8 ms·

Running .NET apps in Docker containers

56 points by friism 13y ago

jmnicolas 13y ago
VirtualBox, Docker and Mono ... at one point you have to ask yourself isn't it too much virtualization ?
- m_mueller 13y ago
  You are missing the point I think: Running a setup like this allows developing and testing the environment only once for the first app you develop with these dependencies. You basically get deployment as well as the development environment for further projects based on this environment for 'free'. Having Docker between VirtualBox and Mono adds almost no overhead while giving you a nice clean slate with no environment properties from other projects that could somehow influence the runtime behavior. Now, the question for me is whether this is worth it for .Net - is Mono so good, that one would want to lock himself into a Linux-only environment like this?
- jimmcslim 13y ago
  VirtualBox: the author is using a Windows machine so needs to run Linux in order to experiment with Docker. Docker: well, this is the subject of the post. Mono: Mono is an application runtime (specifically an open-source implementation of the CLR) just like the JVM (yes, a 'Virtual Machine' but not virtualization, I would argue, in the sense that you are stating there is too much of). Obviously if you had .Net apps and a Windows server environment you would just deploy .Net apps to it. But there might be scenarios in which this is useful. Perhaps migrating away from Windows servers to Linux, but not wanting to rewrite the C#/.Net apps in a new platform. Although whether Mono would be able to run those apps satisfactorily (the coverage of the SDK is not complete) is of course up for debate.
  - d0 13y ago
    The answer to your latter question is: no. Only pretty trivial stuff is portable to Mono. I've tried it on every project I've worked on over the last 6 years to no avail. Show stopper every time.
    - andyjohnson0 13y ago
      Interested in your experience. Were these projects desktop applications or server-side, or a mix of both?
      - d0 13y ago
        Mix of both. The killer on the server-side is always stuff like missing WCF features, odd bugs with DI containers, missing API calls, slight behavioural differences etc. Client-side. No WPF and WinForms is dreadfully incomplete. It's a no go. If you start on Mono and deploy to .Net I imagine it'd work but no-one realistically does that these days. If they were going to do that, Java would be a better choice for the product.
        danabramov 13y ago
        Well, client-side Microsoft has abandoned both (although of course they still run).
        d0 13y ago
        They haven't abandoned any of them. We still have ATL, MFC, Win32, WPF, WinForms and now Metro. Not that I want to use any of them myself :)
    - Guillaume86 13y ago
      Yes it's a big disapointment for me, my predilection language is C# and I would love to be able to code on linux... I wish one day microsoft will be forced to port/support .NET (at least server components) to linux but I'm not holding my breath...
      - d0 13y ago
        I really don't want them to port it. I want to see Java 8!
        13y ago
- cincinnatus 13y ago
  It is abstraction layers all the way down. We all find our level of comfort in the stack, somewhere between the most abstract thing currently achievable and CPU microcode. In this particular case it makes something otherwise tedious much simpler, which is what adding abstraction is always about.
Guillaume86 13y ago
I experimented wih docker a few month ago and made a docker image for the .NET kooboo CMS running on monofastcgi/nginx as an exercise. Here's the link if someone is interested: https://github.com/guillaume86/KoobooCMS https://github.com/guillaume86/KoobooCMS
vinceguidry 13y ago
After some careful thought, I can't see a place anymore for virtualization in a development workflow. If your hosting provider uses it, sure, whatever, but ideally you shouldn't be using it in development or working your production environment around it. Code should be written portably, it should depend on the language runtime, vendored libraries and nothing else. Finicky OS/language combos should be avoided, like Ruby on Windows. If you have to use virtualization to ensure that your dev/prod environments are the same, then that's a code smell. It should work the same on Ruby 2.1.0 on OSX in rbenv as it does on Ubuntu using the 2.1.0 BrightBox PPA install. The most important thing about 12 factor, in my opinion, is the separation of code and configuration. Everything that varies between environments and deploys should be considered configuration and off-loaded to a configuration management system. The VagrantFile embeds configuration directly into your code and makes your application less portable, not more. Configuration management should provide encapsulation at the level of a particular version of an operating system. You should be able to, by only changing your CM scripts, change your OS between different versions of Ubuntu, or even between Ubuntu and Red Hat. If you can't, that's a code smell. Your hosting provider should also be abstracted over and encapsulated as well. Changing hosting providers from Linode to Amazon should not require changing your OS scripts. All of this can and should be done without Big Design Up Front, it should not take you any longer to do this than to configure your app to support Docker. What this buys you is real robustness. Virtualization to me is a crutch that protects lazy programmers, it's fixing the wrong problem. If you find yourself relying on snapshots, it's a code smell and it will come back to bite you in the ass. If you think Docker is going to solve all your portability woes, you'll be in for a shock the first time your OS stops being supported by the vendor and you have to move to a new one. If you've done it the way I've described, then you can copy your CM script for the old OS to the new OS, try a cold deploy, and fix the small number of issues that will come up. If not, then you'll be in for a long weekend. Or worse, you won't do it at all, like the last five guys that came before me at my job.
- camus2 13y ago
  > The most important thing about 12 factor, in my opinion, is the separation of code and configuration. Nothing to do with configuration. Sometimes you need an envirronment where components of that env are not available on your system. For instance redis or nginx used to be linux only. Also it's easier to pass around images in a team,than installing manually every components or libraries one needs. No time is lost in setting up and configuring this or that. Further more virtualisation == 0 consequences on your machine.You can screw up stuff and experiment without worrying about doing something wrong,it doesnt matter. So no side-effects,no configuration,os independent,easy to share images => better development env. You dont have to use docker ,i dont, but cirtualisation really helps.

56 points by friism 13y ago

jmnicolas 13y ago

VirtualBox, Docker and Mono ... at one point you have to ask yourself isn't it too much virtualization ?

m_mueller 13y ago
You are missing the point I think: Running a setup like this allows developing and testing the environment only once for the first app you develop with these dependencies. You basically get deployment as well as the development environment for further projects based on this environment for 'free'. Having Docker between VirtualBox and Mono adds almost no overhead while giving you a nice clean slate with no environment properties from other projects that could somehow influence the runtime behavior. Now, the question for me is whether this is worth it for .Net - is Mono so good, that one would want to lock himself into a Linux-only environment like this?
jimmcslim 13y ago
VirtualBox: the author is using a Windows machine so needs to run Linux in order to experiment with Docker. Docker: well, this is the subject of the post. Mono: Mono is an application runtime (specifically an open-source implementation of the CLR) just like the JVM (yes, a 'Virtual Machine' but not virtualization, I would argue, in the sense that you are stating there is too much of). Obviously if you had .Net apps and a Windows server environment you would just deploy .Net apps to it. But there might be scenarios in which this is useful. Perhaps migrating away from Windows servers to Linux, but not wanting to rewrite the C#/.Net apps in a new platform. Although whether Mono would be able to run those apps satisfactorily (the coverage of the SDK is not complete) is of course up for debate.
- d0 13y ago
  The answer to your latter question is: no. Only pretty trivial stuff is portable to Mono. I've tried it on every project I've worked on over the last 6 years to no avail. Show stopper every time.
  - andyjohnson0 13y ago
    Interested in your experience. Were these projects desktop applications or server-side, or a mix of both?
    - d0 13y ago
      Mix of both. The killer on the server-side is always stuff like missing WCF features, odd bugs with DI containers, missing API calls, slight behavioural differences etc. Client-side. No WPF and WinForms is dreadfully incomplete. It's a no go. If you start on Mono and deploy to .Net I imagine it'd work but no-one realistically does that these days. If they were going to do that, Java would be a better choice for the product.
      - danabramov 13y ago
        Well, client-side Microsoft has abandoned both (although of course they still run).
        d0 13y ago
        They haven't abandoned any of them. We still have ATL, MFC, Win32, WPF, WinForms and now Metro. Not that I want to use any of them myself :)
  - Guillaume86 13y ago
    Yes it's a big disapointment for me, my predilection language is C# and I would love to be able to code on linux... I wish one day microsoft will be forced to port/support .NET (at least server components) to linux but I'm not holding my breath...
    - d0 13y ago
      I really don't want them to port it. I want to see Java 8!
      - 13y ago
cincinnatus 13y ago
It is abstraction layers all the way down. We all find our level of comfort in the stack, somewhere between the most abstract thing currently achievable and CPU microcode. In this particular case it makes something otherwise tedious much simpler, which is what adding abstraction is always about.

Guillaume86 13y ago

I experimented wih docker a few month ago and made a docker image for the .NET kooboo CMS running on monofastcgi/nginx as an exercise. Here's the link if someone is interested: https://github.com/guillaume86/KoobooCMS https://github.com/guillaume86/KoobooCMS

vinceguidry 13y ago

After some careful thought, I can't see a place anymore for virtualization in a development workflow. If your hosting provider uses it, sure, whatever, but ideally you shouldn't be using it in development or working your production environment around it. Code should be written portably, it should depend on the language runtime, vendored libraries and nothing else. Finicky OS/language combos should be avoided, like Ruby on Windows. If you have to use virtualization to ensure that your dev/prod environments are the same, then that's a code smell. It should work the same on Ruby 2.1.0 on OSX in rbenv as it does on Ubuntu using the 2.1.0 BrightBox PPA install. The most important thing about 12 factor, in my opinion, is the separation of code and configuration. Everything that varies between environments and deploys should be considered configuration and off-loaded to a configuration management system. The VagrantFile embeds configuration directly into your code and makes your application less portable, not more. Configuration management should provide encapsulation at the level of a particular version of an operating system. You should be able to, by only changing your CM scripts, change your OS between different versions of Ubuntu, or even between Ubuntu and Red Hat. If you can't, that's a code smell. Your hosting provider should also be abstracted over and encapsulated as well. Changing hosting providers from Linode to Amazon should not require changing your OS scripts. All of this can and should be done without Big Design Up Front, it should not take you any longer to do this than to configure your app to support Docker. What this buys you is real robustness. Virtualization to me is a crutch that protects lazy programmers, it's fixing the wrong problem. If you find yourself relying on snapshots, it's a code smell and it will come back to bite you in the ass. If you think Docker is going to solve all your portability woes, you'll be in for a shock the first time your OS stops being supported by the vendor and you have to move to a new one. If you've done it the way I've described, then you can copy your CM script for the old OS to the new OS, try a cold deploy, and fix the small number of issues that will come up. If not, then you'll be in for a long weekend. Or worse, you won't do it at all, like the last five guys that came before me at my job.

camus2 13y ago
> The most important thing about 12 factor, in my opinion, is the separation of code and configuration. Nothing to do with configuration. Sometimes you need an envirronment where components of that env are not available on your system. For instance redis or nginx used to be linux only. Also it's easier to pass around images in a team,than installing manually every components or libraries one needs. No time is lost in setting up and configuring this or that. Further more virtualisation == 0 consequences on your machine.You can screw up stuff and experiment without worrying about doing something wrong,it doesnt matter. So no side-effects,no configuration,os independent,easy to share images => better development env. You dont have to use docker ,i dont, but cirtualisation really helps.