Fission: Serverless Functions for Kubernetes

Fission is a fast serverless framework for Kubernetes with a focus on developer productivity and high performance.

Fission operates on just the code: Docker and Kubernetes are abstracted away under normal operation, though you can use both to extend Fission if you want to.

Fission is extensible to any language; the core is written in Go, and language-specific parts are isolated in something called environments (more below). Fission currently supports NodeJS and Python, with more languages coming soon.

Performance: 100msec cold start

Fission maintains a pool of "warm" containers that each contain a small dynamic loader. When a function is first called, i.e. "cold-started", a running container is chosen and the function is loaded. This pool is what makes Fission fast: cold-start latencies are typically about 100msec.

Kubernetes is the right place for Serverless

We're built on Kubernetes because we think any non-trivial app will use a combination of serverless functions and more conventional microservices, and Kubernetes is a great framework to bring these together seamlessly.

Building on Kubernetes also means that anything you do for operations on your Kubernetes cluster — such as monitoring or log aggregation — also helps with ops on your Fission deployment.

Fission Concepts

A function is a piece of code that follows the fission function interface.

An environment contains the language- and runtime-specific parts of running a function. Fission comes with NodeJS and Python environments; you can also extend environments or create entirely new ones if you want. (An environment is essentially just a container with a webserver and dynamic loader.)

A trigger is something that maps an event to a function; Fission supports HTTP routes as triggers today, with upcoming support for other types of event triggers, such as timers and Kubernetes events.

Usage

  # Add the stock NodeJS env to your Fission deployment
  $ fission env create --name nodejs --image fission/node-env

  # A javascript one-liner that prints "hello world"
  $ curl https://raw.githubusercontent.com/fission/fission/master/examples/nodejs/hello.js > hello.js

  # Upload your function code to fission
  $ fission function create --name hello --env nodejs --code hello.js

  # Map GET /hello to your new function
  $ fission route create --method GET --url /hello --function hello

  # Run the function.  This takes about 100msec the first time.
  $ curl http://$FISSION_ROUTER/hello
  Hello, world!

See the examples directory for more.

Running Fission on your Cluster

Setup Kubernetes

You can install Kubernetes on your laptop with minikube:

Install and start Kubernetes on OSX:

  $ curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/darwin/amd64/kubectl && chmod +x kubectl && sudo mv kubectl /usr/local/bin
  $ curl -Lo minikube https://storage.googleapis.com/minikube/releases/v0.16.0/minikube-darwin-amd64 && chmod +x minikube && sudo mv minikube /usr/local/bin/
  $ minikube start

Or, install and start Kubernetes on Linux:

  $ curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl && chmod +x kubectl && sudo mv kubectl /usr/local/bin
  $ curl -Lo minikube https://storage.googleapis.com/minikube/releases/v0.16.0/minikube-linux-amd64 && chmod +x minikube && sudo mv minikube /usr/local/bin/
  $ minikube start

Or, you can use Google Container Engine's free trial to get a 3 node cluster.

Verify access to the cluster

  $ kubectl version

Get and Run Fission: Minikube or Local cluster

If you're using minikube or no cloud provider, use these commands to set up services with NodePort. This exposes fission on ports 31313 and 31314.

  $ kubectl create -f http://fission.io/fission.yaml
  $ kubectl create -f http://fission.io/fission-nodeport.yaml

Set the FISSION_URL and FISSION_ROUTER environment variables. FISSION_URL is used by the fission CLI to find the server. FISSION_URL should be prefixed with a http://. (FISSION_ROUTER is only needed for the examples below to work.)

If you're using minikube, use these commands:

  $ export FISSION_URL=http://$(minikube ip):31313
  $ export FISSION_ROUTER=$(minikube ip):31314

Get and Run Fission: GKE or other Cloud

If you're using GKE or any other cloud provider that supports the LoadBalancer service type, use these commands:

  $ kubectl create -f http://fission.io/fission.yaml
  $ kubectl create -f http://fission.io/fission-cloud.yaml

Save the external IP addresses of controller and router services in FISSION_URL and FISSION_ROUTER, respectively. Wait for services to get IP addresses (check this with kubectl --namespace fission get svc). Then:

  $ export FISSION_URL=http://$(kubectl --namespace fission get svc controller -o=jsonpath='{..ip}')
  $ export FISSION_ROUTER=$(kubectl --namespace fission get svc router -o=jsonpath='{..ip}')

Install the client CLI

Get the CLI binary for Mac:

  $ curl http://fission.io/mac/fission > fission && chmod +x fission && sudo mv fission /usr/local/bin/

Or Linux:

  $ curl http://fission.io/linux/fission > fission && chmod +x fission && sudo mv fission /usr/local/bin/

Run an example

Finally, you're ready to use Fission!

  $ fission env create --name nodejs --image fission/node-env

  $ curl https://raw.githubusercontent.com/fission/fission/master/examples/nodejs/hello.js > hello.js

  $ fission function create --name hello --env nodejs --code hello.js
  
  $ fission route create --method GET --url /hello --function hello
  
  $ curl http://$FISSION_ROUTER/hello
  Hello, world!

You can also set up persistence for logs: instructions here.

Compiling Fission

[You only need to do this if you're making Fission changes; if you're just deploying Fission, use fission.yaml which points to prebuilt images.]

You'll need go installed, along with the glide dependency management tool. You'll also need docker for building images.

The server side is compiled as one binary ("fission-bundle") which contains controller, poolmgr and router; it invokes the right one based on command-line arguments.

To build fission-bundle: clone this repo to $GOPATH/src/github.com/fission/fission, then from the top level directory (if you want to build the image with the docker inside minikube, you'll need to set the proper environment variables with eval $(minikube docker-env)):

  # Get dependencies
  $ glide install

  # Build fission server and an image
  $ pushd fission-bundle
  $ ./build.sh

  # Edit push.sh to point to your registry, or comment out the `docker push`
  # line if building into your local minikube for dev purposes
  $ $EDITOR push.sh
  $ ./push.sh
  $ popd

  # To install, update fission.yaml to point to your compiled image
  $ $EDITOR fission.yaml
  $ kubectl create -f fission.yaml

If you're changing the CLI:

  # Build Fission CLI
  $ cd fission && go install

Status

Fission is in early alpha. It's not suitable for production use just yet.

We're looking for early developer feedback -- if you do use Fission, we'd love to hear how it's working for you, what parts in particular you'd like to see improved, and so on. Talk to us on slack or twitter.

ktrance/fission