How to connect to virtual machines in Nebius AI Cloud

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Set up the VM

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Generate a key pair

ssh-keygen -t ed25519

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Configure the user data

• name: Username for connecting to the VM. You can set the name explicitly or use your default one (the value of your machine’s USER environment variable). Do not use the root or admin usernames. They are reserved for internal needs and are not allowed to connect to a VM by SSH.
• sudo: Sudo policy. ALL=(ALL) NOPASSWD:ALL allows users unrestricted sudo access. False prevents sudo access for users.
• shell: Default shell to use.
• ssh_authorized_keys: The public key contents.

export USER_DATA=$(jq -Rs '.' <<EOF
users:
  - name: $USER
    sudo: ALL=(ALL) NOPASSWD:ALL
    shell: /bin/bash
    ssh_authorized_keys:
      - $(cat ~/.ssh/id_ed25519.pub)
EOF
)

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Configure the VM

• Pass the user data with your username and public key to the spec.cloud_init_user_data field.
• To enable public access to the VM, pass an empty object ({}) to the spec.network_interfaces.public_ip_address field. You will not be able to allocate the public IP address to the already created VM.

nebius compute instance create \
- <<EOF
{
  "metadata": {
    "name": "inference-vm"
  },
  "spec": {
    "stopped": false,
    "cloud_init_user_data": $USER_DATA,
    "resources": {
      "platform": "<platform>",
      "preset": "<preset>"
    },
    "boot_disk": {
      <boot_disk_data>
    },
    "network_interfaces": [
      {
        "name": "<network_interface_name>",
        "subnet_id": "<subnet_ID>",
        "public_ip_address": {
          "allocation_id": "<allocation_ID>"
        },
        "ip_address": {}
      }
    ]
  }
}
EOF

​

Connect to the VM by using SSH

1. Get your VM’s IP address and save it to an environment variable:
   • Connecting from the internet
   • Connecting from another VM

   To connect to the VM from the internet (if you have enabled public access to it), get its public IP address:

   export PUBLIC_IP_ADDRESS=$(nebius compute instance get-by-name \
     --name <VM_name> \
     --format json \
     | jq -r '.status.network_interfaces[0].public_ip_address.address | split("/")[0]')
   

   To connect to the VM from another Compute VM, get the private IP address or FQDN of the VM that you connect to:

   • Private IP address:
     nebius compute instance get-by-name \
       --name <VM_name> \
       --format json \
       | jq -r '.status.network_interfaces[0].ip_address.address | split("/")[0]'
     
   • FQDN:
     nebius compute instance get-by-name \
       --name <VM_name> \
       --format json \
       | jq -r '.status.network_interfaces[0].fqdn | split("/")[0]'
     
2. Connect to the VM:
   • Connecting from the internet
   • Connecting from another VM

   ssh $USER@$PUBLIC_IP_ADDRESS
   

   Use the received private address or FQDN:

   ssh $USER@<private_address_or_FQDN>
   

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Shared access to the VM

1. Ask them to generate an SSH key pair and share the contents of the public SSH key (e.g. id_ed25519.pub).
2. Connect to the VM under the name used when creating the VM:
   ssh $USER@$PUBLIC_IP_ADDRESS
   
3. Create a new user for VM access, named newuser in this example:
   sudo useradd -m -d /home/newuser -s /bin/bash newuser
   
4. Switch to the new user:
   sudo su - newuser
   
5. Create the ssh directory:
   mkdir .ssh
   
6. In the directory, create the authorized_keys file:
   cd .ssh
   touch authorized_keys
   
7. Add the new user’s public key to the created file:
   echo "<public_key>" > /home/newuser/.ssh/authorized_keys
   
8. Change the directory’s access permissions:
   chmod 700 ~/.ssh
   chmod 600 ~/.ssh/authorized_keys
   
9. Exit the new user’s shell:
   exit
   
10. Restart the VM:
    sudo reboot
    
11. Ask the other user to check the connection:
    ssh newuser@<public_api_address>
    

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Example

export PUBLIC_IP_ADDRESS=$(nebius compute instance get-by-name \
  --name training-instance \
  --format json \
  | jq -r '.status.network_interfaces[0].public_ip_address.address | split("/")[0]')
ssh $USER@$PUBLIC_IP_ADDRESS