Every AMI publisher on EC2 decides default username is AWS credentials that should used to gain access to Linux distros Ec2 system using ssh. This post describes all default usernames in AWS for logging on to EC2 instance.

Default usernames in AWS

So As defined above you need to use default username for logging on to respective operating system or Distros.

• Logging on RHEL using default user “ec2-user”

Eg. For logging on to RHEL ec2 instance you need to use default AWS username “ec2-user”. Once logged in you need to use sudo command to root user for performing admin tasks as below:

login as: ec2-user
Authenticating with public key "imported-openssh-key"
Last login: Mon May  1 07:55:24 2017 from 103.211.42.43
[ec2-user@ip-172-31-16-106 ~]$
[ec2-user@ip-172-31-16-106 ~]$
[ec2-user@ip-172-31-16-106 ~]$ sudo su -
Last login: Mon May  1 09:21:14 EDT 2017 from 103.211.42.43 on pts/0
[root@ip-172-31-16-106 ~]# uname -a
Linux ip-172-31-16-106.ap-south-1.compute.internal 3.10.0-327.10.1.el7.x86_64 #1 SMP Sat Jan 23 04:54:55 EST 2016 x86_64 x86_64 x86_64 GNU/Linux
[root@ip-172-31-16-106 ~]#

• Logging on Ubuntu using default user “ubuntu”

Same way you need to use default user “ubuntu” for logging onto Ubuntu EC2 instance and then “use sudo su -” for performing admin tasks further.

login as: ubuntu
Authenticating with public key "imported-openssh-key"
Welcome to Ubuntu 16.04.2 LTS (GNU/Linux 4.4.0-1013-aws x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

  Get cloud support with Ubuntu Advantage Cloud Guest:
    http://www.ubuntu.com/business/services/cloud

0 packages can be updated.
0 updates are security updates.


Last login: Mon May  1 12:14:20 2017 from 103.211.42.43
ubuntu@ip-172-31-19-32:~$ sudo su -
root@ip-172-31-19-32:~# uname -a
Linux ip-172-31-19-32 4.4.0-1013-aws #22-Ubuntu SMP Fri Mar 31 15:41:31 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
root@ip-172-31-19-32:~#

Same way you can use default username in AWS described in “Default usernames in AWS” table.

“.