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AWS

Danger

Typhoon for Fedora Atomic is alpha. Expect rough edges and changes.

In this tutorial, we'll create a Kubernetes v1.11.1 cluster on AWS with Fedora Atomic.

We'll declare a Kubernetes cluster using the Typhoon Terraform module. Then apply the changes to create a VPC, gateway, subnets, security groups, controller instances, worker auto-scaling group, network load balancer, and TLS assets. Instances are provisioned on first boot with cloud-init.

Controllers are provisioned to run an etcd peer and a kubelet service. Workers run just a kubelet service. A one-time bootkube bootstrap schedules the apiserver, scheduler, controller-manager, and coredns on controllers and schedules kube-proxy and calico (or flannel) on every node. A generated kubeconfig provides kubectl access to the cluster.

Requirements

  • AWS Account and IAM credentials
  • AWS Route53 DNS Zone (registered Domain Name or delegated subdomain)
  • Terraform v0.11.x installed locally

Terraform Setup

Install Terraform v0.11.x on your system.

$ terraform version
Terraform v0.11.7

Read concepts to learn about Terraform, modules, and organizing resources. Change to your infrastructure repository (e.g. infra).

cd infra/clusters

Provider

Login to your AWS IAM dashboard and find your IAM user. Select "Security Credentials" and create an access key. Save the id and secret to a file that can be referenced in configs.

[default]
aws_access_key_id = xxx
aws_secret_access_key = yyy

Configure the AWS provider to use your access key credentials in a providers.tf file.

provider "aws" {
  version = "~> 1.13.0"
  alias   = "default"

  region                  = "eu-central-1"
  shared_credentials_file = "/home/user/.config/aws/credentials"
}

provider "local" {
  version = "~> 1.0"
  alias = "default"
}

provider "null" {
  version = "~> 1.0"
  alias = "default"
}

provider "template" {
  version = "~> 1.0"
  alias = "default"
}

provider "tls" {
  version = "~> 1.0"
  alias = "default"
}

Additional configuration options are described in the aws provider docs.

Tip

Regions are listed in docs or with aws ec2 describe-regions.

Cluster

Define a Kubernetes cluster using the module aws/fedora-atomic/kubernetes.

module "aws-tempest" {
  source = "git::https://github.com/poseidon/typhoon//aws/fedora-atomic/kubernetes?ref=v1.11.1"

  providers = {
    aws = "aws.default"
    local = "local.default"
    null = "null.default"
    template = "template.default"
    tls = "tls.default"
  }

  # AWS
  cluster_name = "tempest"
  dns_zone     = "aws.example.com"
  dns_zone_id  = "Z3PAABBCFAKEC0"

  # configuration
  ssh_authorized_key = "ssh-rsa AAAAB3Nz..."
  asset_dir          = "/home/user/.secrets/clusters/tempest"

  # optional
  worker_count = 2
  worker_type  = "t2.medium"
}

Reference the variables docs or the variables.tf source.

ssh-agent

Initial bootstrapping requires bootkube.service be started on one controller node. Terraform uses ssh-agent to automate this step. Add your SSH private key to ssh-agent.

ssh-add ~/.ssh/id_rsa
ssh-add -L

Apply

Initialize the config directory if this is the first use with Terraform.

terraform init

Plan the resources to be created.

$ terraform plan
Plan: 106 to add, 0 to change, 0 to destroy.

Apply the changes to create the cluster.

$ terraform apply
...
module.aws-tempest.null_resource.bootkube-start: Still creating... (4m50s elapsed)
module.aws-tempest.null_resource.bootkube-start: Still creating... (5m0s elapsed)
module.aws-tempest.null_resource.bootkube-start: Creation complete after 11m8s (ID: 3961816482286168143)

Apply complete! Resources: 106 added, 0 changed, 0 destroyed.

In 5-10 minutes, the Kubernetes cluster will be ready.

Verify

Install kubectl on your system. Use the generated kubeconfig credentials to access the Kubernetes cluster and list nodes.

$ export KUBECONFIG=/home/user/.secrets/clusters/tempest/auth/kubeconfig
$ kubectl get nodes
NAME             STATUS    AGE       VERSION        
ip-10-0-12-221   Ready     34m       v1.11.1
ip-10-0-19-112   Ready     34m       v1.11.1
ip-10-0-4-22     Ready     34m       v1.11.1

List the pods.

$ kubectl get pods --all-namespaces
NAMESPACE     NAME                                      READY  STATUS    RESTARTS  AGE              
kube-system   calico-node-1m5bf                         2/2    Running   0         34m              
kube-system   calico-node-7jmr1                         2/2    Running   0         34m              
kube-system   calico-node-bknc8                         2/2    Running   0         34m              
kube-system   coredns-1187388186-wx1lg                  1/1    Running   0         34m              
kube-system   kube-apiserver-4mjbk                      1/1    Running   0         34m              
kube-system   kube-controller-manager-3597210155-j2jbt  1/1    Running   1         34m              
kube-system   kube-controller-manager-3597210155-j7g7x  1/1    Running   0         34m              
kube-system   kube-proxy-14wxv                          1/1    Running   0         34m              
kube-system   kube-proxy-9vxh2                          1/1    Running   0         34m              
kube-system   kube-proxy-sbbsh                          1/1    Running   0         34m              
kube-system   kube-scheduler-3359497473-5plhf           1/1    Running   0         34m              
kube-system   kube-scheduler-3359497473-r7zg7           1/1    Running   1         34m              
kube-system   pod-checkpointer-4kxtl                    1/1    Running   0         34m              
kube-system   pod-checkpointer-4kxtl-ip-10-0-12-221     1/1    Running   0         33m

Going Further

Learn about maintenance and addons.

Variables

Check the variables.tf source.

Required

Name Description Example
cluster_name Unique cluster name (prepended to dns_zone) "tempest"
dns_zone AWS Route53 DNS zone "aws.example.com"
dns_zone_id AWS Route53 DNS zone id "Z3PAABBCFAKEC0"
ssh_authorized_key SSH public key for user 'fedora' "ssh-rsa AAAAB3NZ..."
asset_dir Path to a directory where generated assets should be placed (contains secrets) "/home/user/.secrets/clusters/tempest"

DNS Zone

Clusters create a DNS A record ${cluster_name}.${dns_zone} to resolve a network load balancer backed by controller instances. This FQDN is used by workers and kubectl to access the apiserver(s). In this example, the cluster's apiserver would be accessible at tempest.aws.example.com.

You'll need a registered domain name or delegated subdomain on AWS Route53. You can set this up once and create many clusters with unique names.

resource "aws_route53_zone" "zone-for-clusters" {
  name = "aws.example.com."
}

Reference the DNS zone id with "${aws_route53_zone.zone-for-clusters.zone_id}".

If you have an existing domain name with a zone file elsewhere, just delegate a subdomain that can be managed on Route53 (e.g. aws.mydomain.com) and update nameservers.

Optional

Name Description Default Example
controller_count Number of controllers (i.e. masters) 1 1
worker_count Number of workers 1 3
controller_type EC2 instance type for controllers "t2.small" See below
worker_type EC2 instance type for workers "t2.small" See below
disk_size Size of the EBS volume in GB "40" "100"
disk_type Type of the EBS volume "gp2" standard, gp2, io1
worker_price Spot price in USD for workers. Leave as default empty string for regular on-demand instances "" "0.10"
networking Choice of networking provider "calico" "calico" or "flannel"
network_mtu CNI interface MTU (calico only) 1480 8981
host_cidr CIDR IPv4 range to assign to EC2 instances "10.0.0.0/16" "10.1.0.0/16"
pod_cidr CIDR IPv4 range to assign to Kubernetes pods "10.2.0.0/16" "10.22.0.0/16"
service_cidr CIDR IPv4 range to assign to Kubernetes services "10.3.0.0/16" "10.3.0.0/24"
cluster_domain_suffix FQDN suffix for Kubernetes services answered by coredns. "cluster.local" "k8s.example.com"

Check the list of valid instance types.

Warning

Do not choose a controller_type smaller than t2.small. Smaller instances are not sufficient for running a controller.