[Docker 배우기] Section 7. Docker Engine, Storage, and Networking

Docker for the Absolute Beginner - Hands On - DevOps | Udemy

 

Docker Engine

Docker Engine is composed of:

• Docker CLI: running command
  • does not have to be on the same machine with other parts
    • can use the docker -H option to connect to the remote docker-engine
• REST API: interact with docker Deamon
• Docker Deamon: running in the background to execute tasks

PID: id for a process that is unique to the process

• PID can have the same name for both the system and the container, but the PID in the container is changed into a different PID on the system

There is no limit to how much a container can utilize the resources.

• using --cpus and --memory in the docker run can limit the resources used by a container

Docker Storage

By using layered architecture, it greatly reduces the storage size by reusing the existing layer.

 

When a container is running, a new layer called “container layer” is put on top of other layers where modifications can happen.

• The container layer is read/write while image layers are read only.
  • To modify a file in image layers, it is copied to the container layer before writing

docker volume: used to create volume in the docker file system which can be connected to the container layer later on

• mounting volume without creating it creates the
• docker run -v [local]:[internal]

Docker Network

Mapping the network of the container to the host allows it to share the same port with the host.

 

docker network create: used to create another internal network within the docker host.

 

docker network ls: lists all network

 

By using docker inspect, the network of a container can be checked.

 

Docker has a built-in DNS server that allows to access another container by name and not internal IP addresses