Typhoon for Fedora CoreOS is an early preview! Fedora CoreOS itself is a preview! Expect bugs and design shifts. Please help both projects solve problems. Report Fedora CoreOS bugs to [Fedora](https://github.com/coreos/fedora-coreos-tracker/issues). Report Typhoon issues to Typhoon.
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.
Controllers are provisioned to run an `etcd-member` 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 `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 v0.12.x and [terraform-provider-ct](https://github.com/poseidon/terraform-provider-ct) installed locally
## Terraform Setup
Install [Terraform](https://www.terraform.io/downloads.html) v0.12.x on your system.
Add the [terraform-provider-ct](https://github.com/poseidon/terraform-provider-ct) plugin binary for your system to `~/.terraform.d/plugins/`, noting the final name.
Read [concepts](/architecture/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.
Reference the [variables docs](#variables) or the [variables.tf](https://github.com/poseidon/typhoon/blob/master/aws/fedora-coreos/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: 98 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)
In 4-8 minutes, the Kubernetes cluster will be ready.
## Verify
[Install kubectl](https://kubernetes.io/docs/tasks/tools/install-kubectl/) on your system. Use the generated `kubeconfig` credentials to access the Kubernetes cluster and list nodes.
Learn about [maintenance](/topics/maintenance/) and [addons](/addons/overview/).
## Variables
Check the [variables.tf](https://github.com/poseidon/typhoon/blob/master/aws/fedora-coreos/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 'core' | "ssh-rsa AAAAB3NZ..." |
| asset_dir | Absolute 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 `"${aws_route53_zone.zone-for-clusters.zone_id}"`.
!!! tip ""
If you have an existing domain name with a zone file elsewhere, just delegate a subdomain that can be managed on Route53 (e.g. aws.mydomain.com) and [update nameservers](http://docs.aws.amazon.com/Route53/latest/DeveloperGuide/SOA-NSrecords.html).
### Optional
| Name | Description | Default | Example |
|:-----|:------------|:--------|:--------|
| controller_count | Number of controllers (i.e. masters) | 1 | 1 |
| worker_count | Number of workers | 1 | 3 |
| controller_type | EC2 instance type for controllers | "t3.small" | See below |
| worker_type | EC2 instance type for workers | "t3.small" | See below |
| os_image | AMI channel for Fedora CoreOS | not yet used | ? |
| disk_size | Size of the EBS volume in GB | "40" | "100" |
| disk_type | Type of the EBS volume | "gp2" | standard, gp2, io1 |
| disk_iops | IOPS of the EBS volume | "0" (i.e. auto) | "400" |
| worker_target_groups | Target group ARNs to which worker instances should be added | [] | ["${aws_lb_target_group.app.id}"] |
| worker_price | Spot price in USD for workers. Leave as default empty string for regular on-demand instances | "" | "0.10" |
| 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](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.
#### Spot
Add `worker_price = "0.10"` to use spot instance workers (instead of "on-demand") and set a maximum spot price in USD. Clusters can tolerate spot market interuptions fairly well (reschedules pods, but cannot drain) to save money, with the tradeoff that requests for workers may go unfulfilled.
