容器技術之Docker基礎入門

時間 2020-05-23

原文原文鏈接

　　前文咱們瞭解了下LXC的基礎用法以及圖形管理工具LXC WEB Panel的簡單使用，有興趣的朋友能夠參考https://www.cnblogs.com/qiuhom-1874/p/12904188.html；今天這篇隨筆主要是想把docker的相關的基礎知識梳理一下；php

　　1、docker和LXChtml

　　首先咱們來講一下docker和傳統LXC容器有什麼不一樣。傳統LXC是將內核的資源用名稱空間的方式將其不一樣容器的資源，虛擬成多份；使得每一個容器間的資源相互隔離；在前邊咱們也提到過LXC只是容器的一種客戶端工具；真正實現容器的是內核功能；而docker和LXC沒有本質的不一樣，都是容器的客戶端工具；LXC是使用內核的功能將不一樣容器間的資源相互隔離，而docker是LXC上的另外一種封裝；LXC在建立容器時，依賴一個模板，而docker建立容器時，依賴鏡像；node

　　從上面的圖可看出，LXC容器裏跑了不少進程,而docker是一個容器跑一個進程，以及該進程的子進程；LXC更像是系統級容器，而docker更像是進程級容器或者說應用程序級容器；python

　　在docker容器裏一般只會有一個進程和該進程的子進程，一般該進程的進程編號爲1，這也就說明了若是docker容器裏進程編號爲1的進程宕了，那麼該容器也就隨之宕掉；docker的鏡像是採用的一種「分層構建，聯合掛載」的方式實現；將不一樣功能的鏡像經過必定的層次結構進行掛載，組合成一個新的鏡像；在docker啓動爲容器時，它會在該鏡像的最上層加上一個可寫層；這使得咱們能夠在容器內部修改某些數據；而保存修改後的數據只會對當前容器有效，若是在用同一鏡像啓動爲其餘容器時，咱們修改的數據在後面的容器是不存在的，緣由就是鏡像的每一層都是隻讀的；只有鏡像運行爲容器時纔會有一層可寫層，而該可寫層只針對該容器生效；linux

　　2、docker的架構nginx

　　docker是C/S架構，對於客戶端來講主要是docker的命令和其餘工具調用docker API；服務端主要是docker守護進程；客戶端和服務端是基於http或https協議進行通訊；和咱們傳統的其餘服務不一樣的是，docker的服務端沒有監聽在TCP或UDP的某個套接字上；它一般是監聽在unix sock 套接字上（默認是/var/run/docker.sock），這也意味着客戶端和服務端必須在同一主機上；運行docker容器的過程是這樣的；客戶端經過API調用或者命令鍵入經過http或https協議將命令發送給docker服務端，docker服務端收到命令後，它首先要檢查本地倉庫是否有對應版本的鏡像，若是有它就會直接將其運行成容器；若是沒有它會去指定的rigistry（存放鏡像倉庫的倉庫）中找對應的鏡像倉庫，而後再去找對應的版本的鏡像，經過https協議將其下載到本地倉庫中，而後再將其啓動爲容器；默認狀況不指定rigistry的地址時，默認是到dockerhub.com中找對應的鏡像倉庫中的對應版本鏡像；若是沒有指定鏡像的版本，默認會去找latest版本（最新版本）；從上面的過程能夠看到docker運行成容器，最核心的是鏡像，沒有鏡像就不可能運行容器；咱們能夠把鏡像理解成應用程序，就比如咱們要在電腦上運行某個應用，前提是咱們要先安裝好應用程序才行；其實docker的鏡像就是將應用程序和應用程序依賴的庫、文件、環境打包在一塊兒；web

　　3、docker的安裝docker

　　一、配置yum倉庫，默認centos7的extras庫裏有docker的包，可是版本過低了，若是要使用較新版本的docker能夠用阿里雲的鏡像倉庫；配置方法請參考https://developer.aliyun.com/mirror/docker-ce?spm=a2c6h.13651102.0.0.3e221b11mqdEEz；json

　　二、安裝docker-ceubuntu

[root@node1 yum.repos.d]# yum install -y docker-ce
Loaded plugins: fastestmirror
docker-ce-stable                                         | 3.5 kB     00:00     
docker-ce-stable/x86_64/primary_db                         |  42 kB   00:00     
Loading mirror speeds from cached hostfile
 * base: mirrors.cn99.com
 * extras: mirrors.aliyun.com
 * updates: mirrors.aliyun.com
Resolving Dependencies
--> Running transaction check
---> Package docker-ce.x86_64 3:19.03.9-3.el7 will be installed
……省略部份內容
Installed:
  docker-ce.x86_64 3:19.03.9-3.el7                                              

Dependency Installed:
  audit-libs-python.x86_64 0:2.8.5-4.el7                                        
  checkpolicy.x86_64 0:2.5-8.el7                                                
  container-selinux.noarch 2:2.119.1-1.c57a6f9.el7                              
  containerd.io.x86_64 0:1.2.13-3.2.el7                                         
  docker-ce-cli.x86_64 1:19.03.9-3.el7                                          
  libcgroup.x86_64 0:0.41-21.el7                                                
  libsemanage-python.x86_64 0:2.5-14.el7                                        
  policycoreutils-python.x86_64 0:2.5-34.el7                                    
  python-IPy.noarch 0:0.75-6.el7                                                
  setools-libs.x86_64 0:3.3.8-4.el7                                             

Dependency Updated:
  audit.x86_64 0:2.8.5-4.el7                                                    
  audit-libs.x86_64 0:2.8.5-4.el7                                               
  libselinux.x86_64 0:2.5-15.el7                                                
  libselinux-python.x86_64 0:2.5-15.el7                                         
  libselinux-utils.x86_64 0:2.5-15.el7                                          
  libsemanage.x86_64 0:2.5-14.el7                                               
  libsepol.x86_64 0:2.5-10.el7                                                  
  policycoreutils.x86_64 0:2.5-34.el7                                           
  selinux-policy.noarch 0:3.13.1-266.el7                                        
  selinux-policy-targeted.noarch 0:3.13.1-266.el7                               

Complete!
[root@node1 yum.repos.d]#

　　三、啓動docker

[root@node1 yum.repos.d]# systemctl start docker

　　四、添加docker加速器

[root@node1 yum.repos.d]# cd /etc/docker/
[root@node1 docker]# cat >> daemon.json << EOF
> {
>   "registry-mirrors": ["https://cyr1uljt.mirror.aliyuncs.com","https://registry.docker-cn.com"]
> }
> EOF
[root@node1 docker]# cat daemon.json 
{
  "registry-mirrors": ["https://cyr1uljt.mirror.aliyuncs.com","https://registry.docker-cn.com"]
}
[root@node1 docker]# systemctl daemon-reload
[root@node1 docker]# systemctl restart docker
[root@node1 docker]

　　四、驗證docker的版本以及加速器地址

[root@node1 docker]# docker version
Client: Docker Engine - Community
 Version:           19.03.9
 API version:       1.40
 Go version:        go1.13.10
 Git commit:        9d988398e7
 Built:             Fri May 15 00:25:27 2020
 OS/Arch:           linux/amd64
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          19.03.9
  API version:      1.40 (minimum version 1.12)
  Go version:       go1.13.10
  Git commit:       9d988398e7
  Built:            Fri May 15 00:24:05 2020
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.2.13
  GitCommit:        7ad184331fa3e55e52b890ea95e65ba581ae3429
 runc:
  Version:          1.0.0-rc10
  GitCommit:        dc9208a3303feef5b3839f4323d9beb36df0a9dd
 docker-init:
  Version:          0.18.0
  GitCommit:        fec3683
[root@node1 docker]# docker info
Client:
 Debug Mode: false

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 0
 Server Version: 19.03.9
 Storage Driver: overlay2
  Backing Filesystem: xfs
  Supports d_type: true
  Native Overlay Diff: true
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 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: runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 7ad184331fa3e55e52b890ea95e65ba581ae3429
 runc version: dc9208a3303feef5b3839f4323d9beb36df0a9dd
 init version: fec3683
 Security Options:
  seccomp
   Profile: default
 Kernel Version: 3.10.0-693.el7.x86_64
 Operating System: CentOS Linux 7 (Core)
 OSType: linux
 Architecture: x86_64
 CPUs: 4
 Total Memory: 3.686GiB
 Name: node1
 ID: T6OZ:HBP6:Q5UV:RVBY:RCHM:DX3A:4JWY:QY55:OUEX:NRMN:BMRZ:UGCU
 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://cyr1uljt.mirror.aliyuncs.com/
  https://registry.docker-cn.com/
 Live Restore Enabled: false

[root@node1 docker]#

　　提示：能夠看到咱們安裝的docker版本是19.03.9的版本；添加到兩條加速器都在registry mirrors中出現了；到此docker的安裝和配置就基本完成了；接下來咱們來講說一下docker的使用；

　　4、docker的鏡像

　　一、獲取鏡像

　　前面咱們說了要想運行docker就必須得有一鏡像，鏡像是docker容器的最核心之一；那麼咱們怎麼去下載倉庫裏的鏡像呢？docker image pull這個命令是直接從dockerhub倉庫中直接下載鏡像到本地，首先咱們來看看docker image pull 這個命令的幫助文檔吧

[root@node1 ~]# docker image pull --help

Usage:  docker image pull [OPTIONS] NAME[:TAG|@DIGEST]

Pull an image or a repository from a registry

Options:
  -a, --all-tags                Download all tagged images in the repository
      --disable-content-trust   Skip image verification (default true)
      --platform string         Set platform if server is multi-platform
                                capable
  -q, --quiet                   Suppress verbose output
[root@node1 ~]#

　　提示：從上面的幫助信息咱們能夠了解到，這個命令後面必需要跟一個鏡像的名稱，表示從dockerhub倉庫中下載指定名稱的鏡像到本地；其中鏡像的名稱是name:tag的格式，若是隻寫了鏡像名稱，默認會下載該鏡像的最新版本；其中-a表示下載指定鏡像倉庫中的全部鏡像； --disable-content-trust表示忽略鏡像的驗證默認是忽略的；-q表示安靜模式，不輸出多餘的下載信息；

　　下載nginx鏡像

[root@node1 ~]# docker image pull nginx:stable-alpine
stable-alpine: Pulling from library/nginx
cbdbe7a5bc2a: Pull complete 
6ade829cd166: Pull complete 
Digest: sha256:2668e65e1a36a749aa8b3a5297eee45504a4efea423ec2affcbbf85e31a9a571
Status: Downloaded newer image for nginx:stable-alpine
docker.io/library/nginx:stable-alpine
[root@node1 ~]#

　　提示：以上命令表示從dockerhub倉庫中下載nginx的stable-alpine版本的鏡像到本地；docker image pull這個命令等同docker pull，後者是之前老版本的用法，新版docker爲了兼容老版本的docker命令，因此保留了老版本的用法；若是要想從非官方鏡像倉庫中下載鏡像咱們能夠手動指定其餘鏡像倉庫的地址；以下

[root@node1 ~]# docker image pull hub.c.163.com/public/ubuntu:14.04       
14.04: Pulling from public/ubuntu
f4ab0b34ba6a: Pull complete 
2f0787dc0bfe: Pull complete 
54c427d77362: Pull complete 
51e87d5424ff: Pull complete 
5dfa314e7290: Pull complete 
a3ed95caeb02: Pull complete 
Digest: sha256:ffc2fc66f8e0bfa4b417b817054d3ebec130c8db44342b8fa394e25779633257
Status: Downloaded newer image for hub.c.163.com/public/ubuntu:14.04
hub.c.163.com/public/ubuntu:14.04
[root@node1 ~]#

　　查看本地倉庫有哪些鏡像

[root@node1 ~]# docker image ls 
REPOSITORY                    TAG                 IMAGE ID            CREATED             SIZE
nginx                         stable-alpine       ab94f84cc474        3 weeks ago         21.3MB
hub.c.163.com/public/ubuntu   14.04               2fe5c4bba1f9        4 years ago         237MB
[root@node1 ~]# docker images
REPOSITORY                    TAG                 IMAGE ID            CREATED             SIZE
nginx                         stable-alpine       ab94f84cc474        3 weeks ago         21.3MB
hub.c.163.com/public/ubuntu   14.04               2fe5c4bba1f9        4 years ago         237MB
[root@node1 ~]#

　　提示：docker image ls 該命令是查看本地倉庫中的鏡像，會把本地已有的鏡像列出來；等同docker images這個命令；從上面的信息能夠看到咱們本地有兩個鏡像

　　給鏡像打標籤

[root@node1 ~]# docker image tag --help

Usage:  docker image tag SOURCE_IMAGE[:TAG] TARGET_IMAGE[:TAG]

Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
[root@node1 ~]#

　　提示：docker image tag 命令等同 docker tag

[root@node1 ~]# docker image ls
REPOSITORY                    TAG                 IMAGE ID            CREATED             SIZE
nginx                         stable-alpine       ab94f84cc474        3 weeks ago         21.3MB
hub.c.163.com/public/ubuntu   14.04               2fe5c4bba1f9        4 years ago         237MB
[root@node1 ~]# docker image tag hub.c.163.com/public/ubuntu:14.04 163.com/ubuntu:14.04
[root@node1 ~]# docker images
REPOSITORY                    TAG                 IMAGE ID            CREATED             SIZE
nginx                         stable-alpine       ab94f84cc474        3 weeks ago         21.3MB
163.com/ubuntu                14.04               2fe5c4bba1f9        4 years ago         237MB
hub.c.163.com/public/ubuntu   14.04               2fe5c4bba1f9        4 years ago         237MB
[root@node1 ~]# docker tag 163.com/ubuntu:14.04 ub:14.04
[root@node1 ~]# docker images
REPOSITORY                    TAG                 IMAGE ID            CREATED             SIZE
nginx                         stable-alpine       ab94f84cc474        3 weeks ago         21.3MB
163.com/ubuntu                14.04               2fe5c4bba1f9        4 years ago         237MB
ub                            14.04               2fe5c4bba1f9        4 years ago         237MB
hub.c.163.com/public/ubuntu   14.04               2fe5c4bba1f9        4 years ago         237MB
[root@node1 ~]#

　　提示：打標籤的本質就是在給鏡像去別名，從上面的信息能夠看到163.com/ubuntu 、ub和hub.c.163.com/ubuntu這三個鏡像的ID都是相同的，這意味着這三個鏡像是指向同一鏡像的；

　　查看鏡像的詳細信息

[root@node1 ~]# docker image inspect nginx:stable-alpine
[
    {
        "Id": "sha256:ab94f84cc4744a5addf3c896206e1e666abde0eadc26990d640395cfacae24a5",
        "RepoTags": [
            "nginx:stable-alpine"
        ],
        "RepoDigests": [
            "nginx@sha256:2668e65e1a36a749aa8b3a5297eee45504a4efea423ec2affcbbf85e31a9a571"
        ],
        "Parent": "",
        "Comment": "",
        "Created": "2020-04-24T12:59:54.146056172Z",
        "Container": "5cdc5c83fb963292b8ae3ad7abae5069a88c76e51ae91dfb9f9d7fa604f088e6",
        "ContainerConfig": {
            "Hostname": "5cdc5c83fb96",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "ExposedPorts": {
                "80/tcp": {}
            },
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "NGINX_VERSION=1.18.0",
                "NJS_VERSION=0.4.0",
                "PKG_RELEASE=1"
            ],
            "Cmd": [
                "/bin/sh",
                "-c",
                "#(nop) ",
                "CMD [\"nginx\" \"-g\" \"daemon off;\"]"
            ],
            "ArgsEscaped": true,
            "Image": "sha256:5d84a370ed482284aad8af6a5ea7bcca5a91c5bf7f8e061f2d336835cd724e6e",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": {
                "maintainer": "NGINX Docker Maintainers <docker-maint@nginx.com>"
            },
            "StopSignal": "SIGTERM"
        },
        "DockerVersion": "18.09.7",
        "Author": "",
        "Config": {
            "Hostname": "",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "ExposedPorts": {
                "80/tcp": {}
            },
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "NGINX_VERSION=1.18.0",
                "NJS_VERSION=0.4.0",
                "PKG_RELEASE=1"
            ],
            "Cmd": [
                "nginx",
                "-g",
                "daemon off;"
            ],
            "ArgsEscaped": true,
            "Image": "sha256:5d84a370ed482284aad8af6a5ea7bcca5a91c5bf7f8e061f2d336835cd724e6e",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": {
                "maintainer": "NGINX Docker Maintainers <docker-maint@nginx.com>"
            },
            "StopSignal": "SIGTERM"
        },
        "Architecture": "amd64",
        "Os": "linux",
        "Size": 21314634,
        "VirtualSize": 21314634,
        "GraphDriver": {
            "Data": {
                "LowerDir": "/var/lib/docker/overlay2/e175dd426f8fc3b61248f51b13ebbcc0130de67cd0b604e6e5c2f4b5776b5568/diff",
                "MergedDir": "/var/lib/docker/overlay2/eda604afa15f728fe10851129414b80826b909d1741a969eb3587dcd50bfe0da/merged",
                "UpperDir": "/var/lib/docker/overlay2/eda604afa15f728fe10851129414b80826b909d1741a969eb3587dcd50bfe0da/diff",
                "WorkDir": "/var/lib/docker/overlay2/eda604afa15f728fe10851129414b80826b909d1741a969eb3587dcd50bfe0da/work"
            },
            "Name": "overlay2"
        },
        "RootFS": {
            "Type": "layers",
            "Layers": [
                "sha256:3e207b409db364b595ba862cdc12be96dcdad8e36c59a03b7b3b61c946a5741a",
                "sha256:34cf0e74977f5cabe21fd5465978f35ec87b57ed928745a0f2054bc7e1dcbcf9"
            ]
        },
        "Metadata": {
            "LastTagTime": "0001-01-01T00:00:00Z"
        }
    }
]
[root@node1 ~]#

　　提示：使用docker image inspect 命令能夠獲取指定鏡像的詳細信息，包括製做做者、架構以及各層次的摘要信息等等信息；該命令等同docker inspect；上面命令返回了一個json格式的數據，很不方便咱們查看某個字段的信息，若是想要獲取某個字段的信息咱們可使用-f選項來指定要查看的字段；以下

[root@node1 ~]# docker image inspect -f "{{.Config.Cmd}}" nginx:stable-alpine
[nginx -g daemon off;]
[root@node1 ~]# docker image inspect -f "{{.RootFS}}" nginx:stable-alpine          
{layers [sha256:3e207b409db364b595ba862cdc12be96dcdad8e36c59a03b7b3b61c946a5741a sha256:34cf0e74977f5cabe21fd5465978f35ec87b57ed928745a0f2054bc7e1dcbcf9] }
[root@node1 ~]# docker image inspect -f "{{.RootFS.Type}}" nginx:stable-alpine
layers
[root@node1 ~]#

　　提示：使用-f指定字段須要注意，須要從"."開始，字段名稱須要用雙大括號括起來

　　查看鏡像歷史

[root@node1 ~]# docker image history  nginx:stable-alpine           
IMAGE               CREATED             CREATED BY                                      SIZE                COMMENT
ab94f84cc474        3 weeks ago         /bin/sh -c #(nop)  CMD ["nginx" "-g" "daemon…   0B                  
<missing>           3 weeks ago         /bin/sh -c #(nop)  STOPSIGNAL SIGTERM           0B                  
<missing>           3 weeks ago         /bin/sh -c #(nop)  EXPOSE 80                    0B                  
<missing>           3 weeks ago         /bin/sh -c set -x     && addgroup -g 101 -S …   15.7MB              
<missing>           3 weeks ago         /bin/sh -c #(nop)  ENV PKG_RELEASE=1            0B                  
<missing>           3 weeks ago         /bin/sh -c #(nop)  ENV NJS_VERSION=0.4.0        0B                  
<missing>           3 weeks ago         /bin/sh -c #(nop)  ENV NGINX_VERSION=1.18.0     0B                  
<missing>           3 weeks ago         /bin/sh -c #(nop)  LABEL maintainer=NGINX Do…   0B                  
<missing>           4 weeks ago         /bin/sh -c #(nop)  CMD ["/bin/sh"]              0B                  
<missing>           4 weeks ago         /bin/sh -c #(nop) ADD file:b91adb67b670d3a6f…   5.61MB              
[root@node1 ~]#

　　提示：以上命令表示查看nginx:stable-alpine這個鏡像的歷史記錄，該命令顯示了各層鏡像都作了哪些操做；各層鏡像的建立信息；該命令等同docker history；

　　搜索鏡像

[root@node1 ~]# docker search nginx         
NAME                               DESCRIPTION                                     STARS               OFFICIAL            AUTOMATED
nginx                              Official build of Nginx.                        13212               [OK]                
jwilder/nginx-proxy                Automated Nginx reverse proxy for docker con…   1806                                    [OK]
richarvey/nginx-php-fpm            Container running Nginx + PHP-FPM capable of…   775                                     [OK]
linuxserver/nginx                  An Nginx container, brought to you by LinuxS…   113                                     
bitnami/nginx                      Bitnami nginx Docker Image                      83                                      [OK]
tiangolo/nginx-rtmp                Docker image with Nginx using the nginx-rtmp…   73                                      [OK]
jc21/nginx-proxy-manager           Docker container for managing Nginx proxy ho…   61                                      
nginxdemos/hello                   NGINX webserver that serves a simple page co…   49                                      [OK]
jlesage/nginx-proxy-manager        Docker container for Nginx Proxy Manager        43                                      [OK]
nginx/nginx-ingress                NGINX Ingress Controller for Kubernetes         31                                      
privatebin/nginx-fpm-alpine        PrivateBin running on an Nginx, php-fpm & Al…   25                                      [OK]
schmunk42/nginx-redirect           A very simple container to redirect HTTP tra…   18                                      [OK]
nginxinc/nginx-unprivileged        Unprivileged NGINX Dockerfiles                  16                                      
centos/nginx-112-centos7           Platform for running nginx 1.12 or building …   13                                      
centos/nginx-18-centos7            Platform for running nginx 1.8 or building n…   13                                      
blacklabelops/nginx                Dockerized Nginx Reverse Proxy Server.          13                                      [OK]
raulr/nginx-wordpress              Nginx front-end for the official wordpress:f…   12                                      [OK]
nginx/nginx-prometheus-exporter    NGINX Prometheus Exporter                       12                                      
sophos/nginx-vts-exporter          Simple server that scrapes Nginx vts stats a…   7                                       [OK]
mailu/nginx                        Mailu nginx frontend                            6                                       [OK]
bitwarden/nginx                    The Bitwarden nginx web server acting as a r…   5                                       
bitnami/nginx-ingress-controller   Bitnami Docker Image for NGINX Ingress Contr…   5                                       [OK]
wodby/nginx                        Generic nginx                                   1                                       [OK]
ansibleplaybookbundle/nginx-apb    An APB to deploy NGINX                          1                                       [OK]
centos/nginx-110-centos7           Platform for running nginx 1.10 or building …   0                                       
[root@node1 ~]# docker search  -s 500 nginx 
Flag --stars has been deprecated, use --filter=stars=3 instead
NAME                      DESCRIPTION                                     STARS               OFFICIAL            AUTOMATED
nginx                     Official build of Nginx.                        13212               [OK]                
jwilder/nginx-proxy       Automated Nginx reverse proxy for docker con…   1806                                    [OK]
richarvey/nginx-php-fpm   Container running Nginx + PHP-FPM capable of…   775                                     [OK]
[root@node1 ~]# docker search  -s 5000 nginx
Flag --stars has been deprecated, use --filter=stars=3 instead
NAME                DESCRIPTION                STARS               OFFICIAL            AUTOMATED
nginx               Official build of Nginx.   13212               [OK]                
[root@node1 ~]#

　　提示：-s表示顯示指定數以上星級的鏡像

　　刪除鏡像

[root@node1 ~]# docker images
REPOSITORY                    TAG                 IMAGE ID            CREATED             SIZE
nginx                         stable-alpine       ab94f84cc474        3 weeks ago         21.3MB
ub                            14.04               2fe5c4bba1f9        4 years ago         237MB
hub.c.163.com/public/ubuntu   14.04               2fe5c4bba1f9        4 years ago         237MB
163.com/ubuntu                14.04               2fe5c4bba1f9        4 years ago         237MB
[root@node1 ~]# docker image rm 163.com/ubuntu:14.04
Untagged: 163.com/ubuntu:14.04
[root@node1 ~]# docker image rm ub:14.04            
Untagged: ub:14.04
[root@node1 ~]# docker images
REPOSITORY                    TAG                 IMAGE ID            CREATED             SIZE
nginx                         stable-alpine       ab94f84cc474        3 weeks ago         21.3MB
hub.c.163.com/public/ubuntu   14.04               2fe5c4bba1f9        4 years ago         237MB
[root@node1 ~]# docker image rm hub.c.163.com/public/ubuntu:14.04
Untagged: hub.c.163.com/public/ubuntu:14.04
Untagged: hub.c.163.com/public/ubuntu@sha256:ffc2fc66f8e0bfa4b417b817054d3ebec130c8db44342b8fa394e25779633257
Deleted: sha256:2fe5c4bba1f935f179e83cd5354403d1231ffc9df9c1621967194410eaf8d942
Deleted: sha256:085e08b75e744804e23332efb202896749c4aff9433391a775607852d339c26e
Deleted: sha256:7f622f92c76a635c16f506bced3dc1641e9390a26ee9d8cb70f8616c3a21fbdf
Deleted: sha256:ae7b6867bb7b8f3a8235547e0634e7629b4008d807dc768064e760a91413a71f
Deleted: sha256:3eef796012f97f23ffdb11296f6b624a0db4b32eae986da589492b974e6eb596
Deleted: sha256:b268b9bd797e1d58a176fac2a338df41437e853beb5aaa8a4159227fc38c4b72
Deleted: sha256:89688d062a0607fb50d0955de8964659e66f1bb41164b2d2b473d1edd7d8af90
[root@node1 ~]#

　　提示：若是鏡像有多個標籤，指定其標籤名錶示刪除該標籤，只有當鏡像只有一個標籤是，纔會把鏡像徹底刪除；docker image rm 命令等同docker rmi命令；刪除鏡像除了能夠指定的標籤來刪除鏡像外，還能夠指定鏡像ID來刪除鏡像；

　　將指定鏡像運行爲容器

[root@node1 ~]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
nginx               stable-alpine       ab94f84cc474        3 weeks ago         21.3MB
[root@node1 ~]# docker run --name n1 -d nginx:stable-alpine
1b404faab5ba4af597e38a998ad21bca61fe99583234b68882931d766c34ebf3
[root@node1 ~]# docker ps
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS              PORTS               NAMES
1b404faab5ba        nginx:stable-alpine   "nginx -g 'daemon of…"   6 seconds ago       Up 4 seconds        80/tcp              n1
[root@node1 ~]#

　　提示：要想將指定鏡像運行成容器，須要使用docker run來運行；--name表示給容器起一個名稱，-d表示不佔據現有終端，後臺運行；docker ps命令是查看當前系統正在運行的容器；該命令等同docker container ls ，若是想要查看當前系統全部容器運行狀況，可使用docker ps -a ，該命令會把運行狀態的容器和中止狀態的容器一併列出來；

　　查看剛纔建立容器的ip地址

[root@node1 ~]# docker container inspect -f "{{.NetworkSettings.IPAddress}}"  n1 
172.17.0.2
[root@node1 ~]#

　　提示：鏡像和容器的區別就是，鏡像是靜態的，容器是把鏡像運行起來就叫容器，換句話說容器就是鏡像的實例化產物；查看容器的詳細信息咱們須要使用docker container inspect 該命令同docker image inspect 的用法相似，若是不用-f過濾字段信息，它一般會顯示以json格式的全部信息；此時咱們就可使用瀏覽器訪問咱們剛纔啓動的容器裏的nginx服務了

[root@node1 ~]# elinks --dump http://172.17.0.2
                               Welcome to nginx!

   If you see this page, the nginx web server is successfully installed and
   working. Further configuration is required.

   For online documentation and support please refer to [1]nginx.org.
   Commercial support is available at [2]nginx.com.

   Thank you for using nginx.

References

   Visible links
   1. http://nginx.org/
   2. http://nginx.com/
[root@node1 ~]# curl -I http://172.17.0.2
HTTP/1.1 200 OK
Server: nginx/1.18.0
Date: Fri, 22 May 2020 09:00:56 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 21 Apr 2020 15:15:39 GMT
Connection: keep-alive
ETag: "5e9f0e1b-264"
Accept-Ranges: bytes

[root@node1 ~]#

　　提示：默認啓動的容器會把網絡接入到docker0橋，該橋是一個nat橋，因此要想訪問到容器裏的應用服務，須要用docker0橋所在主機去訪問（本機），除此以外也能夠經過搭建代理或者用在docker0橋上的其餘容器又或者將容器裏服務的端口暴露給宿主機；

　　中止容器

[root@node1 ~]# docker ps 
CONTAINER ID        IMAGE                 COMMAND                  CREATED              STATUS              PORTS               NAMES
444eb763efe0        nginx:stable-alpine   "nginx -g 'daemon of…"   About a minute ago   Up About a minute   80/tcp              n2
1b404faab5ba        nginx:stable-alpine   "nginx -g 'daemon of…"   20 minutes ago       Up 20 minutes       80/tcp              n1
[root@node1 ~]# docker container stop n1
n1
[root@node1 ~]# docker ps
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS              PORTS               NAMES
444eb763efe0        nginx:stable-alpine   "nginx -g 'daemon of…"   2 minutes ago       Up 2 minutes        80/tcp              n2
[root@node1 ~]# docker ps -a
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS                     PORTS               NAMES
444eb763efe0        nginx:stable-alpine   "nginx -g 'daemon of…"   2 minutes ago       Up 2 minutes               80/tcp              n2
1b404faab5ba        nginx:stable-alpine   "nginx -g 'daemon of…"   21 minutes ago      Exited (0) 7 seconds ago                       n1
[root@node1 ~]#

　　啓動容器

[root@node1 ~]# docker ps 
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS              PORTS               NAMES
444eb763efe0        nginx:stable-alpine   "nginx -g 'daemon of…"   2 minutes ago       Up 2 minutes        80/tcp              n2
[root@node1 ~]# docker container start n1
n1
[root@node1 ~]# docker ps
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS              PORTS               NAMES
444eb763efe0        nginx:stable-alpine   "nginx -g 'daemon of…"   2 minutes ago       Up 2 minutes        80/tcp              n2
1b404faab5ba        nginx:stable-alpine   "nginx -g 'daemon of…"   22 minutes ago      Up 2 seconds        80/tcp              n1
[root@node1 ~]#

　　刪除容器

[root@node1 ~]# docker container ls
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS              PORTS               NAMES
444eb763efe0        nginx:stable-alpine   "nginx -g 'daemon of…"   3 minutes ago       Up 3 minutes        80/tcp              n2
1b404faab5ba        nginx:stable-alpine   "nginx -g 'daemon of…"   23 minutes ago      Up About a minute   80/tcp              n1
[root@node1 ~]# docker container rm n1
Error response from daemon: You cannot remove a running container 1b404faab5ba4af597e38a998ad21bca61fe99583234b68882931d766c34ebf3. Stop the container before attempting removal or force remove
[root@node1 ~]# docker container stop n1
n1
[root@node1 ~]# docker ps -a
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS                     PORTS               NAMES
444eb763efe0        nginx:stable-alpine   "nginx -g 'daemon of…"   4 minutes ago       Up 4 minutes               80/tcp              n2
1b404faab5ba        nginx:stable-alpine   "nginx -g 'daemon of…"   23 minutes ago      Exited (0) 5 seconds ago                       n1
[root@node1 ~]# docker container rm n1
n1
[root@node1 ~]# docker ps -a
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS              PORTS               NAMES
444eb763efe0        nginx:stable-alpine   "nginx -g 'daemon of…"   4 minutes ago       Up 4 minutes        80/tcp              n2
[root@node1 ~]# docker container ls
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS              PORTS               NAMES
444eb763efe0        nginx:stable-alpine   "nginx -g 'daemon of…"   5 minutes ago       Up 5 minutes        80/tcp              n2
[root@node1 ~]#

　　提示：運行的容器是無法直接刪除的，必須先中止容器才行；若是不中止容器要刪除容器可使用-f選項來指定，固然一般咱們都不建議這樣用；