Docker 0.11 at MaxCDN meetup in Los Angeles

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Docker is the Open Source container engine. It lets you author, run, and manage software containers. Escape from dependency hell, and make deployment a breeze! This presentation includes the standard …

Docker is the Open Source container engine. It lets you author, run, and manage software containers. Escape from dependency hell, and make deployment a breeze! This presentation includes the standard Docker intro (actualized for Docker 0.11) as well as some insights about how to perform orchestration and multi-host container linking.

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  • 1. Introduction to Docker May 2014—Docker 0.11.0XXXXX0.11.1
  • 2. @jpetazzo ● Wrote dotCloud PAAS deployment tools – EC2, LXC, Puppet, Python, Shell, ØMQ... ● Docker contributor – Docker-in-Docker, VPN-in-Docker, router-in-Docker... CONTAINERIZE ALL THE THINGS! ● Runs Docker in production – You shouldn't do it, but here's how anyway!
  • 3. What?
  • 4. Why?
  • 5. Deploy everything ● Webapps ● Backends ● SQL, NoSQL ● Big data ● Message queues ● … and more
  • 6. Deploy almost everywhere ● Linux servers ● VMs or bare metal ● Any distro ● Kernel 3.8 (or RHEL 2.6.32) Currently: focus on x86_64. (But people reported success on arm.)
  • 7. Deploy reliably & consistently
  • 8. Deploy reliably & consistently ● If it works locally, it will work on the server ● With exactly the same behavior ● Regardless of versions ● Regardless of distros ● Regardless of dependencies
  • 9. Deploy efficiently ● Containers are lightweight – Typical laptop runs 10-100 containers easily – Typical server can run 100-1000 containers ● Containers can run at native speeds – Lies, damn lies, and other benchmarks: http://qiita.com/syoyo/items/bea48de8d7c6d8c73435
  • 10. The performance! It's over 9000!
  • 11. Is there really no overhead at all? ● Processes are isolated, but run straight on the host ● CPU performance = native performance ● Memory performance = a few % shaved off for (optional) accounting ● Network and disk I/O performance = small overhead; can be reduced to zero
  • 12. … Container ?
  • 13. High level approach: it's a lightweight VM ● Own process space ● Own network interface ● Can run stuff as root ● Can have its own /sbin/init (different from the host) « Machine Container »
  • 14. Low level approach: it's chroot on steroids ● Can also not have its own /sbin/init ● Container = isolated process(es) ● Share kernel with host ● No device emulation (neither HVM nor PV) « Application Container »
  • 15. How does it work? Isolation with namespaces ● pid ● mnt ● net ● uts ● ipc ● user
  • 16. How does it work? Isolation with cgroups ● memory ● cpu ● blkio ● devices
  • 17. How does it work? Copy-on-write storage ● Create a new machine instantly (Instead of copying its whole filesystem) ● Storage keeps track of what has changed ● Multiple storage plugins available (AUFS, device mapper, BTRFS, VFS...)
  • 18. Union Filesystems (AUFS, overlayfs) Copy-on-write block devices Snapshotting filesystems Provisioning Superfast Supercheap Fast Cheap Fast Cheap Changing small files Superfast Supercheap Fast Costly Fast Cheap Changing large files Slow (first time) Inefficient (copy-up!) Fast Cheap Fast Cheap Diffing Superfast Slow Superfast Memory usage Efficient Inefficient (at high densities) Inefficient (but may improve) Drawbacks Random quirks AUFS not mainline Higher disk usage Great performance (except diffing) ZFS not mainline BTRFS not as nice Bottom line Ideal for PAAS and high density things Dodge Ram 3500 This is the future (Probably!) Storage options
  • 19. Alright, I get this. Containers = nimble VMs.
  • 20. The container metaphor
  • 21. Problem: shipping goods ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
  • 22. Solution: the intermodal shipping container
  • 23. Solved!
  • 24. Problem: shipping code ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
  • 25. Solution: the Linux container
  • 26. Solved!
  • 27. Separation of concerns: Dave the Developer ● Inside my container: – my code – my libraries – my package manager – my app – my data
  • 28. Separation of concerns: Oscar the Ops guy ● Outside the container: – logging – remote access – network configuration – monitoring
  • 29. Docker-what? The Big Picture ● Open Source engine to commoditize LXC ● Using copy-on-write for quick provisioning ● Allowing to create and share images ● Standard format for containers (stack of layers; 1 layer = tarball+metadata) ● Standard, reproducible way to easily build trusted images (Dockerfile, Stackbrew...)
  • 30. Docker-what? History ● Rewrite of dotCloud internal container engine – original version: Python, tied to dotCloud PaaS – released version: Go, legacy-free
  • 31. Docker-what? Under the hood ● The Docker daemon runs in the background – manages containers, images, and builds – HTTP API (over UNIX or TCP socket) – embedded CLI talking to the API
  • 32. Docker-what? Take me to your dealer ● Open Source – GitHub public repository + issue tracking https://github.com/dotcloud/docker ● Nothing up the sleeve – public mailing lists (docker-user, docker-dev) – IRC channels (Freenode: #docker #docker-dev) – public decision process – Docker Governance Advisory Board
  • 33. One-time setup ● On your servers (Linux) – Packages (Ubuntu, Debian, Fedora, Gentoo, Arch...) – Single binary install (Golang FTW!) – Easy provisioning on Rackspace, Digital Ocean, EC2, GCE... ● On your dev env (Linux, OS X, Windows) – Vagrantfile – boot2docker (25 MB VM image) – Natively (if you run Linux)
  • 34. The Docker workflow 1/2 ● Work in dev environment (local machine or container) ● Other services (databases etc.) in containers (and behave just like the real thing!) ● Whenever you want to test « for real »: – Build in seconds – Run instantly
  • 35. The Docker workflow 2/2 Satisfied with your local build? ● Push it to a registry (public or private) ● Run it (automatically!) in CI/CD ● Run it in production ● Happiness! Something goes wrong? Rollback painlessly!
  • 36. Authoring images with run/commit
  • 37. 1) docker run ubuntu bash 2) apt-get install this and that 3) docker commit <containerid> <imagename> 4) docker run <imagename> bash 5) git clone git://.../mycode 6) pip install -r requirements.txt 7) docker commit <containerid> <imagename> 8) repeat steps 4-7 as necessary 9) docker tag <imagename> <user/image> 10) docker push <user/image>
  • 38. Authoring images with run/commit ● Pros – Convenient, nothing to learn – Can roll back/forward if needed ● Cons – Manual process – Iterative changes stack up – Full rebuilds are boring, error-prone
  • 39. Authoring images with a Dockerfile
  • 40. FROM ubuntu RUN apt-get -y update RUN apt-get install -y g++ RUN apt-get install -y erlang-dev erlang-manpages erlang-base- hipe ... RUN apt-get install -y libmozjs185-dev libicu-dev libtool ... RUN apt-get install -y make wget RUN wget http://.../apache-couchdb-1.3.1.tar.gz | tar -C /tmp -zxf- RUN cd /tmp/apache-couchdb-* && ./configure && make install RUN printf "[httpd]nport = 8101nbind_address = 0.0.0.0" > /usr/local/etc/couchdb/local.d/docker.ini EXPOSE 8101 CMD ["/usr/local/bin/couchdb"] docker build -t jpetazzo/couchdb .
  • 41. Authoring images with a Dockerfile ● Minimal learning curve ● Rebuilds are easy ● Caching system makes rebuilds faster ● Single file to define the whole environment!
  • 42. Checkpoint With Docker, I can: ● put my software in containers ● run those containers anywhere ● write recipes to automatically build containers But how do I: ● run containers aplenty? ● manage fleets of container hosts? ● ship to, you know, production?
  • 43. Half Time … Questions so far ? http://docker.io/ http://docker.com/ @docker @jpetazzo
  • 44. What's new in 0.10? ● TLS auth for API ● Tons of stability and usability improvements (devicemapper, hairpin NAT, ptys...) ● FreeBSD support (client)
  • 45. What's new in 0.11? ● SELinux support ● --net flag for special network features (you don't need to use pipework anymore!) ● stability, stability, stability, stability
  • 46. Docker 1.0 ● ☒ Multi-arch, multi-OS ● ☒ Stable control API ● ☒ Stable plugin API ● ☐ Resiliency ● ☑ Clustering
  • 47. Do You Even Ship?
  • 48. Running (some) containers ● SSH to Docker host and manual pull+run ● Fig https://github.com/orchardup/fig ● Maestro NG https://github.com/signalfuse/maestro-ng ● Replace yourself with a simple shell script
  • 49. Running (more) containers More on this in a minute.
  • 50. Identify your containers ● You can name your containers docker run -d -name www_001 myapp ● Ensures uniqueness
  • 51. Connect your containers ● Links! docker run -d -name frontdb mysqlimage docker run -d -link frontdb:sql nginximage → environment vars are injected in web container → twelve-factors FTW!
  • 52. Connect your containers across multiple hosts ● Ambassador pattern host 1 (database) docker run -d -name frontdb mysqlimage docker run -d -link frontdb:sql wiring host 2 (web tier) docker run -d -name frontdb wiring docker run -d -link frontdb:sql nginximage
  • 53. db host web host database container I'm frontdb! web container I want to talk to frontdb! wiring container I actually talk to frontdb! wiring container I pretend I'm frontdb! docker link docker link ?
  • 54. db host web host database container I'm frontdb! web container I want to talk to frontdb! wiring container I actually talk to frontdb! wiring container I pretend I'm frontdb! docker link docker link UNICORNS
  • 55. I can't afford Unicorns! ● Service discovery (registry): Zookeeper / Etcd / Consul ● Traffic routing: stunnel / haproxy / iptables ● Stay Tuned
  • 56. Running (more) containers ● OpenStack (Nova, Heat) ● OpenShift (geard) ● Other PAAS: Deis, Cocaine (Yandex), Flynn... ● Docker Executor for Mesos ● Roll your own with the REST API
  • 57. Can we do better? ● The « dockermux » design pattern ● Run something that: – exposes the Docker API – talks to real Docker hosts – spins up more Docker hosts – takes care of scheduling, plumbing, scaling...
  • 58. Thank you! Questions? http://docker.io/ http://docker.com/ @docker @jpetazzo