clusterctl

README

clusterctl

• Getting Started
  • Prerequisites
  • Limitations
  • Creating a cluster
  • Interacting with your cluster
    • Scaling your cluster
    • Upgrading your cluster
    • Node repair
  • Deleting a cluster
• Contributing

clusterctl is the SIG-cluster-lifecycle sponsored tool that implements the Cluster API.

Read the experience doc here. To gain viewing permissions, please join either the kubernetes-dev or kubernetes-sig-cluster-lifecycle google group.

Getting Started

Due to the limitations described below, you must currently compile and run a clusterctl binary from your chosen provider implementation rather than using the binary from this repository.

Prerequisites

1. Cluster API runs its operations in Kubernetes. A pre-existing or temporary bootstrap cluster is required. Currently, we support multiple methods to bootstrap Cluster API: kind (preferred), minikube or any pre-existing cluster.
   • If you want to use container, install kind. This is preferred.
   • If you want to use VM, install minikube, version 0.30.0 or greater.
   • If you want to use existing Kubernetes cluster, prepare your kubeconfig.
2. If you are using kind or existing Kubernetes cluster, go to step 3. If you are using minikube, install a driver. For Linux, we recommend kvm2. For MacOS, we recommend VirtualBox.
3. Build the clusterctl tool

$ git clone https://github.com/kubernetes-sigs/cluster-api $GOPATH/src/sigs.k8s.io/cluster-api
$ cd $GOPATH/src/sigs.k8s.io/cluster-api/cmd/clusterctl/
$ go build

Limitations

clusterctl can only use a provider that is compiled in. As provider specific code has been moved out of this repository, running the clusterctl binary compiled from this repository isn't particularly useful.

There is current work ongoing to rectify this issue, which centers around removing the ProviderDeployer interface from the clusterdeployer package. The two tracking issues for removing the two functions in the interface are https://github.com/kubernetes-sigs/cluster-api/issues/158 and https://github.com/kubernetes-sigs/cluster-api/issues/160.

Creating a cluster

1. Create the cluster.yaml, machines.yaml, provider-components.yaml, and addons.yaml files configured for your cluster. See the provider specific templates and generation tools for your chosen provider implementation.

2. Create a cluster:

   • Bootstrap Cluster: Use bootstrap-type, currently only kind and minikube are supported.

   ./clusterctl create cluster --provider <provider> --bootstrap-type <bootstrap-type> -c cluster.yaml \
     -m machines.yaml -p provider-components.yaml -a addons.yaml
   

   If you are using minikube, to choose a specific minikube driver, please use the --bootstrap-flags vm-driver=xxx command line parameter. For example to use the kvm2 driver with clusterctl you woud add --bootstrap-flags vm-driver=kvm2.

   • Existing Cluster: Use bootstrap-cluster-kubeconfig. This flag is used when you have an existing Kubernetes cluster.

   ./clusterctl create cluster --provider <provider> --bootstrap-cluster-kubeconfig <kubeconfig> \
     -c cluster.yaml -m machines.yaml -p provider-components.yaml -a addons.yaml
   

Additional advanced flags can be found via help.

Also, some environment variables are supported: CLUSTER_API_MACHINE_READY_TIMEOUT: set this value to adjust the timeout value in minutes for a machine to become ready, The default timeout is currently 30 minutes, export CLUSTER_API_MACHINE_READY_TIMEOUT=45 will extend the timeout value to 45 minutes. CLUSTER_API_KUBECONFIG_READY_TIMEOUT: set this value to adjust the timeout value in minutes to wait for the KubeConfig to be ready. Defaults to 20 minutes.

./clusterctl create cluster --help

Interacting with your cluster

If you are using kind, set the KUBECONFIG environment variable first before using kubectl:

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

Once you have created a cluster, you can interact with the cluster and machine resources using kubectl:

$ kubectl --kubeconfig kubeconfig get clusters
$ kubectl --kubeconfig kubeconfig get machines
$ kubectl --kubeconfig kubeconfig get machines -o yaml

NOTE: There is no need to specify --kubeconfig if your kubeconfig was located in the default directory under $HOME/.kube/config or if you have already exposed env variable KUBECONFIG.

Scaling your cluster

You can scale your cluster by adding additional individual Machines, or by adding a MachineSet or MachineDeployment and changing the number of replicas.

Upgrading your cluster

NOT YET SUPPORTED!

Node repair

NOT YET SUPPORTED!

Deleting a cluster

When you are ready to remove your cluster, you can use clusterctl to delete the cluster:

./clusterctl delete cluster --kubeconfig kubeconfig

Please also check the documentation for your provider implementation to determine if any additional steps need to be taken to completely clean up your cluster.

Contributing

If you are interested in adding to this project, see the contributing guide for information on how you can get involved.