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https://github.com/teticio/terraform-ec2

Terraform code to quickly spin up / tear down an EC2 instance in AWS. A persistent EBS volume is also created and mounted at /home.
https://github.com/teticio/terraform-ec2

ebs ec2 terraform

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Terraform code to quickly spin up / tear down an EC2 instance in AWS. A persistent EBS volume is also created and mounted at /home.

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# Terraform EC2



Terraform code to quickly spin up / tear down an EC2 instance in AWS. A persistent EBS volume is also created and mounted at `/home`.



While it is possible to start and stop EC2 instances and thus only pay for the compute you use, it is generally a good idea to be able to terminate and launch fresh instances. One way to do preserve your work is to decouple your home directory from the EC2 instance by mounting a separate EBS volume configured not to be destroyed on termination.



## Usage



Ensure you have a public key (for example in `~/.ssh/id_rsa.pub`). If not, you can create one with:

    

```bash

ssh-keygen

```



Create a `terraform.tfvars` file:



```terraform

region          = "eu-west-2"         # AWS region

instance_type   = "t2.micro"          # EC2 instance type

volume_size     = 20                  # Size of home EBS volume in GB

public_key_path = "~/.ssh/id_rsa.pub" # Path to public key

ingress_ports   = [22]                # Ports to open



# Commands to run on startup (e.g. to install pip)

startup_commands = [

  <<-EOL

    apt-get update

    apt-get install -y python3-pip

  EOL

]

```



Then run:



```bash

terraform init

terraform apply -auto-approve

```



and take a note of the public IP address and ID of the instance. (You can recover these at any time with `terraform output`.) Alternatively, you can run `./create.sh `.



You can then SSH into the instance with



```bash

ssh ubuntu@

```



or simply `./connect.sh`.



You can terminate the instance from the command line by running:



```bash

aws ec2 terminate-instances --instance-ids 

aws ec2 wait instance-terminated --instance-ids 

```



or `./terminate.sh`.



If you re-run the apply or `./create.sh` command, Terraform will create a new instance with a new public IP address and attach the existing EBS volume to it. Note that your home EBS volume will persist and you will be charged $0.10 per GB-month whether or not it is attached to an EC2 instance (until you run `terraform destroy -auto-approve`).



To debug issues with the `startup_commands`, you can SSH into the instance and inspect the output from `tail -f /var/log/cloud-init-output.log`. Bear in mind that the script may still be running in the background. To wait for the script to finish run `cloud-init status --wait`.



## Grow your own EBS



To increase your the size of your EBS volume without destroying your data, first change the `volume_size` variable in `terraform.tfvars`, run `terraform apply -auto-approve` and connect to your instance. In the instance, run:



```bash

if [ -e /dev/xvda ]; then

    sudo resize2fs /dev/xvda

else

    sudo resize2fs /dev/nvme1n1

fi

```



You can then run `df -h /home` to check that the volume has been resized.



## Opening ports



You can, of course, tunnel to any port via SSH on port 22 with



```bash

ssh -L :localhost: ubuntu@

```



but, if you want to open ports to the public, just set the variable



```terraform

ingress_ports   = [22, 80, 443]       # Ports to open

```



to include the ports you want to make accessible (for example to run a web server on 80 and 443).



## Bring your own AMI



If you plan to always install the same packages every time you spin up an instance, you can create your own AMI with the packages pre-installed by running the following commands:



```bash

instance_id=$(terraform output -json | jq -r '.instance_id.value')

aws ec2 stop-instances --instance-ids $instance_id

aws ec2 wait instance-stopped --instance-ids $instance_id

# Detach home EBS volume, otherwise a snapshot will be created

volume_id=$(terraform output -json | jq -r '.home_ebs_volume.value')

aws ec2 detach-volume --volume-id $volume_id

aws ec2 wait volume-available --volume-id $volume_id

image_id=$(aws ec2 create-image --instance-id $instance_id --name "my_ami" --query 'ImageId' --output text)

aws ec2 wait image-available --image-ids $image_id

```



Then add the following lines to `terraform.tfvars` to select your AMI next time you spin up an instance:



```terraform

ami_owner       = "self"              # Owner of AMI

ami_name        = "my_ami"            # Name of AMI

```