README
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Scalable Microservices with Kubernetes
The code for this talk is from Udacity's Scalable Microservices with Kubernetes. In this talk you will learn how to:
- Provision a complete Kubernetes using Google Container Engine
- Deploy and manage Docker containers using kubectl
All of the code for this course was written by Kelsey Hightower.
Kubernetes Version: 1.2.2
Go Version: 1.6+
Description
In the last decade, user demand for always on applications have grown, exponentially. Many developers choose application patterns (like microservices) to meet this need -- but what about the infrastructure needed to support these ever growing demands?
In this talk, you will be introduced to the next level of automation using hands on examples of industry standard tooling like Docker, a container format, and Kubernetes, a distributed automation platform. We'll cover the basics of modern day applications and how design patterns like microservices drive the need for more robust infrastructure. Then we’ll cover packaging and distributing apps using Docker. Finally, we’ll up our game to running applications on Kubernetes. By the end of this talk you'll have the knowledge to clearn the three major hurdles to writing scalable applications in this always on digital age.
I'll be utilizing the Kubernetes API to deploy, manage, and upgrade applications using an example 12-factor application called "app". During this talk you will see live demos of working with the following Docker images:
- askcarter/monolith - Monolith includes auth and hello services.
- askcarter/auth - Auth microservice. Generates JWT tokens for authenticated users.
- askcarter/hello - Hello microservice. Greets authenticated users.
- ngnix - Frontend to the auth and hello services.
Links
Demos
I've listed all of the steps from every demo during the talk so that you can run them yourself. In the demo, I'll be doing everything in cloud shell. And using Go version 1.6. If you don't have version 1.6, install it.
The First Hurdle: The App
The first hurdle to getting online is the application itself. How do you write it? How do you deploy it?
First off let's set up the code and the go build environment
$ GOPATH=~/go
$ mkdir -p $GOPATH/src/github.com/askcarter
$ cd $GOPATH/src/github.com/askcarter
$ git clone https://github.com/askcarter/io16
Now let's build the app as a static binary and test it's functionality.
cd app/monolith
go build -tags netgo -ldflags "-extldflags '-lm -lstdc++ -static'" .
./monolith --http :10180 --health :10181 &
curl http://127.0.0.1:10180
curl http://127.0.0.1:10180/secure
TOKEN=$(curl http://127.0.0.1:10180/login -u user | jq -r '.token')
curl -H "Authorization: Bearer $TOKEN" http://127.0.0.1:10180/secure
Once we have a binary, we can use Docker to package and distribute it.
cat Dockerfile
docker build -t askcarter/monolith:1.0.0 .
docker push askcarter/monolith:1.0.0
docker run -d askcarter/monolith:1.0.0
docker ps
docker inspect <cid>
curl http://<docker-ip>
docker rm <cid>
docker rmi askcarter/monolith:1.0.0
The Second Hurdle: The Infra
The next hurdle is the infrastructure needed to run manage in production. We'll use Kubernetes (and GKE) to handle that for us.
cd ../../kubernetes
gcloud container clusters create io --num-nodes=6
kubectl run monolith --image askcarter/monolith:1.0.0
kubectl expose deployment monolith --port 80 --type LoadBalancer
kubectl scale deployment monolith --replicas 3
kubectl get service monolith
curl http://<External-IP>
kubectl delete services monolith
kubectl delete deployment monolith
Let's set up services and deployments for our microservices
kubectl create -f services/auth.yaml -f deployments/auth.yaml
kubectl create -f services/hello.yaml -f deployments/hello.yaml
kubectl create configmap nginx-frontend-conf --from-file nginx/frontend.conf
kubectl create secret generic tls-certs --from-file tls/
kubectl create -f services/frontend.yaml -f deployments/frontend.yaml
kubectl get services frontend
curl -k https://<External-IP>
The Third Hurdle: The Wild
The last hurdle is the The Wild. How do we handle rolling out updates to our code?
while true; do curl <IP>; sleep .3; done
sed -i s/hello:1.0.0/hello:2.0.0/g deployments/hello.yaml
kubectl apply -f deployments/hello.yaml
kubectl describe deployments hello
Cleanup
$ gcloud container clusters delete io
Directories