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© Rakhesh Sasidharan


Yay! (VXLAN)

I decided to take a break from my NSX reading and just go ahead and set up a VXLAN in my test lab. Just go with a hunch of what I think the options should be based on what the menus ask me and what I have read so far. Take a leap! :)

*Ahem* The above is actually incorrect, and I am an idiot. A super huge idiot! Each VM is actually just pinging itself and not the other. Unbelievable! And to think that I got all excited thinking I managed to do something without reading the docs etc. The steps below are incomplete. I should just delete this post, but I wrote this much and had a moment of excitement that day … so am just leaving it as it is with this note. 

Above we have two OpenBSD VMs running in my nested EXIi hypervisors. 

  • obsd-01 is running on host 1, which is on network
  • obsd-02 is running on host 2, which is on network 
  • Note that each host is on a separate L3 network.
  • Each host is in a cluster of its own (doesn’t matter but just mentioning) and they connect to the same VDS.
  • In that VDS there’s a port group for VMs and that’s where obsd-01 and obsd-02 connect to. 
  • Without NSX, since the hosts are on separate networks, the two VMs wouldn’t be able to see each other. 
  • With NSX, I am able to create a VXLAN network on the VDS such that both VMs are now on the same network.
    • I put the VMs on a network so that’s my overlay network. 
    • VXLANs are basically port groups within your NSX enhanced VDS. The same way you don’t specify IP/ network information on the VMware side when creating a regular portgroup, you don’t do anything when creating the VXLAN portgroup either. All that is within the VMs on the portgroup.
  • A VDS uses VMKernel ports (vmk ports) to carry out the actual traffic. These are virtual ports bound to the physical NICs on an ESXi host, and there can be multiple vmk ports per VDS for various tasks (vMotion, FT, etc). Similar to this we need to create a new vmk port for the host to connect into the VTEP used by the VXLAN. 
    • Unlike regular vmk ports though we don’t create and assign IP addresses manually. Instead we either use DHCP or create an IP pool when configuring the VXLAN for a cluster. (It is possible to specify a static IP either via DHCP reservation or as mentioned in the install guide). 
    • Each cluster uses one VDS for its VXLAN traffic. This can be a pre-existing VDS – there’s nothing special about it just that you point to it when enabling VXLAN on a cluster; and the vmk port is created on this VDS. NSX automatically creates another portgroup, which is where the vmk port is assigned to. 

And that’s where I am so far. After doing this I went through the chapter for configuring VXLAN in the install guide and I was pretty much on the right track. Take a look at that chapter for more screenshots and info. 

Yay, my first VXLAN! :o)

p.s. I went ahead with OpenBSD in my nested environment coz (a) I like OpenBSD (though I have never got to play around much with it); (b) it has a simple & fast install process and I am familiar with it; (c) the ISO file is small, so doesn’t take much space in my ISO library; (d) OpenBSD comes with VMware tools as part of the kernel, so nothing additional to install; (e) I so love that it still has a simple rc based system and none of that systemd stuff that newer Linux distributions have (not that there’s anything wrong with systemd just that I am unfamiliar with it and rc is way simpler for my needs); (f) the base install has manpages for all the commands unlike minimal Linux ISOs that usually seem to skip these; (g) take a look at this memory usage! :o)

p.p.s. Remember to disable the PF firewall via pfctl -d.

Yay again! :o)

Update: Short-lived excitement sadly. A while later the VMs stopped communicating. Turns out VMware Workstation doesn’t support MTU larger than 1500 bytes, and VXLAN requires 1600 byte. So the VTEP interfaces of both ESXi hosts are unable to talk to each other. Bummer!

Update 2: I finally got this working. Turns out I had missed some stuff; and also I had to make some changes to allows VMware Workstation to with larger MTU sizes. I’ll blog this in a later post