terminal-controller-manager

Gardener Terminal Controller Manager

The terminal-controller-manager is used for the webterminal feature of the gardener/dashboard but is in general independant of the gardener and it's resource kinds like Shoots, Seeds etc.

The terminal-controller-manager watches Terminal resources under the dashboard.gardener.cloud/v1alpha1 API group and ensures the desired state on the host and target cluster. Host and target cluster can also be the same. For more details and a usage scenario see docs here.

Development Setup

Prerequisites:

• golang
• kind
• kustomize
• kubectl

To build and push the images, run docker-build and docker-push make targets. Adapt the image as necessary:

make docker-build docker-push IMG=example/my-repo

There are two options to deploy the terminal-controller-manager into your cluster

• single-cluster setup
  • The hosting and target cluster are the same (see config/overlay/single-cluster).
• multi-cluster setup
  • The terminal-controller-manager is deployed in a hosting cluster, which is called runtime cluster (see config/overlay/multi-cluster/runtime) but watches the terminal resources in another/target cluster, called virtual-garden (see config/overlay/multi-cluster/virtual-garden).
  • The admission webhook configurations of course are created in the virtual-garden.

Single-Cluster Setup with Kind

To deploy the terminal-controller-manager into a single-cluster execute:

kind create cluster

Use the cluster with:

export KUBECONFIG="$(kind get kubeconfig-path --name="kind")"

Run deploy-singlecluster make target.

Optionally specify the IMG in case you built your own image, otherwise the default eu.gcr.io/gardener-project/gardener/terminal-controller-manager:latest is used.

make deploy-singlecluster

To verify that everything worked, check if the terminal-controller-manager pod is running in the terminal-system namespace:

kubectl -n terminal-system get po

NAME                                           READY   STATUS    RESTARTS   AGE
terminal-controller-manager-6d7b5bfbdd-l6vg9   2/2     Running   0          10s

Create Example Terminal Resource

Run the bootstrap-dev make target to bootstrap your cluster with dummy namespaces, serviceaccounts, clusterroles and clusterrolebinding that are required for the example terminal resources config/samples/terminal-cp.yaml and config/samples/terminal-shoot.yaml:

make bootstrap-dev

Apply the terminal resources

kubectl apply -f config/samples/terminal-cp.yaml 

kubectl apply -f config/samples/terminal-shoot.yaml --validate=false

Check if the terminal resources were created. Note that the terminal resources get cleaned if they don't receive a heartbeat.

kubectl get terminals -n garden-coretmp

NAME                AGE
term-lukas-hib      33s
term-lukas-hib-cp   22s

The terminal-controller-manager should create, among other resources, a pod in the respective target namespace that is declared in the terminal resource. E.g. for the example terminal-cp.yaml the target namespace is shoot--core--mycluster.

kubectl -n shoot--core--mycluster get po

NAME                      READY   STATUS    RESTARTS   AGE
term-627737417320032009   1/1     Running   0          17s

Exec into the pod and verify that you can talk to the api server:

kubectl -n shoot--core--mycluster exec -it term-627737417320032009 bash

root at term-627737417320032009 in / on 10.96.0.1 [shoot--core--mycluster]
$ k get po
NAME                      READY   STATUS    RESTARTS   AGE
term-627737417320032009   1/1     Running   0          25s