Creating multi-server clusters

Important note

For the best results (and less unexpected issues), choose 1, 3, 5, … server nodes. (Read more on etcd quorum on etcd.io) At least 2 cores and 4GiB of RAM are recommended.

Embedded etcd

Create a cluster with 3 server nodes using k3s’ embedded etcd database. The first server 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 server nodes.

k3d cluster create multiserver --servers 3

Adding server nodes to a running cluster

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

k3d node create newserver --cluster multiserver --role server

There’s a trap!

If your cluster was initially created with only a single server node, then this will fail.
That’s because the initial server node was not started with the --cluster-init flag and thus is not using the etcd backend.

Last update: September 17, 2021