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
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.