# Terraform infrastructure

This folder contains Terraform resources for provisioning a Nomad cluster on
EC2 instances on AWS to use as the target of end-to-end tests.

Terraform provisions the AWS infrastructure assuming that EC2 AMIs have
already been built via Packer. It deploys a specific build of Nomad to the
cluster along with configuration files for Nomad, Consul, and Vault.

## Setup

You'll need Terraform 0.13+, as well as AWS credentials to create the Nomad
cluster. This Terraform stack assumes that an appropriate instance role has
been configured elsewhere and that you have the ability to `AssumeRole` into
the AWS account.

Optionally, edit the `terraform.tfvars` file to change the number of
Linux clients or Windows clients.

```hcl
region               = "us-east-1"
instance_type        = "t2.medium"
server_count         = "3"
client_count         = "4"
windows_client_count = "1"
profile              = "dev-cluster"
```

Run Terraform apply to deploy the infrastructure:

```sh
cd e2e/terraform/
terraform apply
```

> Note: You will likely see "Connection refused" or "Permission denied" errors
> in the logs as the provisioning script run by Terraform hits an instance
> where the ssh service isn't yet ready. That's ok and expected; they'll get
> retried. In particular, Windows instances can take a few minutes before ssh
> is ready.

## Nomad Version

You'll need to pass one of the following variables in either your
`terraform.tfvars` file or as a command line argument (ex. `terraform apply
-var 'nomad_version=0.10.2+ent'`)

* `nomad_local_binary`: provision this specific local binary of Nomad. This is
  a path to a Nomad binary on your own host. Ex. `nomad_local_binary =
  "/home/me/nomad"`.
* `nomad_sha`: provision this specific sha from S3. This is a Nomad binary
  identified by its full commit SHA that's stored in a shared s3 bucket that
  Nomad team developers can access. That commit SHA can be from any branch
  that's pushed to remote. Ex. `nomad_sha =
  "0b6b475e7da77fed25727ea9f01f155a58481b6c"`
* `nomad_version`: provision this version from
  [releases.hashicorp.com](https://releases.hashicorp.com/nomad). Ex. `nomad_version
  = "0.10.2+ent"`

If you want to deploy the Enterprise build of a specific SHA, include
`-var 'nomad_enterprise=true'`.

## Profiles

The `profile` field selects from a set of configuration files for Nomad,
Consul, and Vault by uploading the files found in `./config/<profile>`. The
profiles are as follows:

* `full-cluster`: This profile is used for nightly E2E testing. It assumes at
  least 3 servers and includes a unique config for each Nomad client.
* `dev-cluster`: This profile is used for developer testing of a more limited
  set of clients. It assumes at least 3 servers but uses the one config for
  all the Linux Nomad clients and one config for all the Windows Nomad
  clients.
* `custom`: This profile is used for one-off developer testing of more complex
  interactions between features. You can build your own custom profile by
  writing config files to the `./config/custom` directory, which are protected
  by `.gitignore`

For each profile, application (Nomad, Consul, Vault), and agent type
(`server`, `client_linux`, or `client_windows`), the agent gets the following
configuration files, ignoring any that are missing.

* `./config/<profile>/<application>/*`: base configurations shared between all
  servers and clients.
* `./config/<profile>/<application>/<type>/*`: base configurations shared
  between all agents of this type.
* `./config/<profile>/<application>/<type>/indexed/*<index>.<ext>`: a
  configuration for that particular agent, where the index value is the index
  of that agent within the total count.

For example, with the `full-cluster` profile, 2nd Nomad server would get the
following configuration files:
* `./config/full-cluster/nomad/base.hcl`
* `./config/full-cluster/nomad/server/indexed/server-1.hcl`

The directory `./config/full-cluster/nomad/server` has no configuration files,
so that's safely skipped.

## Outputs

After deploying the infrastructure, you can get connection information
about the cluster:

- `$(terraform output environment)` will set your current shell's
  `NOMAD_ADDR` and `CONSUL_HTTP_ADDR` to point to one of the cluster's
  server nodes, and set the `NOMAD_E2E` variable.
- `terraform output servers` will output the list of server node IPs.
- `terraform output linux_clients` will output the list of Linux
  client node IPs.
- `terraform output windows_clients` will output the list of Windows
  client node IPs.

## SSH

You can use Terraform outputs above to access nodes via ssh:

```sh
ssh -i keys/nomad-e2e-*.pem ubuntu@${EC2_IP_ADDR}
```

The Windows client runs OpenSSH for convenience, but has a different
user and will drop you into a Powershell shell instead of bash:

```sh
ssh -i keys/nomad-e2e-*.pem Administrator@${EC2_IP_ADDR}
```

## Teardown

The terraform state file stores all the info.

```sh
cd e2e/terraform/
terraform destroy
```