In this scenario you'll learn how to bootstrap a Kubernetes cluster using Kubeadm.
Kubeadm solves the problem of handling TLS encryption configuration, deploying the core Kubernetes components and ensuring that additional nodes can easily join the cluster. The resulting cluster is secured out of the box via mechanisms such as RBAC.
More details on Kubeadm can be found at https://github.com/kubernetes/kubeadm
Getting Started With Kubeadm
Step 1 - Initialise Master
Kubeadm has been installed on the nodes. Packages are available for Ubuntu 16.04+, CentOS 7 or HypriotOS v1.0.1+.
The first stage of initialising the cluster is to launch the master node. The master is responsible for running the control plane components, etcd and the API server. Clients will communicate to the API to schedule workloads and manage the state of the cluster.
The command below will initialise the cluster with a known token to simplify the following steps.
kubeadm init --token=102952.1a7dd4cc8d1f4cc5 --kubernetes-version $(kubeadm version -o short)
In production, it's recommend to exclude the token causing kubeadm to generate one on your behalf.
To manage the Kubernetes cluster, the client configuration and certificates are required. This configuration is created when kubeadm initialises the cluster. The command copies the configuration to the users home directory and sets the environment variable for use with the CLI.
sudo cp /etc/kubernetes/admin.conf $HOME/ sudo chown $(id -u):$(id -g) $HOME/admin.conf export KUBECONFIG=$HOME/admin.conf