Serverless now integrates with IBM OpenWhisk | Hacker News Reader

Serverless now integrates with IBM OpenWhisk

serverless.com

65 pointsAlaskaCasey10 comments

What I don't get about these things is how can they be performant. If for every action you are loading an entire runtime, executing something, and then throwing the runtime away you are paying the cost of starting the runtime every time. It gets worse the more actions you execute per second.

So then you build a "serverless" thing and then it needs scale at which point you have to rewrite the whole thing as a classic "serverful" application that loads the runtime once, caches stuff, etc. So why not just build it right and with proper discipline the first time?

The runtime is not loaded every time. The runtime is only loaded when the cache is cold. For a typical Node.js Serverless function this "cold start" takes about 3 seconds.

After the function is warmed up it is just as fast as if it was on a dedicated server. Unless it cools off. Which it won't if the function gets regular usage.

As the function becomes more popular it will be loaded onto more servers and the work can be spread across those as well.

"load the whole runtime on each request" is nothing new. That's also how PHP and other cgi technologies worked, where for each request a new process was spawned. There are certainly ways to speed it up (maybe only for a pre-spawned process?) - but I guess for a lot of lambda use-cases performance is simply not an isssue, similar to like it was not an issue in old cgi-based web applications.

Well one misconception is that the code needs to be downloaded into the execution context every time. Which is different than a PHP file being loaded off disk (or opcache as the case is more common in PHP). It's more like if you zipped up your PHP program and every time someone hit a page the zip file was downloaded and extracted onto the server.

However, Lambda takes that one step further. The entire app stays running in memory. No loading or recompiling code. The function is sent instructions via interprocess communication.

So you can take advantage of things that are difficult (though not impossible) to take advantage of in PHP such as connection pooling and shared memory.

If you are reusing the app for multiple function executions, how do you enforce things like isolation between functions and execution limits (processor time, etc.)? I think if 2 functions are running in parallel one can't kill the whole process if the first one exceeds limits, because the other one is still running. And in a runtime like node.js it's not possible to isolate different code pieces reliably from each other. Or is a special runtime and things like V8 isolates utilized?

You cannot do that. Each deployed function corresponds to exactly one entry point in code. You can however pipe multiple HTTP endpoints through the same entry function like a router.

So let's say you do that.

If two clients request the same function at the same time it will run the function in two different containers. One for each client. They are isolated (think multiple instances of Node running in multiple Docker containers). They might as well be on different machines entirely.

The platform will not reuse the same container unless the previous request to that container has finished.

These headlines sound like a chatbot having a stroke. I don't know what any of these words mean apart or together.

Awesome! Glad they stuck to their word and added platform agnosticism. Excited to give it a try.

One question: why?

Serverless (in this context) is a framework for running functions on the cloud. The more platforms teh framework supports the more choices the developer has. Which is a win-win.

If you ask why Serverless in general... scaling to millions of users for barely more expensive than running servers with little to no devops cost. At less users it is significantly cheaper. A low-traffic Serverless app could cost pennies a month and you have the full power of your favorite language at your disposal. (assuming your favorite language is Javascript, Java, or Python)

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