Troubleshooting vMotion network connectivity issues
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Troubleshooting vMotion network connectivity issues

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Article ID: 321012

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Updated On:

Products

VMware vSphere ESXi

Issue/Introduction

This article provides information about the tools that can be used to troubleshoot vMotion network connectivity issues.

Environment

VMware vSphere ESXi 6.7

Resolution

To troubleshoot network connectivity issues for vMotion:
  1. Identify which vmknics are used for vMotion on both hosts.

    Option 1 Using the vCenter Server User Interface (UI)


    vmkping vmotion

    Notes: All VMkernel adapters with vMotion Enabled will be used for vMotion. For more information on how to enable vMotion on VMkernel adapters, see Creating a VMkernel port and enabling vMotion on an ESXi/ESX host (2054994). For best practices on which VMkernel adapters to enable for vMotion, see the Networking Best Practices for vSphere vMotion section of the vCenter Server and Host Management Guide.

    Option 2 Using the ESXi command line

    esxcli network ip interface list
     
    Sample output:

    vmk0
    Name: vmk0
    MAC Address: 02:00:45:02:26:65
    Enabled: true
    Portset: vSwitch0
    Portgroup: Management Network
    Netstack Instance: defaultTcpipStack
    VDS Name: N/A
    VDS UUID: N/A
    VDS Port: N/A
    VDS Connection: -1
    Opaque Network ID: N/A
    Opaque Network Type: N/A
    External ID: N/A
    MTU: 1500
    TSO MSS: 65535
    RXDispQueue Size: 1
    Port ID: 33554436

    For each VMkernel adapter entry, run this command:

    esxcli network ip interface tag -i [VMkernel adapter name]

    Example command:

    esxcli network ip interface tag -i vmk0

    Any adapters with tag value vMotion will be used for vMotion.

    Sample vMotion VMKernel adapter value:

    Tags: VMotion
     
  2. Run diagnostic tools between source and destination vMotion VMkernel adapters

    vmkping

    vmkping uses a VMkernel’s TCP/IP stack to send ICMP traffic to a destination host.

    Suppose you have source vMotion VMkernel adapter vmk0 with IP 192.168.0.1, and destination vMotion VMkernel adapter vmk0 with IP 192.168.0.2.

    From source ESXi host, run this command:

    vmkping -I vmk0 192.168.0.2

    Similarly, from destination ESXi host, run this command:

    vmkping -I vmk0 192.168.0.1

    For more information on vmkping, see Testing VMkernel network connectivity with the vmkping command (1003728).

    OR

    Run this command: vmkping --help

    With long distance vMotion, the maximum supported RTT is 150 miliseconds.

    nc

    nc is the netcat utility and can be used to verify connectivity on a specific remote port.

    Suppose you have source vMotion VMkernel adapter vmk0 with IP 192.168.0.1, and destination vMotion VMkernel adapter vmk0 with IP 192.168.0.2. Since vMotion listens on port 8000 of the vMotion VMkernel adapter, you need to verify if you can establish a connection to port 8000.

    From source ESXi host, run this command:

    nc -z 192.168.0.2 8000

    From destination ESXi host, run this command:

    nc -z 192.168.0.1 8000

    Sample successful output:

    Connection to 192.168.0.2 8000 port [tcp/*] succeeded!
For more information on nc and troubleshooting specific tcp/ip port connectivity issues, see:

Workaround:
VMware Skyline Health Diagnostics for vSphere - FAQ (81931)

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