250 lines
9.6 KiB
Markdown
250 lines
9.6 KiB
Markdown
# Digital Ocean
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!!! danger
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Typhoon for Fedora Atomic is alpha. Expect rough edges and changes.
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In this tutorial, we'll create a Kubernetes v1.10.4 cluster on DigitalOcean with Fedora Atomic.
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We'll declare a Kubernetes cluster using the Typhoon Terraform module. Then apply the changes to create controller droplets, worker droplets, DNS records, tags, and TLS assets. Instances are provisioned on first boot with cloud-init.
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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 `flannel` on every node. A generated `kubeconfig` provides `kubectl` access to the cluster.
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## Requirements
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* Digital Ocean Account and Token
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* Digital Ocean Domain (registered Domain Name or delegated subdomain)
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* Terraform v0.11.x installed locally
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## Terraform Setup
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Install [Terraform](https://www.terraform.io/downloads.html) v0.11.x on your system.
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```sh
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$ terraform version
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Terraform v0.11.7
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```
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Read [concepts](../architecture/concepts.md) to learn about Terraform, modules, and organizing resources. Change to your infrastructure repository (e.g. `infra`).
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```
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cd infra/clusters
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```
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## Provider
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Login to [DigitalOcean](https://cloud.digitalocean.com) or create an [account](https://cloud.digitalocean.com/registrations/new), if you don't have one.
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Generate a Personal Access Token with read/write scope from the [API tab](https://cloud.digitalocean.com/settings/api/tokens). Write the token to a file that can be referenced in configs.
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```sh
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mkdir -p ~/.config/digital-ocean
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echo "TOKEN" > ~/.config/digital-ocean/token
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```
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Configure the DigitalOcean provider to use your token in a `providers.tf` file.
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```tf
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provider "digitalocean" {
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version = "0.1.3"
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token = "${chomp(file("~/.config/digital-ocean/token"))}"
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alias = "default"
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}
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provider "local" {
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version = "~> 1.0"
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alias = "default"
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}
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provider "null" {
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version = "~> 1.0"
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alias = "default"
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}
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provider "template" {
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version = "~> 1.0"
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alias = "default"
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}
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provider "tls" {
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version = "~> 1.0"
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alias = "default"
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}
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```
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## Cluster
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Define a Kubernetes cluster using the module `digital-ocean/fedora-atomic/kubernetes`.
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```tf
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module "digital-ocean-nemo" {
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source = "git::https://github.com/poseidon/typhoon//digital-ocean/fedora-atomic/kubernetes?ref=v1.10.4"
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providers = {
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digitalocean = "digitalocean.default"
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local = "local.default"
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null = "null.default"
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template = "template.default"
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tls = "tls.default"
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}
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# Digital Ocean
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cluster_name = "nemo"
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region = "nyc3"
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dns_zone = "digital-ocean.example.com"
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# configuration
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ssh_authorized_key = "ssh-rsa AAAAB3Nz..."
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ssh_fingerprints = ["d7:9d:79:ae:56:32:73:79:95:88:e3:a2:ab:5d:45:e7"]
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asset_dir = "/home/user/.secrets/clusters/nemo"
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# optional
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worker_count = 2
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worker_type = "s-1vcpu-1gb"
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}
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```
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Reference the [variables docs](#variables) or the [variables.tf](https://github.com/poseidon/typhoon/blob/master/digital-ocean/fedora-atomic/kubernetes/variables.tf) source.
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## ssh-agent
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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`.
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```sh
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ssh-add ~/.ssh/id_rsa
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ssh-add -L
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```
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## Apply
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Initialize the config directory if this is the first use with Terraform.
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```sh
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terraform init
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```
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Plan the resources to be created.
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```sh
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$ terraform plan
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Plan: 54 to add, 0 to change, 0 to destroy.
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```
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Apply the changes to create the cluster.
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```sh
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$ terraform apply
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module.digital-ocean-nemo.null_resource.bootkube-start: Still creating... (30s elapsed)
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module.digital-ocean-nemo.null_resource.bootkube-start: Provisioning with 'remote-exec'...
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...
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module.digital-ocean-nemo.null_resource.bootkube-start: Still creating... (6m20s elapsed)
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module.digital-ocean-nemo.null_resource.bootkube-start: Creation complete (ID: 7599298447329218468)
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Apply complete! Resources: 54 added, 0 changed, 0 destroyed.
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```
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In 3-6 minutes, the Kubernetes cluster will be ready.
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## Verify
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[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.
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```
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$ export KUBECONFIG=/home/user/.secrets/clusters/nemo/auth/kubeconfig
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$ kubectl get nodes
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NAME STATUS AGE VERSION
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10.132.110.130 Ready 10m v1.10.4
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10.132.115.81 Ready 10m v1.10.4
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10.132.124.107 Ready 10m v1.10.4
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```
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List the pods.
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```
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NAMESPACE NAME READY STATUS RESTARTS AGE
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kube-system kube-apiserver-n10qr 1/1 Running 0 11m
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kube-system kube-controller-manager-3271970485-37gtw 1/1 Running 1 11m
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kube-system kube-controller-manager-3271970485-p52t5 1/1 Running 0 11m
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kube-system kube-dns-1187388186-ld1j7 3/3 Running 0 11m
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kube-system kube-flannel-1cq1v 2/2 Running 0 11m
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kube-system kube-flannel-hq9t0 2/2 Running 1 11m
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kube-system kube-flannel-v0g9w 2/2 Running 0 11m
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kube-system kube-proxy-6kxjf 1/1 Running 0 11m
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kube-system kube-proxy-fh3td 1/1 Running 0 11m
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kube-system kube-proxy-k35rc 1/1 Running 0 11m
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kube-system kube-scheduler-3895335239-2bc4c 1/1 Running 0 11m
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kube-system kube-scheduler-3895335239-b7q47 1/1 Running 1 11m
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kube-system pod-checkpointer-pr1lq 1/1 Running 0 11m
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kube-system pod-checkpointer-pr1lq-10.132.115.81 1/1 Running 0 10m
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```
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## Going Further
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Learn about [maintenance](../topics/maintenance.md) and [addons](../addons/overview.md).
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## Variables
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Check the [variables.tf](https://github.com/poseidon/typhoon/blob/master/digital-ocean/fedora-atomic/kubernetes/variables.tf) source.
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### Required
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| Name | Description | Example |
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|:-----|:------------|:--------|
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| cluster_name | Unique cluster name (prepended to dns_zone) | nemo |
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| region | Digital Ocean region | nyc1, sfo2, fra1, tor1 |
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| dns_zone | Digital Ocean domain (i.e. DNS zone) | do.example.com |
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| ssh_authorized_key | SSH public key for user 'fedora' | "ssh-rsa AAAAB3NZ..." |
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| ssh_fingerprints | SSH public key fingerprints | ["d7:9d..."] |
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| asset_dir | Path to a directory where generated assets should be placed (contains secrets) | /home/user/.secrets/nemo |
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#### DNS Zone
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Clusters create DNS A records `${cluster_name}.${dns_zone}` to resolve to controller droplets (round robin). This FQDN is used by workers and `kubectl` to access the apiserver(s). In this example, the cluster's apiserver would be accessible at `nemo.do.example.com`.
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You'll need a registered domain name or delegated subdomain in Digital Ocean Domains (i.e. DNS zones). You can set this up once and create many clusters with unique names.
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```tf
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resource "digitalocean_domain" "zone-for-clusters" {
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name = "do.example.com"
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# Digital Ocean oddly requires an IP here. You may have to delete the A record it makes. :(
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ip_address = "8.8.8.8"
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}
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```
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!!! tip ""
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If you have an existing domain name with a zone file elsewhere, just delegate a subdomain that can be managed on DigitalOcean (e.g. do.mydomain.com) and [update nameservers](https://www.digitalocean.com/community/tutorials/how-to-set-up-a-host-name-with-digitalocean).
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#### SSH Fingerprints
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DigitalOcean droplets are created with your SSH public key "fingerprint" (i.e. MD5 hash) to allow access. If your SSH public key is at `~/.ssh/id_rsa`, find the fingerprint with,
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```bash
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ssh-keygen -E md5 -lf ~/.ssh/id_rsa.pub | awk '{print $2}'
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MD5:d7:9d:79:ae:56:32:73:79:95:88:e3:a2:ab:5d:45:e7
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```
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If you use `ssh-agent` (e.g. Yubikey for SSH), find the fingerprint with,
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```
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ssh-add -l -E md5
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2048 MD5:d7:9d:79:ae:56:32:73:79:95:88:e3:a2:ab:5d:45:e7 cardno:000603633110 (RSA)
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```
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Digital Ocean requires the SSH public key be uploaded to your account, so you may also find the fingerprint under Settings -> Security. Finally, if you don't have an SSH key, [create one now](https://help.github.com/articles/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent/).
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### Optional
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| Name | Description | Default | Example |
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| controller_count | Number of controllers (i.e. masters) | 1 | 1 |
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| worker_count | Number of workers | 1 | 3 |
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| controller_type | Droplet type for controllers | s-2vcpu-2gb | s-2vcpu-2gb, s-2vcpu-4gb, s-4vcpu-8gb, ... |
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| worker_type | Droplet type for workers | s-1vcpu-1gb | s-1vcpu-1gb, s-1vcpu-2gb, s-2vcpu-2gb, ... |
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| pod_cidr | CIDR IPv4 range to assign to Kubernetes pods | "10.2.0.0/16" | "10.22.0.0/16" |
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| service_cidr | CIDR IPv4 range to assign to Kubernetes services | "10.3.0.0/16" | "10.3.0.0/24" |
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| cluster_domain_suffix | FQDN suffix for Kubernetes services answered by kube-dns. | "cluster.local" | "k8s.example.com" |
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Check the list of valid [droplet types](https://developers.digitalocean.com/documentation/changelog/api-v2/new-size-slugs-for-droplet-plan-changes/) or use `doctl compute size list`.
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!!! warning
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Do not choose a `controller_type` smaller than 2GB. Smaller droplets are not sufficient for running a controller and bootstrapping will fail.
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