Dart lang应用程序与开放堆栈/ docker / vagrant

Question

I'm newbie for these techs (open stack / docker / vagrant), not sure if I understood them correctly (most likely did not), for me I understood it is something like having a portable application to run it with same development configuration to ensure all the development team have same setup, but did not understand, what after development, and how to get benefit from them with dart app.

my question is: 1. Correct my understanding 2. Do I need the end user to have these things installed in his system, and run my application through them, same as in the development stage? 3. How can I build/develop/distribute dart lang app through them, may be as hese as well as dart are new, I could not find enough info while googling.

thanks

Answer 1

Docker is similar to a virtual machine like VM-Ware or Virtualbox as it creates an abstraction layer between the host operating system and the operating system running within a Docker container. The difference is that Docker doesn't emulate the entire hardware. The disadvantage is that Docker only runs on Linux and only Linux can be run inside Docker. If your host is an Intel system you can't run an ARM Linux inside the container. (theoretically you can run Virtualbox inside Docker and run Windows. or other OSes in it)

With Docker you can test your application locally in the same environment as the application will run when deployed.

When you for example create an application you want to run in Google Compute Engine you install and test it locally inside a Docker container and then deploy the Docker container to Google Compute Engine as a whole unit. When there is a bug in the deployed application you should be able to reproduce it locally as well because it's just a 1:1 copy. No bug could have been introduce because the operating system or other dependencies were installed differently on the deployment environment than in the develeopment/test environment.

The Dockerfile is a set of instructions to set up a Docker container. If you want to create a new Docker container (for example for a new developer) you just let Docker process the Dockerfile and a new Docker container is created from it. This allows to easily create new Containers. If you want to update one dependency to a newer version or want to add remove components to/from the environment you change the Dockerfile and create a new container from it. This way you avoid that manual addition/removal form/to an existing container manually lets containers of different developers/testers/deployment diverge from each other.

I haven't used OpenStack myself but from the web page it seems to provide components and tools to build and manage your own cloud infrastructure.

I also haven't used Vagrant myself but it seems to help to automate a lot of tasks related to creating and managing virtual machines like VM-Ware, Virtualbox, Docker and probably others. When you have for example a server application it probably consist of a number of components you don't want all to run in one container but split up into several containers. One container for the Database, one for the web server, one for the backend application (created in Dart for example), and others. It can become cumbersome to manage all those containers. Vagrant helps to automate related tasks.