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Interns with toasters: how I taught people about load balancers

rachelbythebay.com

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Re: Interns with toasters: how I taught people about load balancers

#11

Post by BillinghamJ »

I don't really see how this is an issue engineers need to be particularly wary of?

Firstly, your typical load balancer doesn't work this way anyway. It will just keep feeding requests to the application hosts on a round robin or random basis. Most don't keep track of how busy each instance is.

Secondly, any decent (HTTP/layer 7) load balancer will notice if an instance is returning exclusively 5xx errors and will stop routing requests to it. Would fail even the most basic of health checks.

Re: Interns with toasters: how I taught people about load balancers

#12

Post by BillinghamJ »

rajacombinator wrote: post #8
scopecreep wrote: post #7

I feel like if you have to teach them about load balancers as college interns, FB needs to find a better school to pull interns from.

What kind of college teaches about load balancers?

If they’re not teaching about the most basic principles of building scalable systems, what is the point of doing a degree, or hiring people who have done a degree?

Re: Interns with toasters: how I taught people about load balancers

#13

Post by xorcist »

amingilani wrote: post #2

Who is Rachel and how do her short and simple stories always hit the front-page? They're interesting but I always think they're a little _too_ simple. I mean this entire thing can be summed up with: 500s (and other errors) are returned faster than processed requests. Load-balancers will find a misbehaving server's queue empty more often and give it all the requests

Light hearted introductions to work related stuff you might encounter is always a crowd pleaser. It makes for great lightning talk ideas too.

However, it might be prudent to point out that these things will feature in the first chapter of any book on load balancing, as an example of the pros and cons of different load balancing methods: least connections, least load, round robin etc.

(Sometimes I suspect picking up a book is becoming a lost art in this day of devops and breaking things fast. Learning from mistakes is all well and good, but there are other ways too.)

Re: Interns with toasters: how I taught people about load balancers

#14

Post by captn3m0 »

BillinghamJ wrote: post #11

I don't really see how this is an issue engineers need to be particularly wary of? Firstly, your typical load balancer doesn't work this way anyway. It will just keep feeding requests to the application hosts on a round robin or random basis. Most don't keep track of how busy each instance is. Secondly, any decent (HTTP/layer 7) load balancer will notice if an instance is returning exclusively 5xx errors and will sto…

AWS ELBs work this way. They offer more requests to clients with the shortest backlog

Re: Interns with toasters: how I taught people about load balancers

#15

Post by feiofh398r39rty »

amingilani wrote: post #2

Who is Rachel and how do her short and simple stories always hit the front-page? They're interesting but I always think they're a little _too_ simple. I mean this entire thing can be summed up with: 500s (and other errors) are returned faster than processed requests. Load-balancers will find a misbehaving server's queue empty more often and give it all the requests

It's really low value compared to the most of the rest of the front page stuff. Interesting in a way but there is a lot of interesting stuff around that does not hug the front page.

Re: Interns with toasters: how I taught people about load balancers

#16

Post by jlgaddis »

scopecreep wrote: post #7

I feel like if you have to teach them about load balancers as college interns, FB needs to find a better school to pull interns from.

Where else might they learn about load balancers? I doubt there are many high schools teaching these concepts.

Re: Interns with toasters: how I taught people about load balancers

#17

Post by dsr_ »

BillinghamJ wrote: post #12
rajacombinator wrote: post #8

Earlier quoted context omitted.

What kind of college teaches about load balancers?

If they’re not teaching about the most basic principles of building scalable systems, what is the point of doing a degree, or hiring people who have done a degree?

In the mid-1990s, a respectable CS program would certainly have all of its graduates familiar with TCP/IP. They would know a little about routing and have built a few toy programs that implemented socket-based communication. Hot topics included "firewalls" and the race to build a gigabit-speed router. (But packet filtering at gigabit speed was quite a ways off in the future.)

The point of a technology degree had better be to teach you how to learn about new technology and experiment with it, or else a 2014 degree will be worthless in 2034.

Re: Interns with toasters: how I taught people about load balancers

#18

Post by banachtarski »

amingilani wrote: post #2

Who is Rachel and how do her short and simple stories always hit the front-page? They're interesting but I always think they're a little _too_ simple. I mean this entire thing can be summed up with: 500s (and other errors) are returned faster than processed requests. Load-balancers will find a misbehaving server's queue empty more often and give it all the requests

My first encounter was the "yak shaving" article that had a bunch of inaccuracies and it was pretty offputting. If that article was any reflection on the general sophistication I wouldn't really want to read any more. It felt like I was reading something out of the 90s.

Re: Interns with toasters: how I taught people about load balancers

#19

Post by r0fls »

captn3m0 wrote: post #14
BillinghamJ wrote: post #11

I don't really see how this is an issue engineers need to be particularly wary of? Firstly, your typical load balancer doesn't work this way anyway. It will just keep feeding requests to the application hosts on a round robin or random basis. Most don't keep track of how busy each instance is. Secondly, any decent (HTTP/layer 7) load balancer will notice if an instance is returning exclusively 5xx errors and will sto…

AWS ELBs work this way. They offer more requests to clients with the shortest backlog

You can configure health checks for ELBs: https://docs.aws.amazon.com/elasticloadbalancing/latest/clas...

Re: Interns with toasters: how I taught people about load balancers

#20

Post by krab »

amingilani wrote: post #2

Who is Rachel and how do her short and simple stories always hit the front-page? They're interesting but I always think they're a little _too_ simple. I mean this entire thing can be summed up with: 500s (and other errors) are returned faster than processed requests. Load-balancers will find a misbehaving server's queue empty more often and give it all the requests

As I read it, this piece wasn't that much about load balancers but rather about teaching.

She experienced trouble explaining a problem in a way the students would understand, so she came up with a better method.

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