Spotify uses Docker and Helios to deploy over 100 backend services across 5000 servers. Docker provides repeatable deployments by running the same tested image in production. Helios ensures Docker containers are deployed and running as intended across servers. Spotify is moving more services to Docker and has its first Docker-based service in production using Helios to deploy containers across its infrastructure.

1. Docker at Spotify
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Rohan Singh
@rohansingh

2. Spotify
“Music for every moment”
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40+ million active users
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20+ million songs available
(we’re in 55+ countries, differs by market)
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Live in the US for 2 years
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3. What are we working with?
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100+ distinct backend services
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5000+ production servers in 4 sites worldwide
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Almost 300 servers per ops engineer
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4. Deployment at Spotify
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5. Build Debian packages
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Requisition new hardware
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Use combination of Puppet
and internal tooling (deployify)
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6. old way:
SSH to a bunch of machines,
apt-get install || upgrade
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deployify:
Uses fabric, which just SSH’s,
runs apt-get install || upgrade
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7. What’s wrong with that?
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8. Requisitioning new hardware is slow
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Hardware utilization is low
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We’ve automated and improved,
but still too slow
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9. Deployments often fail…
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…though usually only partially
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10. !
Machines get denormalized easily
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11. Debian packaging is its own special hell
So many damn files!
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debhelper
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Distro & version specific
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apt-get update
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12. What do we want?
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13. Deployments that are:
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Repeatable
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Straightforward
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Fault-tolerant
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14. Why Docker?
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It gives us “repeatable”,
right out of the box
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And it’s fairly straightforward, too!
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15. Repeatability?
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The code you test isn’t necessarily
the code that runs in prod
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16. Repeatability — Docker
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Build an image
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Run tests against the image
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Run the tested image in prod
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17. Straightforward
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Just one Dockerfile
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Pretty simple syntax
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Immutable images — easy to reason about
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18. Fault-tolerance?
Even if your code is perfect,
deployments might fail
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Puppet or Debian repos are down
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Network issues
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The machine dies
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19. Fault-tolerance — Docker
Just one thing has to work —
pulling & running an image
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If it fails, just try again
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No machines left in weird states*
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*(in theory)
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20. What more do we need?
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21. Deploying Docker containers across
our entire fleet of servers
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Some way to deal with Docker or container failures
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That’s pretty much it
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22. Looking around for a Docker platform
Several really feature-full offerings
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Pretty opinionated and all-encompassing
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All we need is reliably deploying containers
to a fleet of Docker hosts
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23. Helios
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24. Makes sure your containers are deployed & running
exactly where you want them…
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…and that’s pretty much it
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github.com/spotify/helios
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25. What’s in the box?
Helios master
frontend that you talk to
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Helios agent
runs alongside each Docker instance
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Zookeeper
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Straightforward CLI
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26. How does it work?
Create a job —
tell Helios which Docker image to deploy
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Deploy the job —
tell Helios where to run the Docker containers
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27. See it in action
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28. What’s next?
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29. Helios is just the beginning
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Brought up plenty of Helios+Docker agents
in our private cloud for our devs
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Integrated Helios with JUnit —
write JUnit tests run against Docker containers
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30. Dockerized integration tests
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31. This week —
first Helios+Docker-based service in production
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In the future —
Containerizing more of our infrastructure
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32. Give it a go
Open source:
github.com/spotify/helios
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Try it out:
git clone https://github.com/spotify/helios.git
&& cd helios && vagrant up
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Come play with us (spotify.com/jobs)
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