Synapse on Kubernetes

Make a Synapse/Matrix server work on a managed kubernetes cluster hosted by OVH

Prerequisites

an account in OVH hosting provider and its credentials (application key, application secret, consumer secret and endpoint)
to store Terraform state files : a S3 object storage with the credentials to connect to (access key, secret key, endpoint and region) and a bucket named terraform-states-hp-myenv for example.
a user and credentials dedicated to openstack with the following rights : [Network Security Operator, Volume Operator, Network Operator, Backup Operator, Compute Operator, Image Operator, Administrator, Infrastructure Supervisor]
to reach the future synapse homeserver : a valid dns zone hosted by OVH
to send some mails to users : a valid access to a SMTP service

On the computer running this code :

Create in the local folder a local.env.sh file copying the script/local.env.template.sh file and fill it with all the environment variables values needed. OS_variables relate to the openstack part.

Then source this file :
```
source local/local.env.sh
```
Generate the var file for provisioning stage (terraform.tfvars) based on values previously set :
```
sh scripts/generate_provisioning_var_files.sh
```
Go to the terraform folder
```
cd terraform
```

Initialize the Terraform workspace specifying the name of the S3 bucket

terraform init -backend-config="bucket=terraform-states-hp-$ENVIRONMENT"

Create the Terraform execution plan to validate that everything is ok
```
terraform plan
```
Apply the Terraform plan
```
terraform apply
```
This will lead to the creation of a kubernetes cluster with 1 control plane node and several worker nodes

The configuration part will be done with Ansible and is quite independent from the provisioning part.

Generate the files (kubeconfig.yml, ansible/group_vars/all.yml) and vars needed :
```
sh scripts/generate_configuration_var_files.sh
```
For more info on kubeconfig file see https://kubernetes.io/docs/concepts/configuration/organize-cluster-access-kubeconfig/
And then execute :
```
sh scripts/ansible_configuration.sh
```

This will lead to the installation of the following components in the cluster :