vSphere vNetwork

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  • 1.  VM intermittently losses connectivity after reboot or vmotion

    Posted Dec 10, 2019 11:44 PM

    Hi,

    I have a weird issue with one of my clusters where the VMs will lose internet connection after a reboot or vmotion.

    It happens randomly on all the VM's in the cluster.

    The way I usually fixed the issue are by using one of the solution below:

    1. Disable the VM nic for 30 sec and re-enable it
    2. Delete the VM nic and re-add a new nic
    3. Change the NIC vlan and change it back to the correct one
    4. Move it back to the host before the Vmotion

    I've tried to reboot all the ESXI Host in the cluster but the issue still persists.

    Any idea what to check?



  • 2.  RE: VM intermittently losses connectivity after reboot or vmotion

    Broadcom Employee
    Posted Dec 10, 2019 11:56 PM

    I would begin my investigation looking at the vSwitch and port group configuration, then extend that to the physical switch ports that the host physical NICs are connected into - see if everything in that area is configured as you would expect and there’s no mismatch.



  • 3.  RE: VM intermittently losses connectivity after reboot or vmotion

    Posted Dec 11, 2019 12:44 AM

    Hi I've just double checked this, the vSwitch and port group config is fine. The physical connection is fine too.

    More details: When the VM losses internet connection, it still can ping the HOST where it resides but not to another host or to the default gateway.

    Anything else that I should check?



  • 4.  RE: VM intermittently losses connectivity after reboot or vmotion

    Broadcom Employee
    Posted Dec 11, 2019 07:32 AM

    It sounds like it might be ARP/RARP related, so could still be a physical switch issue - with your topology, or the switch port configuration - something along those lines.

    I‘m moving this thread to the vNetwork area of the forum (I‘m a moderator on here which allows me to do that) so that others with more expertise can chime in...



  • 5.  RE: VM intermittently losses connectivity after reboot or vmotion

    Posted Dec 13, 2019 12:53 AM

    Okay.

    Any pointers on what do I need to check?



  • 6.  RE: VM intermittently losses connectivity after reboot or vmotion

    Posted Dec 16, 2019 07:26 PM

    What I could think of, is that the physical switch ports to which the hosts are connected have spanning-tree enabled.

    Ensure that these physical switch ports are configured with e.g. spanning-tree portfast, or as edge-ports (depending on the switch vendor).


    André



  • 7.  RE: VM intermittently losses connectivity after reboot or vmotion

    Posted Dec 16, 2019 06:05 PM

    Is your ESXi networking based on standard vSwitch or distributed vSwitch?

    Is there any special configuration on the vSwitch failover order?

    What is the physical switch port settings on the ESXi uplink connection?

    Did you check the vmware.log file in time of VM startup?