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Glad to hear OS X has official support. I jumped into Docker for the first time last week and have a burning unresolved question for those using boot2docker. W

Glad to hear OS X has official support. I jumped into Docker for the first time last week and have a burning unresolved question for those using boot2docker. What is your development workflow? I am working on a Rails app, so my instinct is to have a shared folder between OS X and boot2docker, but afaik this is not supported as boot2docker doesn't support VirtualBox guest extensions.

shykes 13y ago
Hi Matt, you are not alone :) It turns out that shared folders are not a sustainable solution (independently of whether boot2docker supports them), so the best practices are converging towards this: 1) While developing, your dev environment (including the source code and method for fetching it) should live in a container. This container could be as simple as a shell box with git and ssh installed, where you keep a terminal open and run your unit tests etc. 2) To access your source code on your host machine (eg. for editing on your mac), export it from your container over a network filesystem: samba, nfs or 9p are popular examples. Then mount that from your mac. Samba can be natively mounted with "command-K". NFS and 9p require macfuse. 3) When building the final container for integration tests, staging and production, go through the full Dockerfile + 'docker build' process. 'docker build' on your mac will transparently upload the source over the docker remote API as needed. There are several advantages to exporting the source from the container to the host, instead of the other way around: - It's less infrastructure-specific. If you move from virtualbox to vmware, or get a Linux laptop and run docker straight on the metal, your storage/shared folders configuration doesn't change: all you need is a network connection to the container. - Network filesystems are more reliable than shared folders + bind-mount. For example they can handle different permissions and ownership on both ends - a very common problem with shared folders is "oops the container creates files as root but I don't have root on my mac", or "apache complains that the permissions are all wrong because virtualbox shared folders threw up on me". That said, we need to take that design insight and turn it into a polished user experience - hopefully in Docker 0.9 this will all be much more seamless!
- bstar77 13y ago
  Thanks for taking the time to write this. I've hit a major wall in figuring out the best workflow for this exact scenario. Good to finally hear an official suggestion on the matter. I've been depending on shared directories, so I'll definitely be experimenting with network filesystems. As Docker evolves, it would be great to have some kind of official resource to get suggestions for optimal workflows as new features become available (the weekly docker email is my best resource right now). Searching the internet for info has been a huge chore as most of the resources (including the ones hosted by docker.io) are woefully out of date.
  - shykes 13y ago
    > As Docker evolves, it would be great to have some kind of official resource to get suggestions for optimal workflows as new features become available Yes! We are trying to figure this out. Our current avenue for this is to dedicate a new section in the docs to use cases and best practices. As you point out, our docs (and written content in general) are often inaccurate. We need to fix this. Hopefully in the coming weeks you will start seeing notable improvements in these areas. Thanks for bearing with us!
- tksb 13y ago
  Thank you for this. I found it extremely helpful.
- ecnahc515 13y ago
  This should be a blog post or tutorial or guide on the documentation page. It would be really helpful to have guidance on how to do development work flow using docker while avoiding bad practices like shared volumes.
  - FireBeyond 13y ago
    Seconded. My biggest stumbling block with Docker at the moment is “best practices”, as I work on coming up with a Docker Dev Ecosystem (for myself and for a team).
odonnellryan 13y ago
You can use Docker + Makefiles (test, binary, etc) to really help you with this.

shykes 13y ago

Hi Matt, you are not alone :) It turns out that shared folders are not a sustainable solution (independently of whether boot2docker supports them), so the best practices are converging towards this: 1) While developing, your dev environment (including the source code and method for fetching it) should live in a container. This container could be as simple as a shell box with git and ssh installed, where you keep a terminal open and run your unit tests etc. 2) To access your source code on your host machine (eg. for editing on your mac), export it from your container over a network filesystem: samba, nfs or 9p are popular examples. Then mount that from your mac. Samba can be natively mounted with "command-K". NFS and 9p require macfuse. 3) When building the final container for integration tests, staging and production, go through the full Dockerfile + 'docker build' process. 'docker build' on your mac will transparently upload the source over the docker remote API as needed. There are several advantages to exporting the source from the container to the host, instead of the other way around: - It's less infrastructure-specific. If you move from virtualbox to vmware, or get a Linux laptop and run docker straight on the metal, your storage/shared folders configuration doesn't change: all you need is a network connection to the container. - Network filesystems are more reliable than shared folders + bind-mount. For example they can handle different permissions and ownership on both ends - a very common problem with shared folders is "oops the container creates files as root but I don't have root on my mac", or "apache complains that the permissions are all wrong because virtualbox shared folders threw up on me". That said, we need to take that design insight and turn it into a polished user experience - hopefully in Docker 0.9 this will all be much more seamless!

bstar77 13y ago
Thanks for taking the time to write this. I've hit a major wall in figuring out the best workflow for this exact scenario. Good to finally hear an official suggestion on the matter. I've been depending on shared directories, so I'll definitely be experimenting with network filesystems. As Docker evolves, it would be great to have some kind of official resource to get suggestions for optimal workflows as new features become available (the weekly docker email is my best resource right now). Searching the internet for info has been a huge chore as most of the resources (including the ones hosted by docker.io) are woefully out of date.
- shykes 13y ago
  > As Docker evolves, it would be great to have some kind of official resource to get suggestions for optimal workflows as new features become available Yes! We are trying to figure this out. Our current avenue for this is to dedicate a new section in the docs to use cases and best practices. As you point out, our docs (and written content in general) are often inaccurate. We need to fix this. Hopefully in the coming weeks you will start seeing notable improvements in these areas. Thanks for bearing with us!
tksb 13y ago
Thank you for this. I found it extremely helpful.
ecnahc515 13y ago
This should be a blog post or tutorial or guide on the documentation page. It would be really helpful to have guidance on how to do development work flow using docker while avoiding bad practices like shared volumes.
- FireBeyond 13y ago
  Seconded. My biggest stumbling block with Docker at the moment is “best practices”, as I work on coming up with a Docker Dev Ecosystem (for myself and for a team).

odonnellryan 13y ago

You can use Docker + Makefiles (test, binary, etc) to really help you with this.