my test bed is 2 server which all run service based on jboss-4.0.3sp1, they are configured as cluster and has HA-JNDI online between 2 nodes.
due to some framework change, i need to shutdown the service on one node, how could we shutdown HA-JNDI?
i can not update cluster-service.xml to remove HA JDNI definition, that will cause application start-up error.
thanks,
Emre
Here is from JBoss Clustering documentation:
java.naming.provider.url JNDI setting can now
accept a list of urls separated by a comma. Example:
java.naming.provier.url=server1:1100,server2:1100,server3:1100,server4:1100
When initialising, the JNP client code will try to get in touch with each
server from the list, one after the other, stopping as soon as one server
has been reached.
So set it to server that is up.
I hope it is helps.
Related
I'm a bit confused with this configuration. My Spring Boot app with #EnableDiscoveryClient has spring.cloud.consul.host set to localhost. I'm running a Consul Agent on the host where my Boot app is running, but I've a few questions (can't seem to find my answers in the documentation).
Can this config accept multiple values?
If so, I'd prefer to set the values to a list of Consul server addresses (but then, what's the point of running Consul Agents at all, so this doesn't seem practical, which means I'm not understanding something here)
If not, are we expected to run a Consul Agent on every node a Boot app with #EnableDiscoveryClient is running? (this feels wrong as well; for one, this would seem like a single point of failure even though one agent should be able to tell everything about the cluster; what if I can't contact this one agent?)
What's the best practice for this configuration?
Actuallly this is Consul itself to solve your problem. An agent is runing on every server to handle clustering, failures, sharing data, autodiscovery etc. for you so that you don't neen to know the other hosts in your Spring Boot configuration. Spring Boot app always connects to the agent running on the same machine.
See https://www.consul.io/docs/agent/basics.html
Got a general question about load balancing setup in JBoss (7.1.1.Final). I'm trying to setup a clustered JBoss instance with a master and slave node and I'm using the demo app here (https://docs.jboss.org/author/display/AS72/AS7+Cluster+Howto) to prove the load balancing/session replication. I've basically followed through to just before the 'cluster configuration' section.
I've got the app deployed to the master and slave nodes and if I hit their individual IPs directly I can access the application fine. According to the JBoss logs and admin console the slave has successfully connected to the master. However, if I put something in the session on the slave, take the slave offline, the master cannot read the item that the slave put in the session.
This is where I need some help with the general setup. Do I have to have a separate apache httpd instance sat in front of JBoss to do the load balancing? I thought there was a load balancing capability built into JBoss that wouldn't need the separate server, or am I just completely wrong? If I don't need apache, please could you point me in the direction of instructions to setup the JBoss load balancing?
Thanks.
Yes, you need a Apache or any other software or hardware that allows you to perform load balancing of the HTTP request JBoss Application Server does not provide this functionality.
For proper operation of the session replication you should check that the server configuration and the application configuration is well defined.
On the server must have the cache enabled for session replication (you can use standalone-ha.xml or standalone-full-ha.xml file for initial config).
To configuring the application to replicate the HTTP session is done by adding the <distributable/> element to the web.xml.
You can see a full example in http://blog.akquinet.de/2012/06/21/clustering-in-jboss-as7eap-6/
I have 2 instances of Jboss servers running on eg: 127.0.0.1 and 127.0.0.2.
I have implemented Jboss load balancing, but am not sure how to achieve server failover. I do not have a webserver to monitor the heartbeat and hence using mod_cluster is out the question. Is there any way I can achieve failover using only the two available servers?
Any help would be appreciated. Thanks.
JBoss clustering automatically provides JNDI and EJB failover and also HTTP session replication.
If your JBoss AS nodes are in a cluster then the failover should just work.
The Documentation refers to an older version of JBoss (5.1) but it has clear descriptions of how JBoss clustering works.
You could spun up another instance to server as your domain controller, and the two instances you already have will be your hosts. Then you could go through the domain controller, and it will do the work for you. However, I haven't seen instances going down to often, it usually servers that do, and it looks like you are using just one server (i might be wrong) for both instances, so i would consider splitting it up.
I'm interested in using Celery for an app I'm working on. It all seems pretty straight forward, but I'm a little confused about what I need to do if I have multiple load balanced application servers. All of the documentation assumes that the broker will be on the same server as the application. Currently, all of my application servers sit behind an Amazon ELB and tasks need to be able to come from any one of them.
This is what I assume I need to do:
Run a broker server on a separate instance
Configure each application instance to connect to that broker server
Each application instance will also be be a celery working (running
celeryd)?
My only beef with that is: What happens if my broker instance dies? Can I run 2 broker instances some how so I'm safe if one goes under?
Any tips or information on what to do in a setup like mine would be greatly appreciated. I'm sure I'm missing something or not understanding something.
For future reference, for those who do prefer to stick with RabbitMQ...
You can create a RabbitMQ cluster from 2 or more instances. Add those instances to your ELB and point your celeryd workers at the ELB. Just make sure you connect the right ports and you should be all set. Don't forget to allow your RabbitMQ machines to talk among themselves to run the cluster. This works very well for me in production.
One exception here: if you need to schedule tasks, you need a celerybeat process. For some reason, I wasn't able to connect the celerybeat to the ELB and had to connect it to one of the instances directly. I opened an issue about it and it is supposed to be resolved (didn't test it yet). Keep in mind that celerybeat by itself can only exist once, so that's already a single point of failure.
You are correct in all points.
How to make reliable broker: make clustered rabbitmq installation, as described here:
http://www.rabbitmq.com/clustering.html
Celery beat also doesn't have to be a single point of failure if you run it on every worker node with:
https://github.com/ybrs/single-beat
I have jboss 5.1.0.
we have configured jboss somehow using clustering, but in fact we do not use clustering while developing or testing. But in order to launch the project i have to type the following:
./run.sh -c all -g uniqueclustername
-b 0.0.0.0 -Djboss.messaging.ServerPeerID=1 -Djboss.service.binding.set=ports-01
but while jboss starting i able to see something like this in the console:
17:24:45,149 WARN [GMS]
join(172.24.224.7:60519) sent to
172.24.224.2:61247 timed out (after 3000 ms), retrying 17:24:48,170 WARN
[GMS] join(172.24.224.7:60519) sent to
172.24.224.2:61247 timed out (after 3000 ms), retrying 17:24:51,172 WARN
[GMS] join(172.24.224.7:60519)
here 172.24.224.7 it is my local IP
though 172.24.224.2 other IP of other developer in our room (and jboss there is stoped).
So, it tries to join to the other node or something. (i'm not very familiar how jboss acts in clusters). And as a result the application are not starting.
What may be the problem in? how to avoid this joining ?
You can probably fix this by specifying
-Djgroups.udp.ip_ttl=0
in your startup. This Sets the IP time-to-live on the JGroups packets to zero, so they never get anywhere, and the cluster will never form. We use this in dev here to stop the various developer machines from forming a cluster. There's no need to specify a unique cluster name.
I'm assuming you need to do clustering in production, is that right? Could you just use the default configuration instead of all? This would remove the clustering stuff altogether.
while setting up the server, keeping the host name = localhost and --host=localhost instead of ip address will solve the problem. That makes the server to start in non clustered mode.