Creating an Amazon AWS Image using the CLI

Eric J. Ma

15 December 2016

The One Magic Command

This magic command assumes that you have:

  1. Configured AWS
  2. Created a key-pair that you can use.
  3. Created a security group and that you know which security group settings you're most comfortable using.

These are oftentimes one-off things to configure from that point, the following is all that you have to remember:

$ aws ec2 run-instances \
    --image-id ami-40d28157 \
    --count 1 \
    --instance-type g2.2xlarge \
    --key-name cli_keypair \
    --security-group-ids sg-28e2c455

If you've not done the aforementioned 3 things, then read on.

Install Amazon AWS CLI

Make sure you have Python installed. I recommend using the Anaconda distribution of Python.

After that, run the commands:

$ pip install awscli

Configure AWS

The goal here is to configure the AWS CLI one time round so that you'll be able to use the CLI afterwards.

Follow the instructions here for configuring the AWS CLI. Once done, come back here.

In the AWS control panel, under Users, click on the Permissions tab, and then create new permissions for a group of users, and then add yourself to that group of users.

Now, test whether your AWS CLI works, by running the following command:

$ aws ec2 describe-instances

If everything runs correctly, it will output the instances that you currently have running. If nothing is running, nothing will be printed to the Terminal.

If things are not working, you will most likely get an UnauthorizedOperation error... in which case, I would greatly appreciate Pull Requests to the repository describing how you solved those errors.

(Optional) Create a key-pair.

Only do this if you haven't done so already. The commands are fairly straightforward, and here's the overview first, before providing the code.

Firstly, cd into the directory where you keep your SSH keys. On Unix-based systems, it will typically be ~/.ssh. Then, use the CLI to create the key-pair and output it to disk in the ~/.ssh directory. Finally, we change the permissions on the .pem file to a permission acceptable for use with EC2.

In the following code block, remember to replace cli_keypair with some unique name that you prefer to use.

$ cd ~/.ssh
$ aws ec2 create-key-pair --key-name cli_keypair > cli_keypair.pem
$ chmod 400 cli_keypair.pem

Finally, use a text editor to edit the .pem file to get rid of the text (including the spaces) before -----BEGIN RSA PRIVATE KEY----- and after -----END RSA PRIVATE KEY-----. The .pem file should look like this:


(Optional) Create a security group.

In the short time I gave myself to write this tutorial, I could not figure out an "easy-to-use" way of creating a security group. I would recommend using the web-based interface to create on.

Later on, if you want to figure out what security groups are available, run the following command:

$ aws ec2 describe-security-groups

A list of security groups that you have associated with your account will be printed to screen. Knowing the security group name is important for the next step.

Fire up an EC2 instance

The instructions here are a summary of what's available on Amazon's website. The most important command to run is below:

$ aws ec2 run-instances \
    --image-id ami-40d28157 \
    --count 1 \
    --instance-type g2.2xlarge \
    --key-name cli_keypair \
    --security-group-ids sg-28e2c455

A few things to note here:

Once it's run, after a short while, you will see the instance show up running on your EC2 dashboard (view using web browser). Alternatively, run the following command to see what instances are running. Sample output is also provided.

$ aws ec2 describe-instances

RESERVATIONS    597678314672    r-0a4c508d7779e8356
INSTANCES   0   x86_64      False   xen ami-40d28157    i-027e9ef1e23a4e046 g2.2xlarge  cli_keypair 2016-12-16T00:49:29.000Z    ip-172-31-16-181.ec2.internal   /dev/sda1   ebs True        subnet-8f15f1d7 hvm vpc-999e0ffd
EBS 2016-12-16T00:49:30.000Z    True    attached    vol-0b404dcd8082e61c3
MONITORING  disabled
NETWORKINTERFACES       0e:ea:be:5f:f5:34   eni-efa84c2c    597678314672    ip-172-31-16-181.ec2.internal   True    in-use  subnet-8f15f1d7 vpc-999e0ffd
ATTACHMENT  2016-12-16T00:49:29.000Z    eni-attach-66ee75e0 True    0   attached
GROUPS  sg-28e2c455 SSH-only access
PRIVATEIPADDRESSES  True    ip-172-31-16-181.ec2.internal
PLACEMENT   us-east-1a      default
SECURITYGROUPS  sg-28e2c455 SSH-only access
STATE   16  running

Take note of the addresses provided. They are in the following line, accessible with grep.

$ aws ec2 describe-instances | grep INSTANCES
INSTANCES   0   x86_64      False   xen ami-40d28157    i-027e9ef1e23a4e046 g2.2xlarge  cli_keypair 2016-12-16T00:49:29.000Z    ip-172-31-16-181.ec2.internal   /dev/sda1   ebs True        subnet-8f15f1d7 hvm vpc-999e0ffd

Still not very convenient yet for programmatically starting and stopping instances, but it'll suffice for now. Take note of the address of the instance, it'll look like ec2-[ip-addr-numbers-here] You can now SSH into the instance using the following command:

$ ssh -i ~/.ssh/cli_keypair.pem

Alternatively, you can choose to go back and edit your SSH config file. This is described in the main tutorial.