Allow connection to instances on multiple criteria via Identity-Aware Proxy

Installation :

  pip install google-iap   

Prerequisites:

The service account used must have at least the roles Compute Viewer and IAP Policy Admin
You must authorize the Identity-Aware Proxy network (35.235.240.0/20) on port 22 as input to the desired network at the firewall

Example of use :

  google-iap iap get --credentials=service-account.json --project=<projectId>     

  google-iap iap get --credentials=service-account.json --project=<projectId> --zone=<zone>     

  google-iap iap get --credentials=service-account.json --project=<projectId> --zone=<zone> --instance=<instance>    

  google-iap iap get --credentials=service-account.json --project=<projectId> --zone=<zone> --instance=<instance> --format=yaml    

  google-iap iap get --credentials=service-account.json --project=<projectId> --zone=<zone> --instance=<instance> --format=json    

  google-iap iap set --credentials=service-account.json --project=<projectId> --policy=POLICY_FILE.json    

  google-iap iap set --credentials=service-account.json --project=<projectId> --policy=POLICY_FILE.yaml   

  google-iap iap set --credentials=service-account.json --project=<projectId> --zone=<zone> --policy=POLICY_FILE.yaml    

  google-iap iap set --credentials=service-account.json --project=<projectId> --zone=<zone> --instance=<instance> --policy=POLICY_FILE.yaml    

File example POLICY_FILE.yaml :

---
policy:
  bindings:
  - role: roles/iap.tunnelResourceAccessor
    members:
    - user:[email protected]
    condition:
      title: adm-ssh
      expression: "resource.name.startsWith(\"instance-name\") && resource.type == \"google.cloud.compute.Instance\" && destination.port == 22"

File example POLICY_FILE.json :

{

  "policy": {

    "bindings": [

      {

        "role": "roles/iap.tunnelResourceAccessor",

        "members": ["user:[email protected]"],

        "condition": {

           "title": "adm-ssh",

           "expression": "resource.name.startsWith(\"instance-name\") && resource.type == \"google.cloud.compute.Instance\" && destination.port == 22"

        }

      }

    ]

  }

}

You can show CEL expression -> https://cloud.google.com/iam/docs/conditions-overview?hl=ko#example_destination_ipport_expressions_for_cloud_iap_for_tcp_tunneling

Use :

• Ssh tunneling :

  gcloud beta compute start-iap-tunnel <instance> 80 --local-host-port=localhost:8888 --network-interface=nic0 --zone=<zone>    
  

• Ssh connection :

  gcloud beta compute ssh <instance> --tunnel-through-iap --zone=<zone>