Pass
concept
Paltform as a server. Platform as a service, which rents out the software platform needed to run users as a service.
representative work
Various cloud service components on Alibaba Cloud, such as Kafka, redis, various databases, computing frameworks, etc.;
shortcoming
Once PaaS is used, users must maintain a package for each language, each framework, and even each version of the application. There are no rules to follow in this packaging process. What's more troublesome is that applications that run well locally require a lot of modification and configuration to run in PaaS.
Docker
What Docker image solves is precisely the fundamental problem of packaging . The so-called Docker image is actually a compressed package. Most Docker images are directly composed of all the files and directories of a complete operating system, so the contents of this compressed package are exactly the same as the operating system used in your local development and test environments.
More importantly, this compressed package contains the complete operating system files and directories, that is, all the dependencies required to run the application, so you can use this compressed package to develop and test locally first, and then Upload this compressed package to the cloud to run. In this process, you don't need to make any configuration or modification at all, because this compressed package gives you an extremely valuable ability: a high degree of consistency between the local environment and the cloud environment. This is the essence of Docker images.
The "dimension reduction blow" brought by the Docker project to the PaaS world actually provides a very convenient packaging mechanism . This mechanism directly packages the entire operating system required for the application to run , thereby ensuring a high degree of consistency between the local environment and the cloud environment, and avoiding the painful process of matching the differences between the two different operating environments for users through "trial and error".
OCI
The Open Container Initiative aims to completely separate the implementation of container runtimes and images from the Docker project.
Kubernetes
In a more gentle way, it has undertaken the unfinished business of the Docker project, namely: to build a relatively democratic and open container ecosystem with developers as the core. This is why, the success of the Kubernetes project is actually inevitable.
Reference Geekbang Time: https://time.geekbang.org/column/article/14406