Upgrade the 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.