OSv, a New Operating System Designed for the Cloud

OSv is a new open source operating system for the cloud. It is designed to run a single application per virtual machine and its tuned for applications running under the Java virtual machine.

In this talk, we will introduce OSv, showcase its architecture, and explain performance and application management improvements. We will also talk about OSv specific improvements to the JVM that improve application performance in virtualized environments.

Operating system developers, as well as application developers who deploy to the cloud, may enjoy the talk. No special expertise is required.

* Why do we need a Cloud Operating System?
* OSv design overview
* JVM optimizations for OSv and the cloud
* Management
* Performance
* Future

Transcript

1. OSv
   Designed for the cloud
   Pekka Enberg @penberg
   Tzach Livyatan @TzachL
   Cloudius Systems
   FOSDEM 2014
   

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2. About Cloudius
   ● Founded in December 2012
   ● ~14 people
   ● 7 countries
   ● Open source experience
   ● Linux Foundation member
   

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3. Mission
   ● Be the best OS powering VMs in the cloud.
   

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4. What is OSv?
   

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5. 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
   

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6. Why a new operating
   system?
   

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7. Typical Cloud Stack
   Application
   Application Server
   JVM
   Operating System
   Hypervisor
   Hardware
   Protection
   and
   abstraction
   

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8. ● Single application per VM
   ● No kernel and userspace separation
   ● No fork()
   ● MMU access via OSv APIs
   ● POSIX APIs for compatibility
   “Library OS”
   

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9. “Library OS”
   Application
   Application Server
   JVM + OSv
   Hypervisor
   Hardware
   

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10. Features
    

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11. OS Services
    ● Scheduler
    ● Memory management
    ○ mmap
    ○ demand paging
    ● Networking
    ● File system
    ○ ZFS and ramfs
    

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12. ● Linux system calls
    ○ uname() reports Linux for compatibility
    ● libc
    ● OSv APIs
    APIs
    

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13. ● Pure 64-bit OS
    ● 64-bit x86
    ○ KVM
    ○ Xen HVM
    ○ Xen PV - incomplete
    ○ VMware and VirtualBox - in progress
    ● 64-bit ARM - planned
    ● Others - help wanted!
    Architectures
    

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14. 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
    

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15. Demo
    

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16. Performance
    

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17. Performance
    ● Outperforms Linux
    ○ SpecJVM, memcached, netperf
    ● Same as Linux
    ○ Tomcat
    ○ Cassandra
    ● < 1 second boot time
    ● 4x faster context switch in scheduler
    microbenchmarks than Linux
    

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18. 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
    

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19. How is OSv different?
    

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20. ● 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
    

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21. JVM Balloon
    ● GC heap autotuning
    ● Steal memory from JVM on OS memory
    pressure
    ● Running on unmodified JVM
    ○ Compacting GC causes interesting problems
    ● Nice presentation by Glauber Costa on
    Youtube
    

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22. ● 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
    

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23. Admin
    

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24. 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
    

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25. Admin as collection of services
    OSv
    OSv OSv
    OSv
    Operation Configuration Packaging
    OSv
    Trace / Log
    Binary
    REST
    Metering
    Centralize
    Administration
    

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26. Operation Service
    Base on REST API (GET, POST, …)
    Successful Sync operations - 200
    Successful A-sync operation - 202
    A-sync operation result available in log with correlation id
    REST API definition use Swagger
    OSv
    OSv OSv
    Operations
    OSv
    

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27. Configuration Service
    Level of configuration:
    1. Image configuration: capture as part of the image.
    2. Init configuration: update at init phase (as in cloud-init)
    3. Runtime configuration: instance lifetime
    No configuration overriding
    Same API for all configuration levels
    API is the only way to access configuration
    Configuration is ordered in a tree structure
    OSv
    OSv OSv
    Configuration
    OSv
    

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28. Packaging Services
    pull
    Base
    App
    repository
    run
    search
    new
    App
    ops
    commit
    push
    run
    util
    OSv
    OSv OSv
    Packaging
    OSv
    

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29. Packaging Services
    Repository operations
    search
    pull user/app - download pre built image
    push user/app - upload a new image to the repository
    VM operations
    run app - start OSv instance
    kill app - kill a running OSv node
    VM interactions
    app deploy bar.jar - deploy a jar to an instance
    app deploy foo.rpm - add a RPM to an instance
    run app cli - open an interactive shell
    OSv
    OSv OSv
    Packaging
    OSv
    

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30. Log / Trap Service
    OSv
    OSv OSv
    Log
    Traps
    Requirements Log Traps
    Direction Outbound Outbound
    Bandwidth High Low
    Reliable No Yes
    Format Binary/Text Binary/Text
    Alternatives RabbitMQ
    ZeroMQ
    Gelf
    ...
    See Log
    SNMP
    MQTT
    JMX
    

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31. Alpha Release
    3/2014
    Optimized ZFS
    cache
    Dirty page
    writeback
    JVM page table
    HV support:
    GCE, VMW, VBox
    Git init
    osv,
    12/201
    2
    Java hello world,
    01/2013
    support
    for
    64 vcpu
    02/2013
    UDP,
    03/2013
    ZFS support
    > 1Gbps netperf,
    6/2013
    Cassandra
    outperform
    s Linux,
    8/2013
    Native REST API
    Memcached gain
    > 70%
    1/2014
    Cli and web
    interface
    9/2014
    Tomcat,
    HAProxy
    modules
    10/2013
    Net channels
    JVM ballooning
    >47Gbps
    netperf
    2/2014
    Image Repository
    JVM Read barrier
    elimination
    DPDK support
    More ...
    Roadmap
    

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32. So what about
    containers?
    

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33. Containers
    ● Docker is awesome
    ○ Linux control groups not so awesome...
    ● Fast boot
    ● Fast provisioning
    ● Performance
    

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34. Containers under the hood
    ● Shared kernel image
    ○ Kernel upgrades
    ○ Hardware maintenance
    ● Complexity in the kernel
    ● Copy-on-write userspace
    

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35. OSv - best of both worlds?
    ● Fast boot, fast provisioning, performance
    ● Virtualized
    ○ Live migration
    ○ Elasticity
    ○ MMU access
    ● Great blog post on Google+ “OSv vs
    containers” by Glauber Costa
    

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36. That’s it!
    

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37. 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
    ○ @penberg
    ○ @TzachL
    

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