c12s-kubespray/contrib/terraform/exoscale/README.md

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# Kubernetes on Exoscale with Terraform
Provision a Kubernetes cluster on [Exoscale](https://www.exoscale.com/) using Terraform and Kubespray
## Overview
The setup looks like following
```text
Kubernetes cluster
+-----------------------+
+---------------+ | +--------------+ |
| | | | +--------------+ |
| API server LB +---------> | | | |
| | | | | Master/etcd | |
+---------------+ | | | node(s) | |
| +-+ | |
| +--------------+ |
| ^ |
| | |
| v |
+---------------+ | +--------------+ |
| | | | +--------------+ |
| Ingress LB +---------> | | | |
| | | | | Worker | |
+---------------+ | | | node(s) | |
| +-+ | |
| +--------------+ |
+-----------------------+
```
## Requirements
* Terraform 0.13.0 or newer
*0.12 also works if you modify the provider block to include version and remove all `versions.tf` files*
## Quickstart
NOTE: *Assumes you are at the root of the kubespray repo*
Copy the sample inventory for your cluster and copy the default terraform variables.
```bash
CLUSTER=my-exoscale-cluster
cp -r inventory/sample inventory/$CLUSTER
cp contrib/terraform/exoscale/default.tfvars inventory/$CLUSTER/
cd inventory/$CLUSTER
```
Edit `default.tfvars` to match your setup
```bash
# Ensure $EDITOR points to your favorite editor, e.g., vim, emacs, VS Code, etc.
$EDITOR default.tfvars
```
For authentication you can use the credentials file `~/.cloudstack.ini` or `./cloudstack.ini`.
The file should look like something like this:
```ini
[cloudstack]
key = <API key>
secret = <API secret>
```
Follow the [Exoscale IAM Quick-start](https://community.exoscale.com/documentation/iam/quick-start/) to learn how to generate API keys.
### Encrypted credentials
To have the credentials encrypted at rest, you can use [sops](https://github.com/mozilla/sops) and only decrypt the credentials at runtime.
```bash
cat << EOF > cloudstack.ini
[cloudstack]
key =
secret =
EOF
sops --encrypt --in-place --pgp <PGP key fingerprint> cloudstack.ini
sops cloudstack.ini
```
Run terraform to create the infrastructure
```bash
terraform init ../../contrib/terraform/exoscale
terraform apply -var-file default.tfvars ../../contrib/terraform/exoscale
```
If your cloudstack credentials file is encrypted using sops, run the following:
```bash
terraform init ../../contrib/terraform/exoscale
sops exec-file -no-fifo cloudstack.ini 'CLOUDSTACK_CONFIG={} terraform apply -var-file default.tfvars ../../contrib/terraform/exoscale'
```
You should now have a inventory file named `inventory.ini` that you can use with kubespray.
You can now copy your inventory file and use it with kubespray to set up a cluster.
You can type `terraform output` to find out the IP addresses of the nodes, as well as control-plane and data-plane load-balancer.
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
```
Example to use this with the default sample inventory:
```bash
ansible-playbook -i inventory.ini ../../cluster.yml -b -v
```
## Teardown
The Kubernetes cluster cannot create any load-balancers or disks, hence, teardown is as simple as Terraform destroy:
```bash
terraform destroy -var-file default.tfvars ../../contrib/terraform/exoscale
```
## Variables
### Required
* `ssh_pub_key`: Path to public ssh key to use for 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)*
* `size`: The size to use
* `boot_disk`: The boot disk to use
* `image_name`: Name of the image
* `root_partition_size`: Size *(in GB)* for the root partition
* `ceph_partition_size`: Size *(in GB)* for the partition for rook to use as ceph storage. *(Set to 0 to disable)*
* `node_local_partition_size`: Size *(in GB)* for the partition for node-local-storage. *(Set to 0 to disable)*
* `ssh_whitelist`: List of IP ranges (CIDR) that will be allowed to ssh to the nodes
* `api_server_whitelist`: List of IP ranges (CIDR) that will be allowed to connect to the API server
* `nodeport_whitelist`: List of IP ranges (CIDR) that will be allowed to connect to the kubernetes nodes on port 30000-32767 (kubernetes nodeports)
### Optional
* `prefix`: Prefix to use for all resources, required to be unique for all clusters in the same project *(Defaults to `default`)*
An example variables file can be found `default.tfvars`
## Known limitations
### Only single disk
Since Exoscale doesn't support additional disks to be mounted onto an instance, this script has the ability to create partitions for [Rook](https://rook.io/) and [node-local-storage](https://kubernetes.io/docs/concepts/storage/volumes/#local).
### No Kubernetes API
The current solution doesn't use the [Exoscale Kubernetes cloud controller](https://github.com/exoscale/exoscale-cloud-controller-manager).
This means that we need to set up a HTTP(S) loadbalancer in front of all workers and set the Ingress controller to DaemonSet mode.