High Availability and Clients

The Event Hub publisher and subscriber, also called the clients, will transparently fail-over to a new live Event Hub node without any loss of events. Any open transactions at the time of fail-over will be automatically re-issued after the connection is successfully re-established. All released version two clients are capable of automatic fail-over.


Clients can be configured to circumvent the Grid based address lookup and connect to the Event Hub server using a statically specified host and port. Clients configured to use a static host and port to connect to Event Hub will not work reliably with an Event Hub deployed in high availability mode on more than one host. If this kind of set up is a requirement, for example, when a client application needs to run in a Grid separate from the Event Hub application, Event Hub must be configured to only run on a single host. The scale-in and scale-out functionality in Grid can be used to easily govern the desired number of nodes/hosts used by Event Hub.