Installation using Kubespray

The guide is to use Kubespray for creating an AWS Kubernetes cluster running Cilium as the CNI. The guide uses:

Please consult Kubespray Prerequisites and Cilium System Requirements.

Installing Kubespray

$ git clone --branch v2.6.0 https://github.com/kubernetes-incubator/kubespray

Install dependencies from requirements.txt

$ cd kubespray
$ sudo pip install -r requirements.txt

Infrastructure Provisioning

We will use Terraform for provisioning AWS infrastructure.

Configure AWS credentials

Export the variables for your AWS credentials

export AWS_ACCESS_KEY_ID="www"
export AWS_SECRET_ACCESS_KEY ="xxx"
export AWS_SSH_KEY_NAME="yyy"
export AWS_DEFAULT_REGION="zzz"

Configure Terraform Variables

We will start by specifying the infrastructure needed for the Kubernetes cluster.

$ cd contrib/terraform/aws
$ cp contrib/terraform/aws/terraform.tfvars.example terraform.tfvars`

Open the file and change any defaults particularly, the number of master, etcd, and worker nodes. You can change the master and etcd number to 1 for deployments that don’t need high availability. By default, this tutorial will create:

  • VPC with 2 public and private subnets
  • Bastion Hosts and NAT Gateways in the Public Subnet
  • Three of each (masters, etcd, and worker nodes) in the Private Subnet
  • AWS ELB in the Public Subnet for accessing the Kubernetes API from the internet
  • Terraform scripts using CoreOS as base image.

Example terraform.tfvars file:

#Global Vars
aws_cluster_name = "kubespray"

#VPC Vars
aws_vpc_cidr_block = "XXX.XXX.192.0/18"
aws_cidr_subnets_private = ["XXX.XXX.192.0/20","XXX.XXX.208.0/20"]
aws_cidr_subnets_public = ["XXX.XXX.224.0/20","XXX.XXX.240.0/20"]

#Bastion Host
aws_bastion_size = "t2.medium"


#Kubernetes Cluster

aws_kube_master_num = 3
aws_kube_master_size = "t2.medium"

aws_etcd_num = 3
aws_etcd_size = "t2.medium"

aws_kube_worker_num = 3
aws_kube_worker_size = "t2.medium"

#Settings AWS ELB

aws_elb_api_port = 6443
k8s_secure_api_port = 6443
kube_insecure_apiserver_address = "0.0.0.0"

Apply the configuration

terraform init to initialize the following modules

  • module.aws-vpc
  • module.aws-elb
  • module.aws-iam
$ terraform init

Once initialized , execute:

$ terraform plan -out=aws_kubespray_plan

This will generate a file, aws_kubespray_plan, depicting an execution plan of the infrastructure that will be created on AWS. To apply, execute:

$ terraform init
$ terraform apply "aws_kubespray_plan"

Terraform automatically creates an Ansible Inventory file at inventory/hosts.

Installing Kubernetes cluster with Cilium as CNI

Kubespray uses Ansible as its substrate for provisioning and orchestration. Once the infrastructure is created, you can run the Ansible playbook to install Kubernetes and all the required dependencies. Execute the below command in the kubespray clone repo, providing the correct path of the AWS EC2 ssh private key in ansible_ssh_private_key_file=<path to EC2 SSH private key file>

We recommend using the latest released Cilium version by editing roles/download/defaults/main.yml. Open the file, search for cilium_version, and replace the version with the latest released. As an example, the updated version entry will look like: cilium_version: "v1.2.0".

$ ansible-playbook -i ./inventory/hosts ./cluster.yml -e ansible_user=core -e bootstrap_os=coreos -e kube_network_plugin=cilium -b --become-user=root --flush-cache  -e ansible_ssh_private_key_file=<path to EC2 SSH private key file>

Validate Cluster

To check if cluster is created successfully, ssh into the bastion host with the user core.

# Get information about the basiton host
$ cat ssh-bastion.conf
$ ssh -i ~/path/to/ec2-key-file.pem [email protected]_ip_of_bastion_host

Execute the commands below from the bastion host. If kubectl isn’t installed on the bastion host, you can login to the master node to test the below commands. You may need to copy the private key to the bastion host to access the master node.

$ kubectl get nodes
$ kubectl get pods -n kube-system

You should see that nodes are in Ready state and Cilium pods are in Running state

Demo Application

Follow this link to deploy a demo application and verify the correctness of the installation.

Delete Cluster

$ cd contrib/terraform/aws
$ terraform destroy