Nginx镜像构建-优快云博客

本文链接：https://blog.youkuaiyun.com/power_to_go/article/details/109543264

通过实例来创建一个Nginx 应用镜像，理解创建镜像步骤。

准备好以下文件

root@aliyun:example# tree .
.
├── Dockerfile
└── index.html

0 directories, 2 files

Dockerfile 文件

base images

All Docker images start from a base image.
A base image is the same images from the Docker Registry which are used to start containers.
Along with the image name, we can also include the image tag to indicate which particular version we want, by default, this is latest
所有的 Docker 镜像都需要基于一个 base image

FROM nginx:1.11-alpine  # 基于 nginx:1.11-alpine 这个基础镜像构建 nginx 应用镜像

copy 相关文件到 docker image

COPY allows you to copy files from thedirectory containing the Dockerfile to the container's image.

COPY index.html /usr/share/nginx/index.html # 将应用相关文件复制到镜像中相关文件夹

开放端口,对外服务

Using the EXPOSE <port>command you tell Docker which ports should be open and can be bound to.
You can define multiple ports on the single command, for example, EXPOSE 80 433 or EXPOSE 7000-8000.

EXPOSE 80

定义应用启动命令

define the command that launches the application.
The CMD line in a Dockerfile defines the default command to run when a container is launched.
If the command requires arguments then it’s recommended to use an array, for example [“cmd”, “-a”, “arga value”, “-b”, “argb-value”], which will be combined together and the command cmd -a “arga value” -b argb-value would be run.

CMD ["nginx","-g","daemon off;"]

完整 Docker file

FROM nginx:1.11-alpine

COPY index.html /usr/share/nginx/index.html

EXPOSE 80

CMD ["nginx","-g","daemon off;"]

index.html 内容

<h1>Hello, nginx!</h1>

docker build 制作镜像

root@aliyun:example# docker build -t myapp:v1 .
Sending build context to Docker daemon  3.072kB
Step 1/4 : FROM nginx:1.11-alpine    #1
1.11-alpine: Pulling from library/nginx
709515475419: Pull complete 
4b21d71b440a: Pull complete 
c92260fe6357: Pull complete 
ed383a1b82df: Pull complete 
Digest: sha256:5aadb68304a38a8e2719605e4e180413f390cd6647602bee9bdedd59753c3590
Status: Downloaded newer image for nginx:1.11-alpine
 ---> bedece1f06cc
Step 2/4 : COPY index.html /usr/share/nginx/index.html #2
 ---> 54604ee74078 
Step 3/4 : EXPOSE 80  #3
 ---> Running in d67b9a19bae3
Removing intermediate container d67b9a19bae3
 ---> d445f315dfa0
Step 4/4 : CMD ["nginx","-g","daemon off;"] #4
 ---> Running in 37922caeb43a
Removing intermediate container 37922caeb43a
 ---> f0054c020122
Successfully built f0054c020122
Successfully tagged myapp:v1
root@aliyun:example# docker images
REPOSITORY               TAG                 IMAGE ID            CREATED             SIZE
myapp                    v1                  f0054c020122        28 seconds ago      54.3MB

docker run 启动容器

root@aliyun:example# docker run -d -p 8989:80 myapp:v1
92a4851d68a893ae206d6034bd2a703241afca46d87583431cd8f8247fdd4533
root@aliyun:example# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                           NAMES
92a4851d68a8        myapp:v1            "nginx -g 'daemon of…"   4 seconds ago       Up 2 seconds        443/tcp, 0.0.0.0:8989->80/tcp   naughty_dhawan
root@aliyun:example# docker exec -it naughty_dhawan /bin/sh  # 进入容器
/ # hostname
92a4851d68a8
/ # cd /usr/share/nginx/ #查看容器中的 index.html
/usr/share/nginx # ls
html        index.html
/usr/share/nginx # cat index.html 
<h1>Hello, nginx!</h1>

由上可知，docker 镜像中的 /usr/share/nginx/index.html 就是从主机拷贝的。

分享镜像

root@aliyun:example# docker save -o myappv1.tar myapp:v1 # 镜像保存为 tar 文件
root@aliyun:example# ll *.tar
-rw------- 1 root root 55920640 Nov  7 10:51 myappv1.tar
root@aliyun:example# docker load < myappv2.tar # 装载 tar 文件
Loaded image: myapp:v1

查看解压后的 myappv1.tar

查看镜像分层

root@aliyun:tar# tar -xf myappv1.tar
root@aliyun:tar# ls
19a3c3bc0572a58f29be5d06b28db88cd159c52e386d47de253d6c41f21e7e81
278aa45094fda49d5f1241e0f84fe5b5ee6743c97ae265b52ceceda3b44be58d
34470d46fea52393079a0745396c4122b646b1619852b66c6cc77441b6204d28
3cde60226a035b83e036672471dd6fe889c4aeecfa6f3ebfd54f32a70b899ead
b3128a7c6a22b396d311a9032760820d836d629c54c646d3dc032809d0160bd4
f0054c0201220fa246dd9c81cb00066532168040ac5d6d0601df9115652dc3aa.json
manifest.json
myappv1.tar
repositories

查看镜像层次

root@aliyun:tar# cat repositories 
{"myapp":{"v1":"34470d46fea52393079a0745396c4122b646b1619852b66c6cc77441b6204d28"}}

查看镜像仓库信息 “image name”:{“tage”:“最上层的文件”}

查看镜像配置清单

root@aliyun:tar# cat manifest.json 
[{"Config":"f0054c0201220fa246dd9c81cb00066532168040ac5d6d0601df9115652dc3aa.json","RepoTags":["myapp:v1"],"Layers":["3cde60226a035b83e036672471dd6fe889c4aeecfa6f3ebfd54f32a70b899ead/layer.tar","b3128a7c6a22b396d311a9032760820d836d629c54c646d3dc032809d0160bd4/layer.tar","19a3c3bc0572a58f29be5d06b28db88cd159c52e386d47de253d6c41f21e7e81/layer.tar","278aa45094fda49d5f1241e0f84fe5b5ee6743c97ae265b52ceceda3b44be58d/layer.tar","34470d46fea52393079a0745396c4122b646b1619852b66c6cc77441b6204d28/layer.tar"]}]

格式化后的 manifest.json

[
   {
      "Config":"f0054c0201220fa246dd9c81cb00066532168040ac5d6d0601df9115652dc3aa.json",
      "RepoTags":[
         "myapp:v1"
      ],
      "Layers":[
         "3cde60226a035b83e036672471dd6fe889c4aeecfa6f3ebfd54f32a70b899ead/layer.tar", # 镜像第一层
         "b3128a7c6a22b396d311a9032760820d836d629c54c646d3dc032809d0160bd4/layer.tar", # 镜像第二层
         "19a3c3bc0572a58f29be5d06b28db88cd159c52e386d47de253d6c41f21e7e81/layer.tar", # 镜像第三层
         "278aa45094fda49d5f1241e0f84fe5b5ee6743c97ae265b52ceceda3b44be58d/layer.tar", # 镜像第四层
         "34470d46fea52393079a0745396c4122b646b1619852b66c6cc77441b6204d28/layer.tar"  # 镜像最上层
      ]
   }
]