Hyper-Converged Cynicism

Or “How I’ve come to love my vSAN Ready Nodes”

I’ll admit it, some years ago I was very cynical about HyperConverged Infrastructure (HCI). Outside of VDI workloads I couldn’t see how it would fit in my environment – and this was all down to the scaling model.

With the building-block architecture of HCI; storage, compute, and memory are all expanded in a linear fashion. Adding an extra host to the cluster to expand the storage capacity also increases the available memory and CPU in the pool of resources. But my workloads were varied, one day we might get a new storage-intensive application, the next week it might be one which is memory intensive. I was used to independently expanding the storage through a SAN and just the compute/memory side through the servers and didn’t want to be either running up against a capacity wall or purchasing unnecessary compute just to cater for storage demands.

This opinion changed when my own HCI journey started in 2017 with the purchase of a VMware vSAN cluster built on Dell Ready Nodes. Whist I’ll be writing about that particular technology here, the principles apply to other HCI infrastructures.



If the problem of HCI could is scaling, the solution is scale. These imbalances in load and growth balance out once a number of VMs are on the system- and this scale doesn’t have to be massive, even from the 4-host starting point of a vSAN cluster I found that when the time came to install node 5, the demands on storage and memory were roughly matched to the relevant capacities of the new node.

The original hosts need to be sized correctly, but unless you’re starting in a totally greenfield environment then you will have existing hosts and storage to interrogate and establish a baseline on current usage requirements. Use these figures, allow appropriate headroom for growth, and then add a bit more (particularly when considering the storage) to prevent the new infrastructure from running near capacity. Remember you are trading a certain level of efficiency for resilience – the cluster needs to be able to withstand at least one host loss and still have plenty of capacity for manoeuvre.

If you are going down the vSAN route, I can thoroughly recommend the ReadyNode option. Knowing that hardware will arrive and just work with the software-defined storage layer without spending hours digging in the Hardware Compatibility Lists was a great time saver, and we’re confident that we can turn round to our vendors and say “this didn’t work” without getting told “it’s because you’ve got disk controller chipset X and that’s not compatible with driver Y on version Z”. There’s a reason I named this blog “IT Should Just Work”.DellEMC vSAN ReadyNode

When expanding the cluster I consider best practice to be to expand with hosts of as similar configuration as possible to the original. If larger nodes are added (for example, storage/memory/CPU is now cheaper/bigger/faster) then these can create a performance imbalance in the cluster. For example a process running on host A might get access to a 2.2GHz CPU, but run the same process on host B with a 3GHz CPU and it will finish slower. Also worth considering is what happens when a host fails, or is taken into maintenance mode for patching. If this host is larger than it’s compatriots then (without very careful planning and capacity management) there might not be sufficient capacity on the remaining hosts to keep the workloads running smoothly.

It is possible in vSAN to add “storage-only” nodes, reducing the memory and possibly going single-socket (this saves on your license cost too!) and then using DRS rules to keep VMs off the host. Likewise “compute-only” nodes are possible, where the host doesn’t contribute any storage to the cluster. Whilst there are probably specific use-cases for both these types of nodes, the vast majority of the time I believe them to be best avoided. Without very careful consideration of workloads and operational practices these could easily land you in hot water.

So, I’m a convert. Two years down the line here and HCI is the on-premises infrastructure I’d recommend to anyone who asks. And those clouds gathering on the horizon? Well, if you migrate to VMware Cloud on AWS then you’re going to be running vSAN HCI there too!

Rubrik Build Workshop

Last week (end of May 2019) I was lucky enough to secure a place at the Rubrik Build Workshop in London. This event, which has been touring round the world, is a day of technical learning focussed on API, SDK, and version control.

Roxie at RubrikThe first thing to acknowledge here is even though Rubrik was hosting the event and the presenters  (the awesome pairing of Chris Wahl and Rebecca Fitzhugh) work for the company there was absolutely no sales push. Whilst they used their own APIs and SDKs as examples the majority of the content was very much platform agnostic. Kudos is due here for running this kind of free-of-charge educational event for the tech community without filling it with sales and marketing slides.

The morning started with a session on version control- looking at how git and in particular GitHub – can be used to track and share code. The “RoxieAtRubrik” GitHub account was used in some hands-on demos -we all forked a public project, made changes,  and submitted a pull request. The course material used in the workshops is publicly available via this account- check here: https://github.com/RoxieAtRubrik

There were some insights into how GitHub is used at Rubrik- there’s unit tests for every single function and in the background they have a CI (Continuous Integration) pipeline at work to make sure releases are up to scratch. Quality control can be tricky on community fed projects where developers may not be subject to traditional corporate control and it’s interesting to see how different teams handle this input.

Our dive into version control was followed by a look at how REST APIs work, using the Rubrik APIs as an example. There was plenty of hands-on activity here, with an online lab provided to simulate communicating with a real world device but in a safe environment.

Rubrik Hands on Lab Environment

The schedule of this event was flexible and after a show of hands amongst the 15 delegates we moved on to look at PowerShell, both in general terms for those new to the scripting language but also seeing how the SDK layer of the Rubrik PowerShell module made the API calls we’d looked at previously more user-friendly.

This PowerShell module is open source and available on GitHub- https://github.com/rubrikinc/rubrik-sdk-for-powershell – and as with all these projects contributions are welcome from the community. There was lots of encouragement from the presenters for customers/users to try these SDKs out and feed back any improvements that could be made, either by submitting an feature request or bug report, or by writing some or all of the addition yourself.

The European leg of the Rubrik Build tour has finished, but they’re off to Australia and New Zealand in June if that’s local to you. Check out https://build.rubrik.com/ for details.

VMworld 2018 Banner

Wear Comfortable Shoes

Ladies and Gentlemen of VMworld 2019.

Wear comfortable shoes.

If I could offer you only one tip for the conference, comfy shoes would be it.
The long term benefits of comfortable shoes have been proved by scientists, whereas the rest of my advice has no basis more reliable than my own meandering experience…
I will dispense this advice now.

Enjoy the knowledge and learning imparted at the breakout sessions; oh nevermind; you will not understand all the knowledge and learning imparted until you watch the recordings.
But trust me, in 20 years you’ll look back at your notes from the event and recall in a way you can’t grasp now how much technology lay before you and how fabulous that UI really looked…
You can’t fit in as many parties as you imagine.

Do one thing everyday that scares you.

Present a session.

Don’t ignore other people’s opinions, don’t put up with people who ignore yours.

Talk to people.

Don’t waste your time on free pens;
Sometimes there’s T-shirts,
Sometimes there’s LEGO.
The swag list is long, and in the end, it’s only what fits in your suitcase home that counts.

Drink plenty of water.

Maybe you’ll do the Hackathon, maybe you won’t, maybe you’ll watch a vBrownbag, maybe you won’t, maybe you’ll get an early night, maybe you’ll dance the funky chicken at the VMworld party.
Whatever you do, don’t worry too much when someone says on-premise.
Enjoy your time at the conference, Use it every way you can… Don’t be afraid of doing new things, or what other people think of them,
Spending time wisely is the greatest investment you’ll ever make…

Use that Early Bird pricing, you’ll miss it when it’s gone.

Be nice to your peers in the vCommunity; They are the best way to learn and the people most likely to stick with you in the future

Stretch.

Go to VMworld US once, but leave before it makes you hard;
Go to VMworld EU once, but leave before it makes you soft.

Accept certain inalienable truths, vBeards will grow and turn grey, vendors will talk FUD, you too will get tired, and when you do you’ll fantasise that when you were younger vChins were clean-shaven, vendors were noble, and the flash client was the best thing since sliced bread.

But trust me on the comfortable shoes…

vRealize Log Insight Upgrade-License warning

For several years vSphere admins have been able to use the Log Insight tool for free as a “25 OSI” license was included in vCenter. This has meant that deployments of up to 24 hosts (plus vCenter) have been able to use the VMware tool as a syslog server and troubleshooting tool without having to purchase further licenses.

Due to changes in licensing this is no longer possible- see KB55980: vRealize Log Insight for vCenter Server – End of Availability (EOA). Version 4.6.x of Log Insight was the last to support this free license. This KB was released summer 2018, but now (spring 2019) it’s becoming particularly relevant because of the release cycle of vCenter.

vCenter 6.7 Update 2 has recently been released, and using the VMware product compatibility matrix you can see that this requires existing Log Insight installations to be upgraded to 4.8 as Log Insight 4.6.x (and therefore the “free” license) is not compatible. So be aware, without proper preparation patching your vCenter can break your established log management environment.

To keep running Log Insight in this environment it will be necessary to now purchase separate licenses from VMware. Talk to your re-seller or VMware account manager about this as there are options for both replacing the OSI licensing model or switching to a per-CPU model which would also enable the product to collect logs from any number of guest VMs on the licensed hosts.

Experiences using Microsoft To-Do

2019-04-11_21-39-55-MicrosoftToDOFor over a year now I’ve been using Microsoft’s To-Do application to manage and organise my tasks. This has probably been the longest I’ve stuck with a personal task manager for some time, and I believe the app has just the right amount of features for me, sitting somewhere between Outlook tasks and a more in-depth project management/ planning application. In this post I will discuss how I use the app; you might find To-Do is something you want to check out, or if you’re a current user you might find new ways to use it.

To-Do is not a heavy duty time management application, but it does allow you to manage personal tasks, set due dates or reminders, and have sub-steps if required. For example the “Deploy new Server” task might have “Buy Server”, “Rack Server”, “Configure Network”, and “Install Hypervisor” as steps.

I use the one application for both work and personal tasks, using lists to categorise these but not having a separate application to go to for my non-work tasks. This helps me balance my time focused on the job against my personal time. I believe Work-life balance isn’t just about not working in personal time. When done properly doing some personal activities in work time is balanced against when you have to work in personal time. For example I might answer the odd work email when sat on the couch in the evening, but I won’t feel guilty about instant messaging my family from the office. Microsoft To-Do has a number of features that will help here, not least “My Day”.

My Day is possibly the best feature in To-Do, and can be used similarly to a Work In Progress (WIP) panel on a Kanban board. Tasks from the different categories can all be assigned here, giving me a list of what I need to accomplish next, rather than being overwhelmed by a much longer list. This also allows me to mix those personal and work related tasks – I need to check my VMware licenses today, but I also need to book an appointment at the optician (who won’t be answering their phone when I get home tonight).

When using My Day I set the sort order to put the tasks flagged as important at the top. These are the things I’ve marked that must get done- further down the list are the lower priority things I’d like to get done today, but might not.

2019-04-11_16-06-47-MicrosoftToDo

When starting up To-Do in the morning it offers me the “For Today” listing, so I can pick the tasks I need in my list at the start of today. These may be items passed over from the day before, one’s I’ve had reminders set for today, or emails I’ve flagged and tweets or websites I picked up the evening before for follow up. With To-Do installed on my Android phone I can quickly share from the other apps, for example Twitter or Chrome to automatically create new tasks for my list.

Looking at how my task-lists have evolved, I have general “Tasks” for work related items and “Personal” for non-work ones. I also have a “Learning and Finding Out” list for all those educational links I want to fit in, and a “Blog” list for blog post ideas.

2019-04-11_16-03-06- MicrosoftToDo

In addition to the general work list I have “Delegated/ Parked with Others” for where I have a task which I’ve subsequently passed onto a colleague but want to check back in on progress- things I don’t want to totally disappear from my radar just because someone else is doing the work. I also have a list here for “Project Ideas”; these are those ideas which aren’t quite a task yet, a list of “wouldn’t it be great if we could do x?” or “should we be looking at implementing y?”.

As To-Do is a single-user viewpoint it’s important that it works well with the other work management tools I’m exposed to- project management, collaboration, and service-desk apps can’t just be ignored. My method here is to take those support calls and project actions and add them to my To-Do list, this way I can manage my own time. It’s important to remember that progress updates and documentation need to be recorded in the correct systems, but the use of To-Do as a simple tick list works well for me here.

As someone who has flipped between task management apps and their paper equivalents I’m impressed that I’ve been using To-Do for so long, so if you’re on the lookout for a personal task manager I’d recommend giving it a try. If this app interests you, Microsoft has more details here: https://products.office.com/en-gb/microsoft-to-do-list-app

To Do List

Other task managers are available