docker基础手册
docker常用命令
1.查看当前镜像
[root@centos7-docker ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
nginx latest 08b152afcfae 3 weeks ago 133MB
hello-world latest d1165f221234 5 months ago 13.3kB
centos latest 300e315adb2f 8 months ago 209MB
2.搜索镜像
语法：docker search [options] term
options说明：
- –no-trunc：显示完整的镜像描述
- -f <过滤条件>：列出收藏数不小于指定值的镜像
[root@centos7-docker ~]# docker search tomcat
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
tomcat Apache Tomcat is an open source implementati… 3093 [OK]
tomee Apache TomEE is an all-Apache Java EE certif… 91 [OK]
dordoka/tomcat Ubuntu 14.04, Oracle JDK 8 and Tomcat 8 base… 57 [OK]
kubeguide/tomcat-app Tomcat image for Chapter 1 30
consol/tomcat-7.0 Tomcat 7.0.57, 8080, "admin/admin" 18 [OK]
cloudesire/tomcat Tomcat server, 6/7/8 15 [OK]
aallam/tomcat-mysql Debian, Oracle JDK, Tomcat & MySQL 13 [OK]
#第一列：仓库源名称
#第二列：描述
#第三列：星星
#第四列：是否是官方发布
#第五列：是否是自动构建
#查看星星50个，描述详细的tomcat
[root@centos7-docker ~]# docker search -f stars=50 --no-trunc tomcat
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
tomcat Apache Tomcat is an open source implementation of the Java Servlet and JavaServer Pages technologies 3093 [OK]
tomee Apache TomEE is an all-Apache Java EE certified stack where Apache Tomcat is top dog. 91 [OK]
dordoka/tomcat Ubuntu 14.04, Oracle JDK 8 and Tomcat 8 based docker container. 57 [OK]
3.拉取镜像
语法：docker pull name:tag
例如：docker pull nginx #不加tag，默认拉取最新的
4.创建镜像之docker commit
当我们拉取下来的镜像不能满足需求的时候，想自己设计一个，两种方法
- 从已经创建的容器中更新镜像，并且提交这个镜像
- 使用dockerfile指令自个创建
查看当前系统镜像
[root@centos7-docker ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
zhanghaodong/ubuntu v1 f990b7b8a364 7 minutes ago 63.1MB
ubuntu 18.04 39a8cfeef173 2 weeks ago 63.1MB
nginx latest 08b152afcfae 3 weeks ago 133MB
hello-world latest d1165f221234 5 months ago 13.3kB
centos latest 300e315adb2f 8 months ago 209MB
在centos:latest里安装httpd软件
[root@centos7-docker ~]# docker run -it centos /bin/bash
[root@c7bb5f3a8293 /]# yum -y install httpd
[root@c7bb5f3a8293 /]# rpm -qa | grep -i httpd
httpd-tools-2.4.37-39.module_el8.4.0+778+c970deab.x86_64
centos-logos-httpd-85.8-1.el8.noarch
httpd-filesystem-2.4.37-39.module_el8.4.0+778+c970deab.noarch
httpd-2.4.37-39.module_el8.4.0+778+c970deab.x86_64
[root@c7bb5f3a8293 /]# exit
exit
这个时候退出了，如果再重新进的话，还是原来新的镜像，我需要安装httpd之后的镜像
查看刚才运行centos后的容器ID，进行提交
#看到刚才运行过的centos容器的ID是：c7开头的那个
[root@centos7-docker ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c7bb5f3a8293 centos "/bin/bash" 3 minutes ago Exited (0) About a minute ago youthful_fermi
#进行提交，这里报错了，仓库源首字母不能是大写的
[root@centos7-docker ~]# docker commit -m "install httpd soft" -a "Hejing" c7 Hejing/centos:v1
invalid reference format: repository name must be lowercase
#修改后重新提交
[root@centos7-docker ~]# docker commit -m "install httpd soft" -a "Hejing" c7 hejing/centos:v1
sha256:0e4de65ea5c91925bd262ccb1ae547ae59aab296dc79ac6da1970056132579d9
#查看本地镜像
[root@centos7-docker ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hejing/centos v1 0e4de65ea5c9 4 seconds ago 259MB
zhanghaodong/ubuntu v1 f990b7b8a364 27 minutes ago 63.1MB
ubuntu 18.04 39a8cfeef173 2 weeks ago 63.1MB
nginx latest 08b152afcfae 3 weeks ago 133MB
hello-world latest d1165f221234 5 months ago 13.3kB
centos latest 300e315adb2f 8 months ago 209MB
#进入安装httpd之后的镜像看一下，no problem
[root@centos7-docker ~]# docker run -it hejing/centos:v1 /bin/bash
[root@497b09e5d905 /]# rpm -qa | grep -i httpd
httpd-tools-2.4.37-39.module_el8.4.0+778+c970deab.x86_64
centos-logos-httpd-85.8-1.el8.noarch
httpd-filesystem-2.4.37-39.module_el8.4.0+778+c970deab.noarch
httpd-2.4.37-39.module_el8.4.0+778+c970deab.x86_64
5.构建镜像-Dockerfile指令介绍
dockerfile指令介绍
- Docker通过对于在Dockerfile中的一系列指令的顺序解析实现自动的image的构建
- 通过使用build指令，根据Dockerfile的描述来构建镜像
- 通过源代码路径的方式
- 通过标准输入流的方式
5.1 通过源代码路径
-
Dockerfile需要放置在项目的根目录的位置
-
在构建的时候，Dockerfile client会把整个context打包发送到Docker server端，然后由server端负责build镜像，在构建成功后，会删除context目录
docker build -t {镜像名字} {项目路径可以是相对路径}docker利用Dockerfile来构建新镜像之前，先介绍一下Dockerfile常用的指令
5.2 通过标准输入流
- 通过标准输入流的方式获取Dockerfile的内容
- client不会打包上传context目录，因此对于一些ADD、COPY、等涉及host本地文件复制的操作不支持
docker build -t {镜像名字} - < Dockerfile路径
5.3 build cache
- Dcokerfile中的每一个指令执行完毕之后，都会提交一个image，这样保证指令之间不会由影响
- Dockerfile会尽可能尝试重用已经构建的镜像
- 可以通过在build命令中增加–no-cache的方式来禁用这个cache
5.4 Dockerfile指令：
- 只支持Docker自己定义的一套指令，不支持自定义
- 大小写不敏感，但是建议全部使用大写
- 根据Dockerfile的内容顺序执行
5.5 FROM
- FROM {base镜像}
- 必须放在Dockerfile的第一行，表示从哪个base image开始构建
5.6 MAINTAINER
- 可选的，标识作者
5.7 RUN
- 每一个RUN指令都会是在一个新的container里面运行，并提交一个image作为下一个RUN的base image
- 一个Dockerfile中可以包含多个RUN，按定义顺序执行
- RUN支持两种运行方式：
- RUN 这个会当作/bin/sh -c “cmd” 运行
- RUN [“executable”,“arg1”,…],docker把他当作json的顺序来解析，因此必须使用双引号，而且executable需要是完整路径
- RUN都是启动一个容器、执行命名、然后提交存储层文件变更。第一层RUN commond1的执行仅仅是当前进程，一个内存上的变化而已，其结果不会造成任何文件。而到第二层的时候，启动的是一个全新的容器，跟第一层的容器完全没关系，自然不可能继承前一层构建过程中的内存变化。而如果需要将两条命令或者多条命令联合起来执行需要加上&&。
5.8 CMD
- CMD的作用是作为执行container时候的默认行为（容器默认启动命令）
- 当运行container的时候声明了command，则不再用image中的CMD默认所定义的命令
- 一个Dockerfile中只能有一个有效的CMD，当定义多个CMD的时候，只有最后一个才会有作用
- CMD定义的三种方式：
- CMD #这个会当作/bin/sh -c "cmd"来执行
- CMD [“executable”,“arg1”,…]
- CMD [“arg1”,“arg2”]，这个时候CMD作为ENTRYPOINT的参数
5.9 EXPOSE声明端口
格式为：EXPOSE <端口1> [<端口2>...]
EXPOSE指令是声明运行时容器提供服务端口，这只是一个声明，在运行时并不会因为这个声明，应用就会开启这个端口的服务。在Dockerfile中写入这样的声明有两个好处：
- 其一：帮助镜像使用者理解这个镜像服务的守护端口，以方便配置映射
- 其二：在运行使用随机端口映射时，也就是
docker run -P的时候，会自动映射EXPOSE的端口
5.10 ENTRYPOINT定义方式
- entrypoint [“executable”,“arg1”,“arg2”]，在这种定义方式下，CMD可以通过json方式来定义entrypoint的参数，可以通过在运行container的时候通过指定command的方式传递参数
- entrypoint ，当作/bin/bash -c "cmd"运行命令
5.11 ADD & COPY
- 当在源代码构建的方式下，可以通过ADD和COPY的方式，把host上的文件或者目录复制到image中
- ADD和COPY的源必须在context路径下
- 当src为网络URL的情况下，ADD指令可以把它下载到dest的指定位置，这个在任何build方式下都可以work
- ADD相对COPY还有一个多的功能，能够进行自动解压压缩包
5.12 ENV
ENV key value
- 用来设置环境变量，后续的RUN可以使用他创建的环境变量
- 当创建基于该镜像的container的时候，会自动拥有设置的环境变量
5.13 WORKDIR
- 用来指定当前工作目录（或者称为当前目录）
- 当使用相对目录的情况下，采用上一个WORKDIR指定的目录作为基准
5.14 USER
- 指定UID或者username，来决定运行RUN指令的用户
5.15 ONBUILD
- ONBUILD作为一个trigger的标记，可以用来trigger任何Dockerfile中的指令
- 可以定义多个ONBUILD指令
- 当下一个镜像B使用镜像A作为base的时候，在FROM A指令前，会先按照顺序执行在构建A时候定义的ONBUILD指令
ONBUILD
5.16 VOLUME
- 用来创建一个在image之外的mount point，用来在多个container之间实现数据共享
- 运行使用json array的方式定义多个volume
- VOLUME ["/var/data1","/var/data2"]
- 或者plain text的情况下定义多个VOLUME指令
6.Dockefile实践
指令实践,let's do it
先看下本地image，选一个作为base image：
[root@centos7-docker ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hejing/centos v1 0e4de65ea5c9 21 hours ago 259MB
zhanghaodong/ubuntu v1 f990b7b8a364 21 hours ago 63.1MB
ubuntu 18.04 39a8cfeef173 2 weeks ago 63.1MB
nginx latest 08b152afcfae 3 weeks ago 133MB
hejing/hello-world v1 d1165f221234 5 months ago 13.3kB
hello-world latest d1165f221234 5 months ago 13.3kB
centos latest 300e315adb2f 8 months ago 209MB
centos 7 8652b9f0cb4c 9 months ago 204MB
新建一个专门存放此demo的目录docker_demo，也就是Dockerfile所在的context：
[root@centos7-docker ~]# mkdir docker_demo
[root@centos7-docker ~]# cd docker_demo/
[root@centos7-docker docker_demo]# touch Dockerfile
[root@centos7-docker docker_demo]# pwd
/root/docker_demo
接下来编写Dockfile文件（D要大写，必须的）
这里以编译nginx提供web服务来构建新的image
1.下载ngixn源码包到docker_demo目录下：
下载地址：http://nginx.org/en/download.html
[root@centos7-docker docker_demo]# ll
total 960
-rw-r--r--. 1 root root 0 Aug 13 23:10 Dockerfile
-rw-r--r--. 1 root root 981687 Aug 13 23:14 nginx-1.12.2.tar.gz
2.下面是编写好的Dockerfile v1版本：
[root@centos7-docker docker_demo]# cat Dockerfile
# base image
FROM centos
# MAINTAINER
MAINTAINER hejing
# put nginx-1.12.2.tar.gz into /usr/local/src and unpack nginx
# the ADD can unpack tar
ADD nginx-1.12.2.tar.gz /usr/local/src
# running required command
RUN yum install -y gcc gcc-c++ glibc make autoconf openssl openssl-devel
RUN yum install -y libxslt-devel gd gd-devel GeoIP GeoIP-devel pcre pcre-devel
RUN useradd -M -s /sbin/nologin nginx
# change dir to /usr/local/src/nginx-1.12.2
WORKDIR /usr/local/src/nginx-1.12.2
# execute command to complie nginx
RUN ./configure --user=nginx --group=nginx --prefix=/usr/local/nginx --with-file-aio --with-http_ssl_module --with-http_realip_module --with-http_addition_module --with-http_xslt_module --with-http_image_filter_module --with-http_geoip_module --with-http_sub_module --with-http_dav_module --with-http_flv_module --with-http_mp4_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_auth_request_module --with-http_random_index_module --with-http_secure_link_module --with-http_degradation_module --with-http_stub_status_module && make && make install
EXPOSE 80
3.查看docker_demo目录情况：
[root@centos7-docker docker_demo]# ll
total 964
-rw-r--r--. 1 root root 1106 Aug 13 23:24 Dockerfile
-rw-r--r--. 1 root root 981687 Aug 13 23:14 nginx-1.12.2.tar.gz
4.执行docker build进行构建
命令：docker build -t centos_nginx:v1 .或docker build -t centos_nginx:v1 /root/docker_demo
后面的.代表的是相对路径的当前目录，如果需要全路径就是上面的方式（就是找到Dockerfile文件）
[root@centos7-docker docker_demo]# docker build -t centos7_nginx:v1 . --no-cache
Sending build context to Docker daemon 985.6kB
Step 1/9 : FROM centos:7
---> 8652b9f0cb4c
Step 2/9 : MAINTAINER hejing
---> Running in e59af95193e1
Removing intermediate container e59af95193e1
---> a5465d667dd3
Step 3/9 : ADD nginx-1.12.2.tar.gz /usr/local/src
---> 3ae678f3c162
Step 4/9 : RUN yum install -y gcc gcc-c++ glibc make autoconf openssl openssl-devel
---> Running in f0390567bfee
......
Step 5/9 : RUN yum install -y libxslt-devel gd gd-devel GeoIP GeoIP-devel pcre pcre-devel
---> Running in e1441bb1cd65
Step 6/9 : RUN useradd -M -s /sbin/nologin nginx
---> Running in d5151e31e9d6
Removing intermediate container d5151e31e9d6
---> 8541c8342250
Step 7/9 : WORKDIR /usr/local/src/nginx-1.12.2
---> Running in be68dcd91e6e
Removing intermediate container be68dcd91e6e
---> 5b6f6148ab37
Step 8/9 : RUN ./configure --user=nginx.......
Step 9/9 : EXPOSE 80
---> Running in a9fb28cfabfa
Removing intermediate container a9fb28cfabfa
---> 1ffc4a8e3106
Successfully built 1ffc4a8e3106
Successfully tagged centos7_nginx:v1
构建成功，查看新构建的镜像：
[root@centos7-docker docker_demo]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
centos7_nginx v1 1ffc4a8e3106 8 minutes ago 673MB
hejing/centos v1 0e4de65ea5c9 21 hours ago 259MB
zhanghaodong/ubuntu v1 f990b7b8a364 21 hours ago 63.1MB
ubuntu 18.04 39a8cfeef173 2 weeks ago 63.1MB
nginx latest 08b152afcfae 3 weeks ago 133MB
hejing/hello-world v1 d1165f221234 5 months ago 13.3kB
hello-world latest d1165f221234 5 months ago 13.3kB
centos latest 300e315adb2f 8 months ago 209MB
centos 7 8652b9f0cb4c 9 months ago 204MB
5.使用新构建的镜像启动一个container并开启nginx服务
[root@centos7-docker docker_demo]# docker run -d centos7_nginx:v1 /usr/local/nginx/sbin/nginx -g "daemon off";
4d3a523292df47b59179470af76982583c4194de16c855c3907e055f1484b07d
查看启动的container是否则正在运行：
[root@centos7-docker docker_demo]# docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4d3a523292df centos7_nginx:v1 "/usr/local/nginx/sb…" 52 seconds ago Exited (1) 51 seconds ago trusting_swanson
在这里启动刚才构建的镜像失败了，看了一下message日志，显示如下：
Aug 14 05:50:29 centos7-docker containerd: time="2021-08-14T05:50:29.471934866-04:00" level=info msg="shim disconnected" id=f194c83d48ecaefacf949f0bc401b3317e1dc90af34cc9d2fa4cc
Aug 14 05:50:29 centos7-docker containerd: time="2021-08-14T05:50:29.472029803-04:00" level=error msg="copy shim log" error="reaf/fd/12: file already closed"
Aug 14 05:50:29 centos7-docker kernel: docker0: port 1(veth8dd62fb) entered disabled state
Aug 14 05:50:29 centos7-docker NetworkManager[5999]: [1628934629.5061] manager: (veth201db61): new Veth device (/org/fretworkManager/Devices/180)
Aug 14 05:50:29 centos7-docker kernel: docker0: port 1(veth8dd62fb) entered disabled state
Aug 14 05:50:29 centos7-docker kernel: device veth8dd62fb left promiscuous mode
Aug 14 05:50:29 centos7-docker kernel: docker0: port 1(veth8dd62fb) entered disabled state
Aug 14 05:50:29 centos7-docker NetworkManager[5999]: [1628934629.5259] device (veth8dd62fb): released from master device
Aug 14 05:51:51 centos7-docker systemd: Stopping Docker Application C ontainer Engine...
不晓得是怎么回事，看到了NetworManager，于是查看了一下host的网络服务，发现network服务和Neworkmanager都activing开启着，尝试停止了一下NetworkManager服务，再次重启镜像，发现成功了
这个问题可以详细的看一下这一篇博客http://www.cocoachina.com/articles/60742
虽然nginx服务开启了，但是port并没有进行映射到本机host，所以这个container并不能进行访问，重新启动一个进行映射端口的容器
[root@centos7-docker docker_demo]# docker run -d -p80:80 centos7_nginx:v1 /usr/local/nginx/sbin/nginx -g "daemon off;"
[root@centos7-docker docker_demo]# docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
856bf5558811 centos7_nginx:v1 "/usr/local/nginx/sb…" 5 minutes ago Up 5 minutes 0.0.0.0:80->80/tcp, :::80->80/tcp jovial_heyrovsky
再次查看端口信息(docker port container-ID即可)：
[root@centos7-docker docker_demo]# docker port 85
80/tcp -> 0.0.0.0:80
80/tcp -> :::80
浏览器访问：
6.于是基于Dockerfile的一个简单实例构建完成，现在基于这个Dockerfile文件依次添加其他的指令进行构建
6.1 添加ENV环境便令指令
[root@centos7-docker docker_demo]# cat Dockerfile
# base image
FROM centos:7
# # MAINTAINER
MAINTAINER hejing
# put nginx-1.12.2.tar.gz into /usr/local/src and unpack nginx
# the ADD can unpack tar
ADD nginx-1.12.2.tar.gz /usr/local/src
# running required command
RUN yum install -y gcc gcc-c++ glibc make autoconf openssl openssl-devel
RUN yum install -y libxslt-devel gd gd-devel GeoIP GeoIP-devel pcre pcre-devel
RUN useradd -M -s /sbin/nologin nginx
# change dir to /usr/local/src/nginx-1.12.2
WORKDIR /usr/local/src/nginx-1.12.2
# execute command to complie nginx
RUN ./configure --user=nginx --group=nginx --prefix=/usr/local/nginx --with-file-aio --with-http_ssl_module --with-http_realip_module --with-http_addition_module --with-http_xslt_module --with-http_image_filter_module --with-http_geoip_module --with-http_sub_module --with-http_dav_module --with-http_flv_module --with-http_mp4_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_auth_request_module --with-http_random_index_module --with-http_secure_link_module --with-http_degradation_module --with-http_stub_status_module && make && make install
ENV PATH /usr/local/nginx/sbin:$PATH
EXPOSE 80
然后进行构建：
[root@centos7-docker docker_demo]# docker build -t centos7_nginx:v2 .
Sending build context to Docker daemon 985.6kB
Step 1/10 : FROM centos:7
---> 8652b9f0cb4c
Step 2/10 : MAINTAINER hejing
---> Using cache
---> a5465d667dd3
Step 3/10 : ADD nginx-1.12.2.tar.gz /usr/local/src
---> Using cache
---> 3ae678f3c162
Step 4/10 : RUN yum install -y gcc gcc-c++ glibc make autoconf openssl openssl-devel
---> Using cache
---> b49fa8555f64
Step 5/10 : RUN yum install -y libxslt-devel gd gd-devel GeoIP GeoIP-devel pcre pcre-devel
---> Using cache
---> a81a9003b1bb
Step 6/10 : RUN useradd -M -s /sbin/nologin nginx
---> Using cache
---> 8541c8342250
Step 7/10 : WORKDIR /usr/local/src/nginx-1.12.2
---> Using cache
---> 5b6f6148ab37
Step 8/10 : RUN ./configure --user=nginx --group=nginx --prefix=/usr/local/nginx --with-file-aio --with-http_ssl_module --with-http_realip_module --with-http_addition_module --with-http_xslt_module --with-http_image_filter_module --with-http_geoip_module --with-http_sub_module --with-http_dav_module --with-http_flv_module --with-http_mp4_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_auth_request_module --with-http_random_index_module --with-http_secure_link_module --with-http_degradation_module --with-http_stub_status_module && make && make install
---> Using cache
---> adc42b044d17
Step 9/10 : ENV PATH /usr/local/nginx/sbin:$PATH
---> Running in 5cba8cea3ff0
Removing intermediate container 5cba8cea3ff0
---> 37426b9520d6
Step 10/10 : EXPOSE 80
---> Running in 300ae44ca128
Removing intermediate container 300ae44ca128
---> fad261761053
Successfully built fad261761053
Successfully tagged centos7_nginx:v2
docker有个神奇的功能，上文中说到，docker会尽量以重构的镜像来构建新镜像。即Dockerfile会尽可能尝试重用已经构建的镜像，所以在构建v2的时候很快哦
docker在构建的过程中会采用缓存机制，在构建v2的时候就包含了很多using cache，所以构建的很快，如果你想重新构建的话，不想使用cache的话，那就在构建的时候加一个--no-cache吧
--no-cache Do not use cache when building the image
查看v2版本的镜像
[root@centos7-docker ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
centos7_nginx v2 fad261761053 9 minutes ago 673MB
centos7_nginx v1 1ffc4a8e3106 59 minutes ago 673MB
hejing/centos v1 0e4de65ea5c9 22 hours ago 259MB
zhanghaodong/ubuntu v1 f990b7b8a364 22 hours ago 63.1MB
ubuntu 18.04 39a8cfeef173 2 weeks ago 63.1MB
nginx latest 08b152afcfae 3 weeks ago 133MB
hello-world latest d1165f221234 5 months ago 13.3kB
hejing/hello-world v1 d1165f221234 5 months ago 13.3kB
centos latest 300e315adb2f 8 months ago 209MB
centos 7 8652b9f0cb4c 9 months ago 204MB
下面使用v2版本启动一个container
[root@centos7-docker ~]# docker run -d -p81:80 centos7_nginx:v2 nginx -g "daemon off;"
2c8d00cb0b3ca5808593bd5392cdfffbcbe7647a55a2cb77429ba29bfc8735bb
[root@centos7-docker ~]# docker port 2c
80/tcp -> 0.0.0.0:81
80/tcp -> :::81
[root@centos7-docker ~]# docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
2c8d00cb0b3c centos7_nginx:v2 "nginx -g 'daemon of…" 30 seconds ago Up 29 seconds 0.0.0.0:81->80/tcp, :::81->80/tcp sharp_dewdney
浏览器访问：
上述使用的命令是：
docker run -d -p81:80 centos7_nginx:v2 nginx -g "daemon off;"
没有用/usr/local/nginx/sbin/nginx来启动，是因为我们在Dockerfile文件中执行了ENV啊，添加了环境变量而已
ENV PATH /usr/local/nginx/sbin:$PATH
6.2 添加指令CMD
[root@centos7-docker docker_demo]# cat Dockerfile
# base image
FROM centos:7
# # MAINTAINER
MAINTAINER hejing
# put nginx-1.12.2.tar.gz into /usr/local/src and unpack nginx
# the ADD can unpack tar
ADD nginx-1.12.2.tar.gz /usr/local/src
# running required command
RUN yum install -y gcc gcc-c++ glibc make autoconf openssl openssl-devel
RUN yum install -y libxslt-devel gd gd-devel GeoIP GeoIP-devel pcre pcre-devel
RUN useradd -M -s /sbin/nologin nginx
# change dir to /usr/local/src/nginx-1.12.2
WORKDIR /usr/local/src/nginx-1.12.2
# execute command to complie nginx
RUN ./configure --user=nginx --group=nginx --prefix=/usr/local/nginx --with-file-aio --with-http_ssl_module --with-http_realip_module --with-http_addition_module --with-http_xslt_module --with-http_image_filter_module --with-http_geoip_module --with-http_sub_module --with-http_dav_module --with-http_flv_module --with-http_mp4_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_auth_request_module --with-http_random_index_module --with-http_secure_link_module --with-http_degradation_module --with-http_stub_status_module && make && make install
ENV PATH /usr/local/nginx/sbin:$PATH
EXPOSE 80
CMD /bin/sh -c 'nginx -g "daemon off;"'
然后进行构建：
[root@centos7-docker docker_demo]# docker build -t centos7_nginx:v3 .
查看构建的镜像：
[root@centos7-docker docker_demo]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
centos7_nginx v3 034fca0d39d2 34 seconds ago 673MB
centos7_nginx v2 fad261761053 25 minutes ago 673MB
centos7_nginx v1 1ffc4a8e3106 About an hour ago 673MB
基于v3镜像启动container:
[root@centos7-docker docker_demo]# docker run -d -p82:80 centos7_nginx:v3
95daa1ad57d7c26961e9d3a1804c836c46e52a68eb3923107fd6af0e756acb3d
[root@centos7-docker docker_demo]# docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
95daa1ad57d7 centos7_nginx:v3 "/bin/sh -c '/bin/sh…" 7 seconds ago Up 6 seconds 0.0.0.0:82->80/tcp, :::82->80/tcp sharp_keller
[root@centos7-docker docker_demo]# docker port 95
80/tcp -> 0.0.0.0:82
80/tcp -> :::82
浏览器访问：
新增加的CMD /bin/sh -c 'nginx -g "daemon off;"'表示：
当启动一个container时默认运行的命令，如果在启动container时赋予了command的话，那么定义的CMD中的命令将不会被执行，而是会执行command的命令
6.3 添加ENTRYPOINT指令：
[root@centos7-docker docker_demo]# cat Dockerfile
# base image
FROM centos:7
# # MAINTAINER
MAINTAINER hejing
# put nginx-1.12.2.tar.gz into /usr/local/src and unpack nginx
# the ADD can unpack tar
ADD nginx-1.12.2.tar.gz /usr/local/src
# running required command
RUN yum install -y gcc gcc-c++ glibc make autoconf openssl openssl-devel
RUN yum install -y libxslt-devel gd gd-devel GeoIP GeoIP-devel pcre pcre-devel
RUN useradd -M -s /sbin/nologin nginx
# change dir to /usr/local/src/nginx-1.12.2
WORKDIR /usr/local/src/nginx-1.12.2
# execute command to complie nginx
RUN ./configure --user=nginx --group=nginx --prefix=/usr/local/nginx --with-file-aio --with-http_ssl_module --with-http_realip_module --with-http_addition_module --with-http_xslt_module --with-http_image_filter_module --with-http_geoip_module --with-http_sub_module --with-http_dav_module --with-http_flv_module --with-http_mp4_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_auth_request_module --with-http_random_index_module --with-http_secure_link_module --with-http_degradation_module --with-http_stub_status_module && make && make install
ENV PATH /usr/local/nginx/sbin:$PATH
EXPOSE 80
ENTRYPOINT ["nginx"]
CMD ["-g","daemon off;"]
当ENTRYPOINT和CMD连用时，CMD的命令是ENTRYPOINT命令的参数，两者连用相当于nginx -g “daemon off;”
而当一起连用的时候命令格式最好一致（这里选择的都是json格式的是成功的，如果是sh模式可以试一下）
开始构建v4版本镜像：
[root@centos7-docker docker_demo]# docker build -t centos7_nginx:v4 .
查看v4版本的镜像：
[root@centos7-docker docker_demo]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
centos7_nginx v4 586517a9d3a0 40 seconds ago 673MB
centos7_nginx v3 034fca0d39d2 16 minutes ago 673MB
centos7_nginx v2 fad261761053 41 minutes ago 673MB
centos7_nginx v1 1ffc4a8e3106 2 hours ago 673MB
基于v4镜像启动一个container：
[root@centos7-docker docker_demo]# docker run -d -p83:80 centos7_nginx:v4
9e28be9c461f5c0c5489c6fa56612c4fed7bb3f4e77f439479765535b6b3578d
[root@centos7-docker docker_demo]# docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
9e28be9c461f centos7_nginx:v4 "nginx -g 'daemon of…" 5 seconds ago Up 3 seconds 0.0.0.0:83->80/tcp, :::83->80/tcp laughing_buck
[root@centos7-docker docker_demo]# docker port 9
Error response from daemon: Multiple IDs found with provided prefix: 9
[root@centos7-docker docker_demo]# docker port 9e
80/tcp -> 0.0.0.0:83
80/tcp -> :::83
浏览器访问：
6.4 测试command和CMD运行是否冲突，以哪个为准
[root@centos7-docker docker_demo]# cat Dockerfile
# base image
FROM centos:7
# # MAINTAINER
MAINTAINER hejing
# put nginx-1.12.2.tar.gz into /usr/local/src and unpack nginx
# the ADD can unpack tar
ADD nginx-1.12.2.tar.gz /usr/local/src
# running required command
RUN yum install -y gcc gcc-c++ glibc make autoconf openssl openssl-devel
RUN yum install -y libxslt-devel gd gd-devel GeoIP GeoIP-devel pcre pcre-devel
RUN useradd -M -s /sbin/nologin nginx
# change dir to /usr/local/src/nginx-1.12.2
WORKDIR /usr/local/src/nginx-1.12.2
# execute command to complie nginx
RUN ./configure --user=nginx --group=nginx --prefix=/usr/local/nginx --with-file-aio --with-http_ssl_module --with-http_realip_module --with-http_addition_module --with-http_xslt_module --with-http_image_filter_module --with-http_geoip_module --with-http_sub_module --with-http_dav_module --with-http_flv_module --with-http_mp4_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_auth_request_module --with-http_random_index_module --with-http_secure_link_module --with-http_degradation_module --with-http_stub_status_module && make && make install
ENV PATH /usr/local/nginx/sbin:$PATH
EXPOSE 80
ENTRYPOINT ["nginx"]
CMD ["-g","daemon on;"]
CMD的命令修改为了后台，我们知道如果容器内的进程在后台运行那么容器将不会运行
现在构建v5版本镜像：
[root@centos7-docker docker_demo]# docker build -t centos7_nginx:v5 .
查看v5版本镜像：
[root@centos7-docker docker_demo]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
centos7_nginx v5 00e0e71aa40f 42 seconds ago 673MB
centos7_nginx v4 586517a9d3a0 8 minutes ago 673MB
centos7_nginx v3 034fca0d39d2 24 minutes ago 673MB
centos7_nginx v2 fad261761053 49 minutes ago 673MB
centos7_nginx v1 1ffc4a8e3106 2 hours ago 673MB
现在直接利用v5启动container，不加什么其他命令的话，查看container是否能够运行：
[root@centos7-docker docker_demo]# docker run -d -p85:80 centos7_nginx:v5
1e20de8048e2bfe43942cc908f4bfafae1005cd55fede6176b126f83d428fc9f
[root@centos7-docker docker_demo]# docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
1e20de8048e2 centos7_nginx:v5 "nginx -g 'daemon on…" 4 seconds ago Exited (0) 4 seconds ago friendly_leakey
可以看到容器exit了
下面这样启动container：
[root@centos7-docker docker_demo]# docker run -d -p85:80 centos7_nginx:v5 -g "daemon off;"
354bb397fb44792c52496e9ce25d189cc2f5177e5c86964043fccbe532a894c3
[root@centos7-docker docker_demo]# docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
354bb397fb44 centos7_nginx:v5 "nginx -g 'daemon of…" 5 seconds ago Up 4 seconds 0.0.0.0:85->80/tcp, :::85->80/tcp focused_turing
[root@centos7-docker docker_demo]# docker port 354
80/tcp -> 0.0.0.0:85
80/tcp -> :::85
可以看到在后面添加了command之-g "daemon off;",容器的启动丝毫没有受影响。
上问说过如果新加了command命令后，Dockfile中的CMD命令将不会生效，就是这样
浏览器访问：
6.5 添加VOLUME指令
[root@centos7-docker docker_demo]# cat Dockerfile
# base image
FROM centos:7
# # MAINTAINER
MAINTAINER hejing
# put nginx-1.12.2.tar.gz into /usr/local/src and unpack nginx
# the ADD can unpack tar
ADD nginx-1.12.2.tar.gz /usr/local/src
# running required command
RUN yum install -y gcc gcc-c++ glibc make autoconf openssl openssl-devel
RUN yum install -y libxslt-devel gd gd-devel GeoIP GeoIP-devel pcre pcre-devel
RUN useradd -M -s /sbin/nologin nginx
# mount a dit to container
VOLUME ["/data"]
# change dir to /usr/local/src/nginx-1.12.2
WORKDIR /usr/local/src/nginx-1.12.2
# execute command to complie nginx
RUN ./configure --user=nginx --group=nginx --prefix=/usr/local/nginx --with-file-aio --with-http_ssl_module --with-http_realip_module --with-http_addition_module --with-http_xslt_module --with-http_image_filter_module --with-http_geoip_module --with-http_sub_module --with-http_dav_module --with-http_flv_module --with-http_mp4_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_auth_request_module --with-http_random_index_module --with-http_secure_link_module --with-http_degradation_module --with-http_stub_status_module && make && make install
ENV PATH /usr/local/nginx/sbin:$PATH
EXPOSE 80
ENTRYPOINT ["nginx"]
CMD ["-g"]
开始构建v6：
[root@centos7-docker docker_demo]# docker build -t centos7_nginx:v6 .
查看v6版本镜像：
[root@centos7-docker docker_demo]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
centos7_nginx v6 68954acd27d5 39 seconds ago 673MB
centos7_nginx v5 00e0e71aa40f 11 minutes ago 673MB
centos7_nginx v4 586517a9d3a0 19 minutes ago 673MB
centos7_nginx v3 034fca0d39d2 35 minutes ago 673MB
centos7_nginx v2 fad261761053 About an hour ago 673MB
centos7_nginx v1 1ffc4a8e3106 2 hours ago 673MB
基于v6启动container：
[root@centos7-docker docker_demo]# docker run -d -p86:80 --name=nginx6 centos7_nginx:v6 -g "daemon off;"
7d587fb786ab27c93d8790951410b361445b5de78d4999eb4e2a33b55f33a232
[root@centos7-docker docker_demo]# docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
7d587fb786ab centos7_nginx:v6 "nginx -g 'daemon of…" 6 seconds ago Up 5 seconds 0.0.0.0:86->80/tcp, :::86->80/tcp nginx6
[root@centos7-docker docker_demo]# docker port 7d5
80/tcp -> 0.0.0.0:86
80/tcp -> :::86
利用docker exec进入到container中，查看是否存在卷/data：
[root@centos7-docker docker_demo]# docker exec -it 7d5 /bin/bash
[root@7d587fb786ab /]# ls -ld data/
drwxr-xr-x. 2 root root 6 Aug 14 11:06 data/
这个data目录挂载的目录对应本机host的这个目录
[root@centos7-docker _data]# pwd
/var/lib/docker/volumes/2aee288aa9c7545e0f6e3ccbcb11a52217a33d0b56807ee40d301534ece62067/_data
现在在本机host上的目录创建一个文件：
[root@centos7-docker _data]# pwd
/var/lib/docker/volumes/2aee288aa9c7545e0f6e3ccbcb11a52217a33d0b56807ee40d301534ece62067/_data
[root@centos7-docker _data]# touch 8888
然后到container的data下查看是否有8888
[root@7d587fb786ab data]# ls
8888
6.6 添加ONBUILD指令：
-
Dockerfile1中base image为A镜像，并在Dcokerfile1中定义ONBUILD指令，构建成镜像B镜像
-
Dockerfile2中base image为B镜像，构建成镜像C
-
当使用镜像B启动container1不会执行ONBUILD中定义的内容，而使用C镜像启动container2则会执行ONBUILD定义的内容
-
dockerfile1中：A镜像-centos:7为base image，里面有OBNBUILD指令------形成B-v7版本
-
dockerfile2中：以B镜像v7为base image，构建镜像c-v8
-
当使用v7启动container，不会执行ONBUILD
-
当使用v8启动container，会执行ONBUILD
-
centos:7-----构建centos7_nginx:v7------构建centos7_nginx:v8
| A: centos:7到 | B: centos7_nginx:v7到 | C: centos7_nginx:v8 |
|---|---|---|
| Dockerfile中有ONBUILD指令 | 以此image启动的container不执行ONBUILD内容 | 以此image启动的container会执行ONBUILD内容 |
[root@centos7-docker docker_demo]# cat Dockerfile
# base image
FROM centos:7
# # MAINTAINER
MAINTAINER hejing
# put nginx-1.12.2.tar.gz into /usr/local/src and unpack nginx
# the ADD can unpack tar
ADD nginx-1.12.2.tar.gz /usr/local/src
# running required command
RUN yum install -y gcc gcc-c++ glibc make autoconf openssl openssl-devel
RUN yum install -y libxslt-devel gd gd-devel GeoIP GeoIP-devel pcre pcre-devel
RUN useradd -M -s /sbin/nologin nginx
# mount a dit to container
ONBUILD VOLUME ["/data"]
# change dir to /usr/local/src/nginx-1.12.2
WORKDIR /usr/local/src/nginx-1.12.2
# execute command to complie nginx
RUN ./configure --user=nginx --group=nginx --prefix=/usr/local/nginx --with-file-aio --with-http_ssl_module --with-http_realip_module --with-http_addition_module --with-http_xslt_module --with-http_image_filter_module --with-http_geoip_module --with-http_sub_module --with-http_dav_module --with-http_flv_module --with-http_mp4_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_auth_request_module --with-http_random_index_module --with-http_secure_link_module --with-http_degradation_module --with-http_stub_status_module && make && make install
ENV PATH /usr/local/nginx/sbin:$PATH
EXPOSE 80
ENTRYPOINT ["nginx"]
CMD ["-g"]
使用上面的Dockfile构建镜像v7
docker build -t centos7_nginx:v7 .
查看images
[root@centos7-docker docker_demo]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
centos7_nginx v7 003b917060be 38 seconds ago 673MB
centos7_nginx v6 68954acd27d5 19 hours ago 673MB
centos7_nginx v5 00e0e71aa40f 19 hours ago 673MB
centos7_nginx v4 586517a9d3a0 19 hours ago 673MB
centos7_nginx v3 034fca0d39d2 20 hours ago 673MB
centos7_nginx v2 fad261761053 20 hours ago 673MB
centos7_nginx v1 1ffc4a8e3106 21 hours ago 673MB
运行v7版本镜像
[root@centos7-docker docker_demo]# docker run -d -p87:80 --name=nginx7 centos7_nginx:v7 -g "daemon off;" 99940fb7029d9198048f2edf2fa79f094b2e86482c9cb185ffaf377e625cdace
[root@centos7-docker docker_demo]# docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
99940fb7029d centos7_nginx:v7 "nginx -g 'daemon of…" 20 seconds ago Up 19 seconds 0.0.0.0:87->80/tcp, :::87->80/tcp nginx7
[root@centos7-docker docker_demo]# docker port 999
80/tcp -> 0.0.0.0:87
80/tcp -> :::87
现在进入到容器查看是否有/data
[root@centos7-docker docker_demo]# docker exec -it nginx7 /bin/bash
[root@99940fb7029d nginx-1.12.2]# ll /data
ls: cannot access /data: No such file or directory
现在修改上面的Dockerfile1中的base imagem，并形成Dcokerfile2
[root@centos7-docker docker_demo]# cat Dockerfile
# base image
#FROM centos:7
FROM centos7_nginx:v7
......
现在基于Dockerfile2，开始构建新镜像v8：
[root@centos7-docker docker_demo]# docker build -t centos7_nginx:v8 .
查看v8版本镜像：
[root@centos7-docker docker_demo]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
centos7_nginx v8 d52a7cd5a1ed 10 seconds ago 976MB
centos7_nginx v7 003b917060be 13 minutes ago 673MB
centos7_nginx v6 68954acd27d5 19 hours ago 673MB
centos7_nginx v5 00e0e71aa40f 20 hours ago 673MB
centos7_nginx v4 586517a9d3a0 20 hours ago 673MB
centos7_nginx v3 034fca0d39d2 20 hours ago 673MB
centos7_nginx v2 fad261761053 20 hours ago 673MB
centos7_nginx v1 1ffc4a8e3106 21 hours ago 673MB
现在基于v8启动container：
[root@centos7-docker docker_demo]# docker run -d -p88:80 centos7_nginx:v8 -g "daemon off;"
eeea3992637f39cb33532feb620f302ddd92c7c06528a5fea25a4fcee2fb2729
[root@centos7-docker docker_demo]# docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
eeea3992637f centos7_nginx:v8 "nginx -g 'daemon of…" 4 seconds ago Up 3 seconds 0.0.0.0:88->80/tcp, :::88->80/tcp sleepy_elbakyan
[root@centos7-docker docker_demo]# docker port eee
80/tcp -> 0.0.0.0:88
80/tcp -> :::88
进入container查看data是否存在：
[root@centos7-docker ~]# docker exec -it eee /bin/bash
[root@eeea3992637f nginx-1.12.2]# ll /data
total 0
7.设置镜像标签
使用docker tag为镜像添加新的标签
查看本地镜像
[root@centos7-docker ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hejing/centos v1 0e4de65ea5c9 17 minutes ago 259MB
zhanghaodong/ubuntu v1 f990b7b8a364 44 minutes ago 63.1MB
ubuntu 18.04 39a8cfeef173 2 weeks ago 63.1MB
nginx latest 08b152afcfae 3 weeks ago 133MB
hello-world latest d1165f221234 5 months ago 13.3kB
centos latest 300e315adb2f 8 months ago 209MB
下面给hello-world换一个标签
[root@centos7-docker ~]# docker tag d11 hejing/hello-world:v1
[root@centos7-docker ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hejing/centos v1 0e4de65ea5c9 18 minutes ago 259MB
zhanghaodong/ubuntu v1 f990b7b8a364 45 minutes ago 63.1MB
ubuntu 18.04 39a8cfeef173 2 weeks ago 63.1MB
nginx latest 08b152afcfae 3 weeks ago 133MB
hejing/hello-world v1 d1165f221234 5 months ago 13.3kB
hello-world latest d1165f221234 5 months ago 13.3kB
centos latest 300e315adb2f 8 months ago 209MB
#可以看到镜像ID为d11的有两个标签
8.docker数据卷管理
docker数据卷备份和还原
8.1 利用镜像创建一个nginx服务容器，并挂载一个数据卷
[root@centos7-docker ~]# docker run -v /data -d -p80:80 --name=web1 centos7_nginx:v8 -g "daemon off;"
f1be21798741dd02a3bf3073e4f35778829b9fd36726912db65271fae2c42bfc
8.2 进入web1容器，向空的/data添加数据
[root@centos7-docker volumes]# docker exec -it f1 /bin/bash
[root@f1be21798741 nginx-1.12.2]# cd /data/
[root@f1be21798741 data]# ls
[root@f1be21798741 data]# mkdir hejing
[root@f1be21798741 data]# vi hejing/web1.txt
[root@f1be21798741 data]# cat hejing/web1.txt
this is in web1
8.3 数据卷备份
创建另外一个容器以上面web1容器作为共享数据卷，并将共享的数据卷进行tar压缩备份，并通过映射到本机host
命令解释：
- –volumes-from web1：表示创建的容器基于web1容器内的数据卷（即两个容器共享数据卷），web1的数据卷为/data
- tar cvf /backup/data.tar /data：创建的容器将/data进行压缩
- -v /root/backup:/backup：将容器的/backup与本机的/root/backup进行映射
总：创建一个新容器数据卷基于共享web1容器的数据卷，将数据卷进行tar压缩到容器内某个目录，并映射到本机目录
[root@centos7-docker ~]# docker run -d --volumes-from web1 -v /root/backup:/backup centos:7 tar cvf /backup/data.tar /data
faf11579491a0437a3a89b6ebd4ad87c4b4cc6c2702c57b10feb2baedf78aff2
[root@centos7-docker ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
f1be21798741 centos7_nginx:v8 "nginx -g 'daemon of…" 11 minutes ago Up 11 minutes 0.0.0.0:80->80/tcp, :::80->80/tcp web1
[root@centos7-docker ~]# docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
faf11579491a centos:7 "tar cvf /backup/dat…" 12 seconds ago Exited (0) 11 seconds ago amazing_chatelet
[root@centos7-docker ~]# ls
anaconda-ks.cfg backup docker_demo rpmbuild
[root@centos7-docker ~]# ls backup/data.tar
backup/data.tar
[root@centos7-docker ~]# tar -xf backup/data.tar
[root@centos7-docker ~]# ls
anaconda-ks.cfg backup data docker_demo rpmbuild
[root@centos7-docker ~]# cd data/hejing/
[root@centos7-docker hejing]# ls
web1.txt
[root@centos7-docker hejing]# cat web1.txt
this is in web1
9. docker镜像的导入导出
涉及到的命令：export、import、save、load
其中save和load针对的是image
export和import针对的是container
区别：容器的快照信息将丢弃历史记录和元数据信息（只保留容器当时的快照状态），而镜像的存储文件将保存完整记录。
9.1 docker save-镜像导出
格式：docker save [options] image [images]
[root@centos7-docker ~]# docker save --help
Usage: docker save [OPTIONS] IMAGE [IMAGE...]
Save one or more images to a tar archive (streamed to STDOUT by default)
Options:
-o, --output string Write to a file, instead of STDOUT
-o和>表示输出到文件，xxx.tar是目标文件，centos7_nginx:v8是源镜像名，目标文件后跟image id也可以
#查看host本机镜像
[root@centos7-docker ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
centos7_nginx v8 d52a7cd5a1ed 2 hours ago 976MB
centos7_nginx v7 003b917060be 2 hours ago 673MB
centos7_nginx v6 68954acd27d5 21 hours ago 673MB
centos7_nginx v5 00e0e71aa40f 21 hours ago 673MB
centos7_nginx v4 586517a9d3a0 21 hours ago 673MB
centos7_nginx v3 034fca0d39d2 22 hours ago 673MB
centos7_nginx v2 fad261761053 22 hours ago 673MB
centos7_nginx v1 1ffc4a8e3106 23 hours ago 673MB
hejing/centos v1 0e4de65ea5c9 44 hours ago 259MB
zhanghaodong/ubuntu v1 f990b7b8a364 44 hours ago 63.1MB
ubuntu 18.04 39a8cfeef173 2 weeks ago 63.1MB
nginx latest 08b152afcfae 3 weeks ago 133MB
hejing/hello-world v1 d1165f221234 5 months ago 13.3kB
hello-world latest d1165f221234 5 months ago 13.3kB
centos latest 300e315adb2f 8 months ago 209MB
centos 7 8652b9f0cb4c 9 months ago 204MB
方法1：
[root@centos7-docker ~]# docker save -o centos7_nginx-v9.tar centos7_nginx:v8
[root@centos7-docker ~]# ls
anaconda-ks.cfg backup centos7_nginx-v9.tar docker_demo rpmbuild
方法2：
[root@centos7-docker ~]# docker save > centos7_nginx-v10.tar centos7_nginx:v8
[root@centos7-docker ~]# ls
anaconda-ks.cfg backup centos7_nginx-v10.tar centos7_nginx-v9.tar docker_demo rpmbuild
方法3：
[root@centos7-docker ~]# docker save > centos7_nginx-v11.tar d52
[root@centos7-docker ~]# ls
anaconda-ks.cfg backup centos7_nginx-v10.tar centos7_nginx-v11.tar centos7_nginx-v9.tar docker_demo rpmbuild
9.2 docker load-镜像导入
格式：docker load [options]
[root@centos7-docker ~]# docker load --help
Usage: docker load [OPTIONS]
Load an image from a tar archive or STDIN
Options:
-i, --input string Read from tar archive file, instead of STDIN
-q, --quiet Suppress the load output
其中-i和<表示从文件输入，会成功导入镜像及相关元数据，包括tag
[root@centos7-docker ~]# docker load -i centos7_nginx-v11.tar
或者
[root@centos7-docker ~]# docker load < centos7_nginx-v11.tar
58149cafb515: Loading layer [==================================================>] 6.121MB/6.121MB
ce85612a8b78: Loading layer [==================================================>] 130.6MB/130.6MB
94a3447f3146: Loading layer [==================================================>] 130.5MB/130.5MB
929ffd789d18: Loading layer [==================================================>] 36.33MB/36.33MB
Loaded image ID: sha256:d52a7cd5a1ed35bde142d453f36b0c542ecd130338f5518f142f458b6fd1159f
#导入之后发现源仓库和tag都是
[root@centos7-docker ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
d52a7cd5a1ed 2 hours ago 976MB
centos7_nginx v7 003b917060be 2 hours ago 673MB
centos7_nginx v6 68954acd27d5 22 hours ago 673MB
centos7_nginx v5 00e0e71aa40f 22 hours ago 673MB
centos7_nginx v4 586517a9d3a0 22 hours ago 673MB
centos7_nginx v3 034fca0d39d2 22 hours ago 673MB
centos7_nginx v2 fad261761053 22 hours ago 673MB
centos7_nginx v1 1ffc4a8e3106 23 hours ago 673MB
#更改源仓库和tag
[root@centos7-docker ~]# docker tag d52 centos7_nginx:v8
[root@centos7-docker ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
centos7_nginx v8 d52a7cd5a1ed 2 hours ago 976MB
centos7_nginx v7 003b917060be 2 hours ago 673MB
centos7_nginx v6 68954acd27d5 22 hours ago 673MB
centos7_nginx v5 00e0e71aa40f 22 hours ago 673MB
centos7_nginx v4 586517a9d3a0 22 hours ago 673MB
centos7_nginx v3 034fca0d39d2 22 hours ago 673MB
centos7_nginx v2 fad261761053 23 hours ago 673MB
centos7_nginx v1 1ffc4a8e3106 23 hours ago 673MB
9.3 docker export-容器导出
格式：docker export [options] CONTAINER
[root@centos7-docker ~]# docker export --help
Usage: docker export [OPTIONS] CONTAINER
Export a container's filesystem as a tar archive
Options:
-o, --output string Write to a file, instead of STDOUT
docker export -o ubuntu-18.04.tar b75
其中-o表示输出到文件，ubuntu-18.04.tar为目标文件，b75是容器ID（写容器名也可以）
#查看运行的容器
[root@centos7-docker ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
b756c37a6552 ubuntu:18.04 "/bin/bash" About an hour ago Up 2 seconds nostalgic_mestorf
[root@centos7-docker ~]# docker export -o ubuntu-18.04.tar b75
[root@centos7-docker ~]# ls
backup centos7_nginx-v10.tar centos7_nginx-v11.tar centos7_nginx-v9.tar docker_demo rpmbuild ubuntu-18.04.tar
9.4 docker import-容器导入
格式：docker import [OPTIONS] file|URL|- [REPOSITORY[:TAG]]
[root@centos7-docker ~]# docker import --help
Usage: docker import [OPTIONS] file|URL|- [REPOSITORY[:TAG]]
Import the contents from a tarball to create a filesystem image
Options:
-c, --change list Apply Dockerfile instruction to the created image
-m, --message string Set commit message for imported image
--platform string Set platform if server is multi-platform capable
或者
9.5 总结区别
- export命令导出的tar略小于save命令导出来的
- export命令针对的是container，是从容器container中导出tar文件的，而save命令则是从镜像中导出的
- 基于第二点，export导出的文件在import回去时，无法保留镜像所有历史（即每一层layer信息），不能进行回滚操作；而save是根据镜像而来的，所以导入导出的时候可以完成的保留每一层的信息
下图是save导出load导入的
下图是export导出import导入的
9.6 建议
- 若是只想备份image，用save和load
- 若是在启动容器后，容器内容有变化，需要备份，则使用export和import