Networks

After deploying a vSAN cluster, the need sometimes arises to make changes to its network configuration, such as migrating the vmkernel network of the cluster to a new subnet. This requirement may appear for example when changing the network in which the vSAN cluster is running, or even, in a more complex scenario such as when a standalone vSAN needs to be converted to a stretched cluster. In these sorts of situations, complications may be encountered if the subnet in use for the vSAN vmkernel ports cannot be routed to the network as a whole, as it is in use elsewhere in the organization, and is currently isolated in an L2 segment....

I had a power outage recently that took out my entire lab in a very ungraceful manner - everything, well mostly everything, came back up without a hitch - but NSX was acting a bit weird, so I decided to redeploy the NSX Controllers. I removed all 3 controllers and tried redeploying but ended up with the error “No IPs left in pool NSX-Controllers”. If you’re familiar with NSX, then you know when creating both controllers and VTEPs you’re required to configure IP Pools in NSX Manager to allocate IP addresses from....

Over the last 6-9 months, I have been reviewing the vast majority of a new book just released to print by Frank Denneman ↗ and Niels Hagoort ↗ - The vSphere 6.5 Host Resources Deep Dive ↗. This book is, without a doubt, the most in-depth look at host design I have ever read, we are not talking about standard best practices here, though those are in there too. More, low-level understanding of why best practices exist and even challenging some existing perceptions and paradigms about why technologies should be used and more importantly, how they should be utilised....

Out of morbid curiosity (and lack of IPv4 public address space available to me), I decided I wanted to enable IPv6 in my lab. However, before taking the plunge there, I would try it out on my residential ADSL line, I use the same brand of firewall there as in my lab so the experience should be largely transferable. So for a bit of context; I have a Zen Internet ADSL line (I saw the fiber van around the cabinet recently so maybe that will change) - auth to the provider is done via PPPoE on IPv4....

So we have covered the typical challenges of a multi-tenant network and designed a solution to one of these, it’s time to get down to the bones of it and do some configuration! Let’s implement it in the lab, I have set up an NSX ESG Cust_1-ESG and an NSX DLR control VM Cust_1-DLR with the below IP configuration: I have also enabled OSPF as a NSSA (area 51) between the ESG and the DLR control VM and specified to redistribute connected routes attached to the DLR:...

Based on my last post, you’ll understand some of the challenges that are faced with traditional approaches to datacenter networking so let’s get into the high-level conceptual design here of how we might solve one of these problems. Most service providers have or are at least familiar with using MPLS for customer segregation in a WAN scope as I alluded to in my previous datacenter networking article. What we want to do is simplify the provisioning and distribution of subnets to a customer’s virtual environment, all the way up to the WAN....

As of late, I have been getting my feet wet in more networking things - Firstly out of necessity, but it has grown into a genuine area of interest to me. I have a homelab that I like to simulate a production working environment in, so I had a nice opportunity to lab up what a possible multi-tenant IaaS architecture might look like using NSX. NSX fundamentally changes how customer environments for service providers are designed - it moves the complexity away from the physical network and up into the hypervisor management layer, let’s be honest anything that limits touching the physical infra is good, right?...

I had a bit of a storage outage in my lab due to a funky behaviour on the Synology that I use as primary storage for all my VMs. Most stuff came back up or could at least be trivially fixed (like VCSA, PSCs, etc) you can edit the GRUB boot string ↗ and force into /bin/bash then run fsck from there. One VM that doesn’t allow the GRUB string to be edited or both to be paused in any way is the NSX manager, that was a problem given I was presented with this upon boot:...

Over the last 12 months my posting has been dialled back, this isn’t for lack of wanting or ideas, mainly a lack of time and mental bandwidth. Reason being, I have been designing and implementing a new cloud platform (namely “STC” ↗) for my employer, Novosco - as with any new service or product this requires an element of discretion - but now is the time to let slip some of the detail on what makes the service tick!...

I’ve been putting off doing VCAP level exams for a long time, probably longer than I should have in hind-sight. But a month ago I took my brave pills and booked what would be my first VCAP level exam: VCIX6-NV ↗. So the date was set and I have been studying in pretty much all the free time I have over the last month - repeating HOLs over and over, standing up, breaking, fixing my home lab’s NSX environment, setting all kinds of stuff with API instead of the UI to try and get a grasp of everything this exam is supposed to encompass....