This mode allows to restore the server's operation if the server is unable to start after reboot, or no remote connection is available. One of the templates is loaded from the location to the server when recovery starts. Template is a LiveCD image of the operating system SystemRescueCD. This OS is intended for maintenance, diagnostics and debugging of the server. Read more about SystemRescueCD in the official documentation.

Preparing the server for recovery

Server can be recovered if:

  1. A Linux family OS is installed;
  2. Network boot function via iPXE or PXE is configured;
  3. Connection to power distribution unit (PDU) or BMC (Intel AMT) is configured.

Recovery mode start

To run server recovery mode:

  1. Go to Servers → select server → menu → Run recovery.
  2. Select the Recovery template:
    • Sysrescd6-x86_64 — a template based on SystemRescue CD 6.
  3. Press Run.
  4. Enter Server administrator password.

After the start of operation, DCImanager 6 will proceed to load the selected recovery template to the server. The template loading process is displayed at Servers page in Status column. After completion of loading, you can connect to the server via SSH with superuser permissions using the password you have created.

Recovery mode canceling

Recovery mode does not turn off automatically. To exit recovery mode:

  1. Reboot the server being recovered.
  2. On DCImanager 6 server, go to Servers → select the server → → Cancel the current operation → Cancel recovery.

Example of the superuser password recovery on the server

  1. Connect to the server, loaded with the recovery template via SSH.

  2. Specify the drives connection method. For instance wit the command:
     

    lsblk
    BASH
  3. Define the root directory.

  4. Create the directory:

    mkdir /true_root
    BASH

  5. Mount the root directory:

    mount /dev/device /true_root
    BASH

    Where:

    • device — device of a root directory

  6. Change the root directory:

    chroot /true_root
    BASH

  7. To change the superuser password, run:

    passwd root
    BASH

  8. Insert the new password twice and exit the chroot with:

    exit
    BASH

  9. Unmount the directory:

    umount /true_root
    BASH