Last week on twitter Maish asked a question that got me thinking. Actually, I have been thinking about this for a while now. The question deals with how you design your infrastructure for the various types of workloads (pets and cattle). Whether your workload falls in the “pet” category or the “cattle” category. (If you are not familiar with the terms pets/cattle read this article by Massimo)
Pets vs. cattle – I think that people are mistaken as to what that exactly means for the underlying infrastructure.
— Maish Saidel-Keesing (@maishsk) October 5, 2014
I asked Maish what it actually means for your infrastructure, and at the same time I gave it some more thought over the last week. Cattle is the type of application architecture which handles failures by providing a distributed solution, it scales out instead of up typically, the VMs are disposable as they usually won’t hold state. With pets this is different, they typically scale up and resiliency is often provided by either a 3rd party clustering mechanism or the infrastructure under neath, in many cases contain state and recoverability is key. As you can imagine both types of workloads have different requirements of the infrastructure. Going back to Maish’s question, I guess the real question is if you can afford the “what it means for the underlying infrastructure”. What do I mean with that?
If you look at the requirements of both architectures, you could say that “pets” will typically demand more from the underlying infrastructure when it comes to resiliency / recoverability. Cattle will have less demands from that perspective but flexibility / agility is more important. You can imagine that you could implement two different infrastructure architectures for these specific workloads, but does this make sense? If you are Netflix, Google, Youtube etc then it may make sense to do this due to the scale they operate at and the fact that IT is their core business. In those cases “cattle” is what drives the business, and there are back-end systems. Reality is though that for the majority this is not the case. Your environment will be a hybrid, and more than likely “pets” will have the overhand as that is simply what the state of the world is today.
That does not mean they cannot co-exist. That is what I believe is the true strength of virtualization, it allows you to run many different types of workloads on the same infrastructure. Whether that is your Exchange environment or your in-house developed scale out web application which serves hundreds of thousands of customers does not make a difference to your virtualization platform. From an operational perspective the big benefit here is that you will not have to maintain different run books to manage your workloads. From an ops perspective they will look the same on the outside, although they may differ on the inside. What may change though is the services required for those systems, but with the rich ecosystem available for virtualization platforms these days that should not be a problem. Need extra security / microsegmentation? VMware NSX can provide the security isolation needed to run these applications smoothly. Sub milliseconds latency requirements? Plenty of storage / caching solutions out there that can deliver this!
Will the application architecture shift that is happening right now impact your underlying infrastructure? We have made these huge steps in operational efficiency in the last 5 years, and with SDDC we are about to take the next big step, and although I do believe that the application architecture shift will result in infrastructure changes lets not make the same mistakes we made in the past by creating these infrastructure silos per workload. I strongly believe that repeatability, consistency, reliability and predictability are key and this starts with a solid, scalable and trusted foundation (infrastructure).
When I look at discussions being held around whether server side caching solutions is preferred over an all-flash arrays, which is just another form factor discussion if you ask me, the only right answer that comes to mind is “it depends”. It depends on what your business requirements are, what your budget is, if there are any constraints from an environmental perspective, hardware life cycle, what your staff’s expertise / knowledge is etc etc. It is impossible to to provide a single answer and solution to all the problems out there. What I realized is that what the software-defined movement actually brought us is choice, and in many of these cases the form factor is just a tiny aspect of the total story. It seems to be important though for many people, maybe still an inheritance from the “server hugger” days where hardware was still king? Those times are long gone though if you ask me.