Adding Additional User Accounts to a VM

See Rocky 9 entry below.

For each user, do the following:

For scripting purposes, you can use the useradd command which is non-interactive:-

Next, create a directory where the user’s ssh public key will reside (if this doesn’t make sense to you search for “generating ssh keys” - either on this portal or on the internet.)

To create the directory, use the command:-

..where $user is the username you added earlier.

Now add the ssh key to the “authorized_keys” file, in the /home/<user name>/.ssh folder:-

..where $sshkey is the users’s public ssh key. You can use a command like:-

…and subsequent commands can use the variable $sshkey, so you can use the command “echo $sshkey” to see the contents of sshkey you defined. (you can do the same for “user” as well.)

You then need to set the ownership and permissions of the ssh keys and folder (This is important !: the ssh server is very picky about this being correct):-

Note that by adding the user to the group “wheel” - the user can automatically use the “sudo” command. This means you don't have to add the user to the file /etc/sudoers.d/cloud file (which you should always check has no errors in it by running “visudo -c” to check it - especially if you edit that file).

You shoud then be able to ssh into the VM using a command such as:-

..where the -i points to where your private key is (assuming a command line ssh client rather than putty). the -l (letter L in lower case) is for username and the IP address is the IP address of the Virtual machine yo wish to connect to.

To debug any ssh login issues, it is suggested that you have another user account watching the /var/log/secure logs with a comand like:-

Which will show you incoming ssh client connections, the authentication method used and if it was successful.

For each user, do the following:

First you create the user account using the adduser command. Note that this command will prompt you for some additional details.

You then want to set up the user’s SSH authorized keys file and add their SSH public key to it using an editor of your choice. Please note that key formatting is very important, several examples of acceptable key types and formats are provided below.

Your user should now be able to log in to your machine with their SSH public key using the following command.

If you also want the newly added user to have sudo permissions then you need to edit the /etc/sudoers.d/cloud file using the following command.

Adding the following line to the bottom. Note that because we do not set a password for the user, the NOPASSWD option is necessary.