# Digital Ocean In this tutorial, we'll create a Kubernetes v1.18.1 cluster on DigitalOcean with CoreOS Container Linux or Flatcar Linux. 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. 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. ## Requirements * Digital Ocean Account and Token * Digital Ocean Domain (registered Domain Name or delegated subdomain) * Terraform v0.12.6+ and [terraform-provider-ct](https://github.com/poseidon/terraform-provider-ct) installed locally ## Terraform Setup Install [Terraform](https://www.terraform.io/downloads.html) v0.12.6+ on your system. ```sh $ terraform version Terraform v0.12.21 ``` 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. ```sh wget https://github.com/poseidon/terraform-provider-ct/releases/download/v0.5.0/terraform-provider-ct-v0.5.0-linux-amd64.tar.gz tar xzf terraform-provider-ct-v0.5.0-linux-amd64.tar.gz mv terraform-provider-ct-v0.5.0-linux-amd64/terraform-provider-ct ~/.terraform.d/plugins/terraform-provider-ct_v0.5.0 ``` 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 [DigitalOcean](https://cloud.digitalocean.com) or create an [account](https://cloud.digitalocean.com/registrations/new), if you don't have one. 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. ```sh mkdir -p ~/.config/digital-ocean echo "TOKEN" > ~/.config/digital-ocean/token ``` Configure the DigitalOcean provider to use your token in a `providers.tf` file. ```tf provider "digitalocean" { version = "1.15.1" token = "${chomp(file("~/.config/digital-ocean/token"))}" } provider "ct" { version = "0.5.0" } ``` ### Flatcar Linux Images Flatcar Linux publishes DigitalOcean images, but does not yet upload them. DigitalOcean allows [custom images](https://blog.digitalocean.com/custom-images/) to be uploaded via URLor file. [Download](https://www.flatcar-linux.org/releases/) the Flatcar Linux DigitalOcean bin image. Rename the image with the channel and version (to refer to these images over time) and [upload](https://cloud.digitalocean.com/images/custom_images) it as a custom image. ```tf data "digitalocean_image" "flatcar-stable-2303-4-0" { name = "flatcar-stable-2303.4.0.bin.bz2" } ``` Set the [os_image](#variables) in the next step. ## Cluster Define a Kubernetes cluster using the module `digital-ocean/container-linux/kubernetes`. ```tf module "nemo" { source = "git::https://github.com/poseidon/typhoon//digital-ocean/container-linux/kubernetes?ref=v1.18.1" # Digital Ocean cluster_name = "nemo" region = "nyc3" dns_zone = "digital-ocean.example.com" # configuration os_image = data.digitalocean_image.flatcar-stable-2303-4-0.id ssh_fingerprints = ["d7:9d:79:ae:56:32:73:79:95:88:e3:a2:ab:5d:45:e7"] # optional worker_count = 2 } ``` Reference the [variables docs](#variables) or the [variables.tf](https://github.com/poseidon/typhoon/blob/master/digital-ocean/container-linux/kubernetes/variables.tf) source. ## ssh-agent 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`. ```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: 54 to add, 0 to change, 0 to destroy. ``` Apply the changes to create the cluster. ```sh $ terraform apply module.nemo.null_resource.bootstrap: Still creating... (30s elapsed) module.nemo.null_resource.bootstrap: Provisioning with 'remote-exec'... ... module.nemo.null_resource.bootstrap: Still creating... (6m20s elapsed) module.nemo.null_resource.bootstrap: Creation complete (ID: 7599298447329218468) Apply complete! Resources: 42 added, 0 changed, 0 destroyed. ``` In 3-6 minutes, the Kubernetes cluster will be ready. ## Verify [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). ``` resource "local_file" "kubeconfig-nemo" { content = module.nemo.kubeconfig-admin filename = "/home/user/.kube/configs/nemo-config" } ``` List nodes in the cluster. ``` $ export KUBECONFIG=/home/user/.kube/configs/nemo-config $ kubectl get nodes NAME STATUS ROLES AGE VERSION 10.132.110.130 Ready 10m v1.18.1 10.132.115.81 Ready 10m v1.18.1 10.132.124.107 Ready 10m v1.18.1 ``` List the pods. ``` NAMESPACE NAME READY STATUS RESTARTS AGE kube-system coredns-1187388186-ld1j7 1/1 Running 0 11m kube-system coredns-1187388186-rdhf7 1/1 Running 0 11m kube-system calico-node-1m5bf 2/2 Running 0 11m kube-system calico-node-7jmr1 2/2 Running 0 11m kube-system calico-node-bknc8 2/2 Running 0 11m kube-system kube-apiserver-ip-10.132.115.81 1/1 Running 0 11m kube-system kube-controller-manager-ip-10.132.115.81 1/1 Running 0 11m kube-system kube-proxy-6kxjf 1/1 Running 0 11m kube-system kube-proxy-fh3td 1/1 Running 0 11m kube-system kube-proxy-k35rc 1/1 Running 0 11m kube-system kube-scheduler-ip-10.132.115.81 1/1 Running 0 11m ``` ## Going Further Learn about [maintenance](/topics/maintenance/) and [addons](/addons/overview/). ## Variables Check the [variables.tf](https://github.com/poseidon/typhoon/blob/master/digital-ocean/container-linux/kubernetes/variables.tf) source. ### Required | Name | Description | Example | |:-----|:------------|:--------| | cluster_name | Unique cluster name (prepended to dns_zone) | "nemo" | | region | Digital Ocean region | "nyc1", "sfo2", "fra1", tor1" | | dns_zone | Digital Ocean domain (i.e. DNS zone) | "do.example.com" | | os_image | Container Linux image for instances | "custom-image-id", coreos-stable, coreos-beta, coreos-alpha | | ssh_fingerprints | SSH public key fingerprints | ["d7:9d..."] | #### DNS Zone 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`. You'll need a registered domain name or delegated subdomain in DigitalOcean Domains (i.e. DNS zones). You can set this up once and create many clusters with unique names. ```tf # Declare a DigitalOcean record to also create a zone file resource "digitalocean_domain" "zone-for-clusters" { name = "do.example.com" ip_address = "8.8.8.8" } ``` !!! tip "" 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). #### SSH Fingerprints 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, ```bash ssh-keygen -E md5 -lf ~/.ssh/id_rsa.pub | awk '{print $2}' MD5:d7:9d:79:ae:56:32:73:79:95:88:e3:a2:ab:5d:45:e7 ``` If you use `ssh-agent` (e.g. Yubikey for SSH), find the fingerprint with, ``` ssh-add -l -E md5 2048 MD5:d7:9d:79:ae:56:32:73:79:95:88:e3:a2:ab:5d:45:e7 cardno:000603633110 (RSA) ``` 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/). ### Optional | Name | Description | Default | Example | |:-----|:------------|:--------|:--------| | controller_count | Number of controllers (i.e. masters) | 1 | 1 | | worker_count | Number of workers | 1 | 3 | | controller_type | Droplet type for controllers | "s-2vcpu-2gb" | s-2vcpu-2gb, s-2vcpu-4gb, s-4vcpu-8gb, ... | | worker_type | Droplet type for workers | "s-1vcpu-2gb" | s-1vcpu-2gb, s-2vcpu-2gb, ... | | controller_snippets | Controller Container Linux Config snippets | [] | [example](/advanced/customization/) | | worker_snippets | Worker Container Linux Config snippets | [] | [example](/advanced/customization/) | | networking | Choice of networking provider | "calico" | "flannel" or "calico" | | 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" | 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`. !!! warning Do not choose a `controller_type` smaller than 2GB. Smaller droplets are not sufficient for running a controller and bootstrapping will fail.