Docker核心概念容器

使用容器运行Nginx应用

查找本地容器镜像文件

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执行命令过程一：下载容器镜像
# docker run -d nginx:latest
Unable to find image 'nginx:latest' locally
latest: Pulling from library/nginx
a2abf6c4d29d: Downloading  1.966MB/31.36MB 下载中
a9edb18cadd1: Downloading  1.572MB/25.35MB
589b7251471a: Download complete 下载完成
186b1aaa4aa6: Download complete
b4df32aa5a72: Waiting 等待下载
a0bcbecc962e: Waiting
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执行命令过程二：下载容器镜像
[root@localhost ~]# docker run -d nginx:latest
Unable to find image 'nginx:latest' locally
latest: Pulling from library/nginx
a2abf6c4d29d: Downloading  22.87MB/31.36MB
a9edb18cadd1: Downloading  22.78MB/25.35MB
589b7251471a: Waiting
186b1aaa4aa6: Waiting
b4df32aa5a72: Waiting
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执行命令过程三：下载容器镜像
[root@localhost ~]# docker run -d nginx:latest
Unable to find image 'nginx:latest' locally
latest: Pulling from library/nginx
a2abf6c4d29d: Pull complete 下载完成
a9edb18cadd1: Pull complete
589b7251471a: Pull complete
186b1aaa4aa6: Pull complete
b4df32aa5a72: Waiting 等待下载

1.1.2 观察容器运行情况

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# docker run -d nginx:latest
9834c8c18a7c7c89ab0ea4119d11bafe9c18313c8006bc02ce57ff54d9a1cc0c
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命令解释
docker run 启动一个容器
-d 把容器镜像中需要执行的命令以daemon（守护进程）的方式运行
nginx 应用容器镜像的名称，通常表示该镜像为某一个软件
latest 表示上述容器镜像的版本，表示最新版本，用户可自定义其标识，例如v1或v2等
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# docker ps
CONTAINER ID   IMAGE        COMMAND                  CREATED          STATUS        PORTS     NAMES
9834c8c18a7c   nginx:latest "/docker-entrypoint.…"   24 seconds ago   Up 23 seconds 80/tcp condescending_pare
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命令解释
docker ps 类似于Linux系统的ps命令，查看正在运行的容器，如果想查看没有运行的容器，需要在此命令后使用--all

输出内容解释

CONTAINERID IMAGE COMMAND CREATED STATUS PORTS NAMES
9834c8c18a7c nginx:latest “/docker-entrypoint.…” 24 seconds ago Up 23 seconds 80/tcp condescending_pare

1.2 访问容器中运行的Nginx服务

1.2.1 确认容器IP地址

实际工作中不需要此步操作。

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 # docker inspect 9834
 
 "GlobalIPv6Address": "",
            "GlobalIPv6PrefixLen": 0,
            "IPAddress": "172.17.0.2", 容器IP地址
            "IPPrefixLen": 16,
            "IPv6Gateway": "",
            "MacAddress": "02:42:ac:11:00:02",
            "Networks": {
                "bridge": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "d3de2fdbc30ee36a55c1431ef3ae4578392e552009f00b2019b4720735fe5a60",
                    "EndpointID": "d91f47c9f756ff22dc599a207164f2e9366bd0c530882ce0f08ae2278fb3d50c",
                    "Gateway": "172.17.0.1",
                    "IPAddress": "172.17.0.2",   容器IP地址
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:00:02",
                    "DriverOpts": null
                }
            }
        }
    }
]
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命令解释
docker inspect 为查看容器结构信息命令
9834 为前面生成的容器ID号前4位，使用这个ID号时，由于其较长，使用时能最短识别即可。

1.2.2 容器网络说明

image-20220121172037253

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# ip a s
......
docker0网桥，用于为容器提供桥接，转发到主机之外的网络
5: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
    link/ether 02:42:d5:c3:d4:cc brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:d5ff:fec3:d4cc/64 scope link
       valid_lft forever preferred_lft forever
       
       
与容器中的虚拟网络设备在同一个命名空间中，用于把容器中的网络连接到主机
9: veth393dece@if8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP group default
    link/ether 02:e3:11:58:54:0f brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet6 fe80::e3:11ff:fe58:540f/64 scope link
       valid_lft forever preferred_lft forever

1.2.3 使用curl命令访问

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# curl http://172.17.0.2

返回结果，表示访问成功！
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

二、Docker命令

2.1 Docker命令获取帮助方法

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# docker -h
Flag shorthand -h has been deprecated, please use --help

Usage:  docker [OPTIONS] COMMAND  用法

A self-sufficient runtime for containers 功能介绍

Options: 选项
      --config string      Location of client config files (default "/root/.docker")
  -c, --context string     Name of the context to use to connect to the daemon (overrides
                           DOCKER_HOST env var and default context set with "docker context use")
  -D, --debug              Enable debug mode
  -H, --host list          Daemon socket(s) to connect to
  -l, --log-level string   Set the logging level ("debug"|"info"|"warn"|"error"|"fatal")
                           (default "info")
      --tls                Use TLS; implied by --tlsverify
      --tlscacert string   Trust certs signed only by this CA (default "/root/.docker/ca.pem")
      --tlscert string     Path to TLS certificate file (default "/root/.docker/cert.pem")
      --tlskey string      Path to TLS key file (default "/root/.docker/key.pem")
      --tlsverify          Use TLS and verify the remote
  -v, --version            Print version information and quit

Management Commands: 管理类命令
  app*        Docker App (Docker Inc., v0.9.1-beta3)
  builder     Manage builds
  buildx*     Docker Buildx (Docker Inc., v0.7.1-docker)
  config      Manage Docker configs
  container   Manage containers
  context     Manage contexts
  image       Manage images
  manifest    Manage Docker image manifests and manifest lists
  network     Manage networks
  node        Manage Swarm nodes
  plugin      Manage plugins
  scan*       Docker Scan (Docker Inc., v0.12.0)
  secret      Manage Docker secrets
  service     Manage services
  stack       Manage Docker stacks
  swarm       Manage Swarm
  system      Manage Docker
  trust       Manage trust on Docker images
  volume      Manage volumes

Commands: 未分组命令
  attach      Attach local standard input, output, and error streams to a running container
  build       Build an image from a Dockerfile
  commit      Create a new image from a container's changes
  cp          Copy files/folders between a container and the local filesystem
  create      Create a new container
  diff        Inspect changes to files or directories on a container's filesystem
  events      Get real time events from the server
  exec        Run a command in a running container
  export      Export a container's filesystem as a tar archive
  history     Show the history of an image
  images      List images
  import      Import the contents from a tarball to create a filesystem image
  info        Display system-wide information
  inspect     Return low-level information on Docker objects
  kill        Kill one or more running containers
  load        Load an image from a tar archive or STDIN
  login       Log in to a Docker registry
  logout      Log out from a Docker registry
  logs        Fetch the logs of a container
  pause       Pause all processes within one or more containers
  port        List port mappings or a specific mapping for the container
  ps          List containers
  pull        Pull an image or a repository from a registry
  push        Push an image or a repository to a registry
  rename      Rename a container
  restart     Restart one or more containers
  rm          Remove one or more containers
  rmi         Remove one or more images
  run         Run a command in a new container
  save        Save one or more images to a tar archive (streamed to STDOUT by default)
  search      Search the Docker Hub for images
  start       Start one or more stopped containers
  stats       Display a live stream of container(s) resource usage statistics
  stop        Stop one or more running containers
  tag         Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
  top         Display the running processes of a container
  unpause     Unpause all processes within one or more containers
  update      Update configuration of one or more containers
  version     Show the Docker version information
  wait        Block until one or more containers stop, then print their exit codes

2.2 Docker官网提供的命令说明

网址链接：https://docs.docker.com/reference/

image-20220121173519802

image-20220121173613294

image-20220121173705508

2.3 docker命令应用

2.3.1 docker run

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# docker run -i -t --name c1 centos:latest bash
[root@948f234e22a1 /]#
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命令解释
docker run 运行一个命令在容器中，命令是主体，没有命令容器就会消亡
-i 交互式
-t 提供终端
--name c1 把将运行的容器命名为c1
centos:latest 使用centos最新版本容器镜像
bash 在容器中执行的命令
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查看主机名
[root@948f234e22a1 /]#
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查看网络信息
[root@948f234e22a1 /]# ip a s
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 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
12: eth0@if13: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
    link/ether 02:42:ac:11:00:03 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 172.17.0.3/16 brd 172.17.255.255 scope global eth0
       valid_lft forever preferred_lft forever
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查看进程
[root@948f234e22a1 /]# ps aux
USER        PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root          1  0.0  0.1  12036  2172 pts/0    Ss   09:58   0:00 bash
root         16  0.0  0.0  44652  1784 pts/0    R+   10:02   0:00 ps aux
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查看用户
[root@948f234e22a1 /]# cat /etc/passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:65534:65534:Kernel Overflow User:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
systemd-coredump:x:999:997:systemd Core Dumper:/:/sbin/nologin
systemd-resolve:x:193:193:systemd Resolver:/:/sbin/nologin
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查看目录
[root@948f234e22a1 /]# pwd
/
[root@948f234e22a1 /]# ls
bin  etc   lib    lost+found  mnt  proc  run   srv  tmp  var
dev  home  lib64  media       opt  root  sbin  sys  usr
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退出命令执行，观察容器运行情况
[root@948f234e22a1 /]# exit
exit
[root@localhost ~]#

2.3.2 docker ps

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# docker ps
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES
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命令解释
docker ps 查看正在运行的容器，本案例由于没有命令在容器中运行，因此容器被停止了，所以本次查看没有结果。
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# docker ps --all
CONTAINER ID   IMAGE           COMMAND     CREATED             STATUS                         PORTS     NAMES
948f234e22a1   centos:latest   "bash"    10 minutes ago      Exited (0) 2 minutes ago                    c1
CONTAINERID IMAGE COMMAND CREATED STATUS PORTS NAMES
948f234e22a1 centos:latest “bash” 10 minutes ago Exited (0) 2 minutes ago c1 
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命令解释
docker ps --all 可以查看正在运行的和停止运行的容器

2.3.3 docker inspect

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# docker run -it --name c2 centos:latest bash
[root@9f2eea16da4c /]# 
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操作说明
在上述提示符处按住ctrl键，再按p键与q键，可以退出交互式的容器，容器会处于运行状态。
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# docker ps
CONTAINER ID   IMAGE           COMMAND   CREATED          STATUS          PORTS     NAMES
9f2eea16da4c   centos:latest   "bash"    37 seconds ago   Up 35 seconds             c2
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命令解释
可以看到容器处于运行状态
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# docker inspect c2

"Networks": {
                "bridge": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "d3de2fdbc30ee36a55c1431ef3ae4578392e552009f00b2019b4720735fe5a60",
                    "EndpointID": "d1a2b7609f2f73a6cac67229a4395eef293f695c0ac4fd6c9c9e6913c9c85c1c",
                    "Gateway": "172.17.0.1",
                    "IPAddress": "172.17.0.2",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:00:02",
                    "DriverOpts": null
                }
            }
        }
    }
]

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命令解释
docker inpect 查看容器详细信息

2.3.4 docker exec

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# docker exec -it c2 ls /root
anaconda-ks.cfg  anaconda-post.log  original-ks.cfg
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命令解释
docker exec 在容器外实现与容器交互执行某命令
-it 交互式
c2 正在运行的容器名称
ls /root 在正在运行的容器中运行相关的命令
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下面命令与上面命令执行效果一致
# docker exec c2 ls /root
anaconda-ks.cfg
anaconda-post.log
original-ks.cfg

2.3.5 docker attach

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查看正在运行的容器
# docker ps
CONTAINER ID   IMAGE           COMMAND   CREATED          STATUS          PORTS     NAMES
9f2eea16da4c   centos:latest   "bash"    13 minutes ago   Up 13 minutes             c2
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[root@localhost ~]# docker attach c2
[root@9f2eea16da4c /]#
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命令解释
docker attach 类似于ssh命令，可以进入到容器中
c2 正在运行的容器名称
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说明
docker attach 退出容器时，如不需要容器再运行，可直接使用exit退出；如需要容器继续运行，可使用ctrl+p+q

2.3.6 docker stop

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# docker ps
CONTAINER ID   IMAGE           COMMAND   CREATED          STATUS          PORTS     NAMES
9f2eea16da4c   centos:latest   "bash"    22 minutes ago   Up 22 minutes             c2
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# docker stop 9f2eea
9f2eea
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# docker ps --all
CONTAINER ID   IMAGE           COMMAND                  CREATED          STATUS                       PORTS     NAMES
9f2eea16da4c   centos:latest   "bash"                   22 minutes ago   Exited (137) 4 seconds ago             c2

2.3.7 docker start

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# docker ps --all
CONTAINER ID   IMAGE           COMMAND     CREATED          STATUS                       PORTS     NAMES
9f2eea16da4c   centos:latest   "bash"      22 minutes ago   Exited (137) 4 seconds ago              c2
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# docker start 9f2eea
9f2eea
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# docker ps
CONTAINER ID   IMAGE           COMMAND   CREATED          STATUS          PORTS     NAMES
9f2eea16da4c   centos:latest   "bash"    24 minutes ago   Up 16 seconds             c2

2.3.8 docker top

在Docker Host查看容器中运行的进程信息

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# docker top c2
UID    PID     PPID      C      STIME        TTY              TIME                CMD
root  69040   69020      0      18:37       pts/0           00:00:00              bash
UID PID PPID C STIME TTY TIME CMD
root 69040 69020 0 18:37 pts/0 00:00:00 bash 
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命令解释
docker top 查看container内进程信息，指在docker host上查看，与docker exec -it c2 ps -ef不同。
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输出说明
UID 容器中运行的命令用户ID
PID 容器中运行的命令PID
PPID 容器中运行的命令父PID，由于PPID是一个容器，此可指为容器在Docker Host中进程ID
C     占用CPU百分比
STIME 启动时间
TTY   运行所在的终端
TIME  运行时间
CMD   执行的命令

2.3.9 docker rm

如果容器已停止，使用此命令可以直接删除；如果容器处于运行状态，则需要提前关闭容器后，再删除容器。下面演示容器正在运行关闭后删除的方法。

2.3.9.1 指定删除容器

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# docker ps
CONTAINER ID   IMAGE           COMMAND   CREATED      STATUS         PORTS     NAMES
9f2eea16da4c   centos:latest   "bash"    2 days ago   Up 3 seconds             c2
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# docker stop c2
或
# docker stop 9f2eea16da4c
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# docker rm c2
或
# docker rm 9f2eea16da4c

2.3.9.2 批量删除容器

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# docker ps --all
CONTAINER ID   IMAGE           COMMAND          CREATED      STATUS                  PORTS    NAMES
948f234e22a1   centos:latest   "bash"           2 days ago   Exited (0) 2 days ago            c1
01cb3e01273c   centos:latest   "bash"           2 days ago   Exited (0) 2 days ago            systemimage1
46d950fdfb33   nginx:latest    "/docker-ent..." 2 days ago   Exited (0) 2 days ago            upbeat_goldberg
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# docker ps --all | awk '{if (NR>=2){print $1}}' | xargs docker rm