# Kubernetes on UpCloud with Terraform

Provision a Kubernetes cluster on [UpCloud](https://upcloud.com/) using Terraform and Kubespray

## Overview

The setup looks like following

```text
   Kubernetes cluster
+--------------------------+
|      +--------------+    |
|      | +--------------+  |
| -->  | |              |  |
|      | | Master/etcd  |  |
|      | | node(s)      |  |
|      +-+              |  |
|        +--------------+  |
|              ^           |
|              |           |
|              v           |
|      +--------------+    |
|      | +--------------+  |
| -->  | |              |  |
|      | |    Worker    |  |
|      | |    node(s)   |  |
|      +-+              |  |
|        +--------------+  |
+--------------------------+
```

The nodes uses a private network for node to node communication and a public interface for all external communication.

## Requirements

* Terraform 0.13.0 or newer

## Quickstart

NOTE: Assumes you are at the root of the kubespray repo.

For authentication in your  cluster you can use the environment variables.

```bash
export TF_VAR_UPCLOUD_USERNAME=username
export TF_VAR_UPCLOUD_PASSWORD=password
```

To allow API access to your UpCloud account, you need to allow API connections by visiting [Account-page](https://hub.upcloud.com/account) in your UpCloud Hub.

Copy the cluster configuration file.

```bash
CLUSTER=my-upcloud-cluster
cp -r inventory/sample inventory/$CLUSTER
cp contrib/terraform/upcloud/cluster-settings.tfvars inventory/$CLUSTER/
export ANSIBLE_CONFIG=ansible.cfg
cd inventory/$CLUSTER
```

Edit  `cluster-settings.tfvars`  to match your requirement.

Run Terraform to create the infrastructure.

```bash
terraform init ../../contrib/terraform/upcloud
terraform apply --var-file cluster-settings.tfvars \
    -state=tfstate-$CLUSTER.tfstate \
     ../../contrib/terraform/upcloud/
```

You should now have a inventory file named `inventory.ini` that you can use with kubespray.
You can use the inventory file with kubespray to set up a cluster.

It is a good idea to check that you have basic SSH connectivity to the nodes. You can do that by:

```bash
ansible -i inventory.ini -m ping all
```

You can setup Kubernetes with kubespray using the generated inventory:

```bash
ansible-playbook -i inventory.ini ../../cluster.yml -b -v
```

## Teardown

You can teardown your infrastructure using the following Terraform command:

```bash
terraform destroy --var-file cluster-settings.tfvars \
      -state=tfstate-$CLUSTER.tfstate \
      ../../contrib/terraform/upcloud/
```

## Variables

* `prefix`: Prefix to add to all resources, if set to "" don't set any prefix
* `template_name`: The name or UUID  of a base image
* `username`: a user to access the nodes, defaults to "ubuntu"
* `private_network_cidr`: CIDR to use for the private network, defaults to "172.16.0.0/24"
* `ssh_public_keys`: List of public SSH keys to install on all machines
* `zone`: The zone where to run the cluster
* `machines`: Machines to provision. Key of this object will be used as the name of the machine
  * `node_type`: The role of this node *(master|worker)*
  * `plan`: Preconfigured cpu/mem plan to use (disables `cpu` and `mem` attributes below)
  * `cpu`: number of cpu cores
  * `mem`: memory size in MB
  * `disk_size`: The size of the storage in GB
  * `additional_disks`: Additional disks to attach to the node.
    * `size`: The size of the additional disk in GB
    * `tier`: The tier of disk to use (`maxiops` is the only one you can choose atm)
* `firewall_enabled`: Enable firewall rules
* `firewall_default_deny_in`: Set the firewall to deny inbound traffic by default. Automatically adds UpCloud DNS server and NTP port allowlisting.
* `firewall_default_deny_out`: Set the firewall to deny outbound traffic by default.
* `master_allowed_remote_ips`: List of IP ranges that should be allowed to access API of masters
  * `start_address`: Start of address range to allow
  * `end_address`: End of address range to allow
* `k8s_allowed_remote_ips`: List of IP ranges that should be allowed SSH access to all nodes
  * `start_address`: Start of address range to allow
  * `end_address`: End of address range to allow
* `master_allowed_ports`: List of port ranges that should be allowed to access the masters
  * `protocol`: Protocol *(tcp|udp|icmp)*
  * `port_range_min`: Start of port range to allow
  * `port_range_max`: End of port range to allow
  * `start_address`: Start of address range to allow
  * `end_address`: End of address range to allow
* `worker_allowed_ports`: List of port ranges that should be allowed to access the workers
  * `protocol`: Protocol *(tcp|udp|icmp)*
  * `port_range_min`: Start of port range to allow
  * `port_range_max`: End of port range to allow
  * `start_address`: Start of address range to allow
  * `end_address`: End of address range to allow
* `loadbalancer_enabled`: Enable managed load balancer
* `loadbalancer_plan`: Plan to use for load balancer *(development|production-small)*
* `loadbalancers`: Ports to load balance and which machines to forward to. Key of this object will be used as the name of the load balancer frontends/backends
  * `port`: Port to load balance.
  * `backend_servers`: List of servers that traffic to the port should be forwarded to.