常见问题

Internal error cannot find character device (null)

  • Symptom

    This error message appears when attempting to connect to a guest virtual machine’s console:

    1
    2
    3
    4
    # virsh console test2
    Connected to domain test2 
    Escape character is ^] 
    error: internal error cannot find character device (null)

  • Investigation

    This error message shows that there is no serial console configured for the guest virtual machine.

  • Solution

    Set up a serial console in the guest’s XML file.

    Procedure B.1. Setting up a serial console in the guest’s XML

    1. Add the following XML to the guest virtual machine’s XML using virsh edit:

      1
      2
      3
      4
      5
      6
      <serial type='pty'>
        <target port='0'/>
      </serial>
      <console type='pty'>
        <target type='serial' port='0'/>
      </console>

    2. Set up the console in the guest kernel command line.

      To do this, either log in to the guest virtual machine to edit the /boot/grub/grub.conf file directly, or use the virt-edit command line tool. Add the following to the guest kernel command line:

      1
      console=ttyS0,115200

    3. Run the followings command:

      1
      # virsh start vm && virsh console vm

参考文档