247 lines
9.8 KiB
Markdown
247 lines
9.8 KiB
Markdown
# Digital Ocean
|
|
|
|
In this tutorial, we'll create a Kubernetes v1.8.2 cluster on Digital Ocean.
|
|
|
|
We'll declare a Kubernetes cluster in Terraform using the Typhoon Terraform module. On apply, firewall rules, DNS records, tags, and droplets for Kubernetes controllers and workers will be created.
|
|
|
|
Controllers and workers are provisioned to run a `kubelet`. A one-time [bootkube](https://github.com/kubernetes-incubator/bootkube) bootstrap schedules an `apiserver`, `scheduler`, `controller-manager`, and `kube-dns` on controllers and runs `kube-proxy` and `flannel` on each 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 v0.10.1+ and [terraform-provider-ct](https://github.com/coreos/terraform-provider-ct) installed locally
|
|
|
|
## Terraform Setup
|
|
|
|
Install [Terraform](https://www.terraform.io/downloads.html) v0.10.1+ on your system.
|
|
|
|
```sh
|
|
$ terraform version
|
|
Terraform v0.10.1
|
|
```
|
|
|
|
Add the [terraform-provider-ct](https://github.com/coreos/terraform-provider-ct) plugin binary for your system.
|
|
|
|
```sh
|
|
wget https://github.com/coreos/terraform-provider-ct/releases/download/v0.2.0/terraform-provider-ct-v0.2.0-linux-amd64.tar.gz
|
|
tar xzf terraform-provider-ct-v0.2.0-linux-amd64.tar.gz
|
|
sudo mv terraform-provider-ct-v0.2.0-linux-amd64/terraform-provider-ct /usr/local/bin/
|
|
```
|
|
|
|
Add the plugin to your `~/.terraformrc`.
|
|
|
|
```
|
|
providers {
|
|
ct = "/usr/local/bin/terraform-provider-ct"
|
|
}
|
|
```
|
|
|
|
Read [concepts](concepts.md) 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" {
|
|
token = "${chomp(file("~/.config/digital-ocean/token"))}"
|
|
}
|
|
```
|
|
|
|
## Cluster
|
|
|
|
Define a Kubernetes cluster using the module `digital-ocean/container-linux/kubernetes`.
|
|
|
|
```tf
|
|
module "digital-ocean-nemo" {
|
|
source = "git::https://github.com/poseidon/typhoon//digital-ocean/container-linux/kubernetes"
|
|
|
|
region = "nyc3"
|
|
dns_zone = "digital-ocean.example.com"
|
|
|
|
cluster_name = "nemo"
|
|
image = "coreos-stable"
|
|
controller_count = 1
|
|
controller_type = "2gb"
|
|
worker_count = 2
|
|
worker_type = "512mb"
|
|
ssh_fingerprints = ["d7:9d:79:ae:56:32:73:79:95:88:e3:a2:ab:5d:45:e7"]
|
|
|
|
# output assets dir
|
|
asset_dir = "/home/user/.secrets/clusters/nemo"
|
|
}
|
|
```
|
|
|
|
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 `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
|
|
```
|
|
|
|
!!! warning
|
|
`terrafrom apply` will hang connecting to a controller if `ssh-agent` does not contain the SSH key.
|
|
|
|
## Apply
|
|
|
|
Initialize the config directory if this is the first use with Terraform.
|
|
|
|
```sh
|
|
terraform init
|
|
```
|
|
|
|
Get or update Terraform modules.
|
|
|
|
```sh
|
|
$ terraform get # downloads missing modules
|
|
$ terraform get --update # updates all modules
|
|
Get: git::https://github.com/poseidon/typhoon (update)
|
|
Get: git::https://github.com/poseidon/bootkube-terraform.git?ref=v0.8.0 (update)
|
|
```
|
|
|
|
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.digital-ocean-nemo.null_resource.bootkube-start: Still creating... (30s elapsed)
|
|
module.digital-ocean-nemo.null_resource.bootkube-start: Provisioning with 'remote-exec'...
|
|
...
|
|
module.digital-ocean-nemo.null_resource.bootkube-start: Still creating... (6m20s elapsed)
|
|
module.digital-ocean-nemo.null_resource.bootkube-start: Creation complete (ID: 7599298447329218468)
|
|
|
|
Apply complete! Resources: 54 added, 0 changed, 0 destroyed.
|
|
```
|
|
|
|
In 3-6 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.
|
|
|
|
```
|
|
$ KUBECONFIG=/home/user/.secrets/clusters/nemo/auth/kubeconfig
|
|
$ kubectl get nodes
|
|
NAME STATUS AGE VERSION
|
|
10.132.110.130 Ready 10m v1.8.2
|
|
10.132.115.81 Ready 10m v1.8.2
|
|
10.132.124.107 Ready 10m v1.8.2
|
|
```
|
|
|
|
List the pods.
|
|
|
|
```
|
|
NAMESPACE NAME READY STATUS RESTARTS AGE
|
|
kube-system kube-apiserver-n10qr 1/1 Running 0 11m
|
|
kube-system kube-controller-manager-3271970485-37gtw 1/1 Running 1 11m
|
|
kube-system kube-controller-manager-3271970485-p52t5 1/1 Running 0 11m
|
|
kube-system kube-dns-1187388186-ld1j7 3/3 Running 0 11m
|
|
kube-system kube-flannel-1cq1v 2/2 Running 0 11m
|
|
kube-system kube-flannel-hq9t0 2/2 Running 1 11m
|
|
kube-system kube-flannel-v0g9w 2/2 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-3895335239-2bc4c 1/1 Running 0 11m
|
|
kube-system kube-scheduler-3895335239-b7q47 1/1 Running 1 11m
|
|
kube-system pod-checkpointer-pr1lq 1/1 Running 0 11m
|
|
kube-system pod-checkpointer-pr1lq-10.132.115.81 1/1 Running 0 10m
|
|
```
|
|
|
|
## Going Further
|
|
|
|
Learn about [version pinning](concepts.md#versioning), maintenance, and [addons](addons/overview.md).
|
|
|
|
!!! note
|
|
On Container Linux clusters, install the `container-linux-update-operator` addon to coordinate reboots and drains when nodes auto-update. Otherwise, updates may not be applied until the next reboot.
|
|
|
|
## Variables
|
|
|
|
### 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 |
|
|
| ssh_fingerprints | SSH public key fingerprints | ["d7:9d..."] |
|
|
| asset_dir | Path to a directory where generated assets should be placed (contains secrets) | /home/user/.secrets/nemo |
|
|
|
|
#### 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. In this example, the cluster's apiserver would be accessible at `nemo.do.example.com`.
|
|
|
|
You'll need a registered domain name or subdomain registered in Digital Ocean Domains (i.e. DNS zones). You can set this up once and create many clusters with unqiue names.
|
|
|
|
```tf
|
|
resource "digitalocean_domain" "zone-for-clusters" {
|
|
name = "do.example.com"
|
|
# Digital Ocean oddly requires an IP here. You may have to delete the A record it makes. :(
|
|
ip_address = "8.8.8.8"
|
|
}
|
|
```
|
|
|
|
!!! tip ""
|
|
If you have an existing domain name with a zone file elsewhere, just carve out 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 -lf ~/.ssh/id_rsa.pub | awk '{print $2}'
|
|
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)
|
|
```
|
|
|
|
If you uploaded an SSH key to DigitalOcean (not required), 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 |
|
|
|:-----|:------------|:--------|:--------|
|
|
| image | OS image for droplets | "coreos-stable" | coreos-stable, coreos-beta, coreos-alpha |
|
|
| controller_count | Number of controllers (i.e. masters) | 1 | 1 |
|
|
| controller_type | Digital Ocean droplet size | 2gb | 2gb (min), 4gb, 8gb |
|
|
| worker_count | Number of workers | 1 | 3 |
|
|
| worker_type | Digital Ocean droplet size | 512mb | 512mb, 1gb, 2gb, 4gb |
|
|
| networking | Choice of networking provider | "flannel" | "flannel" |
|
|
| pod_cidr | CIDR range to assign to Kubernetes pods | "10.2.0.0/16" | "10.22.0.0/16" |
|
|
| service_cidr | CIDR range to assgin to Kubernetes services | "10.3.0.0/16" | "10.3.0.0/24" |
|
|
|
|
!!! warning
|
|
Do not choose a `controller_type` smaller than `2gb`. The `1gb` droplet is not sufficient for running a controller and bootstrapping will fail.
|
|
|
|
!!! bug
|
|
Digital Ocean firewalls do not yet support the IP tunneling (IP in IP) protocol used by Calico. You can try using "calico" for `networking`, but it will only work if the cloud firewall is removed (unsafe).
|