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Compute Cloud

Connecting to a VM's serial console via SSH

After enabling access, you can connect to the serial console to interact with the VM. Before connecting to the serial console, carefully read the Security section.

Security

Warning

When assessing the risk of enabling access via the serial console, consider the following:

  • The VM can still be managed from the internet even if there is no external IP address.
    To access the VM serial console from the Nebius Israel management console, a user must be authenticated in the Nebius Israel management console and have the proper rights to the VM. One can access the VM serial console from an SSH client application (such as PuTTY) or the Nebius Israel CLI via SSH key authentication. To reduce the risk of web session hijacking, you should closely monitor your SSH key and make sure you terminate the web session.

  • The session will be simultaneously shared by all users who have access to the serial console.
    Users will be able to see each other's actions if concurrently watching the serial console's output.

  • A valid session can be exploited by another user.

We recommend using the serial console only when absolutely necessary, grant access to a narrow group of people, and use strong VM passwords.

Make sure you disable access after you finish using the serial console.

Federated users can only connect to the serial console using the CLI or SSH. These users cannot access the serial console from the Nebius Israel management console.

For remote access, it is important to ensure protection against MITM attacks. To do that, you can use client/server encryption.

To set up a secure connection:

  • You can download the current SHA256 fingerprint of the SSH key before each connection to the VM.

    The first time you connect to the VM, the client sends the SSH key fingerprint to the server and awaits a decision on establishing a connection:

    • YES: Establish the connection.
    • NO: Reject.

    Make sure the fingerprint from the link matches the fingerprint received from the client.

  • You can download the public SSH key of the host before each connection to the serial console.

    Use the public SSH key you receive when connecting to the serial console.

    Recommended startup options:

    ssh -o ControlPath=none -o IdentitiesOnly=yes -o CheckHostIP=no -o StrictHostKeyChecking=yes -o UserKnownHostsFile=./serialssh-knownhosts -p 9600 -i ~/.ssh/<name of private SSH key> <VM ID>.<username>@serialssh.il.nebius.cloud

    The host's public SSH key may be changed in the future.

Check the specified files often. Download these files only via HTTPS after verifying the validity of the https://storage.il.nebius.cloud website certificate. If the website cannot securely encrypt your data due to certificate problems, the browser will warn you about that.

Connecting to the serial console

Note

How the serial console works depends on the operating system settings. Compute Cloud provides a communication channel between the user and COM port on the VM, but it does not guarantee that the console works properly on the OS.

To connect to the VM, you need its ID. For information about how to get the ID of a VM, see Getting information about a VM.

Connection command example:

ssh -t -p 9600 -o IdentitiesOnly=yes -i ~/.ssh/<name of private SSH key> <VM ID>.<username>@serialssh.il.nebius.cloud

Example with yc-user and the VM with the ID fhm0b28lgfp4tkoa3jl6:

ssh -t -p 9600 -o IdentitiesOnly=yes -i ~/.ssh/id_ed25519 fhm0b28lgfp4tkoa3jl6.yc-user@serialssh.il.nebius.cloud

The yc-user user is generated automatically when the VM is being created. For more information, see Creating a VM from a public Linux image.

Troubleshooting

  • If you connect to the serial console and nothing appears on the screen, press Enter.
  • If the OS requests user credentials to provide access to the VM, enter the login and password.
  • If you see the Warning: remote host identification has changed! error when trying to connect to the VM, run ssh-keygen -R <VM's IP>.

Disconnecting from the serial console

To disconnect from the serial console:

  1. Press Enter.
  2. Enter the following characters in order: ~..
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