Run health check APIs to verify compatibility between VLAN ID ranges you specified and the MTU settings on a transport node with the corresponding settings on a physical switch.

VLAN or MTU configuration mismatch is a common configuration error that can lead to connectivity outage.
Note:
  • Health check results are only indicators of possible network configuration errors. For example, health check run on hosts from different L2 domains results in untrunked VLAN IDs. This result cannot be considered as a configuration error as hosts must be in the same L2 domain for the health check tool to give correct results.
  • Only 50 health check operations can be in progress at any given time.
  • After a health check finishes, NSX-T Data Center preserves that result on the system only for 24 hours.

In a health check operation, the NSX-T Data Center opsAgent sends probe packets from a transport node to another node to verify compatibility between VLAN ID range you specified and the MTU value on the transport node with corresponding settings on the physical switch.

As the number of VLAN ID ranges to be verified increases, the waiting time increases.
Number of VLANs Waiting Time (secs)
[3073,4095] 150
[1025, 3072] 120
[513, 1024] 80
[128, 512] 60
[64, 127] 30
[1, 63] 20

Prerequisites

  • At least two uplinks configured on N-VDS for VLAN and MTU check to work.
  • Transport nodes on the same L2 domain.
  • Health check supported on ESX hosts running v6.7U2 or later.

Procedure

  1. Create a manual health check.
    POST https://<NSXManager_IP>/api/v1/manual-health-checks 
    Example Request:
POST https://<nsx-mgr>/api/v1/manual-health-checks
{
  "resource_type": "ManualHealthCheck",
  "display_name": "Manual HealthCheck 002",
  "transport_zone_id": "7754341c-8f3c-443f-9c1a-2d635d5b0d1c",
  "vlans":{
    "vlan_ranges":[{
      "start": 0,
      "end": 6
    },]
  },
}
Example Response:
{
    "operation_status": "FINISHED",
    "transport_zone_id": "7754341c-8f3c-443f-9c1a-2d635d5b0d1c",
    "vlans": {
        "vlan_ranges": [
            {
                "start": 0,
                "end": 6
            }
        ]
    },
    "result": {
        "vlan_mtu_status": "UNTRUNKED",
        "results_per_transport_node": [
            {
                "transport_node_id": "dfcabffa-8839-11e9-b30e-6f45344d8a04",
                "result_on_host_switch": {
                    "host_switch_name": "nsxvswitch",
                    "results_per_uplink": [
                        {
                            "uplink_name": "uplink1",
                            "vlan_and_mtu_allowed": [
                                {
                                    "start": 0,
                                    "end": 0
                                }
                            ],
                            "mtu_disallowed": [],
                            "vlan_disallowed": [
                                {
                                    "start": 1,
                                    "end": 6
                                }
                            ]
                        }
                    ]
                }
            },
            {
                "transport_node_id": "a300ea62-8839-11e9-a94e-31732bb71949",
                "result_on_host_switch": {
                    "host_switch_name": "nsxvswitch",
                    "results_per_uplink": [
                        {
                            "uplink_name": "uplink1",
                            "vlan_and_mtu_allowed": [
                                {
                                    "start": 0,
                                    "end": 0
                                }
                            ],
                            "mtu_disallowed": [],
                            "vlan_disallowed": [
                                {
                                    "start": 1,
                                    "end": 6
                                }
                            ]
                        }
                    ]
                }
            }
        ]
    },
    "resource_type": "ManualHealthCheck",
    "id": "8a56ed9e-a31b-479e-987b-2dbfbde07c38",
    "display_name": "mc1",
    "_create_user": "admin",
    "_create_time": 1560149933059,
    "_last_modified_user": "system",
    "_last_modified_time": 1560149971220,
    "_system_owned": false,
    "_protection": "NOT_PROTECTED",
    "_revision": 0
}
    A new health check object is created with id 8a56ed9e-a31b-479e-987b-2dbfbde07c38.
  2. To get a list of all manual health check operations initiated, make the API call.
    GET https://<NSXManager_IP>/api/v1/manual-health-checks
  3. To delete a manual health check, make the API call.
    DELETE https://<NSXManager_IP>/api/v1/manual-health-checks/<Health-check-ID>
  4. To get a single health check initiated manually, make the API call.
    GET https://<NSXManager_IP>/api/v1/manual-health-checks/< Health-check-ID>

Results

The API response section contains the health check results. The NSX Ops agent waits for an acknowledgement packet from the destination transport node to retrieve VLAN ID ranges supported on the physical switch.

  • Untrunked: Lists the VLAN ID ranges that are not compatible with a physical switch. The VLAN ID ranges that are compatible with the physical switch are also listed.
  • Trunked: Lists the VLAN ID ranges that are compatible with a physical switch.
  • Unknown: There is no valid result for some or all uplinks because of infrastructure issues or unsupported platform types such as KVM and Edge.
Parameters in the API response section:
  • vlan_and_mtu_allowed: Lists the VLAN ID ranges that are compatible.
  • mtu_disallowed: Lists the VLAN ID ranges for which the MTU value is not compatible with a physical switch.
  • vlan_disallowed: Lists the VLAN ID ranges that are not compatible with a physical switch.

What to do next

  • In an overlay-based transport zone, update both VLAN ID and MTU config in the uplink profile on N-VDS. Likewise, update VLAN or MTU on the physical switch.

  • In a vlan-based transport zone, update MTU config in the uplink profile. And, update VLAN config on logical switches of that transport zone. Likewise update VLAN or MTU on the physical switch.