Serial-over-USB

Specifically to V2+. This can be used for terminal access from the target host to the PiKVM, or for any other purpose that requires a serial connection. In the last case, you only need to perform step 1 and reboot.

Warning

This allows access from the host to PiKVM. Make sure that you trust the host enough to do this, and change the default passwords of PiKVM if you haven't already done so.

Changing PiKVM Passwords

PiKVM comes with the following default passwords:

• Linux OS-level admin (SSH, console...):

  • Username: root
  • Password: root

• KVM user (Web Interface, API, VNC...):

  • Username: admin
  • Password: admin
  • No 2FA code

They are two separate accounts with independent passwords.

To change passwords, you will need to use the console access via SSH or the Web Terminal. If you are using the Web Terminal, enter the su - command to get the root access (enter the root user password).

[root@pikvm ~]# rw
[root@pikvm ~]# passwd root
[root@pikvm ~]# kvmd-htpasswd set admin
[root@pikvm ~]# ro

If you require additional user for the Web UI access, use the following:

[root@pikvm ~]# kvmd-htpasswd add <user> # Add a new user with password
[root@pikvm ~]# kvmd-htpasswd del <user> # Remove/delete a user

Optionally you can enable the two-factor authentication for more security.

Changing the VNCAuth key and IPMI password at the first start of PiKVM is not required, since these services are disabled by default. But it is here just so that you remember their existence.

USB limitations

Each emulated USB device consumes a limited hardware resource called endpoints.

Short info: by default, you can add only one additional USB device.

To get more information about the endpoints, add more devices, and flexibly manage the configuration on the fly, see here.

1. Update your PiKVM:

   Updating PiKVM OS

   Tip

   We recommend updating PiKVM OS only if you have physical access to the device, or in the most extreme cases. The update process is very reliable, but there is always a small chance that something may go wrong so reflashing will be required. PiKVM cannot be bricked, but you need physical access to the memory card for this operation.

   To update, run following commands under the root user:

   [root@pikvm ~]# pikvm-update
   

   If you encounter an error like:

   [root@pikvm ~]# pikvm-update
   bash: pikvm-update: command not found
   

   It's most likely you have an old OS release. You can update the OS as follows:

   [root@pikvm ~]# rw
   [root@pikvm ~]# pacman -Syy
   [root@pikvm ~]# pacman -S pikvm-os-updater
   [root@pikvm ~]# pikvm-update
   

   Next time you will be able to use the usual method with pikvm-update.

2. Edit /etc/kvmd/override.yaml and add these lines:

   otg:
       devices:
           serial:
               enabled: true
   

3. Run the following command:

   [root@pikvm ~]# echo ttyGS0 >> /etc/securetty
   

4. Run these comands:

   [root@pikvm ~]# systemctl enable kvmd-otg-getty@ttyGS0.service
   [root@pikvm ~]# reboot
   

5. Once PiKVM is rebooted you will have access to a virtual serial port on the server that the USB is connected to. Use mingetty, screen, putty, or something like this to access the kvm from the server. The port is called /dev/ttyAMA0.