the twelve factor container

The Twelve-Factor Container

1 ! @caseywest #S1P #containers #operability #ops #12factor #realtalk #til

The Twelve-Factor Container• Twitter @caseywest

• Email [email protected]

• Web caseywest.com


This isn't really a talk about containers


This is a talk about operational maturity


You must be this tall to ride this ride


Who has used…• Containers?• Schedulers?• Cloud?


Docker

Docker

Docker

Docker

Docker

Docker

Docker

Docker


The factors


1: One codebase tracked in revision control, many deploys


Anti-patternBuilding separate images for staging and production


Anti-patternTags for dev and prod


Best PracticeUse the environment and/or feature flags


2: Explicitly declare and isolate dependencies


Anti-patternlatest


Best PracticeDeclare version numbers of upstream dependencies


Best PracticeDepend on base images for default filesystem and runtimes


3: Store config in the environment


Anti-patternconfig.yml


Anti-patternproperties.xml


Anti-patternHard-coded feature flags


Best PracticeThis one is literally about environment variables


Best PracticeThis one is literally about environment variables ! ⬇24 ! @caseywest #S1P #containers #operability #ops #12factor #realtalk #til

4: Treat backing services as attached resources


Anti-patternNo local disk


Anti-pattern

No local disk


Best PracticeConnect to network-attached services using connection info from the environment29 ! @caseywest #S1P #containers #operability #ops #12factor #realtalk #til

5: Strictly separate build and run stages


Anti-patternInstall on deploy


Best PracticeBuild immutable images then run those images


Painfully Obvious Best PracticesEat when hungrySleep when tiredBook Casey West for speaking gigs33 ! @caseywest #S1P #containers #operability #ops #12factor #realtalk #til

Best PracticeRespect the lifecycle: build, run, destroy


6: Execute the app as one or more stateless processes


Best PracticeSchedule LRPs by distributing them across a cluster of physical hardware36 ! @caseywest #S1P #containers #operability #ops #12factor #realtalk #til

Anti-patternNFS


Anti-patternNFSNeed I say more?


7: Export services via port binding


Best Practiceport = Env.fetch(:PORT)


Best Practicemy $port = $ENV{PORT};


Best Practiceprivate String getPort() { Map<String, String> env = System.getenv(); return env.get("PORT");}


Best Practicelet port = env::var("PORT").unwrap()


8: Scale out via the process model


Best PracticeHorizontally scale by adding instances


9: Maximize robustness with fast startup and graceful shutdown


10: Keep development, staging, and production as similar as possible


Best PracticeRun containers in development


11: Treat logs as event streams


Anti-patternRandom log files #yolo'd all over the file system


Anti-patternRandom log files #yolo'd all over the file system, bro


Best PracticeSTDOUTSTDOUTSTDOUTSTDOUT52 ! @caseywest #S1P #containers #operability #ops #12factor #realtalk #til

12: Run admin/management tasks as one-off processes


Anti-patternCustom containers for tasks


Best PracticeReuse application images with specific entrypoints for tasks


You are now cloud-native


RepeatabilityReliabilityResiliency57 ! @caseywest #S1P #containers #operability #ops #12factor #realtalk #til

@caseywestLet's be friends

!58 ! @caseywest #S1P #containers #operability #ops #12factor #realtalk #til

the twelve factor container

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