Setting up a Zeebe Cluster
To set up a cluster you need to adjust the
in the Zeebe configuration file. Below is a snippet
of the default Zeebe configuration file, it should be self-explanatory.
[cluster] # This section contains all cluster related configurations, to set up a Zeebe cluster # Specifies the unique id of this broker node in a cluster. # The id should be between 0 and the number of nodes in the cluster (exclusive). # # This setting can also be overridden using the environment variable ZEEBE_NODE_ID. # nodeId = 0 # Controls the number of partitions, which should exist in the cluster. # # This can also be overridden using the environment variable ZEEBE_PARTITIONS_COUNT. # partitionsCount = 1 # Controls the replication factor, which defines the count of replicas per partition. # The replication factor cannot be greater than the number of nodes in the cluster. # # This can also be overridden using the environment variable ZEEBE_REPLICATION_FACTOR. # replicationFactor = 1 # Specifies the Zeebe cluster size. This value is used to determine which broker # is responsible for which partition. # # This can also be overridden using the environment variable ZEEBE_CLUSTER_SIZE. # clusterSize = 1 # Allows to specify a list of known other nodes to connect to on startup # The contact points of the management api must be specified. # The format is [HOST:PORT] # Example: # initialContactPoints = [ "192.168.1.22:26502", "192.168.1.32:26502" ] # # This setting can also be overridden using the environment variable ZEEBE_CONTACT_POINTS # specifying a comma-separated list of contact points. # # To guarantee the cluster can survive network partitions, all nodes must be specified # as initial contact points. # # Default is empty list: # initialContactPoints = 
In this example, we will set up a Zeebe cluster with five brokers. Each broker needs to get a unique node id. To scale well, we will bootstrap five partitions with a replication factor of three. For more information about this, please take a look into the Clustering section.
The clustering setup will look like this:
The configuration of the first broker could look like this:
[cluster] nodeId = 0 partitionsCount = 5 replicationFactor = 3 clusterSize = 5 initialContactPoints = [ ADDRESS_AND_PORT_OF_NODE_0, ADDRESS_AND_PORT_OF_NODE_1, ADDRESS_AND_PORT_OF_NODE_2, ADDRESS_AND_PORT_OF_NODE_3, ADDRESS_AND_PORT_OF_NODE_4 ]
For the other brokers the configuration will slightly change.
[cluster] nodeId = NODE_ID partitionsCount = 5 replicationFactor = 3 clusterSize = 5 initialContactPoints = [ ADDRESS_AND_PORT_OF_NODE_0, ADDRESS_AND_PORT_OF_NODE_1, ADDRESS_AND_PORT_OF_NODE_2, ADDRESS_AND_PORT_OF_NODE_3, ADDRESS_AND_PORT_OF_NODE_4 ]
Each broker needs a unique node id. The ids should be in the range of
clusterSize - 1. You need to replace the
NODE_ID placeholder with an
appropriate value. Furthermore, the
brokers need an initial contact point to start their gossip
conversation. Make sure that you use the address and
management port of another broker. You need to replace the
To guarantee that a cluster can properly recover from network partitions, it is currently required that all nodes be specified as initial contact points. It is not necessary for a broker to list itself as initial contact point, but it is safe to do so, and probably simpler to maintain.
On bootstrap, each node will create a partition matrix.
This matrix depends on the partitions count, replication factor and
the cluster size. If you did the configuration right and
used the same values for
clusterSize on each node, then all nodes will generate
the same partition matrix.
For the current example the matrix will look like the following:
|Node 0||Node 1||Node 2||Node 3||Node 4|
The matrix ensures that the partitions are well distributed between the different nodes. Furthermore, it guarantees that each node knows exactly, which partitions it has to bootstrap and for which it will become the leader at first (this could change later, if the node needs to step down for example).