microservices - jug saxony day · microservices chaos kontrolle mit kubernetes robert kubis -...

MicroservicesChaos Kontrolle mit Kubernetes

Robert Kubis - Developer Advocate, Google@hostirosti

2@hostirosti #kubernetesio #googlecloud #jsd2015

Robert KubisDeveloper AdvocateGoogle Cloud PlatformLondon, UK

hostirosti github.com/hostirosti

About me

Agenda

Motivation (Microservices)

Container Overview

Cluster Management & Kubernetes

Demo

1

2

3

4

Google Cloud Platform 4

Microservices


A B

C D

Decomposing Monolithic apps


A B

CD



Curated runtimes Rich services Auto-everything … just add code

Platform

Basic atom Run anything Self-managed

VM

More agility

More Flexibility

build and deploy appsbuild and deploy vm images

Where should I run my microservices?


Curated runtimes Rich services Auto-everything … just add code

● Managed collections● Declarative + Dynamic

PlatformCluster

Basic atom Run anything Self managed

VM

More agility

More Flexibility

build and deploy containers build and deploy appsbuild and deploy vm images

Where should I run my microservices?


What is a container?

Containers Overview


No isolation

No namespacing

Common libs

Highly coupled apps and OS

Old Way: Shared Machines

kernel

libs

app

app app

app


Some isolation

Inefficient

Still highly coupled to the guest OS

Hard to manage

Old Way: Virtual Machines

app

libskernel

libs

app app

kernel

app

libs

libskernel

kernel


New Way: Containers

libs

app

kernel

libs

app

libs

app

libs

app


Concrete Docker Example - Images● An image is a stack of Read-Only file

system layers.

● Usual process:○ build○ push to repository○ pull to execution host○ start container from image

Debian

App

JRE

Libs


Concrete Docker Example - Images

Read / Write Read / Write

Debian

App

JRE

Libs

Read / Write● A container is a process

○ started with kernel restrictions○ a stack of shared Read-Only file

system layers○ plus a process specific Read-

Write layer● Every new container gets a new

Read-Write later. All containers from the same image start from exactly the same state!


Debian

App

PHP & Apache

Libs

Read / Write

host dir

● It's possible to mount host directories into a container's filesystem.

● These are mutable and do outlive the container.

● They're only available on that host.

Mounting Host Directories


Concrete Docker Example

Server

Debian

Docker Engine

Service BService A

libs

libs

libslibs

App

PHP & Apache

19@hostirosti #kubernetesio #jsd2015

Why containers?

Performance

Images by Connie Zhou


Why containers?

Performance

Repeatability



Why containers?

Performance

Repeatability

Quality of service



Why containers?

Performance

Repeatability

Quality of service

Accounting



Why containers?

Performance

Repeatability

Quality of service

Accounting

Portability



Why containers?

Performance

Repeatability

Quality of service

Accounting

Portability

A fundamentally different way of managing applications



containers are awesomelet's use lots of them!


Cluster Management and Kubernetes


Everything at Google runs in containers:Gmail, Web Search, Maps, ...

MapReduce, batch, ...

GFS, Colossus, ...

Even Google Compute Engine: VMs in containers!

28Image by Connie

Zhou


job hello_world = {

runtime = { cell = 'ic' } // Cell (cluster) to run in

binary = '.../hello_world_webserver' // Program to run

args = { port = '%port%' } // Command line parameters

requirements = { // Resource requirements

ram = 100M

disk = 100M

cpu = 0.1

}

replicas = 5 // Number of tasks

}

10000

Developer View


Developer View


web browsers

BorgMaster

link shard

UI shardBorgMaster

link shard

UI shardBorgMaster

link shard

UI shardBorgMaster

link shard

UI shard

Scheduler

borgcfg web browsers

scheduler

Borglet Borglet Borglet Borglet

Config file

BorgMaster

link shard

UI shard

persistent store (Paxos)

Binary

What justhappened?

32

Hello world!

Hello world!

Hello world!

Hello world!Hello

world! Hello world! Hello

world!

Hello world!

Hello world!

Hello world!

Hello world!

Hello world!

Hello world!

Hello world!

Hello world!

Hello world!

Hello world!Hello world!

Hello world!

Hello world!

Hello world!

Hello world!

Hello world! Hello

world!

Hello world!

Hello world!

Hello world!

Image by Connie Zhou

Hello world!

Hello world!

Hello world! Hello

world!

Hello world! Hello

world!

Hello world!

Hello world!

Hello world!

Hello world!

Hello world! Hello

world!

Hello world! Hello

world!

Hello world!

Hello world!

Hello world!

Hello world!

Hello world! Hello

world!

Hello world! Hello

world!

Hello world!

Hello world!

http://goo.gl/1C4nuo (Borg paper)https://youtu.be/elHbkoJOBNE?t=4426


Greek for “Helmsman”; also the root of the word “Governor”

Container orchestrator Runs Docker containers Supports different cloud and bare-metal

environments Inspired and informed by Google’s experiences

and internal systems Open source, written in Go

Manage applications, not machines

Enter Kubernetes


Kubernetes Architecture web browsers

yKubelet Kubelet Kubelet Kubelet

Kubernetes Master

ReplicationController Scheduler

API Server

Kube-UI

ContainerRegistry

kubectl

Proxy

<Your App>

web browsers


Desired State


Guestbook App

phpphp

phpNginx

Mongo

Redis

phpSpringJava


Challenges

Which host machine(s) should each process run on?

How does the Java microservice find the cache process?

How do we keep all of these processes running?

What happens if a host machine has trouble?

Are the processes healthy?

How do we scale when load changes?

Run this in another environment? QA, dev, another cloud, your servers?


Kubernetes Concepts

A small group of tightly coupled containers

Example: static site generator & web server

A loop that drives current state towards desired state

Example: replication controller

A set of running pods that work together

Example: load-balanced backends

Arbitrary metadata to organize components

Example: phase=productionrole=frontend

PodReplication Controller Service Labels


Pods

Pod

Web Server

Volume

ConsumersThe atom of cluster scheduling & placement

Ephemeral can die and be replaced

Application specific “logical host”

Single container pods can be created directly from a container image


The atom of cluster scheduling & placement

Ephemeral can die and be replaced

Small group of containers & volumes

Tightly coupled

Shared namespace share IP address & localhost

Pods

Pod

Site generator Web Server

Volume

ConsumersContent Manager


Responsible for maintaining the desired state

Monitor the current state

Similar to a process supervisor

Replication Controller

observe

diff

act


A group of pods that act as one == ServiceLoad balances across healthy podsGets a stable virtual IP and port

also a DNS name

Hide complexity ideal for non-native apps

Services

stable IP / port


Arbitrary metadataAttached to any API objectGenerally represent identityQueryable by selectors

think SQL ‘select ... where ...’The only grouping mechanism

pods under a ReplicationController pods in a Service capabilities of a node (constraints)

Example: “phase: canary”

App: GuestbookPhase: Dev

Role: Frontend

App: GuestbookPhase: Dev

Role: Backend

App: GuestbookPhase: Test

Role: Frontend

App: GuestbookPhase: Test

Role: Backend

Labels


Predicate based currently Pod Selection Node Capacity (based on requested resource limits)

Prioritisation

Nodes that match all predicates are ranked Priority for Node whose already-running pods consume the

least resources

More to come!

Scheduling


Map to Kubernetes

phpphp

phpNginx

Mongo

Redis

phpSpringJava


Google Container Engine

Managed Kubernetes (v1)

Manages Kubernetes Uptime

Manages Updates

Logging agents run on cluster instances, recording log entries that can be viewed in Cloud Logging

Use Google Cloud VPN to have cluster IPs coexist with your private network IPs


Demo - Guestbook


Frequently Asked Questions

Q. How does Kubernetes handle secrets?docs/secrets.md

Q. How will Kubernetes scale pods?docs/proposals/autoscaling.md(Based on Traffic, predictive analysis or arbitrary data)

Q. How will Kubernetes scale nodes?http://www.slideshare.net/craigbox/autoscaling-kubernetes(Likely based on Utilization and signals from scheduler)

Q. How can we make Kubernetes highly availabledocs/availability.md


Google Container Enginehttps://cloud.google.com/container-engine

google-containers google group

Kubernetes https://github.com/kubernetes/kubernetes

irc.freenode.net #google-containers

@kubernetesio


@hostirosti #kubernetesio #googlecloud#jsd2015

Vielen Dank fuer die Aufmerksamkeit!Fragen?

microservices - jug saxony day · microservices chaos kontrolle mit kubernetes robert kubis -...

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