Upgrade from MKE 3.7 or 3.8

Comprehensive information is offered herein on how to migrate your existing MKE 3.7 or 3.8 cluster to MKE 4k.

Following a successful upgrade:

• Any swarm workloads will no longer exist.

• It is necessary to download new kubeconfig files from k0s.

• The UCP Controller API will no longer be active or supported, and thus the MKE 3 client bundle will become invalid.

• The terminal prints a summary of the process.

  Example: Upgrade Summary

  Upgrade Summary
  ---------------
  
  Configuration file
  ---------------
  All MKE 3 TOML settings were successfully converted into MKE 4 YAML settings.
  
  Authentication
  ---------------
  Users found in the MKE3 cluster: 1
  
  All users were upgraded to the MKE 4k cluster successfully.
  
  Authorization
  ---------------
  Organizations found in the MKE3 cluster: 1
  Teams found in the MKE3 cluster: 0
  
  All organizations and teams were translated to aggregated roles in the MKE 4k cluster successfully.
  
  Ports
  ---------------
  The following MKE3 ports are no longer used by MKE 4k and (unless otherwise needed) may be made unavailable on all nodes: [2377,6444,7946,9055,12376,12378,12379,12380,12381,12382,12383,12384,12385,12386,12387,12388,12389,12391,12392,179,12390,2376,443]
  
  MCR
  ---------------
  MCR may safely be uninstalled
  
  MKE3 Cleanup
  ---------------
  MKE 3.8.5 was uninstalled from the cluster successfully.

Be aware that any workloads running in your MKE 3 system will not be available during the upgrade process.

The upgrade period depends on the size of your cluster. You can track the progress of your upgrade by way of the terminal, which displays step-by-step logs on the current state of upgrade.

Prerequisites

Verify that you have the following components in place before you begin upgrading MKE 3 to MKE 4:

• An MKE cluster running the latest 3.7.x or 3.8.x release:

  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

• A backup of the MKE cluster. For comprehensive instruction on how to create an MKE 3 back up, refer to Back up MKE.

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

  mkectl version

  Example output:

  Version: v4.1.0

• 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>

• A calico_kdd flag is set to true in the MKE 3 configuration file and applied to the MKE 3 cluster:

  calico_kdd = true

• Calico KDD (Kubernetes Datastore Driver), enabled:

  1. Verify that the MKE 3.x instance being upgraded to MKE 4k is running the latest 3.7.x or 3.8.x release.

  2. Obtain the MKE 3 configuration file:

     export MKE_USERNAME=<mke-username>
     export MKE_PASSWORD=<mke-password>
     export MKE_HOST=<mke-fqdn-or-ip-address>
     curl --silent --insecure -X GET "https://$MKE_HOST/api/ucp/config-toml" -H "accept: application/toml" -H "Authorization: Bearer $AUTHTOKEN" > mke-config.toml

  3. In the cluster_config section of the MKE 3 configuration file, set the calico_kdd parameter to true.

  4. Apply the modified MKE 3 configuration file:

     $ AUTHTOKEN=$(curl --silent --insecure --data '{"username":"'$MKE_USERNAME'","password":"'$MKE_PASSWORD'"}' https://$MKE_HOST/auth/login | jq --raw-output .auth_token)
     $ curl --silent --insecure -X PUT -H "accept: application/toml" -H "Authorization: Bearer $AUTHTOKEN" --upload-file 'mke-config.toml' https://$MKE_HOST/api/ucp/config-toml
     {"message":"Calico datastore migration from etcd to kdd successful"}

{"message":"Calico datastore upgrade from etcd to kdd successful"}

Considerations

Before you upgrade to MKE 4, confirm the existence of a backup of your MKE 3 cluster and review the Back up MKE disaster recovery documentation for MKE 3.

Back up all non-MKE components separately, making sure to check both manager and worker nodes, as these are at risk of being deleted rather than migrated during the upgrade to MKE 4.

Migrate configuration

Kubernetes Custom Flags

MKE 3 and MKE 4 both support the application of additional flags to Kubernetes components that have the following fields in the MKE configuration file, each specified as a list of strings:

custom_kube_api_server_flags
custom_kube_controller_manager_flags
custom_kubelet_flags
custom_kube_scheduler_flags
custom_kube_proxy_flags

MKE 4 supports an extraArgs field for each of these components, though, which accepts a map of key-value pairs. During upgrade from MKE 3, MKE 4 converts these custom flags to the corresponding extraArgs field. Any flags that cannot be automatically converted are listed in the upgrade summary.

Example of custom flags conversion:

• MKE 3 configuration file:

  [cluster_config.custom_kube_api_server_flags] = ["--enable-garbage-collector=false"]

• MKE 4 configuration file:

  spec:
    apiServer:
      extraArgs:
        enable-garbage-collector: false

Kubelet Custom Flag Profiles

MKE 3 supports a map of kubelet flag profiles to specific nodes using the custom_kubelet_flags_profiles setting in the toml configuration file.

MKE 4 does not support kubelet flag profiles, but you can use Kubelet custom profiles to map KubeletConfiguration values to specific nodes. MKE 4 does support the migration of MKE 3 kubelet flag profiles to kubelet custom profiles.

The conversion of flags to KubeletConfiguration values is best-effort, and any flags that cannot be converted are listed in the upgrade summary. Hosts with a custom flag profile label are marked for the corresponding kubelet custom profile.

Perform the migration

An upgrade from MKE 3 to MKE 4k 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 an upgrade from a hyperkube-based MKE 3 cluster to a k0s-based MKE 4k cluster.
• Upgrade manager nodes to k0s.
• Upgrade worker nodes to k0s.
• Carry out post-upgrade cleanup to remove MKE 3 components.
• Output the new mke4.yaml configuration 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 4k configuration file will be automatically created and saved during upgrade. 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 4k cluster is operating:

sudo k0s kc get nodes

Example output:

NAME                                           STATUS   ROLES           AGE   VERSION
ip-172-31-111-4.us-west-1.compute.internal     Ready    control-plane   45h   v1.31.2+k0s
ip-172-31-216-253.us-west-1.compute.internal   Ready    <none>          45h   v1.31.2+k0s

Offline upgrade

To perform an offline upgrade from MKE 3 to MKE 4k, prepare your environment as described in Offline installation, and add the following flags to the mkectl upgrade command:

• --image-registry=<registry_full_path>
• --chart-registry=oci://<registry_full_path>
• --mke3-airgapped=true

Migration failure

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

Example output:

WARN[0096] Initiating rollback because of upgrade failure. upgradeErr = aborting upgrade due to signal interrupt
INFO[0096] Initiating rollback of MKE to version: 3.7.15
INFO[0096] Step 1 of 2: [Rollback Upgrade Tasks]
INFO[0096] Resetting k0s using k0sctl ...
INFO[0106] ==> Running phase: Connect to hosts
INFO[0106] [ssh] 54.151.30.20:22: connected
INFO[0106] [ssh] 54.215.145.126:22: connected
INFO[0106] ==> Running phase: Detect host operating systems
INFO[0106] [ssh] 54.151.30.20:22: is running Ubuntu 22.04.5 LTS
INFO[0106] [ssh] 54.215.145.126:22: is running Ubuntu 22.04.5 LTS
INFO[0106] ==> Running phase: Acquire exclusive host lock
INFO[0107] ==> Running phase: Prepare hosts
INFO[0107] ==> Running phase: Gather host facts
INFO[0107] [ssh] 54.151.30.20:22: using ip-172-31-8-69.us-west-1.compute.internal as hostname
INFO[0107] [ssh] 54.215.145.126:22: using ip-172-31-48-46.us-west-1.compute.internal as hostname
INFO[0107] [ssh] 54.151.30.20:22: discovered ens5 as private interface
INFO[0107] [ssh] 54.215.145.126:22: discovered ens5 as private interface
INFO[0107] [ssh] 54.151.30.20:22: discovered 172.31.8.69 as private address
INFO[0107] [ssh] 54.215.145.126:22: discovered 172.31.48.46 as private address
INFO[0107] ==> Running phase: Gather k0s facts
INFO[0108] [ssh] 54.215.145.126:22: found existing configuration
INFO[0108] [ssh] 54.215.145.126:22: is running k0s controller+worker version v1.31.1+k0s.1
WARN[0108] [ssh] 54.215.145.126:22: the controller+worker node will not schedule regular workloads without toleration for node-role.kubernetes.io/master:NoSchedule unless 'noTaints: true' is set
INFO[0108] [ssh] 54.215.145.126:22: listing etcd members
INFO[0110] [ssh] 54.151.30.20:22: is running k0s worker version v1.31.1+k0s.1
INFO[0110] [ssh] 54.215.145.126:22: checking if worker ip-172-31-8-69.us-west-1.compute.internal has joined
INFO[0110] ==> Running phase: Reset workers
INFO[0111] [ssh] 54.151.30.20:22: reset
INFO[0111] ==> Running phase: Reset controllers
INFO[0114] [ssh] 54.215.145.126:22: reset
INFO[0114] ==> Running phase: Reset leader
INFO[0114] [ssh] 54.215.145.126:22: reset
INFO[0114] ==> Running phase: Reload service manager
INFO[0114] [ssh] 54.151.30.20:22: reloading service manager
INFO[0114] [ssh] 54.215.145.126:22: reloading service manager
INFO[0115] ==> Running phase: Release exclusive host lock
INFO[0115] ==> Running phase: Disconnect from hosts
INFO[0115] ==> Finished in 8s
INFO[0125] Running etcd cleanup service ...
INFO[0128] MKE3 etcd directories successfully cleaned up ...
INFO[0128] Restoring etcd from the previously taken system backup ...
INFO[0128] Successfully restored etcd with output:
INFO[0128] Deploying etcd server ...
INFO[0129] Successfully deployed the etcd server with output: fb09c3e5e514d9ffe03a3df4bc461c29a695cf73d703ace5294702b7023021af
INFO[0129] Waiting for etcd to be healthy ...
INFO[0131] etcd health check succeeded!
INFO[0178] [Rollback Upgrade Tasks] Completed
INFO[0178] Step 2 of 2: [Rollback Pre Upgrade Tasks]
INFO[0178] [Rollback Pre Upgrade Tasks] Completed
INFO[0178] Rollback to MKE version 3.7.15 completed successfully ...
FATA[0178] Upgrade failed due to error: aborting upgrade due to signal interrupt

Revert the upgrade

To revert a cluster upgraded to MKE 4k back to MKE 3:

1. Uninstall MKE 4.

2. Restore MKE 3 from a backup.

RBAC upgrades

As MKE 4k does not support Swarm mode, the platform uses standard Kubernetes RBAC authorization. As such, the Swarm authorization configuration that is in place for MKE 3 is not present in MKE 4.

Groups

To enable the same RBAC hierarchy as in MKE 3 with orgs and teams groups, but without the two-level limitation, MKE 4k replaces orgs and teams with the Kubernetes AggregatedRoles.

Authorization structure comparison:

MKE 3:                           MKE 4:

├── entire-company (org)         ├── entire-company-org (AggregatedRole)
│   ├── development (team)       ├── development-team (AggregatedRole)
│   │   ├── bob (user)           │   ├── bob (user)
│   ├── production (team)        ├── production-team (AggregatedRole)
│   │   ├── bob (user)│          │   ├── bob (user)
│   │   ├── bill (user)          │   ├── bill (user)
│   ├── sales (team)             ├── sales-team (AggregatedRole)

Roles

Roles are bound to the aggregated roles for integration into the org, team, and user structure. Thus, what was previously an organization or a team role will have -org or -team appended to its name.

A role can be assigned at any level in the hierarchy, with its permissions granted to all members at that same level.

Example organization binding:

├── entire-company-org (AggregatedRole) -- entire-company-org (RoleBinding) -- view (Role)
│   ├── development-team (AggregatedRole)
│   │   ├── bob (user)
│   ├── production-team (AggregatedRole)
│   │   ├── bob (user)
│   │   ├── bill (user)
│   ├── sales-team (AggregatedRole)

In the example above, all members of the entire-company org group have view permissions. This includes the development-team, production-team, sales-team, bob, and bill.

Example team binding:

│   ├── development:team (AggregatedRole) -- development:team (RoleBinding) -- edit (Role)
│   │   ├── bob (user)

In the example above, the binding grants edit permissions only to the members of the development team, which only includes bob.

CoreDNS Lameduck upgrade

MKE 4k supports upgrading from MKE 3 systems that are running with CoreDNS and Lameduck enabled. Refer to the table below for a comparison of the CoreDNS Lameduck configuration parameters between MKE 3 and MKE 4:

Troubleshoot the upgrade

You can address various potential MKE upgrade issues using the tips and suggestions detailed herein.

During the upgrade from MKE 3 to MKE 4, which defaults to the etcdv3 backend, you may receive the following error:

mkectl upgrade --hosts-path hosts.yaml --mke3-admin-username admin --mke3-admin-password <mke_admin_password> -l debug --config-out new-mke4.yaml --external-address <mke4_external_address>
...
Error: unable to generate upgrade config: unsupported configuration for mke4 upgrade: mke3 cluster is using etcdv3 and not kdd backend for calico

To resolve the issue, ensure that:

• The MKE 3 source is the latest 3.7.x or 3.8.x release.
• The calico_kdd flag in the MKE 3 configuration file is set to true.
• The configuration is applied to the MKE 3 cluster.

Example output:

$ AUTHTOKEN=$(curl --silent --insecure --data '{"username":"'$MKE_USERNAME'","password":"'$MKE_PASSWORD'"}' https://$MKE_HOST/auth/login | jq --raw-output .auth_token)

$ curl --silent --insecure -X PUT -H "accept: application/toml" -H "Authorization: Bearer $AUTHTOKEN" --upload-file 'mke-config.toml' https://$MKE_HOST/api/ucp/config-toml
{"message":"Calico datastore upgrade from etcd to kdd successful"}