Kubernetes is a cluster manager that schedules Docker containers across a cluster using pods. Pods are sets of Docker containers that are guaranteed to run on the same host. Replication controllers ensure that the desired number of pods for an application are running. Services provide a single IP address to load balance traffic to backend pods. Google Container Engine provides a hosted Kubernetes service. YAML files can be used to define replication controllers and services to deploy and expose applications on Kubernetes.

1. Kubernetes and Docker
Eric Oestrich

2. Docker
Idempotent builds
Images are portable
Containers should run a single application

3. Dockerfile
FROM ruby:2.2
MAINTAINER Eric Oestrich
ADD . /app
WORKDIR /app
RUN bundle install
CMD ["rails", "server"]

4. Kubernetes
Cluster manager
Schedules Docker containers

5. Pods
Set of docker containers that are guaranteed
to run on a host

6. Replication Controllers
Schedules pods to run
Set an amount of pods to run

7. Services
Load balancer
Single IP address to talk to backend pods

8. Google Container Engine
Hosted Kubernetes

9. Creating a Replication Controller
apiVersion: v1
kind: ReplicationController
metadata:
name: app
labels:
name: app

10. Creating a Replication Controller
spec:
replicas: 3
selector:
name: app
template:
metadata:
labels:
name: app

11. Creating a Replication Controller
spec:
template:
spec:
containers:
- name: rails
image: smartlogic/rails
imagePullPolicy: Always
ports:
- containerPort: 5000

12. Creating a Service
apiVersion: v1
kind: Service
metadata:
name: rails-app
labels:
name: rails-app
spec:
ports:
- port: 5000
selector:
name: rails-app

13. Viewing Pods (and RC and Services)
kubectl get pods
kubectl get replicationcontrollers
kubectl get services

14. Questions?