Connect to a VM

Google Distributed Cloud (GDC) air-gapped appliance uses key-based SSH authentication to establish connections to virtual machine (VM) instances. By default, passwords aren't configured for local users on VMs with an operating system (OS).

Before you begin

Before connecting to a VM, you must meet the following prerequisites:

• Enable access management. You cannot proceed without access management enabled on the guest environment. By default, access management is enabled on new VMs.
• Enable VM external access for any peer on Transmission Control Protocol (TCP) port 22.

Set up a ProjectNetworkPolicy (PNP) custom resource in the project where the VM resides.

• By setting up a PNP in the project, you can access the VM outside of the project or organization.
• To diagnose if you don't have a PNP, ask your Infrastructure Operator (IO).

Login access to the cluster. Follow the CLI steps in Sign in to log in to the cluster.

To use gdcloud command-line interface (CLI) commands, ensure that you have downloaded, installed, and configured the gdcloud CLI. All commands for GDC air-gapped appliance use the gdcloud or kubectl CLI, and require an operating system (OS) environment.

Get the kubeconfig file path

To run commands against the admin cluster, ensure you have the following resources:

1. Locate the admin cluster name, or ask your Platform Administrator (PA) what the cluster name is.

2. Sign in and generate the kubeconfig file for the admin cluster if you don't have one.

3. Use the path to replace ADMIN_KUBECONFIG in these instructions.

Establish a VM connection

This section describes how to establish a connection to a VM with a specific operating system (OS).

Connect to a VM

To establish a connection to a VM with a specific OS, use the GDC console, gdcloud CLI, or the Virtual Machine Manager API.

Console

1. In the navigation menu, click Virtual Machines > Instances.

2. In the list of VMs, find the row for the running VM that you want to connect to. In the Connect column, click SSH.

3. An SSH browser terminal opens. Enter any command in the shell or click FTP to navigate the file structure and upload files.

gdcloud

Connect to a VM using SSH by running the gdcloud compute ssh command

gdcloud compute ssh VM_NAME --project=PROJECT_ID

Replace the following variables:

• VM_NAME: the name of the VM.
• PROJECT_ID: the ID of the project that contains the VM.

If you have set default properties for the CLI, you can omit the --project flag from this command. For example:

gdcloud compute ssh VM_NAME

API

Connect to a VM:

• Open a terminal.
• Create an SSH key pair.
• Upload the public key and username with a time-to-live (TTL) value.

GDC retrieves the SSH key and username and creates a user account with the username. On VMs, GDC stores the public key in your user's ~/.ssh/authorized_keys file on the VM.

Complete the following steps to connect to a VM from the command line:

1. Create an SSH key pair and a username.

   On OS workstations, use the ssh-keygen utility to create a new SSH key pair. The following code sample creates an RSA (Rivest–Shamir–Adleman) key pair:

   ssh-keygen -t rsa -f ~/.ssh/KEY_FILENAME -C USERNAME -b 2048
   

   Replace the variables by using the following definitions.

   Variable	Definition
   KEY_FILENAME	The name for your SSH key file. For example, the my-ssh-key filename generates a private key file named my-ssh-key and a public key file named my-ssh-key.pub.
   USERNAME	Your username on the VM, such as testuser or testuser_gmail_com.

   The ssh-keygen utility saves your private key file in the ~/.ssh/KEY_FILENAME path and your public key file in the ~/.ssh/KEY_FILENAME.pub path.

   A public key for the user, testuser, is similar to the following example:

   ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDAu5kKQCPF... testuser
   

2. Upload your key to the VM and create a Kubernetes resource with your public key, username, and time to live (TTL) value for the key.

   The following example uses an access_request.yaml file to grant access to the VM instance with the KEY_FILENAME private key and a TTL value of ten minutes:

   apiVersion: virtualmachine.gdc.goog/v1
   kind: VirtualMachineAccessRequest
   metadata:
     namespace: VM_NAMESPACE
     name: AR_NAME
   spec:
     ssh:
       key: |
         ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDAu5kKQCPF... cloudysanfrancisco
       ttl: 10m
     user: USERNAME
     vm: VM_NAME
   

   Replace the variables, using the following definitions:

   Variable	Definition
   VM_NAMESPACE	The namespace for the VM.
   AR_NAME	The access request name.
   USERNAME	Your username on the VM, such as testuser or testuser_gmail_com.
   VM_NAME	The name of the VM instance.

   Important: After reaching the TTL value of ten minutes, the VM denies future connections with that key unless you add it again.

3. Create the key:

   kubectl create -f access_request.yaml --kubeconfig ORG_ADMIN_KUBECONFIG
   

4. Check the status of your access request:

   kubectl get virtualmachineaccessrequests.virtualmachine.gdc.goog -n VM_NAMESPACE --kubeconfig ORG_ADMIN_KUBECONFIG
   

   Replace VM_NAMESPACE with the namespace for the VM.

   A configured status indicates that you can connect to the VM.

5. Connect to the VM:

   ssh -i PATH_TO_PRIVATE_KEY USERNAME@EXTERNAL_IP
   

   Replace the following values:

   • PATH_TO_PRIVATE_KEY with the path to the private SSH key file that corresponds to the public key you added to the VM.
   • USERNAME with the username that you specified when you created the SSH key. For example, cloudysanfrancisco_example_com or cloudysanfrancisco.
   • EXTERNAL_IP with the external ingress IP address of the VM.

Troubleshooting

This section describes how to troubleshoot issues that might occur while connecting to a VM instance after creating the access request.

Work through the following steps to identify possible issues:

1. Verify that the VM is running. Replace the editable variables with your values in the following command:

   kubectl get virtualmachines.virtualmachine.gdc.goog VM_NAME -n VM_NAMESPACE --kubeconfig ORG_ADMIN_KUBECONFIG
   

   If the VM is not running, you cannot connect or configure new requests.

2. Verify that the VM has been running for a few minutes. If the VM has just started, the required services for SSH access might not be running yet. Typically, they run within five minutes of the boot.

3. Verify that you didn't exceed the TTL value on the access request. The key is removed after time reaches the TTL value.

4. If your VirtualMachineAccessRequest shows a configured status, verify the following requirements:

   1. You enabled data transfer in to your VM on port 22.
   2. Your machine routes to the VM. For example, you can use the
      curl -vso /dev/null --connect-timeout 5 EXTERNAL_IP:22 command to check routing.

5. If your VirtualMachineAccessRequest shows a failed status, view the complete status and review the error message indicating what caused the request to fail:

   kubectl describe virtualmachineaccessrequest.virtualmachine.gdc.goog AR_NAME -n VM_NAMESPACE --kubeconfig ORG_ADMIN_KUBECONFIG
   

   Replace the editable variables in the preceding command with your own values.

6. If the status of your VirtualMachineAccessRequest is blank, the guest environment might not be running.