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* Stop providing example manifests for the Container Linux Update Operator (CLUO) * CLUO requires patches to support Kubernetes v1.16+, but the project and push access is rather unowned * CLUO hasn't been in active use in our clusters and won't be relevant beyond Container Linux. Not to say folks can't patch it and run it on their own. Examples just aren't provided here Related: https://github.com/coreos/container-linux-update-operator/pull/197
258 lines
10 KiB
Markdown
258 lines
10 KiB
Markdown
# Digital Ocean
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In this tutorial, we'll create a Kubernetes v1.17.4 cluster on DigitalOcean with CoreOS Container Linux or Flatcar Linux.
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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.
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Controller hosts are provisioned to run an `etcd-member` peer and a `kubelet` service. Worker hosts run a `kubelet` service. Controller nodes run `kube-apiserver`, `kube-scheduler`, `kube-controller-manager`, and `coredns`, while `kube-proxy` and `calico` (or `flannel`) run 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 v0.12.6+ and [terraform-provider-ct](https://github.com/poseidon/terraform-provider-ct) installed locally
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## Terraform Setup
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Install [Terraform](https://www.terraform.io/downloads.html) v0.12.6+ on your system.
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```sh
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$ terraform version
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Terraform v0.12.21
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```
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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.
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```sh
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wget https://github.com/poseidon/terraform-provider-ct/releases/download/v0.4.0/terraform-provider-ct-v0.4.0-linux-amd64.tar.gz
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tar xzf terraform-provider-ct-v0.4.0-linux-amd64.tar.gz
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mv terraform-provider-ct-v0.4.0-linux-amd64/terraform-provider-ct ~/.terraform.d/plugins/terraform-provider-ct_v0.4.0
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```
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Read [concepts](/architecture/concepts/) 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 = "1.14.0"
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token = "${chomp(file("~/.config/digital-ocean/token"))}"
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}
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provider "ct" {
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version = "0.4.0"
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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/container-linux/kubernetes`.
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```tf
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module "nemo" {
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source = "git::https://github.com/poseidon/typhoon//digital-ocean/container-linux/kubernetes?ref=v1.17.4"
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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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image = "coreos-stable"
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# configuration
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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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# optional
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worker_count = 2
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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/container-linux/kubernetes/variables.tf) source.
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### Flatcar Linux Only
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!!! warning
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Typhoon for Flatcar Linux on DigitalOcean is alpha. Also IPv6 is unsupported with DigitalOcean custom images.
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Flatcar Linux publishes DigitalOcean images, but does not upload them. DigitalOcean allows [custom boot images](https://blog.digitalocean.com/custom-images/) by file or URL.
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[Download](https://www.flatcar-linux.org/releases/) the Flatcar Linux DigitalOcean bin image (or copy the URL) and [upload](https://cloud.digitalocean.com/images/custom_images) it as a custom image. Rename the image with the channel and version to refer to these images over time.
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```tf
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module "nemo" {
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...
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image = data.digitalocean_image.flatcar-stable.id
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}
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data "digitalocean_image" "flatcar-stable" {
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name = "flatcar-stable-2303.4.0.bin.bz2"
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}
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```
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Set the [image](#variables) to the custom image id.
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## ssh-agent
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Initial bootstrapping requires `bootstrap.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.nemo.null_resource.bootstrap: Still creating... (30s elapsed)
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module.nemo.null_resource.bootstrap: Provisioning with 'remote-exec'...
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...
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module.nemo.null_resource.bootstrap: Still creating... (6m20s elapsed)
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module.nemo.null_resource.bootstrap: Creation complete (ID: 7599298447329218468)
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Apply complete! Resources: 42 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://kubernetes.io/docs/tasks/tools/install-kubectl/) on your system. Obtain the generated cluster `kubeconfig` from module outputs (e.g. write to a local file).
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```
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resource "local_file" "kubeconfig-nemo" {
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content = module.nemo.kubeconfig-admin
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filename = "/home/user/.kube/configs/nemo-config"
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}
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```
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List nodes in the cluster.
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```
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$ export KUBECONFIG=/home/user/.kube/configs/nemo-config
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$ kubectl get nodes
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NAME STATUS ROLES AGE VERSION
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10.132.110.130 Ready <none> 10m v1.17.4
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10.132.115.81 Ready <none> 10m v1.17.4
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10.132.124.107 Ready <none> 10m v1.17.4
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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 coredns-1187388186-ld1j7 1/1 Running 0 11m
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kube-system coredns-1187388186-rdhf7 1/1 Running 0 11m
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kube-system calico-node-1m5bf 2/2 Running 0 11m
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kube-system calico-node-7jmr1 2/2 Running 0 11m
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kube-system calico-node-bknc8 2/2 Running 0 11m
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kube-system kube-apiserver-ip-10.132.115.81 1/1 Running 0 11m
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kube-system kube-controller-manager-ip-10.132.115.81 1/1 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-ip-10.132.115.81 1/1 Running 0 11m
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```
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## Going Further
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Learn about [maintenance](/topics/maintenance/) and [addons](/addons/overview/).
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## Variables
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Check the [variables.tf](https://github.com/poseidon/typhoon/blob/master/digital-ocean/container-linux/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_fingerprints | SSH public key fingerprints | ["d7:9d..."] |
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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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# Declare a DigitalOcean record to also create a zone file
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resource "digitalocean_domain" "zone-for-clusters" {
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name = "do.example.com"
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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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| asset_dir | Absolute path to a directory where generated assets should be placed (contains secrets) | "" (disabled) | "/home/user/.secrets/nemo" |
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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-2gb" | s-1vcpu-2gb, s-2vcpu-2gb, ... |
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| image | Container Linux image for instances | "coreos-stable" | coreos-stable, coreos-beta, coreos-alpha, "custom-image-id" |
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| controller_clc_snippets | Controller Container Linux Config snippets | [] | [example](/advanced/customization/) |
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| worker_clc_snippets | Worker Container Linux Config snippets | [] | [example](/advanced/customization/) |
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| networking | Choice of networking provider | "calico" | "flannel" or "calico" |
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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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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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