阿里云linux环境安装Docker（期间问题记录：执行到 “测试是否成功安装”，提示Unable to find image ‘hello-world:latest‘ locally）_unable to find image 'hello-world:latest' locally

1. 服务器不存在Docker旧版本，直接安装
2. 安装软件包并设置存储库：

sudo yum install -y yum-utils
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出现Complete!表示执行成功

sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
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如图所示，成功添加/etc/yum.repos.d/docker-ce.repo

3.安装最新版本Docker

sudo yum install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
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…
期间会询问是否接受密钥，输入y

Is this ok [y/N]: y
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出现Complete!表示执行成功

4. 启动 Docker

sudo systemctl start docker
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5. 验证 Docker 是否安装成功

sudo docker run hello-world
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提示：Unable to find image ‘hello-world:latest’ locally
latest: Pulling from library/hello-world
719385e32844: Pull complete
Digest: sha256:fc6cf906cbfa013e80938cdf0bb199fbdbb86d6e3e013783e5a766f50f5dbce0
Status: Downloaded newer image for hello-world:latest

Hello from Docker!
This message shows that your installation appears to be working correctly.

To generate this message, Docker took the following steps:

1. The Docker client contacted the Docker daemon.
2. The Docker daemon pulled the “hello-world” image from the Docker Hub.
   (amd64)
3. The Docker daemon created a new container from that image which runs the
   executable that produces the output you are currently reading.
4. The Docker daemon streamed that output to the Docker client, which sent it
   to your terminal.

To try something more ambitious, you can run an Ubuntu container with:
$ docker run -it ubuntu bash

Share images, automate workflows, and more with a free Docker ID:
https://hub.docker.com/

For more examples and ideas, visit:
https://docs.docker.com/get-started/

不慌，小问题再执行一次语句

sudo systemctl start docker
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Hello from Docker!

恭喜你，可以进一步Docker的学习了！

文章参考：
https://docs.docker.com/engine/install/centos/
https://blog.csdn.net/CaoMei_HuaCha/article/details/87544109