Kubernetes

Kubernetes, also known as K8s, is an open-source system for automating deployment, scaling, and management of containerized applications.

Kubernetes in the Dashboard

Our Dashboard has supported Kubernetes as a service discovery from version 7.2.0 onwards. You can switch to the Node page, then select a k8s namespace, and CAP will list all Services under that namespace. After clicking the Switch button, the Dashboard will detect whether the CAP service of that node is available. If it is available, it will proxy to the switched node for data viewing.

Here is a configuration example:

services.AddCap(x =>
{
    // ...
    x.UseDashboard();
    x.UseK8sDiscovery();
});

The component will automatically detect whether it is inside the cluster. If it is inside the cluster, the Pod must be granted Kubernetes Api permissions. Refer to the next section.

Assign Pod Access to Kubernetes Api

If the ServiceAccount associated with your Deployment does not have access to the K8s Api, you need to grant the namespaces, services resources the get, list permissions.

Here is an example yaml. First create a ServiceAccount and ClusterRole and set the related permissions, then bind them using ClusterRoleBinding. Finally, use serviceAccountName: api-access to specify in Deployment.

apiVersion: v1
kind: ServiceAccount
metadata:
  name: api-access

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: ns-svc-reader
rules:
- apiGroups: [""]
  resources: ["namespaces", "services"]
  verbs: ["get", "watch", "list"]

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: read-pods
subjects:
- kind: ServiceAccount
  name: api-access
  namespace: default
roleRef:
  kind: ClusterRole
  name: ns-svc-reader
  apiGroup: rbac.authorization.k8s.io

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: api-access-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: api-access-app
  template:
    metadata:
      labels:
        app: api-access-app
    spec:
      serviceAccountName: api-access
      containers:
      - name: api-access-container
        image: your_image

---
apiVersion: v1
kind: Service
metadata:
  name: api-access-service
spec:
  selector:
    app: api-access-app
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80

Using Dashboard Standalone

You can use the Dashboard standalone without configuring CAP, in this case, the Dashboard can be deployed as a separate Pod in the Kubernetes cluster just for data viewing. The service to be viewed no longer needs to configure the cap.UseK8sDiscovery() option.

services.AddCapDashboardStandalone();

Similarly, you need to configure the access for the ServiceAccount for this Pod.