noah_alexis as the worker names. You should check, that the URLs produced by your application include the ;jsessionid=32Characters.jvmRoute or - in case you use cookies - the same info is in your session cookie. mod_jk then automatically strips the jvmRoute part from the session identifier and lloks for a worker of the same name. You will only need to use the domain attribute in case you have a lot of tomcat instances and some of them have the sessions replicated, others not. Then you can give all members of a replication domain the same domain name and mod_jk will know, that in case the correct worker is down, which alternatives are good. Beautiful - worked like a charm. That might take the cake as far as longest question to quickest, shortest answer goes. ha. Thanks a bunch. I might have to gripe about doucmentation in a second (nother thread).. Noah Edgar Alves wrote: Try adding these two lines to worker.properties: worker.bl_worker_dev.domain=dev_alexis worker.bl_worker_noah.domain=noah_alexis -- Edgar Alves Mott Leroy wrote: Hi - I'm unable to get mod_jk load balancing working. The usual mod_jk setup works just fine, but using a load balancing worker however, is not. [Oddly, my webserver crashed during testing of this, but that could very well be unrelated] The problem is with user sessions. The instances (nodes) do not seem to recognize an already established session with the user and are creating new sessions. It's possible that is a session-stickiness issue, but it appears like the requests are hitting the same instance, just not getting the previously established session. As a result, I can't even reliably login to my application. I created a session listener for debugging purposes and it reports -no- destroyed sessions, but plenty of newly created sessions on both instances that make up the cluster. The session IDs, I noticed, have the jvmRoute name attached to them, which should be a good sign. I have a webserver running Apache (1.3.33), mod_jk (1.2.14), and an application server running the cluster -- 2 instances tomcat (5.0.28) on different ports. I added a unique jvmRoute to both instances in the server.xml: Engine name=Catalina defaultHost=localhost jvmRoute=dev_alexis Engine name=Catalina defaultHost=localhost jvmRoute=noah_alexis My worker.properties loadbalancer settings: worker.list=load_balancer_test worker.load_balancer_test.type=lb worker.load_balancer_test.balance_workers=bl_worker_dev,bl_worker_noah worker.load_balancer_test.sticky_session=true worker.load_balancer_test.sticky_session_force=false worker.bl_worker_dev.type=ajp13 worker.bl_worker_dev.host=alexis worker.bl_worker_dev.port=9003 worker.bl_worker_dev.lbfactor=1 worker.bl_worker_dev.socket_keepalive=1 worker.bl_worker_dev.recycle_timeout=300 worker.bl_worker_noah.type=ajp13 worker.bl_worker_noah.host=alexis worker.bl_worker_noah.port=8063 worker.bl_worker_noah.lbfactor=3 worker.bl_worker_noah.socket_keepalive=1 worker.bl_worker_noah.recycle_timeout=300 Any ideas, things I could try would be much appreciated. - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Newbie question
See - http://jakarta.apache.org/tomcat/tomcat-5.5-doc/manager-howto.html#Configuring%20Manager%20Application%20Access From what I remember, admin access follows that same rules as manager app access, so the instructions on that page are the same except the role should be admin not manager. Mário Gamito wrote: Hi, Sorry for this newbie question :( I've just installed Tomcat 5.5 for Linux and so far so good, except... that i've installed also Tomcat Administration module (not the Manager one) and it asks me for a login and a password and i can't find how to define it. I see a file named admin.xml in $CATALINA_HOME/conf/Catalina/localhost saying to uncoment the valve and another two files, but i don't know how to set the login and the password. Any help would be apreciated. Warm Regards, Mário Gamito - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Help - Alias or Symlink to external(to the context) images directory?
http://jakarta.apache.org/tomcat/tomcat-5.0-doc/config/context.html - see the allowLinking property. As far as how to create the symlink when the app is deployed, not sure beyond running some sort of script when the application loads (using a context listener perhaps). Matt Galvin wrote: Hi All, Does anyone know of a way to set an alias to an external directory that contains images to be displayed on a web page? Maybe explaining what I need to do would help: I have a directory, for example: /tmp/images I have a webapp in: /opt/tomcat/webapps/myapp I need to be able to store uploaded images in /tmp/images (which I have working fine) and I need to be able to display those images via the jsp's in myapp. Is it possible to have an alias called myapp/images that points to /tmp/images or can I maybe use a symlink(can tomcat follow the symlink?) or is there some other way I can do this, other than using a servlet to retrieve/return the images? I need to be able to do this so that when the webapp is updated/redeployed, the images will not get deleted. I am running tomcat 5.0.28 on SUN's Java 1.4.2_08 on a variety or Linux/UNIX systems. Thanks in advance, Matt - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Avoiding deploying an application twice
I wasn't able to find this particular error when I did a search, so I thought I'd post here in case someone has a similar problem. I was having an error when remotely deploying an application (tomcat 5.0.28) using the tomcat manager (via Ant tasks). I did not explicitly define a context.xml file for the application and used a more or less out of the box standard host configuration. The tomcat error would say during deployment: May 2, 2005 11:13:51 AM org.apache.catalina.startup.HostConfig deployWARs WARNING: Exception while expanding web application archive appname.war May 2, 2005 11:14:01 AM org.apache.catalina.startup.HostConfig deployWARs WARNING: Exception while expanding web application archive appname.war [And repeat ...] That was all the information it would give. I believe this error resulted from tomcat attempting to deploy/unpack the application twice. When I set autoDeploy=false on the host (as opposed to the default behavior, which is true), the errors disappeared. The relevant section of the documentation is below: http://jakarta.apache.org/tomcat/tomcat-5.0-doc/config/host.html#Automatic%20Application%20Deployment When using automatic deployment, the |docBase| defined by an XML Context http://jakarta.apache.org/tomcat/tomcat-5.0-doc/config/context.html file should be outside of the |appBase| directory. If this is not the case difficulties may be experienced deploying the web application or the application may be deployed twice. Finally, note that if you are defining contexts explicitly, you should probably turn off automatic application deployment. Otherwise, your context will be deployed twice each, and that may cause problems for your app. I did not define an explicit context, but I guess the implicit context (or generated context) defaults to a docbase inside the appbase directory, which results in the behavior described above. - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
