Simple ec2 management from command line

Launch EC2 instances is the level zero for cloud computing. You can manage most of it using online console, but of course there is a way to handle it from command line.

Make sure you have a default vpc

First of all, make sure you have a default vpc:

aws ec2 create-default-vpc

You will need it in order to add firewall exceptions among other things.

Create an ssh key

In order to access your computers in the cloud, a ssh key is needed. You can create it from command line too:

aws ec2 create-key-pair --key-name default-key > default-key.json

It's a bit trickier than doing it from web console because the key content comes encoded inside the json output. So you can use a few command line tools to proper extract the key from it:

X=$(cat default-key.json | jq .KeyMaterial) ; echo -e $X > default-key.pem
sed -i 's/"//g' default-key.pem
chmod 400 default-key.pem

While jq extracts the raw key content from json file, echo -e interprets the line breakers and finally sed removes the dangling double quotes. Finally, key files should have read-only permissions.

Launch an EC2 instance

aws ec2 run-instances --image-id ami-0cff7528ff583bf9a --region us-east-1 --instance-type t2.small --key-name default-key

It's very important to provide a key otherwise you won't be able to log in into the new machine.

The instance type tells which resources you want to provide to this computer (cpu, memory, etc).

You must provide an image id so EC2 knows which kind of operating system you want.

For a complete list of image ids try aws ec2 describe-images (a little slow).

Connecting into the machine

First figure out the machine name:

aws ec2 describe-instances | jq ".Reservations[].Instances[].PublicDnsName"
"ec2-3-219-31-221.compute-1.amazonaws.com"

Then connect into it using your key file:

ssh -i default-key.pem ec2-user@ec2-3-219-31-221.compute-1.amazonaws.com

Important note, the selected image is amazon linux which comes with this handy user pre-configured, some other images might not come with it.

Also, your security group might not have ssh port open, add the rule if needed.

Clean up

aws ec2 terminate-instances --instance-ids i-00491fb41d556a2bd

The machine might be listed for a while, but eventually it will disappear.