Failover

Failover Load Balancer, with this policy in case of failures the exchange will be tried on the next endpoint.

Options

The Failover EIP supports 4 options which are listed below:

Name	Description	Default	Type
exception	A list of class names for specific exceptions to monitor. If no exceptions are configured then all exceptions are monitored		List
roundRobin	Whether or not the failover load balancer should operate in round robin mode or not. If not, then it will always start from the first endpoint when a new message is to be processed. In other words it restart from the top for every message. If round robin is enabled, then it keeps state and will continue with the next endpoint in a round robin fashion. You can also enable sticky mode together with round robin, if so then it will pick the last known good endpoint to use when starting the load balancing (instead of using the next when starting).		String
sticky	Whether or not the failover load balancer should operate in sticky mode or not. If not, then it will always start from the first endpoint when a new message is to be processed. In other words it restart from the top for every message. If sticky is enabled, then it keeps state and will continue with the last known good endpoint. You can also enable sticky mode together with round robin, if so then it will pick the last known good endpoint to use when starting the load balancing (instead of using the next when starting).		String
maximumFailoverAttempts	A value to indicate after X failover attempts we should exhaust (give up). Use -1 to indicate never give up and continuously try to failover. Use 0 to never failover. And use e.g. 3 to failover at most 3 times before giving up. his option can be used whether or not roundRobin is enabled or not.	-1	String

Name

Description

Default

Type

exception

A list of class names for specific exceptions to monitor. If no exceptions are configured then all exceptions are monitored

List

roundRobin

Whether or not the failover load balancer should operate in round robin mode or not. If not, then it will always start from the first endpoint when a new message is to be processed. In other words it restart from the top for every message. If round robin is enabled, then it keeps state and will continue with the next endpoint in a round robin fashion. You can also enable sticky mode together with round robin, if so then it will pick the last known good endpoint to use when starting the load balancing (instead of using the next when starting).

String

sticky

Whether or not the failover load balancer should operate in sticky mode or not. If not, then it will always start from the first endpoint when a new message is to be processed. In other words it restart from the top for every message. If sticky is enabled, then it keeps state and will continue with the last known good endpoint. You can also enable sticky mode together with round robin, if so then it will pick the last known good endpoint to use when starting the load balancing (instead of using the next when starting).

String

maximumFailoverAttempts

A value to indicate after X failover attempts we should exhaust (give up). Use -1 to indicate never give up and continuously try to failover. Use 0 to never failover. And use e.g. 3 to failover at most 3 times before giving up. his option can be used whether or not roundRobin is enabled or not.

-1

String

Examples

In this case we are using the header test as correlation expression:

from("direct:start")
    .loadBalance()
    .failover(MyException.class)
    .to("seda:x", "seda:y", "seda:z");

In XML you’ll have a route like this

<from uri="direct:start"/>
    <loadBalance>
       <failover>
           <exception>com.example.camel.MyException</exception>
       </failover>
       <to uri="seda:x"/>
       <to uri="seda:y"/>
       <to uri="seda:z"/>
    </loadBalance>