docker基础用法

什么是docker

docker中的容器：

• lxc --> libcontainer --> runC

OCI

Open Container-initiative

• 由Linux基金会主导于2015年6月创立
• 旨在围绕容器格式和运行时制定一个开放的工业化标准
• contains two specifications
  • the Runtime Specification（runtime-spec）
  • the Image Specification（image-spec）

OCF

Open Container Format

runC is a CLI tool for spawning and running containers according to the OCI specification

• Containers are started as a child process of runC and can be embedded into various other systems without having to run a daemon
• runC is built on libcontainer, the same container technology powering millions of Docker Engine installations

docker提供了一个专门容纳容器镜像的站点：https://hub.docker.com

docker架构

docker镜像与镜像仓库

为什么镜像仓库名字是Registry而不是repository？在docker中仓库的名字是以应用的名称取名的。

镜像是静态的，而容器是动态的，容器有其生命周期，镜像与容器的关系类似于程序与进程的关系。镜像类似于文件系统中的程序文件，而容器则类似于将一个程序运行起来的状态，也即进程。所以容器是可以删除的，容器被删除后其镜像是不会被删除的。

docker对象

When you use docker, you are creating and using images, containers, networks, volumes, pluginns, and other objects.

• IMAGES
  • An image is a read-only template with instructions for creating a docker container.
  • Often, an image is based on another image, with some additional customization.
  • You might create your own images or you might only use those created by others and published in a registry.
• CONTAINERS
  • A conntainer is a runnable instance of an image.
  • You can create, run, stop, move, or delete a container using the docker API or CLI.
  • You can connect a container to one or more networks, attach storage to it, or even create a new image based on its current state.

docker加速

docker-ce的配置文件是/etc/docker/daemon.json，此文件默认不存在，需要我们手动创建并进行配置，而docker的加速就是通过配置此文件来实现的。

docker的加速有多种方式：

• docker cn
• 中国科技大学加速器
• 阿里云加速器（需要通过阿里云开发者平台注册帐号，免费使用个人私有的加速器

https://cr.console.aliyun.com/cn-hangzhou/instances/mirrors

[root@lvs ~]# systemctl start docker
[root@lvs docker]# cat daemon.json 
{
  "registry-mirrors": ["https://8iitoqxc.mirror.aliyuncs.com"]
}
[root@lvs docker]# 
[root@lvs docker]# systemctl restart docker
[root@lvs docker]# docker version
[root@lvs docker]# docker info
Client: Docker Engine - Community
 Version:    24.0.7
Insecure Registries:
  127.0.0.0/8
 Registry Mirrors:
  https://8iitoqxc.mirror.aliyuncs.com/   //看到这表示成功
 Live Restore Enabled: false

docker常用操作

命令	功能
docker search	Search the Docker Hub for images
docker pull	Pull an image or a repository from a registry
docker images	List images
docker create	Create a new conntainer
docker start	Start one or more stopped containers
docker run	Run a command in a new container
docker attach	Attach to a runninng container
docker ps	List containers
docker logs	Fetch the logs of a container
docker restart	Restart a container
docker stop	Stop one or more running containers
docker kill	Kill one or more running containers
docker rm	Remove onne or more containers
docker exec	Run a command in a running container
docker info	Display system-wide information
docker inspect	Return low-level information on Docker objects

[root@lvs ~]# docker search http
[root@lvs docker]# docker images
REPOSITORY   TAG       IMAGE ID   CREATED   SIZE
[root@lvs docker]# docker pull httpd
[root@lvs ~]# docker ps
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES
[root@lvs ~]# docker create --name httpd httpd
[root@lvs ~]# docker inspect httpd
[root@lvs ~]# docker ps -a
[root@lvs ~]# docker create --name httpd httpd
[root@lvs ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND              CREATED          STATUS       PORTS     NAMES
f22488055a15   httpd     "httpd-foreground"   58 seconds ago   Created                httpd
03cbb799ad7b   centos    "/bin/bash"          8 hours ago      Up 2 hours             https
[root@lvs ~]# docker start httpd  
httpd
# 容器退出后进入容器
[root@lvs ~]# docker exec -it https /bin/bash
[root@lvs ~]# docker kill https
# 把容器的端口映射到真机上面
[root@lvs ~]# docker ps 
CONTAINER ID   IMAGE     COMMAND       CREATED       STATUS         PORTS     NAMES
03cbb799ad7b   centos    "/bin/bash"   8 hours ago   Up 7 minutes             https
[root@lvs ~]# docker run -d --name centos -p 8080:80 https