镜像的获取
- pull from
registry(online) 从registry拉取- public（公有）
- private（私有）
- build from
Dockerfile(online) 从Dockerfile构建 - load from
file(offline) 文件导入 （离线）
Docker Image Registry
镜像的基本操作
$ docker image Usage: docker image COMMAND Manage images Commands: build Build an image from a Dockerfile history Show the history of an image import Import the contents from a tarball to create a filesystem image inspect Display detailed information on one or more images load Load an image from a tar archive or STDIN ls List images prune Remove unused images pull Pull an image or a repository from a registry push Push an image or a repository to a registry rm Remove one or more images save Save one or more images to a tar archive (streamed to STDOUT by default) tag Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE Run 'docker image COMMAND --help' for more information on a command.
镜像的拉取Pull Image
默认从Docker Hub拉取，如果不指定版本，会拉取最新版。
$ docker pull nginx Using default tag: latest latest: Pulling from library/nginx 69692152171a: Pull complete 49f7d34d62c1: Pull complete 5f97dc5d71ab: Pull complete cfcd0711b93a: Pull complete be6172d7651b: Pull complete de9813870342: Pull complete Digest: sha256:df13abe416e37eb3db4722840dd479b00ba193ac6606e7902331dcea50f4f1f2 Status: Downloaded newer image for nginx:latest docker.io/library/nginx:latest
指定版本
$ docker pull nginx:1.20.0 1.20.0: Pulling from library/nginx 69692152171a: Already exists 965615a5cec8: Pull complete b141b026b9ce: Pull complete 8d70dc384fb3: Pull complete 525e372d6dee: Pull complete Digest: sha256:ea4560b87ff03479670d15df426f7d02e30cb6340dcd3004cdfc048d6a1d54b4 Status: Downloaded newer image for nginx:1.20.0 docker.io/library/nginx:1.20.0
从Quay上拉取镜像
$ docker pull quay.io/bitnami/nginx Using default tag: latest latest: Pulling from bitnami/nginx 2e6370f1e2d3: Pull complete 2d464c695e97: Pull complete 83eb3b1671f4: Pull complete 364c139450f9: Pull complete dc453d5ae92e: Pull complete 09bd59934b83: Pull complete 8d2bd62eedfb: Pull complete 8ac060ae1ede: Pull complete c7c9bc2f4f9d: Pull complete 6dd7098b85fa: Pull complete 894a70299d18: Pull complete Digest: sha256:d143befa04e503472603190da62db157383797d281fb04e6a72c85b48e0b3239 Status: Downloaded newer image for quay.io/bitnami/nginx:latest quay.io/bitnami/nginx:latest
镜像的查看
$ docker image ls REPOSITORY TAG IMAGE ID CREATED SIZE quay.io/bitnami/nginx latest 0922eabe1625 6 hours ago 89.3MB nginx 1.20.0 7ab27dbbfbdf 10 days ago 133MB nginx latest f0b8a9a54136 10 days ago 133MB
镜像的删除
$ docker image rm 0922eabe1625 Untagged: quay.io/bitnami/nginx:latest Untagged: quay.io/bitnami/nginx@sha256:d143befa04e503472603190da62db157383797d281fb04e6a72c85b48e0b3239 Deleted: sha256:0922eabe16250e2f4711146e31b7aac0e547f52daa6cf01c9d00cf64d49c68c8 Deleted: sha256:5eee4ed0f6b242e2c6e4f4066c7aca26bf9b3b021b511b56a0dadd52610606bd Deleted: sha256:472a75325eda417558f9100ff8b4a97f4a5e8586a14eb9c8fc12f944b26a21f8 Deleted: sha256:cdcb5872f8a64a0b5839711fcd2a87ba05795e5bf6a70ba9510b8066cdd25e76 Deleted: sha256:e0f1b7345a521469bbeb7ec53ef98227bd38c87efa19855c5ba0db0ac25c8e83 Deleted: sha256:11b9c2261cfc687fba8d300b83434854cc01e91a2f8b1c21dadd937e59290c99 Deleted: sha256:4819311ec2867ad82d017253500be1148fc335ad13b6c1eb6875154da582fcf2 Deleted: sha256:784480add553b8e8d5ee1bbd229ed8be92099e5fb61009ed7398b93d5705a560 Deleted: sha256:e0c520d1a43832d5d2b1028e3f57047f9d9f71078c0187f4bb05e6a6a572993d Deleted: sha256:94d5b1d6c9e31de42ce58b8ce51eb6fb5292ec889a6d95763ad2905330b92762 Deleted: sha256:95deba55c490bbb8de44551d3e6a89704758c93ba8503a593cb7c07dfbae0058 Deleted: sha256:1ad1d903ef1def850cd44e2010b46542196e5f91e53317dbdb2c1eedfc2d770c
镜像的导出和导入 (offline)
PS C:\Users\Peng Xiao\docker.tips\image> docker image ls
nginx 1.20.0 7ab27dbbfbdf 12 days ago 133MB
nginx latest f0b8a9a54136 12 days ago 133MB
PS C:\Users\Peng Xiao\docker.tips\image> docker image save nginx:1.20.0 -o nginx.image
PS C:\Users\Peng Xiao\docker.tips\image> ls
Directory: C:\Users\Peng Xiao\docker.tips\image
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a---- 5/24/2021 1:40 PM 137379328 nginx.image
PS C:\Users\Peng Xiao\docker.tips\image> docker image rm 7ab
Untagged: nginx:1.20.0
Deleted: sha256:7ab27dbbfbdf4031f0603a4b597cc43031ff883b54f9329f0309c80952dda6f5
Deleted: sha256:5b2a9404d052ae4205f6139190fd4b0921ddeff17bf2aaf4ee97f79e1a8242fe
Deleted: sha256:03ebf76f0cbf5fd32ca010bb589c2139ce7e44c050fe3de2d77addf4cfd25866
Deleted: sha256:0191669d087dce47072254a93fe55cbedd687f27d3798e2260f846e8f8f5729a
Deleted: sha256:17651c6a0ba04d31da14ac6a86d8fb3f600883f9e155558e8aad0b94aa6540a2
Deleted: sha256:5a673ff4c07a1b606f2ad1fc53697c99c45b0675734ca945e3bb2bd80f43feb8
PS C:\Users\Peng Xiao\docker.tips\image> docker image ls
REPOSITORY TAG IMAGE ID CREATED SIZE
nginx latest f0b8a9a54136 12 days ago 133MB
PS C:\Users\Peng Xiao\docker.tips\image> docker image load -i .\nginx.image
1839f9962bd8: Loading layer [==================================================>] 64.8MB/64.8MB
a2f4f809e04e: Loading layer [==================================================>] 3.072kB/3.072kB
9b63e6289fbe: Loading layer [==================================================>] 4.096kB/4.096kB
f7141923aaa3: Loading layer [==================================================>] 3.584kB/3.584kB
272bc57d3405: Loading layer [==================================================>] 7.168kB/7.168kB
Loaded image: nginx:1.20.0
PS C:\Users\Peng Xiao\docker.tips\image> docker image ls
REPOSITORY TAG IMAGE ID CREATED SIZE
nginx 1.20.0 7ab27dbbfbdf 12 days ago 133MB
nginx latest f0b8a9a54136 12 days ago 133MB
PS C:\Users\Peng Xiao\docker.tips\image>
Dockerfile 介绍
Docker can build images automatically by reading the instructions from a Dockerfile. A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image. Using docker build users can create an automated build that executes several command-line instructions in succession.
https://docs.docker.com/engine/reference/builder/
- Dockerfile是用于构建docker镜像的文件
- Dockerfile里包含了构建镜像所需的“指令”
- Dockerfile有其特定的语法规则
举例：执行一个Python程序
容器及进程，所以镜像就是一个运行这个进程所需要的环境。
假如我们要在一台ubuntu 21.04上运行下面这个hello.py的Python程序
hello.py的文件内容：
print("hello docker")
第一步，准备Python环境
apt-get update && \ DEBIAN_FRONTEND=noninteractive apt-get install --no-install-recommends -y python3.9 python3-pip python3.9-dev
第二步，运行hello.py
$ python3 hello.py hello docker
一个Dockerfile的基本结构
Dockerfile
FROM ubuntu:21.04
RUN apt-get update && \
DEBIAN_FRONTEND=noninteractive apt-get install --no-install-recommends -y python3.9 python3-pip python3.9-dev
ADD hello.py /
CMD ["python3", "/hello.py"]
镜像的构建和分享
通过 commit 创建镜像
关于 scratch 镜像
Scratch是一个空的Docker镜像。
通过scratch来构建一个基础镜像。
hello.c
#include <stdio.h>
int main()
{
printf("hello docker\n");
}
编译成一个二进制文件
$ gcc --static -o hello hello.c $ ./hello hello docker $
Dockerfile
FROM scratch ADD hello / CMD ["/hello"]
构建
$ docker build -t hello . $ docker image ls REPOSITORY TAG IMAGE ID CREATED SIZE hello latest 2936e77a9daa 40 minutes ago 872kB
运行
$ docker container run -it hello hello docker