The Cedalo high availability feature provides the ability to run a cluster of Mosquitto nodes with a single leader and multiple followers, so that broker availability can be ensured even if a single node becomes unavailable through fault or for an upgrade. This document describes the recommended cluster architecture and how to configure the cluster for first use, and in the future.
To understand more about the underlying architecture and configuration visit the Mosquitto documentation
Enable Cluster Management
To enable the Cluster Management feature, make sure you are using the Pro Edition of Mosquitto and that you have the feature enabled in your license. Also, ensure that your config file (specified with
CEDALO_MC_PROXY_CONFIG environmental variable or by default saved in
management-center/config/config.json) contains the following entry inside of the
On start-up, the Management Center will print a message that the
cluster-management plugin is enabled and loaded into the console:
Loaded plugin: "cedalo_cluster_management" (Cedalo Cluster Management)
Before creating a cluster, it is necessary to connect your future cluster nodes to the Management Center. Make sure to be connected via Port 1885, to allow direct communication to the individual nodes, using a client with ACLs to read and write on the $CONTROL topic of the broker.
To navigate to the High Availability Cluster overview, select the "Cluster Management" menu entry from the left main menu.
To create a new high availability cluster, click on the button "New cluster".
On the following page you can enter the detail information about the cluster that you want to create.
Select a unique Node ID, enter the IP address of the broker with in its private network and select the preconfigured connection.
When you have entered all the necessary information, click on "Save". The new cluster will now be set up and the configuration will appear in the overview list.
Select the cluster in the overview list. This will navigate you to the detail view of the cluster. The leader and follower are indicated by different icons
To add a new node, first switch into edit mode by clicking on the button "Edit". Then, click on "Add node", which will open a select dialog that lists all available Mosquitto connections.
See here a cluster with four nodes, with the leader being the one with "Node ID" 2.
Remove nodes from a cluster
Navigate to the cluster detail page (e.g., by selecting it in the overview list) and click the "Edit" button. Then, in order to remove a node, click on the "Remove" button next to that node.
Delete a Cluster
Delete the Cluster by clicking the "bin" icon in the overview menu.