156 lines
4.1 KiB
Markdown
156 lines
4.1 KiB
Markdown
Fission: Serverless Functions for Kubernetes
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============================================
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Fission is a fast serverless framework for Kubernetes with a focus on
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developer productivity and high performance.
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Fission operates on _just code_: Docker and Kubernetes are abstracted
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away.
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Fission is extensible to any language. It currently supports NodeJS
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and Python, with more languages coming soon.
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100msec cold start
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------------------
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Fission maintains a pool of "warm" containers that each contain a
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small dynamic loader. When a function is first called,
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i.e. "cold-started", a running container is chosen and the function is
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loaded. This pool is what makes Fission fast: cold-start latencies
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are typically about 100msec.
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Kubernetes is the right place for Serverless
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--------------------------------------------
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We're built on Kubernetes because we think any non-trivial app will
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use a combination of serverless functions and more conventional
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microservices, and Kubernetes is a great framework to bring these
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together seamlessly.
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Fission Concepts
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================
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A _function_ is a piece of code with an entry point.
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An _environment_ is a container with a webserver and dynamic loader
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for functions. Today, Fission comes with NodeJS and Python
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environments. You can also add your own: for example, if you want to
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add a binary to your Python image, you can edit the Python
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environment's Dockerfile, rebuild it, and add your new environment to
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Fission.
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A _trigger_ is something that maps an event to a function; Fission
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supports HTTP triggers today, with upcoming support for other types of
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event triggers.
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Running Fission on your Cluster
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===============================
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### Setup Kubernetes
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You can install Kubernetes on your laptop with minikube: https://github.com/kubernetes/minikube
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Or, you can use Google Container Engine's free trial to get a 3 node cluster.
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### Verify access to the cluster
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```
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$ kubectl version
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```
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### Get and Run Fission
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If you're using GKE, use the fission.yaml unmodified. If you're using
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minikube, change all instances of LoadBalancer services to NodePort.
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```
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$ curl http://fission.io/fission.yaml | kubectl create -f -
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$ kubectl --namespace fission get services
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```
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Save the external IP addresses of controller and router services in
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FISSION_URL and FISSION_ROUTER, respectively. FISSION_URL is used by
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the fission CLI to find the server. (FISSION_ROUTER is only needed
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for the examples below to work.)
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### Install the client CLI
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```
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$ curl http://fission.io/fission > fission
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$ chmod +x fission
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$ sudo mv fission /usr/local/bin/
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```
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### Run an example
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```
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$ fission env create --name nodejs --image fission/node-env
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$ echo 'module.exports = function(context, callback) { callback(200, "Hello, world!\n"); }' > hello.js
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$ fission function create --name hello --env nodejs --code hello.js
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$ fission route create --method GET --url /hello --function hello
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$ curl http://$FISSION_ROUTER/hello
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Hello, world!
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```
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Compiling Fission
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=================
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[You only need to do this if you're making Fission changes; if you're
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just deploying Fission, use fission.yaml which points to prebuilt
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images.]
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You'll need go installed, along with the glide dependecy management
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tool. You'll also need docker for building images.
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The server side is compiled as one binary ("fission-bundle") which
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contains controller, poolmgr and router; it invokes the right one
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based on command-line arguments.
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To build fission-bundle: clone this repo, then from the top level
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directory:
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```
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# Get dependencies
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$ glide install
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# Build fission server and an image
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$ pushd fission-bundle
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$ ./build.sh
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# Edit push.sh to point to your registry
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$ $EDITOR push.sh
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$ ./push.sh
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$ popd
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# To install, update fission.yaml to point to your compiled image
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$ $EDITOR fission.yaml
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$ kubectl create -f fission.yaml
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```
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If you're changing the CLI:
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```
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# Build Fission CLI
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$ cd fission-cli && go install
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```
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Status
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======
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Fission is in early alpha. Don't use it in production just yet.
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We're looking for developer feedback -- tell us which languages you
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care about, what use cases you might use it for, and so on.
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