VMware vSphere and other products from the VMware ecosphere highly rely on DNS resolution. Name resolution is crucial to the virtual world and there’s a rule amongst troubleshooters:
“If you’ve ruled out DNS as the origin of your problem – check DNS again.”
In the corporate sector there are usually DNS servers of various types. Either hardware appliances with DNS functionality, or entire Microsoft Active Directory servers. However, if you want to set up a homelab, your office usually has only a small DSL router with a (poor) DHCP server functionality. It is possible to run DNS servers or whole ADS domain controllers inside a VM, but then we have the chicken and egg problem. The VM will start after cluster and vCenter are online. Until then wild things can happen in a vSphere cluster without DNS. So we are looking for a small, energy-saving, inexpensive and configurable hardware solution as DNS server for our homelab. Sounds like the Swiss-Army knive, but it can be easily realized with a Raspberry Pi.
In this article I will explain what you need to build your DNS server and how to configure a subnet for the lab.
Raspi as DNS-server
For this project we don’t need the latest model of the Raspberry Pi. A Raspi 3b model is fine for this purpose and the accessories are also available at low prices.
Raspberry Pi 3b+ / 1GB / 4-Core / 1,4 GHz
Micro SD card 32 GB
Power supply 2,5A (optional)
Parts list with average prices as of June 2020
For much less than 100€ you’ll get a tiny server which can also fulfill other tasks like home automization or as ad-blocker pi-hole.
There are a few things to consider. In principle you can power the Raspi via USB. But you have to make sure that the source delivers at least and reliably 1.2A. Power sources with 2.5A are recommended. My first boot attempts failed because my USB power supply did not provide enough power.
The Raspi requires a micro-SD card as permanent boot and storage media. Here you shouldn’t take the cheapest product, but for less than 10 € you can get 32 GB from a trustworthy brand.
After a failed firmware update on my Intel x722 NICs one host came up without its 10 Gbit kernelports (vSAN Network). Every effort of recovery failed and I had to send in my “bricked” host to Supermicro. Normally this shouldn’t be a big issue in a 4-node cluster. But the fact that management interfaces were up and vSAN interfaces were not must have caused some “disturbance” on the cluster and all my VM objects were marked as “invalid” on the 3 remaining hosts.
I was busy on projects so I didn’t have much lab-time anyway, so I waited for the repair of the 4th host. Last week it finally arrived and I instantly assembled boot media, cache and capacity disks. I checked MAC addresses and settings on the repaired host and everything looked good. But after booting the reunited cluster still all objects were marked invalid.
Time for troubleshooting
First I opened SSH shells to each host. There’s a quick powerCLI one-liner to enable SSH throughout the cluster. Too bad I didn’t have a functional vCenter at that time, so I had to activate SSH on each host with the host client.
From the shell of the repaired host I’ve checked the vSAN-Network connection to all other vSAN kernel ports . The command below pings from interface vmk1 (vSAN) to IP 10.0.100.11 (vSAN kernel port of esx01 for example)
vmkping -I vmk1 10.0.100.11
I received ping responses from all hosts on all vSAN kernel ports. So I could conclude there’s no connection issue in the vSAN-network.
Servers and switches are built for use in data centers where noise pollution is only a minor issue. The focus is on maximum performance and cooling. In the Homelab, however, things look different. Server rooms in private households are probably the exception and so most homelabs are located somewhere near the desk. A case fan with high speed can be very annoying.
For my vSAN cluster I use a Netgear XS716T 10 Gigabit switch. During system startup the fans rotate at maximum speed and then settle down a bit in normal mode. But even the lower noise level is still annoying.
We need new fans
As part of a handicraft experiment, I tried to get the noise problem under control and bought some Noctua fans which are popular in the homlab scene. The Netgear switch is equipped with two 40 mm fans. These will be replaced by two Noctua NF-A4x20 fans. A simple exchange would be somewhat unsatisfactory, though. There should be at least some kind of quantification (just a science habit).
In the picture below you can see the original fans of the Netgear 10G switch. The 16-port model is equipped with two fans while the 8-port model has just one.
Disclaimer No.1: Before removing the casing cover, the power supply must be disconnected!
Disclaimer No.2: Opening the casing may void your warranty.
There have been many new releases in the first quarter of 2020. The long anticipated release of Veeam Backup & Replication version 10, we’ve been waiting for since 2017 and also the latest generation of VMware vSphere. While I had vSAN 7 beta running on my homelab cluster before GA, I’ve worked with Veeam Backup 10 only in customer projects. There’s unfortunately no room for playing with new features unless the customer requests it. One of the new features of Veeam v10 is the ability to use Linux proxies and repositories. With XFS filesystem on the repository you can use the fast clone feature which is similar to ReFS on Windows.
In this tutorial I will show how to:
Deploy and size the Veeam server
Show base configuration to integrate vCenter
Build, configure and deploy a Linux proxy and its integration into backup infrastructure
Build, configure and deploy a Linux XFS repository
Using Veeam Backup on a vSAN Cluster has special design requirements. There’s no direct SAN backup on VMware vSAN because there’s neither a SAN, nor a fabric and nor HBAs. There are only two backup methods available: Network Mode (nbd) and Virtual Appliance Mode (hotadd). The latter is recommended for vSAN, but you should deploy one proxy per host to avoid unnecessary traffic on the vSAN interfaces. Hotadd also utilizes Veeam Advanced Data Fetcher (ADF).
Talking about licenses: Having Linux proxies on each host will reduce the cost of Windows licensing. One more reason to play around with this new feature. A Veeam license will be required too, but as a vExpert I can get a NFR (not for resale) license which is valid for one year. Just one of the advantages of being a vExpert. 🙂
Let the games begin. We’ll need a Veeam server that holds the job database and the main application. The proxy and repository role will be kept on individual (Linux) servers.