V3 Multi-Datacenter Replication: Quickstart

This guide will walk you through the process of configuring Riak’s v3 Replication to perform replication between two sample Riak clusters on separate networks. This guide will also cover bidirectional replication, which is accomplished by setting up unidirectional replication in both directions between the clusters. It is important to note that both clusters must have the same ring size, but can have a different number of nodes.

Prerequisites

This guide assumes that you have completed the following steps:

About v3 Replication in 1.3

In Riak’s v3 Replication in 1.3, the nomenclature for Source and Site clusters has changed. To more accurately reflect the behavior of each of the clusters, “listeners” and “sites” are now known as “sources” and “sinks.” Data transfer now originates at the “source” and replicates to the “sink;” initiation is always from the primary (source) to the backup (sink) data center.

Additionally, knowledge of the state of each cluster is now managed by a cluster manager process, which greatly simplifies the setup and maintenance of Multi-Datacenter replication.

Scenario

Configure Riak MDC to perform replication, given the following two Riak Enterprise Clusters, each of which consists of three nodes:

Cluster 1

Name	IP	Node name
`node1`	`10.60.67.149`	`riak@10.60.67.149`
`node2`	`10.60.83.39`	`riak@10.60.83.39`
`node3`	`10.60.90.252`	`riak@10.60.90.252`

Cluster 2

Name	IP	Node name
`node4`	`10.60.77.10`	`riak@10.60.77.10`
`node5`	`10.60.84.41`	`riak@10.60.84.41`
`node6`	`10.60.92.44`	`riak@10.60.92.44`

Set up Cluster1 → Cluster2 Connection

Set up the Source on Cluster1

On a node in Cluster1, node1 for example, initiate and name this cluster with riak-repl clustername <name>:

riak-repl clustername Cluster1

Setup the Sink on Cluster2

On a node in Cluster2, node4 for example, initiation and name this cluster with riak-repl clustername <name>:

riak-repl clustername Cluster2

Connect the Source to the Sink

From Cluster1, connect to the IP and port of Cluster2 with riak-repl connect <sink_ip>:<port>:

riak-repl connect 10.60.77.10:9080

The port can be found in the riak_core section of the advanced.config under cluster_mgr.

View your active connections

From Cluster1, view your active connections with riak-repl connections:

Sink             Cluster Name         <Ctrl-Pid>      [Members]
----             ------------         ----------      ---------
Cluster2          Cluster2            <0.7985.0>      ["10.60.77.10:9080"] (via 10.60.77.10:9080)

Set up Cluster2 → Cluster1 Connection (if bidirectional replication is desired)

Connect the Source to the Sink

From Cluster2, connect to the IP and port of Cluster1 with riak-repl connect <sink_ip>:<port>:

riak-repl connect 10.60.67.149:9080

View Your Active Connections

From Cluster2, view your active connections with riak-repl connections:

Sink             Cluster Name         <Ctrl-Pid>      [Members]
----             ------------         ----------      ---------
Cluster1          Cluster1            <0.4456.0>      ["10.60.67.149:9080"] (via 10.60.67.149:9080)

Note on connections

At this point, if you do not have connections, replication will not work. Check your IP bindings by running netstat -a on all nodes. You should see *:9080 LISTENING. If not, you have configuration problems.

Enable Realtime Replication

From Cluster1, run riak-repl realtime enable <clustername> to start queuing updates on Cluster1 for replication:

riak-repl realtime enable Cluster2

Also on Cluster1, run riak-repl realtime start <clustername> to establish connectivity from Cluster1 to Cluster2 to push queued updates:

riak-repl realtime start Cluster2

To enable bidirectional replication, do the reverse from Cluster2. Once this is done, bidirectional replication should be operating.

More information

For a full list of commands, you may enter riak-repl to see full instructions on usage, or check the Operations documentation.