Containers, Clusters & Kubernetes

Brendan BurnsStaff Software Engineer

Motivations

Make writing BigTable a CS 101

Exercise

What is a container?

What is a container?

● Lightweight Linux environment● Hermetically sealed, deployable

application● Introspectable, runnable artifact● Recently popularized by Docker

What is a cluster?

The transition to logical compute

VM

Logical Compute Substrate

Container

Container

Container

Container

Container

Container

Container

Container

Container

VM VM VM VM VM VM VM VMVM

Container

Container

Container

Container

Container

Container

Container

Container

Container

Modular Application Design

VM

Database

Dependencies

WebServer

MiddleWareVM

DatabaseContainer

Dependency

WebServerContainer

Dependency

MiddlewareContainer

Dependency

vs.

Modular Scaling

VMDatabase

Dependencies

WebServerMiddleWare

DatabaseContainer

Dependency

WebServerContainer

Dependency

MiddlewareContainer

Dependency

vs.

VM

Dependencies

WebServerMiddleWare

Database

VM

Dependencies

WebServerMiddleWare

Database

VM VM

MiddlewareContainer

Dependency

WebServerContainer

Dependency

WebServerContainer

Dependency

What is Kubernetes?

● Open source container cluster manager● Inspired by the technology that drives

Google

● Runs anywhere:○ Public Cloud○ Private Cloud○ Bare Metal

● Strong ecosystem○ Partners: Red Hat, VMWare, CoreOS,

Microsoft, ...○ Community: Client libs, integration, ...

The Cloud Dichotomy

IaaS

PaaS

A brief history of programming languages

Assembly

PostScript

Assembly

A brief history of programming languages

Assembly

PostScript

AssemblyObject Oriented Languages

The Cloud Dichotomy

PaaS

IaaS

IaaSCaaS

Components

Kubernetes Pod

Components: Pods

Container-1 Container-2

Shared Volume(s)

Kubernetes Pod

Components: Sidecars

Serving Container

Git Sync Container

Shared Volume

Git Repo

Sidecars Extend and Enhance

Components: Adapters

Kubernetes Pod

Redis Service Redis Adapter

Kubernetes PodMongoDB Service

MongoDB Adapter

Kubernetes PodMySQL Service

MySQL Adapter

Monitoring Service

Adapters Normalize and Abstract

Kubernetes Pod

Components: Ambassadors

Frontend Container

MySQL Ambassador

Write Master

Read Slaves

Container Container Container

Container

localhost

Ambassadors Proxy and Represent

Encapsulation

Abstractions, ftw! : Reliability

{Container, Health Check}

Kubernetes

Container

Web: http://<container>/some/path/to/healthShell: exec /some/path/health.shTCP: open <container> <port>

Abstractions, ftw! : Replication

{Template, Identifier, Num. Replicas}

Replication Controller

Container Container Container Container

Abstractions, ftw! : Services

{IP:Port, Identifier, Name}

DiscoverableService

Container Container Container Container

DNS

Service IPContainer

Patterns

Patterns and Interfaces: Master Election

Container Container Container Container

Cluster Manager

Lock Service

http://<container>/healthz

Patterns and Interfaces: Master Election

Container Container Container Container

Lock Service

Cluster Manager

http://.../master?master=container1

Patterns: Sharded HTTP Service

Container Container Container

Kubernetes Service

http://foo.com/beta http://foo.com/gammahttp://foo.com/alpha

http://foo.com/alphahttp://foo.com/betahttp://foo.com/gamma

Patterns: Hot Sharded HTTP Service

Container Container Container

http://foo.com/alpha http://foo.com/betahttp://foo.com/gamma

http://foo.com/alpha

http://foo.com/alpha @ 20 qpshttp://foo.com/beta @ 5 qpshttp://foo.com/gamma @ 5 qps

Kubernetes Service

http://.../api/get?key=<key>http://.../api/set?key=<k>&val=<v>

Patterns: Bigtable

Container

Kubernetes Service

http://.../manage/shard/<shard>/splithttp://.../manage/shard/<shard>/mergehttp://.../manage/shard/<shard>/loadhttp://.../manage/shard/<shard>/unload

Data Interface

Management Interface

We’re building an os for the datacenter.

Join us!#google-containers on FreeNodehttps://github.com/GoogleCloudPlatform/kuberneteshttps://cloud.google.com/container-engine/

Stop