A real doozie: Changing VM port group drops networking for 10 minutes

Update:  Support had nothing, so we are forced to chalk it up to the vDS stuff being wonky.  If anyone runs across this, would be interesting to hear their solution.

What follows is the ticket we've submitted (with a few additions that might help the general public).  This being the first time I've really had the chance to play around with and design my own VDS solution, mistakes were made.  Long story short I wanted to do X initially, switches didn't like that and our network guy recommended against it, so we did Y.  Turns out X does work, but we get weird un-sanctioned behaviour.  (X being 'let vSphere handle networking, just give me VLAN trunk switchports', Y being 'let's use LAGs/LACP/MLAG/etc'.)

I will update once we have a solution...

March12 - Quick update, I moved the rest of the VMs off the old VDS, roughly 25% of them had the same failure issue.  We're still waiting for something concrete from Extreme - I suspect with our failure scenario now 'non-reproducible', we're out of luck.

-----------------------
We are running into an issue while changing VMware port groups between virtual distributed switches.  Some VMs work, some VMs go into a state where they can communicate with other VMs in that new port group, but cannot ping the default gateway.

Environment overview:

  • vSphere 5.5, VDSes are 5.5 (not upgraded)
  • Switches are Extreme Networks
  • Old port group is the same VLAN, single uplink, different port group name, different virtual distributed switch.
  • New port group is the same VLAN, single uplink, different port group name, different virtual distributed switch.
  • Old VDS is using “route based on originating virtual port”
  • New VDS is using “route based on physical NIC load”
  • VMs are running successfully on the new port group/VDS/uplink
  • On the switch, MLAG is turned off and the switchports are configured as VLAN trunks


Process:

  1. We change the network label (port group) from ‘Old PG’ to ‘New PG’
  2. Press ‘OK’
  3. Symptoms begin


Symptoms:

  1. Happens on multiple hosts (all with known good VMs in respective port groups)
  2. VM cannot ping its Default Gateway
  3. Clients on other switches cannot ping the VM
  4. VM can ping other VMs on the new port group (same VLAN)
  5. VM cannot ping other VMs on the old port group (same VLAN)
  6. When we were able to reproduce the issue, it took ~10 minutes before connectivity was restored with no action on our part.


What we tried to restore connectivity:

  1. Move back to old PG (this worked some of the time)
  2. Disconnect NIC->press OK->reconnect NIC->press OK via vSphere Client  (did not work)
  3. Disconnect->press OK->change port group back to old->press OK->reconnect->press OK  (did not work)
  4. Reboot the guest OS  (did not work)
  5. On the guest OS: arp –d  (did not work)
  6. On the guest OS: disable/enable the network adapter (Windows and Linux)


Research indicates this is an issue on the physical switch, but we cannot find any (obvious) errors/configuration issues.


Some research links...

  • https://communities.vmware.com/thread/420029
  • https://communities.vmware.com/thread/462638


Comments

Post a Comment

Popular posts from this blog

Learning through failure - a keyboard creation journey

Image
tl;dr Built a custom keyboard cuz I have weirdo nerve pain issues.   Learned a lot cuz I failed a lot.   Maybe 'do it right the first time' is a bad frame of mind.   The keyboard ended up being kinda nifty.   It has lights, and a trackball, and QMK, and it helps my issues.   \o/ ( tl;dr is internet lingo that means, too long; didn't read ) Pain as a key ingredient An old proverb says, 'necessity is the mother of invention', and that is how this story begins. Over the last few years, age or stress or something has caught up with me and I developed the need to change my human-to-computer interface.  Mousing changed to trackballing.  The traditional keyboard was swapped out for an ergonomic, and then split keyboard.  Complicated multi-finger-and-hand key combinations were replaced by single keypress macros.  And yet more was still needed. It's often said that change only happens with pain - indeed, the organizations many...
Read more

Learning Opportunities - Watching/listening list

Over the last year I've spent a lot of time learning (thank you, long commute & lunch hours).  Many topics ranging from Chef to DevOps to architecture concepts to management concepts and everything in between.  Why have I done this? DevOps Demystified with Ben Rockwood: https://www.youtube.com/watch?v=h5E--QSBVBY DevOps at ancestry.com: https://www.youtube.com/watch?v=pF5ya0q53kk Those two presentations were key in sending me down this road.  First, and most important, was Mr. Rockwood's explanation as to the real 'why', and the point behind DevOps from an operational perspective.  Second, and no less important but for a different reason, the continuous delivery system at ancestry.com really made it real to me because they are a 'Windows shop'.  So much of what I'd been reading about Chef/config mgmt. relied on amazing tools (see the error there?) only available to the Linux world.  Suddenly here's this guy telling me that it's possible...
Read more

DFSR - eventid 4312 - replication just won't work

This warning isn't documented that well on the googles, so here's some google fodder: You are trying to set up replication for a DFS folder (no existing replication) Source server is 2008R2, 'branch office' server is 2012R2 (I'm moving all our infra to 2012R2) You have no issues getting replication configured You see the DFSR folders get created on the other end, but nothing stages Finally you get EventID 4312: The DFS Replication service failed to get folder information when walking the file system on a journal wrap or loss recovery due to repeated sharing violations encountered on a folder. The service cannot replicate the folder and files in that folder until the sharing violation is resolved.    Additional Information:  Folder: F:\Users$\user.name\Desktop\Random Folder Name\  Replicated Folder Root: F:\Users$  File ID: {00000000-0000-0000-0000-000000000000}-v0  Replicated Folder Name: Users  Replicated Folder ID: 33F0449D...
Read more