Galera does not need this as it manages replication on its own. You can use root_node_as_master=true to force all MaxScales to use the same node as the master.

There is some use for this: being able to determine which MaxScale performs tasks that must only be done once. In 2.6 this will include the replication of data from MariaDB into external systems (avrorouter and kafkacdc) so there's some merit to having something to coordinate this with. For Galeramon, this would be as simple as acquiring a lock on the node currently assigned as the Master.

"For Galeramon, this would be as simple as acquiring a lock on the node currently assigned as the Master."
But there is no flag as "Primary" for galeramon to determine if a maxscale instance has acquired lock on master node.
like this

Monitor Diagnostics │ {                                                          │

│                     │     "master": "server1",                             │

│                     │     "master_gtid_domain_id": 0,                            │

│                     │     "primary": true,                                       │

│                     │     "server_info": [                                       │

│                     │         {                         

Yes, this would have to be added if this was done for Galeramon as well.

ok. Actually we are planning use multiple maxscale instances monitoring the same galera backends. We can do it using Mariadb monitor for primary-replica setup.
Could you provide any tentative timeline for this feature to be implemented in available stable releases of maxscale ?

At this point in time I don't think we can give an estimate.

any reason please, why this "won't be" implemented?

In a maxscale configuration of 2 or more units
Deadlock occurs when using galeramon.
A problem arises.

kyoung-yeon are you using root_node_as_master=true in Galeramon?

What if the node with root_node_as_master=true and wsrep_local_index=0 goes down?

The Galera cluster will reorganize itself and reassign the nodes so that another node will be the one with wsrep_local_index=0.