Amazon WS EC2 – connect via SSH RSA

Intro

So you own an up and running Amazon EC2 instance. And you want it to access via hassle free way. This guided post will describe on how you can do it with few steps.

Note: Just for the convenience I’m referring some steps from this blog here

OK before I start assume you have an up and running EC2 instance. If so grab the public DNS from your AWS management console

It will be probably something like

ec2-#############.compute-1.amazonaws.com

Once that is acquired I again assume you have already made your Key-pair and saved it while you are in the process of creating a new instance

Once that is also in place go to your terminal and CD to the location you saved your Key [your-key-pair.pem] and try to do SSH.

$ ssh -i your-key-pair.pem ubuntu@ec2-#############.compute-1.amazonaws.com

[the default user will be ubuntu for Amazon Machine Images (AMIs)]

Now you should be inside the AMS terminal

Ok now you have to do is add your self up as a new user and give the root privileges (sudoers). Simply follow execute the following commands on to the AWS terminal

Adding yourself as a user:

$ adduser yourself

granting privileges

$ sudo visudo

find the line root ALL=(ALL:ALL) ALL and the line yourself ALL=(ALL) ALL under it.

Then enable password authentication via (I used the nano editor)

$ sudo nano /etc/ssh/sshd_config

PasswordAuthentication no to PasswordAuthentication yes

Afterward reload the ssh configuration

$ sudo /etc/init.d/ssh reload

OK now logout from the current session and log back as yourself

$ ssh yourself@ec2-#############.compute-1.amazonaws.com

And to make sure everything is working just fine, execute following

$ sudo -v

You will be promted to enter the password you have provided while creating the user(yourself). Enter that and if everything went well you will get no output on terminal.

Now lets remove this troublesome password authentication replacing SSH RSA public key authentication

To do that first you need to create a SSH RSA public key

So logout from the AWS terminal and from your local terminal execute the following command (Just press return for all the steps)

local-host$ ssh-keygen -t rsa

And you will be promted as below

Enter file in which to save the key (/home/yourself/.ssh/id_rsa):
Created directory ‘/home/yourself/.ssh’.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/yourself/.ssh/id_rsa.
Your public key has been saved in /home/yourself/.ssh/id_rsa.pub.
The key fingerprint is:
58:3a:80:a5:df:17:b0:af:4f:90:07:c5:3c:01:50:c2 yourself@inux-cc6a
Your public key will be stored in /home/yourself/.ssh/

Now what you have to do is add that key to AWS in order to identify yourself as authorize user.

local-host$ scp ~/.ssh/id_rsa.pub yourself@ec2-#############..compute-1.amazonaws.com:/home/yourself

Then again login to the AWS

local-host$ ssh yourself@ec2-#############..compute-1.amazonaws.com:/home/yourself

And place the key file in right place

$ mkdir .ssh
$ mv id_rsa.pub .ssh/authorized_keys
$ chmod 700 .ssh
$ chmod 600 .ssh/authorized_keys

Now you should be able to login without using a password

local-host$ ssh yourself@ec2-#############.compute-1.amazonaws.com

Finally remove the password authentication and root user access

$ sudo vim /etc/ssh/sshd_config

Find the line PasswordAuthentication yes and change it to PasswordAuthentication no

Also PermitRootLogin yes to PermitRootLogin no

Finally reload the SSH configurations again

$ sudo /etc/init.d/ssh reload

That’s all you need for crating a new user account and allowing authentication via SSH RSA.

If you are still lazy enough to type that long public DNS you can simply assign it to an alias and place it in the ~/.bash_proflle or ~/.bashrc to make it permanent.

amazon cloud ssh
alias connect-amazon='ssh yourself@ec2-#############..compute-1.amazonaws.com'

$ connect-amazon