# AWS

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

In this tutorial, we'll create a Kubernetes v1.11.0 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](https://github.com/kubernetes-incubator/bootkube) bootstrap schedules the `apiserver`, `scheduler`, `controller-manager`, and `kube-dns` 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](https://www.terraform.io/downloads.html) v0.11.x on your system.

```sh
$ terraform version
Terraform v0.11.7
```

Read [concepts](../architecture/concepts.md) 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.

```tf
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](https://www.terraform.io/docs/providers/aws/).

!!! tip
    Regions are listed in [docs](http://docs.aws.amazon.com/general/latest/gr/rande.html#ec2_region) or with `aws ec2 describe-regions`.

## Cluster

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

```tf
module "aws-tempest" {
  source = "git::https://github.com/poseidon/typhoon//aws/fedora-atomic/kubernetes?ref=v1.11.0"

  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](#variables) or the [variables.tf](https://github.com/poseidon/typhoon/blob/master/aws/fedora-atomic/kubernetes/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`.

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

## Apply

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

```sh
terraform init
```

Plan the resources to be created.

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

Apply the changes to create the cluster.

```sh
$ 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](https://coreos.com/kubernetes/docs/latest/configure-kubectl.html) 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       v1.11.0
ip-10-0-19-112   Ready     34m       v1.11.0
ip-10-0-4-22     Ready     34m       v1.11.0
```

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   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-dns-1187388186-wx1lg                 3/3    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](../topics/maintenance.md) and [addons](../addons/overview.md).

## Variables

Check the [variables.tf](https://github.com/poseidon/typhoon/blob/master/aws/fedora-atomic/kubernetes/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.

```tf
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}"`.

!!! tip ""
    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](http://docs.aws.amazon.com/Route53/latest/DeveloperGuide/SOA-NSrecords.html).

### 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 kube-dns. | "cluster.local" | "k8s.example.com" |

Check the list of valid [instance types](https://aws.amazon.com/ec2/instance-types/).

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

!!! tip "MTU"
    If your EC2 instance type supports [Jumbo frames](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/network_mtu.html#jumbo_frame_instances) (most do), we recommend you change the `network_mtu` to 8981! You will get better pod-to-pod bandwidth.