SSH to AWS Instance without key pairs

Question

1: Is there a way to log in to an AWS instance without using key pairs? I want to set up a couple of sites/users on a single instance. However, I don't want to give out key pairs for clients to log in.

2: What's the easiest way to set up hosting sites/users in 1 AWS instance with different domains pointing to separate directories?

Answer 1

I came here through Google looking for an answer to how to setup cloud init to not disable PasswordAuthentication on AWS. Both the answers don't address the issue. Without it, if you create an AMI then on instance initialization cloud init will again disable this option.

The correct method to do this, is instead of manually changing sshd_config you need to correct the setting for cloud init (Open source tool used to configure an instance during provisioning. Read more at: https://cloudinit.readthedocs.org/en/latest/). The configuration file for cloud init is found at: /etc/cloud/cloud.cfg

This file is used for setting up a lot of the configuration used by cloud init. Read through this file for examples of items you can configure on cloud-init. This includes items like default username on a newly created instance)

To enable or disable password login over SSH you need to change the value for the parameter ssh_pwauth. After changing the parameter ssh_pwauth from 0 to 1 in the file /etc/cloud/cloud.cfg bake an AMI. If you launch from this newly baked AMI it will have password authentication enabled after provisioning.

You can confirm this by checking the value of the PasswordAuthentication in the ssh config as mentioned in the other answers.

Answer 2

1) You should be able to change the ssh configuration (on Ubuntu this is typically in /etc/ssh or /etc/sshd) and re-enable password logins.

2) There's nothing really AWS specific about this - Apache can handle VHOSTS (virtual hosts) out-of-the-box - allowing you to specify that a certain domain is served from a certain directory. I'd Google that for more info on the specifics.

Answer 3

Answer to Question 1

Here's what I did on a Ubuntu EC2:

A) Login as root using the keypairs

B) Setup the necessary users and their passwords with

# sudo adduser USERNAME
# sudo passwd USERNAME

C) Edit /etc/ssh/sshd_config setting

For a valid user to login with no key

PasswordAuthentication yes

Also want root to login also with no key

PermitRootLogin yes

D) Restart the ssh daemon with

# sudo service ssh restart

just change ssh to sshd if you are using centOS

Now you can login into your ec2 instance without key pairs.

Answer 4

su - root

Goto /etc/ssh/sshd_config

vi sshd_config

Authentication:

PermitRootLogin yes

To enable empty passwords, change to yes (NOT RECOMMENDED)

PermitEmptyPasswords no

Change to no to disable tunnelled clear text passwords

PasswordAuthentication yes

:x!

Then restart ssh service

root@cloudera2:/etc/ssh# service ssh restart
ssh stop/waiting
ssh start/running, process 10978

Now goto sudoers files (/etc/sudoers).

User privilege specification

root  ALL=(ALL)NOPASSWD:ALL
yourinstanceuser  ALL=(ALL)NOPASSWD:ALL    / This is the user by which you are launching instance.