By default, Cumulus Linux has two user accounts: cumulus and root.

The cumulus account:

  • Uses the default password CumulusLinux!
  • Is a user account in the sudo group with sudo privileges.
  • Can log in to the system through all the usual channels, such as console and SSH.
  • Along with the cumulus group, has both show and edit rights for NCLU.

The root account:

  • Has the default password disabled by default.
  • Has the standard Linux root user access to everything on the switch.
  • Disabled password prohibits login to the switch by SSH, telnet, FTP, and so on.

For optimal security, change the default password with the passwd command before you configure Cumulus Linux on the switch.

You can add additional  user accounts as needed. Like the cumulus account, these accounts must use sudo to execute privileged commands; be sure to include them in the sudo group.

To access the switch without a password, you need to boot into a single shell/user mode.

You can add and configure user accounts in Cumulus Linux with read-only or edit permissions for NCLU. For more information, see Configure User Accounts.

Enable Remote Access for the root User

The root user does not have a password and cannot log into a switch using SSH. This default account behavior is consistent with Debian. To connect to a switch using the root account, you can do one of the following:

  • Generate an SSH key
  • Set a password

Generate an SSH Key for the root Account

  1. In a terminal on your host system (not the switch), check to see if a key already exists:

    root@host:~# ls -al ~/.ssh/

    The key is named something like id_dsa.pub, id_rsa.pub or id_ecdsa.pub.

  2. If a key does not exist, generate a new one by first creating the RSA key pair:

    root@host:~# ssh-keygen -t rsa
  3. You are prompted to enter a file in which to save the key (/root/.ssh/id_rsa)Press Enter to use the home directory of the root user or provide a different destination.
  4. You are prompted to enter a passphrase (empty for no passphrase). This is optional but it does provide an extra layer of security.
  5. The public key is now located in /root/.ssh/id_rsa.pub. The private key (identification) is now located in /root/.ssh/id_rsa.
  6. Copy the public key to the switch. SSH to the switch as the cumulus user, then run:

    cumulus@switch:~$ sudo mkdir -p /root/.ssh
    cumulus@switch:~$ echo <SSH public key string> | sudo tee -a /root/.ssh/authorized_keys

Set the root User Password

  1. Run the following command: 

    cumulus@switch:~$ sudo passwd root
  2. Change the PermitRootLogin setting in the /etc/ssh/sshd_config file from without-password to yes

    cumulus@switch:~$ sudo nano /etc/ssh/sshd_config
    
    ... 
          
    # Authentication:
    LoginGraceTime 120
    PermitRootLogin yes
    StrictModes yes
          
    ...  
  3. Restart the ssh service:

    cumulus@switch:~$ sudo systemctl reload ssh.service