emqx4.3/examples/broker.conf.example

##--------------------------------------------------------------------
## Broker
##
## Message broker options
##--------------------------------------------------------------------
## Note: This is an example of how to configure this feature
##       you should copy and paste the below data into the emqx.conf for working

## Note: If you and finding how to configure EMQX itself, have a look at the node.conf.example

broker {
    ## Session locking strategy in a cluster
    ## Type:
    ##   - local :: only lock the session on the current node
    ##   - leader :: select only one remote node to lock the session
    ##   - quorum :: select some nodes to lock the session
    ##   - all :: lock the session on all the nodes in the cluster
    session_locking_strategy = quorum

    ## Dispatch strategy for shared subscription
    ## Type:
    ##   - random :: dispatch the message to a random selected subscriber
    ##   - round_robin :: select the subscribers in a round-robin manner
    ##   - round_robin_per_group :: select the subscribers in round-robin fashion within each shared subscriber group
    ##   - local :: select random local subscriber otherwise select random cluster-wide
    ##   - sticky :: always use the last selected subscriber to dispatch, until the subscriber disconnects.
    ##   - hash_clientid :: select the subscribers by hashing the `clientIds`
    ##   - hash_topic :: select the subscribers by hashing the source topic"""
    shared_subscription_strategy = round_robin
 }