1258baeb7f
* fn: agent eviction revisited
Previously, the hot-container eviction logic used
number of waiters of cpu/mem resources to decide to
evict a container. An ejection ticker used to wake up
its associated container every 1 sec to reasses system
load based on waiter count. However, this does not work
for non-blocking agent since there are no waiters for
non-blocking mode.
Background on blocking versus non-blocking agent:
*) Blocking agent holds a request until the
the request is serviced or client times out. It assumes
the request can be eventually serviced when idle
containers eject themselves or busy containers finish
their work.
*) Non-blocking mode tries to limit this wait time.
However non-blocking agent has never been truly
non-blocking. This simply means that we only
make a request wait if we take some action in
the system. Non-blocking agents are configured with
a much higher hot poll frequency to make the system
more responsive as well as to handle cases where an
too-busy event is missed by the request. This is because
the communication between hot-launcher and waiting
requests are not 1-1 and lossy if another request
arrives for the same slot queue and receives a
too-busy response before the original request.
Introducing an evictor where each hot container can
register itself, if it is idle for more than 1 seconds.
Upon registry, these idle containers become eligible
for eviction.
In hot container launcher, in non-blocking mode,
before we attempt to emit a too-busy response, now
we attempt an evict. If this is successful, then
we wait some more. This could result in requests
waiting for more than they used to only if a
container was evicted. For blocking-mode, the
hot launcher uses hot-poll period to assess if
a request has waited for too long, then eviction
is triggered.
Quickstart | Tutorials | Docs | API | Operating | Flow | UI
Welcome
Fn is an event-driven, open source, Functions-as-a-Service (FaaS) compute platform that you can run anywhere. Some of its key features:
- Open Source
- Native Docker: use any Docker container as your Function
- Supports all languages
- Run anywhere
- Public, private and hybrid cloud
- Import Lambda functions and run them anywhere
- Easy to use for developers
- Easy to manage for operators
- Written in Go
- Simple yet powerful extensibility
The fastest way to experience Fn is to follow the quickstart below, or you can jump right to our full documentation, API Docs, or hit us up in our Slack Community!
Quickstart
Pre-requisites
- Docker 17.10.0-ce or later installed and running
- A Docker Hub account (Docker Hub) (or other Docker-compliant registry)
- Log Docker into your Docker Hub account:
docker login
Install CLI tool
The command line tool isn't required, but it sure makes things a lot easier. There are a few options to install it:
1. Homebrew - macOS
If you're on a Mac and use Homebrew, this one is for you:
brew install fn
2. Shell script - Linux and macOS
This one works on Linux and macOS (partially on Windows).
If you are running behind a proxy first set your http_proxy and https_proxy environmental variables:
curl -LSs https://raw.githubusercontent.com/fnproject/cli/master/install | sh
This will download a shell script and execute it. If the script asks for a password, that is because it invokes sudo.
3. Download the bin - Linux, macOS and Windows
Head over to our releases and download it.
Run Fn Server
Now fire up an Fn server:
fn start
This will start Fn in single server mode, using an embedded database and message queue. You can find all the configuration options here. If you are on Windows, check here. If you are on a Linux system where the SELinux security policy is set to "Enforcing", such as Oracle Linux 7, check here.
Your First Function
Functions are small but powerful blocks of code that generally do one simple thing. Forget about monoliths when using functions, just focus on the task that you want the function to perform. Our CLI tool will help you get started super quickly.
Create hello world function:
fn init --runtime go hello
This will create a simple function in the directory hello, so let's cd into it:
cd hello
Feel free to check out the files it created or just keep going and look at it later.
# Set your Docker Hub username
export FN_REGISTRY=<DOCKERHUB_USERNAME>
# Run your function locally
fn run
# Deploy your functions to your local Fn server
fn deploy --app myapp --local
Now you can call your function:
curl http://localhost:8080/r/myapp/hello
# or:
fn call myapp /hello
Or in a browser: http://localhost:8080/r/myapp/hello
That's it! You just deployed your first function and called it. Try updating the function code in func.go then deploy it again to see the change.
Learn More
- With our Fn Getting Started Series, quickly create Fn Hello World applications in multiple languages. This is a great Fn place to start!
- Visit Fn tutorials for step by step guides to creating apps with Fn . These tutorials range from introductory to more advanced.
- See our full documentation
- View all of our examples
- View our YouTube Channel
- View our API Docs
- Check out our sub-projects: Flow, UI, FnLB
- For a full presentation with lots of content you can use in your own presentations, see The Fn Project Presentation Master
Get Help
- Ask your question on StackOverflow and tag it with
fn - Join our Slack Community
Get Involved
- Join our Slack Community
- Learn how to contribute
- See issues for issues you can help with
- Join us at one of our Fn Events or even speak at one!