OCM Cluster-Gateway Manager
TL;DR: "OCM Cluster-Gateway Manager" addon installs an operator component into the hub cluster that help the administrator to easily operate the configuration of cluster-gateway instances via "ClusterGatewayConfiguration" custom resource. WARNING this addon will restart the cluster-gateway instances upon the first-time installation.
What does "Cluster-Gateway Manager" do?
Basically it helps us to sustainably operate the cluster-gateway instances from the following aspects:
- Automatic cluster-gateway's server TLS certificate rotation.
- Automatic cluster discovery.
- Structurize the component configuration for cluster-gateway.
- Manages the "egress identity" for cluster-gateway to access each clusters.
Note that the requests proxied by cluster-gateway will use the identity of
open-cluster-management-managed-serviceaccount/cluster-gateway
to access
the managed clusters, and by default w/ cluster-admin permission, so please
be mindful of that.
How to confirm if the addon installation is working?
Run the following commands to check the healthiness of the addons:
$ kubectl -n <cluster> get managedclusteraddon
kubectl get managedclusteraddon -A
NAMESPACE NAME AVAILABLE DEGRADED PROGRESSING
<cluster> cluster-gateway True
<cluster> cluster-proxy True
<cluster> managed-serviceaccount True
In case you have too many clusters to browse at a time, install the command-line binary via:
curl -L https://raw.githubusercontent.com/open-cluster-management-io/clusteradm/main/install.sh | bash
Then run the following commands to see the details of the addon:
$ clusteradm get addon
<ManagedCluster>
└── managed1
└── cluster-gateway
│ ├── <Status>
│ │ ├── Available -> true
│ │ ├── ...
│ ├── <ManifestWork>
│ └── clusterrolebindings.rbac.authorization.k8s.io
│ │ ├── open-cluster-management:cluster-gateway:default (applied)
│ └── ...
└── cluster-proxy
│ ├── <Status>
│ │ ├── Available -> true
│ │ ├── ...
│ ├── <ManifestWork>
│ └── ...
└── managed-serviceaccount
└── <Status>
│ ├── Available -> true
│ ├── ...
└── <ManifestWork>
└── ...
Sample of ClusterGatewayConfiguration API
You can read or edit the overall configuration of cluster-gateway deployments via the following command:
$ kubectl get clustergatewayconfiguration -o yaml
apiVersion: v1
kind: List
items:
- apiVersion: proxy.open-cluster-management.io/v1alpha1
kind: ClusterGatewayConfiguration
metadata: ...
spec:
egress:
clusterProxy:
credentials:
namespace: open-cluster-management-addon
proxyClientCASecretName: proxy-server-ca
proxyClientSecretName: proxy-client
proxyServerHost: proxy-entrypoint.open-cluster-management-addon
proxyServerPort: 8090
type: ClusterProxy
image: oamdev/cluster-gateway:v1.1.11
installNamespace: vela-system
secretManagement:
managedServiceAccount:
name: cluster-gateway
type: ManagedServiceAccount
secretNamespace: open-cluster-management-credentials