k3d/docs/usage/multimaster.md

Creating multi-master clusters

!!! info "Important note" For the best results (and less unexpected issues), choose 1, 3, 5, ... master nodes.

Embedded dqlite

Create a cluster with 3 master nodes using k3s' embedded dqlite database. The first master to be created will use the --cluster-init flag and k3d will wait for it to be up and running before creating (and connecting) the other master nodes.

    k3d create cluster multimaser --masters 3

Adding master nodes to a running cluster

In theory (and also in practice in most cases), this is as easy as executing the following command:

    k3d create node newmaster --cluster multimaster --role master

!!! important "There's a trap!" If your cluster was initially created with only a single master node, then this will fail. That's because the initial master node was not started with the --cluster-init flag and thus is not using the dqlite backend.