Tag Archives: Mayflies

Short lived VM (Mayflies) research yields surprising scheduling benefit

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Last semester, Alex Hirschfeld (my son) did a simulation to explore the possible efficiency benefits of the Mayflies concept proposed by Josh McKenty and me.

Mayflies swarming from Wikipedia

In the initial phase of the research, he simulated a data center using load curves designed to oversubscribe the resources (he’s still interesting in actual load data).  This was sufficient to test the theory and find something surprising: mayflies can really improve scheduling.

Alex found an unexpected benefit comes when you force mayflies to have a controlled “die off.”  It allows your scheduler to be much smarter.

Let’s assume that you have a high mayfly ratio (70%), that means every day 10% of your resources would turn over.  If you coordinate the time window and feed that information into your scheduler, then it can make much better load distribution decisions.  Alex’s simulation showed that this approach basically eliminated hot spots and server over-crowding.

Here’s a snippet of his report explaining the effect in his own words:

On a system that is more consistent and does not have a massive virtual machine through put, Mayflies may not help with balancing the systems load, but with the social engineering aspect, it can increase the stability of the system.

Most of the time, the requests for new virtual machines on a cloud are immutable. They came in at a time and need to be fulfilled in the order of their request. Mayflies has the potential to change that. If a request is made, it has the potential to be added to a queue of mayflies that need to be reinitialized. This creates a queue of virtual machine requests that any load balancing algorithm can work with.

Mayflies can make load balancing a system easier. Knowing the exact size of the virtual machine that is going to be added and knowing when it will die makes load balancing for dynamic systems trivial.

My OpenStack Vancouver Session Promotion Dilemma – please, vote outside your block

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We need people to promote their OpenStack Sessions, but how much is too much?

Megaphone!Semi-annually, I choose to be part of the growing dog pile of OpenStack summit submissions.  Looking at the list, I see some truly amazing sessions by committed and smart community members.  There are also a fair share of vendor promotions.

The nature of the crowded OpenStack vendor community is that everyone needs to pick up their social media megaphones (and encourage some internal block voting) to promote their talks.   Consequently, please I need to ask you to consider voting for my list:

  1. DefCore 2015 
  2. The DefCore Show: “is it core or not” feud episode
  3. Mayflies: Improve Cloud Utilization by Forcing Rapid Server Death [Research Analysis] (xref)
  4. It’s all about the Base. If you want stability, start with the underlay [Crowbar] 
  5. State of OpenStack Product Management

Why am I so reluctant to promote these excellent talks?  Because I’m concerned about fanning the “PROMOTE MY TALKS” inferno.

For the community to function, we need for users and operators to be heard.  The challenge is that the twin Conference/Summit venue serves a lot of different audiences.

In my experience, that leads to a lot of contributor navel gazing and vendor-on-vendor celebrations.  That in turn drowns out voices from the critical, but non-block-enabled users and operators.

Yes, please vote those sessions of mine that interest you; however, please take time to vote more broadly too.  The system randomized which talks you see to help distribute voting too.

Thanks.

Research showing that Short Lived Servers (“mayflies”) create efficiency at scale [DATA REQUESTED]

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Last summer, Josh McKenty and I extended the puppies and cattle metaphor to limited life cattle we called “mayflies.” It was an attempt to help drive the cattle mindset (I think of it as social engineering, or maybe PsychOps) by forcing churn. I’ve come to think of it a step in between cattle and chaos monkeys (see Adrian Cockcroft).

While our thoughts were on mainly ops patterns, I’ve heard that there could be a real operational benefit from encouraging this behavior. The increased turn over in the environment improves scheduler optimization, planned load drains and coping with platform/environment migration.

Now we have a chance to quantify this benefit: a college student (disclosure: he’s my son) has created a data center emulation to see if Mayflies help with utilization. His model appears to work.

Now, he needs some real world data, here’s his request for assistance [note: he needs data by 1/20 to be included in this term]:

Hello!

I am Alexander Hirschfeld, a freshman at Rose-Hulman Institute of Technology. I am working on an independent study about Mayflies, a new idea in virtual machine management in cloud computing. Part of this management is load balancing and resource allocation for virtual machines across a collection of servers. The emulation that I am working on needs a realistic set of data to be the most accurate when modeling the results of using the methods outlined by the theory of mayflies.

Mayflies are an extension of the puppies verses cattle approach to machines, they are the extreme version of cattle as they have a known limited lifespan, such as 7 days. This requires the users of the cloud to build inherently more automated and fault-resistant applications. If you could send me a collection of the requests for new virtual machines(per standard unit of time and their requested specs/size), as well as an average lifetime for the virtual machines (or a graph or list of designated/estimated life times), and a basic summary of the collection of servers running the virtual machines(number, ram, cores), I would be better able to understand how Mayflies can affect a cloud.

Thanks,
Alexander Hirschfeld, twitter: @d-qoi

Needless to say, I’m really excited about the progress on demonstrating some the impact of this practice and am looking forward to posting about his results in the near future.

If you post in the comments, I will make sure you are connected to Alex.