阿里云服务器执行yum，一直下载docker-ce-stable失败_Docker

~# yum update
docker ce stable - x86_64                               0.0  b/s |   0  b     02:00    
errors during downloading metadata for repository 'docker-ce-stable':
  - curl error (28): timeout was reached for https://download.docker.com/linux/centos/8/x86_64/stable/repodata/repomd.xml [connection timed out after 30000 milliseconds]
error: failed to download metadata for repo 'docker-ce-stable': cannot download repomd.xml: cannot download repodata/repomd.xml: all mirrors were tried

这可能是由于yum配置文件中包含了docker仓库的配置，或者您的yum源中包含了docker的相关依赖。您可以尝试以下步骤解决问题：

1. 查看yum配置：查看 `/etc/yum.repos.d/` 目录下是否有与docker相关的repo文件，如`docker.repo`或`docker-ce.repo`，并临时移除或注释掉相关配置。

本人通过查看`/etc/yum.repos.d/` 目录，发现有docker-ce.repo，打开

[docker-ce-stable]
name=docker ce stable - $basearch
baseurl=https://download.docker.com/linux/centos/$releasever/$basearch/stable
enabled=1
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg

[docker-ce-stable-debuginfo]
name=docker ce stable - debuginfo $basearch
baseurl=https://download.docker.com/linux/centos/$releasever/debug-$basearch/stable
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg

[docker-ce-stable-source]
name=docker ce stable - sources
baseurl=https://download.docker.com/linux/centos/$releasever/source/stable
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg

[docker-ce-test]
name=docker ce test - $basearch
baseurl=https://download.docker.com/linux/centos/$releasever/$basearch/test
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg

[docker-ce-test-debuginfo]
name=docker ce test - debuginfo $basearch
baseurl=https://download.docker.com/linux/centos/$releasever/debug-$basearch/test
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg

[docker-ce-test-source]
name=docker ce test - sources
baseurl=https://download.docker.com/linux/centos/$releasever/source/test
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg

[docker-ce-nightly]
name=docker ce nightly - $basearch
baseurl=https://download.docker.com/linux/centos/$releasever/$basearch/nightly
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg

[docker-ce-nightly-debuginfo]
name=docker ce nightly - debuginfo $basearch
baseurl=https://download.docker.com/linux/centos/$releasever/debug-$basearch/nightly
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg

[docker-ce-nightly-source]
name=docker ce nightly - sources
baseurl=https://download.docker.com/linux/centos/$releasever/source/nightly
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg

发现第4行，enabled=1，其他都是0，将其改为0，解决

2. 临时禁用docker源：在执行yum命令时，可以使用`--disablerepo=docker*`参数来临时忽略docker仓库。