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Sticky Load Balancing#

The sticky load balancer selects a single service instance and keeps using it until it fails. Then, it selects another one.

It is possible to configure a backoff time to specify for how long a failing service instance should not be retried.

Precisely, the load balancer works as follows:

  • if no service instance has been selected so far, select the first instance from the collection;
  • else if the previously selected service instance has not failed, and is still available, return it;
  • else return the first available service instance that has no recorded failure, if one exists;
  • else, find the available instance for which the time since the last failure is the longest, and
    • if the backoff time since the failure passed, return it;
    • or, throw an NoAcceptableServiceInstanceFoundException as no acceptable instances are available.

Configuration#

To use the sticky load service selection strategy, set the load balancer type to sticky:

stork.my-service.load-balancer.type=sticky

quarkus.stork.my-service.load-balancer.type=sticky

The following attributes are supported:

Attribute Mandatory Default Value Description
failure-backoff-time No 0 After how much time, a service instance that has failed can be reused.