how to create pem file and access linux server via pem file

How to create pem file

The SSH client that you use to connect to the cluster needs to use the private key file associated with this key pair. ... This is a . pem file for SSH clients using Linux, Unix and linux. You must set permissions so that only the key owner has permission to access the file.

Server side task

1) Genrate SSH Key 

$ ssh-keygn 

2) Create a file authorized_keys file.

$ touch ~/.ssh/authorized_keys

3) Change the permissions of the authorized_keys file.

$ chmod   600  ~/.ssh/authorized_keys

4) Change the following details in /etc/ssh/sshd_config file.

$ vim  /etc/ssh/sshd_config

RSAAuthentication                  yes

PubkeyAuthentication               yes

AuthorizedKeysFile            %h/.ssh/authorized_keys

PasswordAuthentication             no

ChallengeResponseAuthentication    no

UsePAM                             yes

Client side task

1) Genrate SSH Key 

$ ssh-keygn 

2) copy contant of id_rsa.pub file.

$ sudo cat ~/.ssh/id_rsa.pub

3) paste id_rsa.pub contant into server_side in ~/.ssh/authorized_keys file, and save and exit from the file.

$ sudo vim  ~/.ssh/authorized_keys

4) create a duplicate file of id_rsa with .pem extention.

$ sudo cp -a  ~/.ssh/id_rsa    ~/.ssh/id_rsa.pem

5) change the permission of you id_rsa.pem file.

$ sudo chmod 400   ~/.ssh/id_rsa.pem

6) Now you can access the server over ssh with pem file.

$ ssh -i  ~/.ssh/id_rsa.pem   ubuntu@192.168.20.20