osv – the os designed for the cloud

OSvDesigned for the cloud

Lord Glauber Costa of Sealandglommer@cloudius-systems.coom

Cloudius Systems

About myself

● Some contributions to Xen● Extensive contributions to Linux and QEMU● Early employee at Cloudius (#4), OSv● после моего выступления, помочь мне

практиковать (медленно пожалуйста)

About Sealand

● Mightiest country on Earth● 0.025 m² area size● Fought and won a war (15 min) against UK● De facto recognition by Germany and UK

About Cloudius

● Founded in December 2012● ~15 people● 9 countries● Open source experience● Linux Foundation member

About OSv

OSv

● “Cloud OS” written from scratch● C++11● BSD licensed● Networking stack and ZFS imported from

FreeBSD○ We are modifying the networking stack○ Switching to OpenZFS in the future

Typical Cloud Stack

Application

Application Server

JVM

Operating System

Hypervisor

Hardware

Protection and

abstraction

● Single application per VM● No kernel and userspace separation● No fork()● MMU access via OSv APIs● POSIX APIs for compatibility

“Library OS”

“Library OS”

Application

Application Server

JVM + OSv

Hypervisor

Hardware

Features

OS Services

● Scheduler● Memory management

○ mmap○ demand paging

● Networking● File system

○ ZFS and ramfs

● Linux system calls○ uname() reports Linux for compatibility

● libc● OSv APIs

APIs

● Pure 64-bit OS● 64-bit x86

○ KVM○ Xen HVM○ Xen PV - incomplete○ VMware and VirtualBox - in progress

● 64-bit ARM - started!● Others - help wanted!

Architectures

Status

● JVM languages○ Java, JRuby, Scala, Groovy, Clojure, JavaScript

● JVM applications○ Cassandra○ Tomcat

● Other runtimes○ mruby○ I would love to see someone port Node.js...

● Native applications○ memcached○ haproxy

Performance

Performance

● Outperforms Linux○ SpecJVM, memcached, netperf

● Same as Linux○ Tomcat○ Cassandra

● < 1 second boot time● 4x faster context switch in scheduler

microbenchmarks than Linux

Image Size

● 17 MB minimal image○ kernel + libc

● 29 MB mruby image○ kernel + libc + mruby

● 465 MB default image (!)○ kernel + libc + openjdk○ openjdk is 127 MB○ ZFS intent log related, working on a fix

How is OSv different?

● Linux network channels by Van Jacobson○ Proposed in 2006, never merged○ Packet processing overhead reduced by 25% for 1

CPU and 20% for 2 CPUs (source: lwn.net)● Network channels in OSv

○ Channel connected to the application● Netperf throughput increases 30% from ~36

Gbps to ~47 Gbps○ Linux on host, OSv in guest

Network channels

JVM Balloon

● GC heap autotuning● Steal memory from JVM on OS memory

pressure● Running on unmodified JVM

○ Compacting GC causes interesting problems● Nice presentation at our youtube channel

● Replace GC card tables with MMU remapping

● Modified OpenJDK● Azul C4’s GC uses similar MMU tricks on

x86○ Out-of-tree Linux patches

JVM and MMU

Admin

OS Admin

Traditional OS● Built for a standalone desktop● CLI oriented● Human oriented● File base configuration● Hard to automate

Cloud OS● Built for mass deployment● API oriented● Machine oriented● API base configuration● Easy to automate

Alpha Release3/2014

Optimized ZFS cacheDirty page writebackJVM page tableHV support:GCE, VMW, VBox

Git init osv, 12/2012

Java hello world, 01/2013

support for64 vcpu 02/2013

UDP, 03/2013

ZFS support> 1Gbps netperf, 6/2013

Cassandra outperforms Linux, 8/2013

Native REST APIMemcached gain > 70%1/2014

Cli and web interface9/2014

Tomcat,HAProxy modules10/2013

Net channelsJVM ballooning >47Gbps netperf 2/2014

Image RepositoryJVM Read barrier eliminationDPDK supportMore ...

Roadmap

So what about containers?

Containers

● Docker is awesome○ Linux control groups not so awesome...

● Fast boot● Fast provisioning● Performance

Containers under the hood

● Shared kernel image○ Kernel upgrades○ Hardware maintenance

● Complexity in the kernel● Copy-on-write userspace

OSv - best of both worlds?

● Fast boot, fast provisioning, performance● Virtualized

○ Saner abstraction layer○ Stronger Isolation○ Heterogeneous datacenter○ MMU access, and other hardware primitives

● Great blog post on Google+ “OSv vs containers”

That’s it!

Thank you!

● Web○ http://osv.io

● Github○ http://github.com/cloudius-systems/osv

● Mailing List○ osv-dev@googlegroups.com

● You should follow us on Twitter:○ @CloudiusSystems