The GlusterFS add-on provides comprehensive monitoring of GlusterFS clusters with Checkmk. It monitors cluster members, peer connections, volumes, and their associated bricks. Heal and split-brain states are detected alongside running, completed, or failed rebalance operations. Detailed status information and metrics highlight pending heal operations, split-brain entries, and rebalance failures at an early stage. The included Linux agent plug-in can be deployed conveniently through the Checkmk Agent Bakery or installed manually. GlusterFS servers are automatically identified using a host label, making the add-on easy to integrate into existing Checkmk environments. The add-on supports Checkmk 2.3 through 2.5 and has been tested with GlusterFS 11.x.