The conclusion Docker is all about process isolation.
Docker is a clever use of OS-level virtualization support that allows multiple docker containers to run on a single machine. a container is a running instance of a container image. containers are by default seperated from one another and from the host machine.
- each docker container has its own private and loopback interface, just like a seperate os running in a seperate machine which re-inforce process isolation.
- docker basically has its own fucking network stack , isn't that wild
At a high level (which only what i know for now..), docker uses the following linux kernel features to isolate the processes: - cgroups (control groups) : limit, measure, and control the resources a process can use - namespaces : isolate the processes from the host machine - union file systems : overlay multiple file systems into a single one
What is the difference between VM adond container? Key Sentence: containers are about process isolation, VMs are about machine virtualization.
Two analogous way to look at the difference between containers and images: - like programs and processes. In the same way that a process is an executing program, a container is an executing image. - like classes and objects. In the same way that an object is an instance of a class, a container is an instance of an image.
READ CHAPTER 5 of Docker in Action book
fairly intresting course
absolutely intresting course
- Host file system pollution problem (e.g. node_modules, .env, etc.)
- Versions dependencies conflicts (e.g. node, npm, etc.)
- Different OS (e.g. Windows, Mac, Linux, etc.)
A study case (how netflix transitioned to microservices architecture)
- given we can create a 65is "how many containers we can create a single host