一.什么是docker容器

docker是容器技术的一个前端工具，容器是内核的一项技术，docker只是把这一项技术的使用得以简化，使之普及而已

docker中的容器：

  • lxc --> libcontainer --> runC

二.OCI&OCF

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
  • 包含两个规格
  • the Runtime Specification（runtime-spec）  运行时的规范
  • the Image Specification（image-spec） 镜像的规范

OCF

Open Container Format（开放的容器格式）

runC is a CLI tool for spawning and running containers according to the OCI specification（是一个根据OCI标准来创建和运行容器的命令行工具）

  • Containers are started as a child process of runC and can be embedded into various other systems without having to run a daemon（将容器启动为runC的子进程 可以嵌入到其他各种系统中，而无需运行守护进程）
  • runC is built on libcontainer, the same container technology powering millions of Docker Engine installations（runC构建在libcontainer之上，以同样的技术支持着很多人使用）

三.docker架构

docker部署阅读 docker in practice_Docker

dock客户端和主机在一台主机上，客户机执行命令，向主机发送请求寻找服务，查找本地有无此服务，有的话就则启动，没有则去镜像中下载后启动
docker-ee 付费

docker--ee 企业版商业化，需要付费

docker--ce 开源版本

四.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。

docker部署阅读 docker in practice_linux_02

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

五.docker对象

When you use docker, you are creating and using images, containers, networks, volumes, pluginns, and other objects.（当你在使用docker时，你可以去创建和使用镜像、容器、网络、卷、插件和其他对象）

  • IMAGES（镜像）
  • An image is a read-only template with instructions for creating a docker container.（镜像是一个只读的模板，用来创建docker容器的模板）
  • Often, an image is based on another image, with some additional customization.（通常来说，镜像是基于另一个镜像，并带有一些额外的定制）
  • You might create your own images or you might only use those created by others and published in a registry.（您可以创建自己所拥有镜像，也可以只使用其他人创建并且发布在仓库中的镜像）
  • CONTAINERS（容器）
  • A conntainer is a runnable instance of an image.（容器是一个运行中的镜像）
  • You can create, run, stop, move, or delete a container using the docker API or CLI.（你可以去创建、运行、停止、移动或者删除一个容器，用docker的API或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（您可以将一个容器连接到一个或多个网络，并且附加存储到容器中，并且基于你当前的状态创造一个镜像）

六.安装及使用docker

1.docker安装

[root@localhost yum.repos.d]# yum -y install wget vim    //安装wget和vim
[root@localhost yum.repos.d]# ls
CentOS-Base.repo   epel.repo                  epel-testing.repo
epel-modular.repo  epel-testing-modular.repo  redhat.repo
[root@localhost yum.repos.d]# wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo   //下载docker源
[root@localhost yum.repos.d]# ls
CentOS-Base.repo   epel.repo                  redhat.repo
docker-ce.repo     epel-testing-modular.repo
epel-modular.repo  epel-testing.repo
[root@localhost ~]# dnf makecache     //建立缓存
[root@localhost ~]# dnf -y install docker-ce   //安装docker-ce

 2.docker加速

[root@localhost ~]# ls /etc/docker   //查看配置文件
ls: 无法访问'/etc/docker': 没有那个文件或目录
[root@localhost ~]# systemctl enable --now docker    //开启docker，并且加入开机自启
Created symlink /etc/systemd/system/multi-user.target.wants/docker.service → /usr/lib/systemd/system/docker.service.
[root@localhost ~]# systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vend>
   Active: active (running) since Sun 2022-04-24 20:26:50 CST
[root@localhost ~]# ls /etc/docker     //再次查看，则已经有了配置文件
key.json

[root@localhost ~]# cd /etc/docker/
[root@localhost docker]# ls
key.json
[root@localhost docker]# vim daemon.json
[root@localhost docker]# cat daemon.json 
{
          "registry-mirrors": ["https://onmth88j.mirror.aliyuncs.com"]
}
[root@localhost docker]# systemctl daemon-reload
[root@localhost docker]# systemctl restart docker
[root@localhost docker]# docker info
Client:
 Context:    default
 Debug Mode: false
 Plugins:
  app: Docker App (Docker Inc., v0.9.1-beta3)
  buildx: Docker Buildx (Docker Inc., v0.8.1-docker)
  scan: Docker Scan (Docker Inc., v0.17.0)

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 0
 Server Version: 20.10.14
 Storage Driver: overlay2
  Backing Filesystem: xfs
  Supports d_type: true
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 1
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 io.containerd.runtime.v1.linux runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 3df54a852345ae127d1fa3092b95168e4a88e2f8
 runc version: v1.0.3-0-gf46b6ba
 init version: de40ad0
 Security Options:
  seccomp
   Profile: default
 Kernel Version: 4.18.0-193.el8.x86_64
 Operating System: Red Hat Enterprise Linux 8.2 (Ootpa)
 OSType: linux
 Architecture: x86_64
 CPUs: 1
 Total Memory: 1.757GiB
 Name: localhost.localdomain
 ID: 3QCD:ZJMJ:VE6H:US3E:CUR4:Y5LC:OBH5:J5SS:VA2Y:7MKF:Y5UJ:OO3N
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Registry Mirrors:
  https://onmth88j.mirror.aliyuncs.com/     //有此行则代表加速器配置成功
 Live Restore Enabled: false

3.docker的常用操作

docker search ——从docker hub 查找镜像

[root@localhost ~]# docker search httpd  //查找带有httpd的镜像
NAME                                 DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED
httpd                                The Apache HTTP Server Project                  3976      [OK]       
centos/httpd-24-centos7              Platform for running Apache httpd 2.4 or bui…   44                   
centos/httpd                                                                         35                   [OK]
hypoport/httpd-cgi                   httpd-cgi 
                                      2                    [OK]

docker pull ——从镜像仓库中拉取镜像

[root@localhost ~]# docker pull httpd   //拉取httpd镜像，可以在拉取的镜像后加：和版本号，如果不接则自动拉取最新版本
Using default tag: latest
latest: Pulling from library/httpd
a2abf6c4d29d: Pull complete 
dcc4698797c8: Pull complete 
41c22baa66ec: Pull complete 
67283bbdd4a0: Pull complete 
d982c879c57e: Pull complete 
Digest: sha256:0954cc1af252d824860b2c5dc0a10720af2b7a3d3435581ca788dff8480c7b32
Status: Downloaded newer image for httpd:latest
docker.io/library/httpd:latest

docker images——列出所有镜像

[root@localhost ~]# docker images
REPOSITORY   TAG       IMAGE ID       CREATED        SIZE
httpd        latest    dabbfbe0c57b   4 months ago   144MB

docker create——创造一个新的容器

[root@localhost ~]# docker create --name web -p 80:80 httpd    //创造一个名字为web的容器，指定端口号为80端口
ae628538767484d218b382b01b90ea0f091ddfa724a3e677dc21518dd6635f7e

docker ps ——列出容器

[root@localhost ~]# docker ps  //列出正在运行的容器
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES
[root@localhost ~]# docker ps -a  //参数 -a 列出所有容器，包括未开启的
CONTAINER ID   IMAGE     COMMAND              CREATED              STATUS    PORTS     NAMES
ae6285387674   httpd     "httpd-foreground"   About a minute ago   Created             web

docker start ——启动容器

[root@localhost ~]# docker start web   //启动web容器，使用name启动，也可以使用id号启动
web
[root@localhost ~]# docker ps
CONTAINER ID   IMAGE     COMMAND              CREATED         STATUS         PORTS                               NAMES
ae6285387674   httpd     "httpd-foreground"   8 minutes ago   Up 2 minutes   0.0.0.0:80->80/tcp, :::80->80/tcp   web

docker stop ——关闭容器

[root@localhost ~]# docker stop ae6285387674  //关闭web容器，可使用id关闭也可以使用name
ae6285387674
[root@localhost ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND              CREATED         STATUS                     PORTS     NAMES
ae6285387674   httpd     "httpd-foreground"   9 minutes ago   Exited (0) 4 seconds ago             web

docker restart——重启容器

[root@localhost ~]# docker restart web
web
[root@localhost ~]# docker ps
CONTAINER ID   IMAGE     COMMAND              CREATED          STATUS         PORTS                               NAMES
ae6285387674   httpd     "httpd-foreground"   12 minutes ago   Up 2 seconds   0.0.0.0:80->80/tcp, :::80->80/tcp   web

docker kill——杀死运行中的容器

stop正常关闭 kill强制关闭

[root@localhost ~]# docker kill web
web
[root@localhost ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND              CREATED          STATUS                       PORTS     NAMES
ae6285387674   httpd     "httpd-foreground"   14 minutes ago   Exited (137) 4 seconds ago

docker logs——查看日志

[root@localhost ~]# docker logs web

docker rm ——删除一个或者多个容器，运行时可以不删除

在容器运行时，rm无法删除容器，但是加上参数-f 即可强制删除

但镜像依然存在

[root@localhost ~]# docker rm -f web
web
[root@localhost ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES
[root@localhost ~]# docker images
REPOSITORY   TAG       IMAGE ID       CREATED        SIZE
httpd        latest    dabbfbe0c57b   4 months ago   144MB

docker run ——创建一个新的容器并且运行一个命令

[root@localhost ~]# docker run -it --name test busybox /bin/sh
Unable to find image 'busybox:latest' locally
latest: Pulling from library/busybox
5cc84ad355aa: Pull complete 
Digest: sha256:5acba83a746c7608ed544dc1533b87c737a0b0fb730301639a0179f9344b1678
Status: Downloaded newer image for busybox:latest
/ # 
/ # exit  //退出会直接关闭容器
[root@localhost ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND     CREATED              STATUS                     PORTS     NAMES
45832a741a6c   busybox   "/bin/sh"   About a minute ago   Exited (0) 2 seconds ago             test

docker attach ——连接到正在运行的容器

[root@localhost ~]# docker start test
test
[root@localhost ~]# docker attach test
/ # exit
[root@localhost ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND     CREATED         STATUS                     PORTS     NAMES
45832a741a6c   busybox   "/bin/sh"   4 minutes ago   Exited (0) 2 seconds ago             test

docker exec ——在运行的容器中执行命令

[root@localhost ~]# docker start test
test
[root@localhost ~]# docker exec -it test /bin/sh
/ # exit
[root@localhost ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND     CREATED         STATUS         PORTS     NAMES
45832a741a6c   busybox   "/bin/sh"   7 minutes ago   Up 2 minutes             test