Dashboard

K8s dashboard tricks.

v1.x

Deploy Dashboard

Deploy it.

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v1.10.1/src/deploy/recommended/kubernetes-dashboard.yaml

Proxy.

kubectl proxy

Access.

http://localhost:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/

Reference

GitHub - kubernetes-retired/dashboard: General-purpose web UI for Kubernetes clustersGitHub

Dashboard permissions

Allow full public access

cat > /tmp/k8s-dashboard-public.yml <<EOF
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: kubernetes-dashboard
  labels:
    k8s-app: kubernetes-dashboard
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: kubernetes-dashboard
  namespace: kube-system

EOF

Apply:

kubectl create -f /tmp/k8s-dashboard-public.yml

This is not recommended for production environments.

Create user

Create a user called admin-user

cat > /tmp/k8s-user.yml <<EOF
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin-user
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: admin-user
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: admin-user
  namespace: kube-system

EOF

Apply:

kubectl apply -f /tmp/k8s-user.yml

Get token:

kubectl -n kube-system \
  describe secret $(kubectl -n kube-system get secret | grep admin-user | awk '{print $1}')

References

https://github.com/kubernetes/dashboard/wiki/Creating-sample-user

Get dashboard URL

kubectl cluster-info

If you are using kubectl proxy, the dashboard URL should be:

http://localhost:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/#!/overview?namespace=_all

Expose the Dashboard

Edit kubernetes-dashboard service:

kubectl -n kube-system edit service kubernetes-dashboard

You should see yaml representation of the service. Change type: ClusterIP to type: NodePort and save file.

Next we need to check port on which Dashboard was exposed.

$ kubectl -n kube-system get service kubernetes-dashboard
NAME                   CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes-dashboard   10.100.124.90   <nodes>       443:31707/TCP   21h

Dashboard has been exposed on port 31707 (HTTPS). Now you can access it from your browser at: https://<master-ip>:31707. master-ip can be found by executing kubectl cluster-info

References

https://github.com/kubernetes/dashboard/wiki/Accessing-Dashboard---1.7.X-and-above

v2.x

Deploy Dashboard

Deploy it.

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0-beta4/aio/deploy/recommended.yaml

Proxy.

kubectl proxy

Access.

http://localhost:8001/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/

Reference

https://kubernetes.io/docs/tasks/access-application-cluster/web-ui-dashboard/

Dashboard permissions

Create user

Create a user called dashboard-admin-user

cat > /tmp/k8s-user.yml <<EOF
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: dashboard-admin-user
  namespace: kubernetes-dashboard
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: dashboard-admin-user
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: dashboard-admin-user
  namespace: kubernetes-dashboard

EOF

Apply:

kubectl apply -f /tmp/k8s-user.yml

Get token:

kubectl -n kubernetes-dashboard describe secret $(kubectl -n kubernetes-dashboard get secrets |grep dashboard-admin-user-token | awk '{print $1}')

Deploying a publicly accessible Kubernetes Dashboard

1. Certificates

You need a dashboard.key and dashboard.crt files for HTTPS.

It is easy to create self signed ones like so:

mkdir $HOME/certs
cd $HOME/certs
openssl genrsa -out dashboard.key 2048
openssl rsa -in dashboard.key -out dashboard.key
openssl req -sha256 -new -key dashboard.key -out dashboard.csr -subj '/CN=localhost'
openssl x509 -req -sha256 -days 365 -in dashboard.csr -signkey dashboard.key -out dashboard.crt

Replace localhost accordingly.

Next, load the certificates into a secret:

kubectl -n kube-system \
  create secret generic kubernetes-dashboard-certs \
  --from-file=$HOME/certs

2. Deploy dashboard

Use the recommended setup to magically deploy the kubernetes-dashboard service account, role, rolebinding, deployment and service.

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/recommended/kubernetes-dashboard.yaml

3. Check if the replica set is fulfuilled

Find the dashboard replica set:

kubectl -n kube-system get rs

If the desired, current and ready counts are all 1, then congratulations! You can skip to step 5.

Otherwise, if desired is 1 but current and ready counts are 0, then chances are you using Pod Security Policy - in the absense of a valid policy, the default is to reject.

Get the details:

kubectl -n kube-system describe rs kubernetes-dashboard-xxxxxxxxxx

If you see a message such as unable to validate against any pod security policy: [], then continue to step 4.

4. Set up Pod Security Policy

If you haven’t already done so, create an appropriate Pod Security Policy that will be used to create the dashboard pod.

4.1 Create a PSP

Tweak to your requirements. A permissive example but blocking privileged mode:

kubectl -n kube-system create -f - <<EOF
apiVersion: extensions/v1beta1
kind: PodSecurityPolicy
metadata:
  name: dashboard
spec:
  privileged: false
  seLinux:
    rule: RunAsAny
  supplementalGroups:
    rule: RunAsAny
  runAsUser:
    rule: RunAsAny
  fsGroup:
    rule: RunAsAny
  volumes:
  - '*'
EOF

4.2 Create a role to allow use of the PSP

kubectl -n kube-system create role psp:dashboard --verb=use --resource=podsecuritypolicy --resource-name=dashboard

4.3 Bind the role to kubernetes-dashboard service account

kubectl -n kube-system create rolebinding kubernetes-dashboard-policy --role=psp:dashboard --serviceaccount=kube-system:kubernetes-dashboard

Check that the output of the following command is yes:

kubectl --as=system:serviceaccount:kube-system:kubernetes-dashboard -n kube-system auth can-i use podsecuritypolicy/dashboard

After a while, check the status of your replica set and it should now have been able to create the pods!

If you still have trouble, check that the permissions of your PSP are appropriate for the dashboard (this is left as an exercise for the reader).

5. Expose dashboard service on a NodePort

Finally, we can expose the dashboard service on a NodePort. This will allow it to be publically accessible via a port forwarded on the Kubernetes hosts.

Edit the kubernetes-dashboard service and change the following options:

• spec.type from ClusterIP to NodePort

• spec.ports[0].nodePort from 32641 to whatever port you want it to be exposed on

kubectl -n kube-system edit service kubernetes-dashboard

When you save the close the text file, find out which port was allocated:

# kubectl -n kube-system get services
NAME                   TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)         AGE
kube-dns               ClusterIP   ...              <none>        53/UDP,53/TCP   28d
kubernetes-dashboard   NodePort    ...              <none>        443:32641/TCP   27m

Here you can see that the dashboard was assigned port 32641. It should now be accessible in your browser on that port, and because we created a self-signed (or installed a valid) certificate, you won’t run into the corrupt certificate problem on Windows clients.

Then access https://YOUR.MASTER.IP:32641

Reference

https://joshh.info/2018/kubernetes-dashboard-https-nodeport/