Deployment Tools and Techniques at Spotify: Virtualenv in debian by Chris Angove

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Spotify Tech

Web/iOS/Android/Native clients Service oriented architecture > 50 services in Java and Python Primarily using Cassandra for persistent storage 7,000 Servers in production ~500 in Engineers worldwide

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Lost in the forest of dependency building

What have we been doing?

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Deploy via Debian Packages

Use Debian Stable repositories Package/Backport needed libraries as needed All Dependencies defined in Debian package Deployed via Puppet/Aptitude

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Package  

Mirroring  

Apps  

PyPi  

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Spending too much time managing dependencies and not enough building cool shit

What’s wrong with that?

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Using Debian Stable does not included latest and greatest

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Requires “Backporting” for newer libraries

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Does not used normal python packaging

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Limited use on developer systems

(or bad/duplicated information)

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Full rollback non-existent

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What you test is NOT what you deploy

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Dependency lock in due to sharing a common python environment

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Avoid duplication of effort

There MUST be a better way

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Increase stability and repeatability

There MUST be a better way

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Offer easy rollback

There MUST be a better way

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Scale

There MUST be a better way

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Deploying Python @ Scale

What about now?

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Enter Dh-viurtualenv

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Dh == Debian Helper

•  Registers itself as a Debian Helper •  Bundles the requirements in requirements.txt into virtual environment •  Deploys virtualenv into /usr/share/python/<package-name> •  Still requires native dependencies to be installed via packaging •  Just include the following in the debian/rules:

%:                                dh  $@  -­‐-­‐with  python-­‐virtualenv

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Virtualenv  

Mirroring  

Apps  

Pip  

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IT Works!

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Example: Using Sentry

Define Dependencies in requirements.txt

sentry[postgres]==6.2.0  eventlet==0.13.0  hiredis==0.1.1  django-­‐auth-­‐ldap==1.1.4

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Example: Using Sentry

Define Debian dependencies in control file

Build-Depends: python (>= 2.6.6-3~), debhelper (>= 8), dh-virtualenv, python-dev, libpq-dev, libldap2-dev, libsasl2-dev, Standards-Version: 3.9.3 X-Python-Version: >= 2.6

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Example: Using Sentry

Use dh_virtualenv in Debian rules file

%: dh $@ --with python-virtualenv

override_dh_virtualenv:

dh_virtualenv --index-url='http://localhost/simple'

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Have done this with RPMs as well (@ Amplify)

Within RPM build virtaulenv and mark it as relocatable:

/usr/local/bin/virtualenv --no-site-packages build_venv source build_venv/bin/activate env CFLAGS="$RPM_OPT_FLAGS" easy_install -Z . deactivate /usr/local/bin/virtualenv --relocatable build_venv

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Benefits

No longer stuck on Debian stable

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Benefits

No more backporting of new libraries or versions

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Benefits

Code isolation/use own dependencies

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Benefits

Single package rollback option

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Benefits

Development and Deployed systems using same cross-platform setup

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What’s Next?

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Not Sure…

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Dh_virtualenv now available (ironically) in Debian Unstable repositories

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Still requires managing native dependencies locally

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But experimenting with containers!

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Stay Tuned!

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Whitepaper: http://labs.spotify.com/2013/10/10/packaging-in-your-packaging-dh-virtualenv/ Code: https://github.com/spotify/dh-virtualenv

Thanks to Jyrki Pulliainen and Jim Whitehead @ Spotify Stockholm!

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Chris Angove, Chapter Lead - Backend Email: [email protected] Blog: http://labs.spotify.com/ Listen: https://play.spotify.com/

Questions?

January 24, 2014

Check out spotify.com/jobs or @Spotifyjobs for more information.

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