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https://github.com/dockersamples/example-voting-app.git
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bdac94dee9
Clarify architecture not a repr of proper arch, since lots of viewers are likely to be new to the world of containerized apps
101 lines
3.7 KiB
Markdown
101 lines
3.7 KiB
Markdown
Example Voting App
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=========
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A simple distributed application running across multiple Docker containers.
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Getting started
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---------------
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Download [Docker Desktop](https://www.docker.com/products/docker-desktop) for Mac or Windows. [Docker Compose](https://docs.docker.com/compose) will be automatically installed. On Linux, make sure you have the latest version of [Compose](https://docs.docker.com/compose/install/).
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## Linux Containers
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The Linux stack uses Python, Node.js, .NET Core (or optionally Java), with Redis for messaging and Postgres for storage.
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> If you're using [Docker Desktop on Windows](https://store.docker.com/editions/community/docker-ce-desktop-windows), you can run the Linux version by [switching to Linux containers](https://docs.docker.com/docker-for-windows/#switch-between-windows-and-linux-containers), or run the Windows containers version.
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Run in this directory:
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```
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docker-compose up
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```
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The app will be running at [http://localhost:5000](http://localhost:5000), and the results will be at [http://localhost:5001](http://localhost:5001).
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Alternately, if you want to run it on a [Docker Swarm](https://docs.docker.com/engine/swarm/), first make sure you have a swarm. If you don't, run:
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```
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docker swarm init
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```
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Once you have your swarm, in this directory run:
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```
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docker stack deploy --compose-file docker-stack.yml vote
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```
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## Windows Containers
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An alternative version of the app uses Windows containers based on Nano Server. This stack runs on .NET Core, using [NATS](https://nats.io) for messaging and [TiDB](https://github.com/pingcap/tidb) for storage.
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You can build from source using:
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```
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docker-compose -f docker-compose-windows.yml build
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```
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Then run the app using:
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```
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docker-compose -f docker-compose-windows.yml up -d
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```
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> Or in a Windows swarm, run `docker stack deploy -c docker-stack-windows.yml vote`
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The app will be running at [http://localhost:5000](http://localhost:5000), and the results will be at [http://localhost:5001](http://localhost:5001).
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Run the app in Kubernetes
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-------------------------
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The folder k8s-specifications contains the yaml specifications of the Voting App's services.
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First create the vote namespace
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```
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$ kubectl create namespace vote
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```
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Run the following command to create the deployments and services objects:
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```
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$ kubectl create -f k8s-specifications/
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deployment "db" created
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service "db" created
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deployment "redis" created
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service "redis" created
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deployment "result" created
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service "result" created
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deployment "vote" created
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service "vote" created
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deployment "worker" created
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```
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The vote interface is then available on port 31000 on each host of the cluster, the result one is available on port 31001.
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Architecture
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-----
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* A front-end web app in [Python](/vote) or [ASP.NET Core](/vote/dotnet) which lets you vote between two options
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* A [Redis](https://hub.docker.com/_/redis/) or [NATS](https://hub.docker.com/_/nats/) queue which collects new votes
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* A [.NET Core](/worker/src/Worker), [Java](/worker/src/main) or [.NET Core 2.1](/worker/dotnet) worker which consumes votes and stores them in…
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* A [Postgres](https://hub.docker.com/_/postgres/) or [TiDB](https://hub.docker.com/r/dockersamples/tidb/tags/) database backed by a Docker volume
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* A [Node.js](/result) or [ASP.NET Core SignalR](/result/dotnet) webapp which shows the results of the voting in real time
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Notes
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-----
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The voting application only accepts one vote per client. It does not register votes if a vote has already been submitted from a client.
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This isn't an example of a properly architected perfectly designed distributed app... it's just a simple
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example of the various types of pieces and languages you might see (queues, persistent data, etc), and how to
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deal with them in Docker at a basic level.
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