0

I am aware that the Tibco EMS provides Fault Tolerance in a hot backup configuration on the server side as detailed in the User's Guide, this answer and here.

But on the client side does Tibco EMS provide out of the box solution for fault-tolerant clients? An example: on the topic Sports.F1.PitStop two clients (server1, server2) register as publishers. The idea being that should something go wrong on server1 (i.e. publisher on server1 goes down), server2 would seamlessly continue to publish on the topic. So the question is, does Tibco EMS provide such client-side fault-tolerance capability?

Community
  • 1
  • 1
aateeque
  • 2,161
  • 5
  • 23
  • 35

3 Answers3

0

No.

EMS (or JMS) does not support a client-side fault tolerance feature. The reason is simple : typically, publishers processes don't know each other.

To elaborate:

Topics usually accepts many publishers (more than two). In a pub/sub scenario, publishers don't know subscribers, and to an extent they don't typically know the other publishers.

Your solution:

My first question regarding your solution: Why can't both servers publish messages at the same time ?

I assume you have a good reason (like messages from server1 and server2 being redundant). In that case, then you will have to have some kind of communication between your "active" and "passive" server.

Possibility 1 : Server2 is connected to a simple service/rmi/other heartbeat mechanism, and can tell if/when Server1 as stopped publishing.

Possibility 2 : Server2 is itself subscribed to the topic, and can tell when messages have stopped.

Last note: In case you meant shared "subscriptions" (as in, one durable subscription being shared between two servers): the new JMS 2.0 API is supporting this feature. EMS 8 is the only version of EMS supporting JMS 2.0.

GhislainCote
  • 1,502
  • 11
  • 18
0

I'm not sure if I fully understand your question. EMS is a message broker. It brokers messages. Thats all it does. If you have multiple servers publishing to the same topic, then that is fine for EMS. If your publishers themselves are in a fail-over configuration, so that only one is actively sending and the other takes over when the first one fails, then EMS doesn't care.

Managing the fail-over mechanism from one publisher to the other, that is something you have to develop yourself. EMS doesn't offer anything to support that. You need some kind of mechanism for server2 to know when server1 is down. There are several ways you can do that:

  • Use a heartbeat mechanism where the active server sends periodical heartbeat messages (possibly across EMS as well) and the passive server listens to them and when they stop, assume server1 is down.
  • Use an active open connection between server1 and server2 (open a simple tcp port for example and stop it from closing automatically by periodically sending a dummy message), and have an open read on that port. You'll get a connection error the moment server1 goes down and you don't have to wait for timeouts on heartbeats.
  • Use a third party monitoring tool, such as openview, tivoli or nagios to detect server1 is down and inform server2.
  • There is a feature on EMS you can use. EMS has system admin topics that you can subscribe to and that log basically anything that goes on internally. You can subscribe to connect and disconnect events to monitor any component connecting to or disconnecting from EMS. If server1 fails, this will be visible as a disconnect event.
Pascal Rottier
  • 69
  • 2
  • 7
0

heartbeat mecanism:

https://support.tibco.com/s/article/Tibco-KnowledgeArticle-Article-33918

For example: 

client_heartbeat_server=10
client_timeout_server_connection=35
server_heartbeat_client=10
server_timeout_client_connection=35
B2B
  • 1
  • 1