Boot the server in recovery and diagnostic mode
If the server does not boot or is unreachable over the network, boot it in one of the recovery and diagnostic modes. Once booted, you can diagnose the server and fix OS configuration errors.
If the server becomes unreachable some time after a reboot, check if hibernation is enabled in the OS. Hibernation may be enabled automatically when installing certain analytics packages (anaconda, cudatoolkit, nvidiautils, etc.). For an example of how to diagnose and disable hibernation, see the Selectel blog article How to disable hibernation in Ubuntu.
For issues with Mac Mini M1 and Raspberry Pi servers, create a ticket.
- Select a recovery and diagnostic mode.
- Change the server boot template.
- Connect to the server.
- Return to the previous server boot template.
1. Select a recovery and diagnostic mode
Recovery and diagnostic modes provide full access to the server file system.
We recommend using a recovery and diagnostic mode based on your tasks and server OS:
- Rescue — for Linux servers;
- WinPE — for Windows servers;
- Boot menu — for any server OS;
- Veeam Recovery Media 13 for Windows — for restoring a server from a backup;
- Talos — for working with Kubernetes.
Rescue
WinPE
Boot menu
Veeam Recovery Media 13 for Windows
Talos
Rescue is a recovery mode that loads the operating system into RAM without using the server's local drives. It contains pre-installed system diagnostics and recovery tools. You can install additional tools yourself through the pacman`` package manager.
You can connect to a server in Rescue mode via SSH or a KVM console.
When you log in to the server for the first time, the SSH key is saved to the ~/.ssh/known_hosts file. If the server has been rebooted, a REMOTE HOST IDENTIFICATION HAS CHANGED error may appear when you try to log in again. To fix this, remove the host information for the IP address:
ssh-keygen -f "/home/<username>/.ssh/known_hosts" -R "<ip_address>"
Specify:
<username>— username (login). You can view it in the control panel: in the top menu, click Products → Dedicated Servers → Servers → server page → Operating System tab → Login;<ip_address>— public IP address of the server. You can view it in the control panel: in the top menu, click Products → Dedicated Servers → Servers → server page → Operating System tab → IP.
2. Change the server boot template
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In the control panel, on the top menu, click Products and select Dedicated Servers.
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In the Servers section, open the server page → Operating System.
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Click Change boot template.
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Select a boot template:
- Boot to Rescue;
- Boot to WinPE;
- Boot to Boot menu;
- Boot to Veeam Recovery Media 13 for Windows;
- Boot to Talos.
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In the New password field, click . A new password will be generated; it is used only to connect to the server in recovery and diagnostic mode.
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Click Save and reboot. The server will be rebooted, and all data on it will be preserved.
3. Connect to the server
The password for connecting to the server in recovery and diagnostic mode can be viewed in the control panel in the Products → Dedicated Servers → Servers → server page → Operating System tab. You generated the password when changing the server boot template in step 5.
The connection process depends on the selected recovery and diagnostics mode:
- in all modes — via KVM console. For Chipcore Line servers, you can order the additional IP-KVM connection for 3 hours service;
- in Rescue — via SSH – to protect servers against attacks, the number of login attempts is limited when connecting to a server in Rescue. If there are 10 failed login attempts from a single IP address within an hour, this IP address will be blocked for a day. To unblock the IP address sooner, reboot the server;
- in WinPE — via VNC;
- in Veeam Recovery Media 13 for Windows — VNC;
- in Talos — VNC.
4. Return to the previous server boot template
When the server is rebooted from the OS, the boot template will automatically change back to the one that was set before changing the server boot template.
- In the control panel, on the top menu, click Products and select Dedicated Servers.
- In the Servers section, open the server page → Operating System tab.
- Click Change boot template.
- In the Boot template field, select the previous boot template.
- Click Save and reboot.