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Docker explicitly violates the principles of the Twelve-Factor App. Docker apps don’t rely on any external environment. In fact, Docker demands that you store a

Docker explicitly violates the principles of the Twelve-Factor App. Docker apps don’t rely on any external environment. In fact, Docker demands that you store all config values, dependencies, everything inside of the container itself. Apps communicate with the rest of the world via ports and via Docker itself. The trade-off is that apps become a little bit bulkier (though not significantly), but the benefit is apps become maximally portable. In essence, Docker makes almost no assumptions about the app’s next home. Docker apps care about where they are even less than twelve-factor apps. They can be passed to and fro across servers—and, more importantly, across virtualization platforms—and everything needed to run them (besides the OS) comes along for the ride.

tieTYT 12y ago
This is the first time I've heard the phrase "twelve-factor app". Although I'm ignorant of this term and docker, it wasn't obvious to me how it violates the concepts. Which factor does it violate? For reference: http://12factor.net/ http://12factor.net/
zenlikethat 12y ago
Very good points, and as the author here (http://blog.lusis.org/blog/2014/06/14/paas-for-realists/ http://blog.lusis.org/blog/2014/06/14/paas-for-realists/) points out: > I should state up front that I disagree with quite a few bits of the 12 Factor model. It’s important to remember that, imho, the 12 Factor model was designed as a business strategy for Heroku. The steps follow exactly what makes an app work best on Heroku, not what is best for an application.
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ferrouswheel 12y ago
> In fact, Docker demands that you store all config values, dependencies, everything inside of the container itself. No it doesn't. In fact, parameterised containers are a thing that many people encourage. This is where you specify configuration when you run the container instead of when you build it. This can done using arguments to the CMD, environment variables, config volumes, or using something like etcd.

tieTYT 12y ago

This is the first time I've heard the phrase "twelve-factor app". Although I'm ignorant of this term and docker, it wasn't obvious to me how it violates the concepts. Which factor does it violate? For reference: http://12factor.net/ http://12factor.net/

zenlikethat 12y ago

Very good points, and as the author here (http://blog.lusis.org/blog/2014/06/14/paas-for-realists/ http://blog.lusis.org/blog/2014/06/14/paas-for-realists/) points out: > I should state up front that I disagree with quite a few bits of the 12 Factor model. It’s important to remember that, imho, the 12 Factor model was designed as a business strategy for Heroku. The steps follow exactly what makes an app work best on Heroku, not what is best for an application.

deleted 12y ago

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ferrouswheel 12y ago

> In fact, Docker demands that you store all config values, dependencies, everything inside of the container itself. No it doesn't. In fact, parameterised containers are a thing that many people encourage. This is where you specify configuration when you run the container instead of when you build it. This can done using arguments to the CMD, environment variables, config volumes, or using something like etcd.