什么是docker

docker中的容器：

• lxc --> libcontainer --> runC

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
• 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

Docker镜像，容器，网络，卷，插件等是Docker对象。

在Dockerland，有镜像，有容器。这两者密切相关，但截然不同。但这一切都始于Dockerfile。

一个Dockerfile是您创建镜像时，你建立的一个文件。它包含一堆指令，告知Docker如何构建Docker镜像。

你可以把它与烹饪联系起来。在烹饪中你有食谱。通过配方，您可以了解必须采取的所有步骤，以便生成您想要烹饪的任何内容。烹饪行为正在建立食谱。
 

docker安装

下载 centos源 epel源  docker源

docker加速

启动服务  开机自启
[root@localhost ~]# systemctl enable --now docker
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; vendo>
   Active: active (running) since Sun 2022-04-24 16:11:11 CST; 36s 

 

[root@localhost ~]# cd /etc/docker/
[root@localhost docker]# ls
key.json
[root@localhost docker]# vi daemon.json
[root@localhost docker]# vi daemon.json
[root@localhost docker]# systemctl daemon-reload
[root@localhost docker]# systemctl restart docker
[root@localhost docker]# cd
[root@localhost ~]# 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: 4.18.0-365.el8.x86_64
 Operating System: CentOS Stream 8
 OSType: linux
 Architecture: x86_64
 CPUs: 2
 Total Memory: 1.744GiB
 Name: localhost
 ID: DJ4R:W3Q2:3VDI:FAJ4:W4PM:GMMX:TMIJ:WVQR:CVCN:ELIL:J5LX:NSCM
 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://4tw3yr47.mirror.aliyuncs.com/
 Live Restore Enabled: false

[root@localhost ~]# docker version
Client: Docker Engine - Community
 Version:           20.10.14
 API version:       1.41
 Go version:        go1.16.15
 Git commit:        a224086
 Built:             Thu Mar 24 01:47:44 2022
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true

Server: Docker Engine - Community
 Engine:
  Version:          20.10.14
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.16.15
  Git commit:       87a90dc
  Built:            Thu Mar 24 01:46:10 2022
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.5.11
  GitCommit:        3df54a852345ae127d1fa3092b95168e4a88e2f8
 runc:
  Version:          1.0.3
  GitCommit:        v1.0.3-0-gf46b6ba
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

docker常用操作

命令	功能
docker search	在 Docker Hub 中搜索镜像
docker pull	从注册表中拉取镜像或存储库
docker images	列出镜像
docker create	创建一个新的容器
docker start	启动一个或多个停止的容器
docker run	在新容器中运行命令
docker attach	附加到正在运行的容器
docker ps	列出容器
docker logs	获取容器的日志
docker restart	重启一个容器
docker stop	停止一个或多个正在运行的容器
docker kill	杀死一个或多个正在运行的容器
docker rm	移除一个或多个容器
docker exec	在正在运行的容器中运行命令
docker info	显示系统范围的信息
docker inspect	返回有关 Docker 对象的低级信息

docker search

[root@localhost ~]# docker search httpd
NAME                                 DESCRIPTION                                STARS     OFFICIAL   AUTOMATED
httpd                                The Apache HTTP Server Project             3975      [OK]       
centos/httpd-24-centos7              Platform for running Apache http or bui…   44                   
centos/httpd                                                                    35                   [OK]
hypoport/httpd-cgi                   httpd-cgi                                  2                    [OK]
solsson/httpd-openidc                mod_auth_openidc on official httage, ve…   2                    [OK]
manageiq/httpd                       Container with httpd, built on C for Ma…   1                    [OK]
lead4good/httpd-fpm                  httpd server which connects via proxy h…   1                    [OK]
dockerpinata/httpd                                                              1                    
publici/httpd                        httpd:latest                               1                    [OK]
dariko/httpd-rproxy-ldap             Apache httpd reverse proxy with authent…   1                    [OK]
inanimate/httpd-ssl                  A play container with httpd, sslled, an…   1                    [OK]
centos/httpd-24-centos8                                                         1                    
clearlinux/httpd                     httpd HyperText Transfer ProtocoTP) ser…   1                    
manageiq/httpd_configmap_generator   Httpd Configmap Generator                  0                    [OK]
manasip/httpd                                                                   0                    
e2eteam/httpd                                                                   0                    
paketobuildpacks/httpd                                                          0                    
httpdocker/kubia                                                                0                    
sandeep1988/httpd-new                httpd-new                                  0                    
httpdocker/kubia-unhealthy                                                      0                    
amd64/httpd                          The Apache HTTP Server Project             0                    
patrickha/httpd-err                                                             0                    
httpdss/archerysec                   ArcherySec repository                      0                    [OK]
19022021/httpd-connection_test       This httpd image will test the ctivity …   0                    
itsziget/httpd24                     Extended HTTPD Docker image basethe off…   0                    [OK]

docker pull  

[root@localhost ~]# docker pull httpd
Using default tag: latest 
latest: Pulling from library/httpd           最新的

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

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

docker create 创建容器 docker ps 查看     docker start开启 

[root@localhost ~]# docker create --name web -p 80:80 httpd
30aadc28b10b37ba01301649d3a84722c0ba13d512acf15f112dd8e9f30a4f28
[root@localhost ~]# docker ps
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES
[root@localhost ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND              CREATED          STATUS    PORTS     NAMES
30aadc28b10b   httpd     "httpd-foreground"   32 seconds ago   Created             web
[root@localhost ~]# docker start web
web
[root@localhost ~]# docker ps
CONTAINER ID   IMAGE     COMMAND              CREATED              STATUS         PORTS                               NAMES
30aadc28b10b   httpd     "httpd-foreground"   About a minute ago   Up 5 seconds   0.0.0.0:80->80/tcp, :::80->80/tcp   web


然后关闭防火墙 就可以访问

 

docker stop 停用容器

[root@localhost ~]# docker stop 30aadc28b10b   用id停用 也可
30aadc28b10b
[root@localhost ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND              CREATED         STATUS                     PORTS     NAMES
30aadc28b10b   httpd     "httpd-foreground"   7 minutes ago   Exited (0) 5 seconds ago             web

docker restart  重启容易

[root@localhost ~]# docker restart web
web
[root@localhost ~]# docker ps
CONTAINER ID   IMAGE     COMMAND              CREATED          STATUS         PORTS                               NAMES
30aadc28b10b   httpd     "httpd-foreground"   12 minutes ago   Up 5 seconds   0.0.0.0:80->80/tcp, :::80->80/tcp   web

docker kill  强制退出

[root@localhost ~]# docker kill web
web
[root@localhost ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND              CREATED          STATUS                  PORTS     NAMES
30aadc28b10b   httpd     "httpd-foreground"   13 minutes ago   Exited) 6 seconds ago             web

docker logs 

[root@localhost ~]# docker logs web
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 172.17.0.2. Set the 'ServerName' directive globally to suppress this message
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 172.17.0.2. Set the 'ServerName' directive globally to suppress this message
[Sun Apr 24 09:40:07.676129 2022] [mpm_event:notice] [pid 1:tid 139654408637760] AH00489: Apache/2.4.52 (Unix) configured -- resuming normal operations
[Sun Apr 24 09:40:07.676400 2022] [core:notice] [pid 1:tid 139654408637760] AH00094: Command line: 'httpd -D FOREGROUND'
10.10.10.1 - - [24/Apr/2022:09:43:03 +0000] "GET /favicon.ico HTTP/1.1" 404 196
10.10.10.1 - - [24/Apr/2022:09:43:04 +0000] "GET /favicon.ico HTTP/1.1" 404 196
10.10.10.1 - - [24/Apr/2022:09:43:06 +0000] "GET / HTTP/1.1" 200 45
10.10.10.1 - - [24/Apr/2022:09:43:06 +0000] "GET /favicon.ico HTTP/1.1" 404 196
10.10.10.1 - - [24/Apr/2022:09:43:07 +0000] "GET /favicon.ico HTTP/1.1" 404 196

docker rm

[root@localhost ~]# docker rm -f web
web
[root@localhost ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES


容易删除 镜像还在

docker run

[root@localhost ~]# docker run -it --name test busybox /bin/sh    交互模式
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
/ # ip a
1: lo:  mtu 65536 qdisc noqueue qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
11: eth0@if12:  mtu 1500 qdisc noqueue 
    link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.2/16 brd 172.17.255.255 scope global eth0
       valid_lft forever preferred_lft forever
/ # exit 

docker attach

[root@localhost ~]# docker attach test
/ # 

docker exec

[root@localhost ~]# docker exec -it test /bin/sh
/ #  ip a 
/ # ip a
1: lo:  mtu 65536 qdisc noqueue qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
11: eth0@if12:  mtu 1500 qdisc noqueue 
    link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.2/16 brd 172.17.255.255 scope global eth0
       valid_lft forever preferred_lft forever
/ # exit