1. The emergence of docker
A product goes from development to launch , from operating system, to operating environment, and to application configuration. As the cooperation between development + operation and maintenance, we need to care about many things. This is also a problem that many Internet companies have to face. Especially after the iteration of various versions, the compatibility of different versions of the environment is a test for operation and maintenance personnel.
The reason why Docker has developed so rapidly is also because it provides a standardized solution to this.
The environment configuration is so troublesome, and if you change a machine, you have to do it again, which is laborious and time-consuming. Many people think, can the problem be solved fundamentally, and the software can be installed with the environment? In other words, when installing, copy the original environment exactly. Developers can use Docker to eliminate the problem of "works on my machine" during collaborative coding.
Before configuring the running environment of an application on the server, you need to install various software, take the environment of the Silicon Valley e-commerce project, Java/Tomcat/MySQL/JDBC driver package, etc. Let's not say how troublesome it is to install and configure these things, it is not yet cross-platform. If we install these environments on Windows, we have to reinstall them when we reach Linux. Moreover, even if it does not cross operating systems, it is very troublesome to migrate applications to another server with the same operating system.
Traditionally, it is believed that after software coding development/testing is over, the result is a program or binary bytecode that can be compiled and executed (java as an example). In order for these procedures to be executed smoothly, the development team must also prepare a complete deployment file so that the maintenance team can deploy the application. The development needs to clearly inform the operation and maintenance deployment team of all configuration files + all software environments. However, even so, deployment failures still often occur. The design of the Docker image allows Docker to break the past "program is an application" concept. Excluding the core of the operating system through images (images), the system environment required to run the application is packaged from bottom to top to achieve cross-application