Upgrade clusters below 3.1.9

Upgrade a Pro Edition for Eclipse Mosquitto (Pro Mosquitto) cluster to 3.2 when any node is below 3.1.9.

A node on 3.2 can share the cluster with nodes below 3.1.9 only when communication settings match. Below 3.1.9, apply delay was hardcoded to 0. From 3.1.9, the setting is plugin_opt_apply_delay. In 3.2 the default is 10.

Update each node as described in Updating Pro Edition for Eclipse Mosquitto. In a cluster, update followers first and the leader last.

Use one of these paths: Path A — Via 3.1.9 (recommended) or Path B — Direct to 3.2.

danger

Upgrade one node at a time: followers first, leader last. Confirm the node has rejoined the cluster before you upgrade the next node.

Docker images:

• Interim step: registry.cedalo.com/mosquitto/mosquitto:3.1.9
• Target: registry.cedalo.com/mosquitto/mosquitto:3.2

On RPM installs, use the matching package instead of the image tag.

Path A — Via 3.1.9, then 3.2

Leave plugin_opt_apply_delay unset on every node.

1. Move each node to 3.1.9 or higher (followers first, leader last). Follow Updating Pro Edition for Eclipse Mosquitto, then verify the node has rejoined the cluster.
2. Confirm every node is on 3.1.9 or higher and the cluster is healthy.
3. Repeat the same update to move each node to 3.2.

Path B — Direct to 3.2

Upgrade one node at a time (followers first, leader last):

1. Stop Mosquitto on the node.

2. Temporarily set plugin_opt_apply_delay 0 in mosquitto.conf:

   plugin_opt_apply_delay 0

3. Update the node to 3.2. Follow Updating Pro Edition for Eclipse Mosquitto.

4. Verify the node has rejoined the cluster and is processing traffic.

5. Repeat for the remaining nodes.

When every node runs 3.2, set plugin_opt_apply_delay to the same value on all nodes, or remove it to use the default 10.