Kubernetes Setup

Set up a Kubernetes cluster from scratch

Requirements

• All hosts need to run Ubuntu 16.04
• All hosts need to be able to communicate with each other

Features

• High-availability etcd Cluster
• PKI Tools
• CNI
• Weave
• Cloud-platform independent
• Your API Master can talk to the rest

Getting Started

Fetching dependencies

1. ./extras/install_cfssl.sh
2. ./extras/download_kubernetes_binaries.sh

Setting up the inventory file

A sample inventory file.

[all:vars]
kube_version=v1.9.1 // This should be fixed to v1.9.1
kube_cluster_name=$YOURCLUSTERNAME // Whatever name you want to give your cluster
kube_public_address=$IP_OF_MASTER // The IP address of the master
kube_master=$IP_OF_MASTER // The IP address of the master
kube_cluster_dns=$IP_OF_DNS_SERVICES // The IP address where your DNS service will run (most likely 10.32.0.10)

[kube-master]
// The IP address of the master

[kube_nodes]
// Multiple IP addresses where kubelets will run
// Has to be in the following format:
// ip hostname=hostname internal_ip=internal_ip external_ip=external_ip

[kube_apiservers]
// Multiple IP addresses where you want your API servers to run

[kube_scheduler]
// IP address where you want the scheduler to run

[kube_controller_manager]
// IP Address where you want the controller manager to run

[etcd]
// Multiple IP addresses where you want the etcd servers to run.
// Has to be in this format:
// 10.0.0.1 etcd_name=yourname

Save this as inventory.ini in the root directory

Setting up the PKI

Because we're using cert based authentication we have to setup a proper pki. Run:

python setup.py

Bootstrapping your cluster

With the steps above completed, it's time to bootstrap the cluster:

ansible-playbook -i inventory.ini bootstrap.yml

Connecting to your cluster using kubectl

kubectl config set-cluster $CLUSTER_NAME \
  --certificate-authority=./files/certificates/ca.pem \
  --embed-certs=true \
  --server=https://${IP_OF_MASTER_API_SERVER}:6443

kubectl config set-credentials admin \
  --client-certificate=./files/certificates/admin.pem \
  --client-key=./files/certificates/admin-key.pem

kubectl config set-context $CLUSTER_NAME \
  --cluster=$CLUSTER_NAME \
  --user=admin

Make sure you're using the right context by calling: kubectl config use-context $CLUSTER_NAME

Confirm everything works

If you run kubectl get componentstatuses you should see the following output:

NAME                 STATUS    MESSAGE              ERROR
controller-manager   Healthy   ok
scheduler            Healthy   ok
etcd-2               Healthy   {"health": "true"}
etcd-0               Healthy   {"health": "true"}
etcd-1               Healthy   {"health": "true"}

Add the DNS Add-on

kubectl apply -f ./extras/kube-dns.yaml;

Adding Weave for networking

To make sure pods can talk to each other you have to run Weave on all your pods.

./extras/add_weave.sh

Extras

Installing Kubernetes dashboard

kubectl apply -f ./extras/kubernetes-dashboard.yml;
kube proxy

Now go to localhost:8001/ui to manage your Kubernetes cluster via the UI!

Compatability

Tested on:

• Virtual Machines
• Digital Ocean