Migrate from MKE 3.x

This section instructs you on how to migrate your existing MKE 3.7 cluster to the MKE 4.x version.

Prerequisites

Verify that you have the following components in place before you begin upgrading MKE3 to MKE 4:

• A running MKE 3.7.x cluster:

  kubectl get nodes

  NAME                                           STATUS   ROLES    AGE     VERSION
  ip-172-31-103-202.us-west-2.compute.internal   Ready    master   7m3s    v1.27.7-mirantis-1
  ip-172-31-104-233.us-west-2.compute.internal   Ready    master   7m3s    v1.27.7-mirantis-1
  ip-172-31-191-216.us-west-2.compute.internal   Ready    <none>   6m59s   v1.27.7-mirantis-1
  ip-172-31-199-207.us-west-2.compute.internal   Ready    master   8m4s    v1.27.7-mirantis-1

• The latest mkectl binary, installed on your local enviroment:

  mkectl version

  Example output:

  Version: v4.0.0-alpha.1.0

• k0sctl version 0.17.4, installed on your local enviroment:

  k0sctl version

  Example output:

  version: v0.17.4
  commit: 372a589

• A hosts.yaml file, to provide the information required by mkectl to connect to each node with SSH.

  Example hosts.yaml file:

  cat hosts.yaml

  hosts:
    - address: <host1-external-ip>
      port: <ssh-port>
      user: <ssh-user>
      keyPath: <path-to-ssh-key>
    - address: <host2-external-ip>
      port: <ssh-port>
      user: <ssh-user>
      keyPath: <path-to-ssh-key>

Migrate configuration

In migrating to MKE 4 from MKE 3, you can directly transfer settings using mkectl.

To convert a local MKE 3 configuration for MKE 4: set the --mke3-config flag to convert a downloaded MKE 3 configuration file into a valid MKE 4 configuration file:

mkectl init --mke3-config </path/to/mke3-config.toml>

Perform the migration

An upgrade from MKE 3 to MKE 4 consists of the following steps, all of which are performed through the use of the mkectl tool:

• Run pre-upgrade checks to verify the upgradability of the cluster.
• Carry out pre-upgrade migrations to prepare the cluster for a migration from a hyperkube-based MKE 3 cluster to a k0s-based MKE 4 cluster.
• Migrate manager nodes to k0s.
• Migrate worker nodes to k0s.
• Carry out post-upgrade cleanup, to remove MKE 3 components.
• Output the new MKE 4 config file.

To upgrade an MKE 3 cluster, use the mkectl upgrade command:

mkectl upgrade --hosts-path <path-to-hosts-yaml> \
  --mke3-admin-username <admin-username> \
  --mke3-admin-password <admin-password> \
  --external-address <external-address>\
  --config-out <path-to-desired-file-location>

The external address is the domain name of the load balancer. For details, see System requirements: Load balancer requirements.

The --config-out flag allows you to specify a path where the MKE 4 configuration file will be automatically created and saved during migration. If not specified, the configuration file prints to your console on completion. In this case, save the output to a file for future reference

The upgrade process requires time to complete. Once the process is complete, run the following command to verify that the MKE 4 cluster is operating:

sudo k0s kc get nodes

Example output:

NAME                                           STATUS   ROLES    AGE   VERSION
ip-172-31-103-202.us-west-2.compute.internal   Ready    master   29m   v1.29.3+k0s
ip-172-31-104-233.us-west-2.compute.internal   Ready    master   29m   v1.29.3+k0s
ip-172-31-191-216.us-west-2.compute.internal   Ready    <none>   29m   v1.29.3+k0s
ip-172-31-199-207.us-west-2.compute.internal   Ready    master   30m   v1.29.3+k0s

In the event of an upgrade failure, the upgrade process rolls back, restoring the MKE 3 cluster to its original state.

RBAC Migrations

The RBAC model MKE 4 uses differs significantly from the one in use by MKE 3.

As MKE 4 no longer supports Swarm mode, the platform uses Kubernetes RBAC for authorization. Thus, the RBAC configuration for Swarm mode does not exist in MKE 4. The Swarm mode roles have Kubernetes RBAC roles associated with them, however, and the MKE 4 upgrade process migrates these Kubernetes roles and bindings to the new MKE 4 cluster.

The sections that follow detail the MKE 3 Swarm mode roles and their corresponding Kubernetes RBAC permissions:

View Only

Restricted Control

Full Control

Scheduler

No Kubernetes RBAC permissions correlate to the Scheduler role.