yum安装软件的时候经常出现找不到镜像的情况
https://download.docker.com/linux/centos/7/x86_64/stable/repodata/repomd.xml: [Errno 12] Timeout on
解决方法：更新/etc/yum.repos.d目录下的docker.repo文件内容，使用阿里的镜像源
[docker-ce-stable] name=Docker CE Stable - $basearch baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/$basearch/stable enabled=1 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg [docker-ce-stable-debuginfo] name=Docker CE Stable - Debuginfo $basearch baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/debug-$basearch/stable enabled=0 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg [docker-ce-stable-source] name=Docker CE Stable - Sources baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/source/stable enabled=0 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg [docker-ce-edge] name=Docker CE Edge - $basearch baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/$basearch/edge enabled=0 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg [docker-ce-edge-debuginfo] name=Docker CE Edge - Debuginfo $basearch baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/debug-$basearch/edge enabled=0 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg [docker-ce-edge-source] name=Docker CE Edge - Sources baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/source/edge enabled=0 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg [docker-ce-test] name=Docker CE Test - $basearch baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/$basearch/test enabled=0 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg [docker-ce-test-debuginfo] name=Docker CE Test - Debuginfo $basearch baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/debug-$basearch/test enabled=0 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg [docker-ce-test-source] name=Docker CE Test - Sources baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/source/test enabled=0 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg [docker-ce-nightly] name=Docker CE Nightly - $basearch baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/$basearch/nightly enabled=0 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg [docker-ce-nightly-debuginfo] name=Docker CE Nightly - Debuginfo $basearch baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/debug-$basearch/nightly enabled=0 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg [docker-ce-nightly-source] name=Docker CE Nightly - Sources baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/source/nightly enabled=0 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg
如果是CentOS-Base.repo，则改成
1 # CentOS-Base.repo 2 # 3 # The mirror system uses the connecting IP address of the client and the 4 # update status of each mirror to pick mirrors that are updated to and 5 # geographically close to the client. You should use this for CentOS updates 6 # unless you are manually picking other mirrors. 7 # 8 # If the mirrorlist= does not work for you, as a fall back you can try the 9 # remarked out baseurl= line instead. 10 # 11 # 12 13 [base] 14 name=CentOS-$releasever - Base - mirrors.aliyun.com 15 failovermethod=priority 16 baseurl=http://mirrors.aliyun.com/centos/$releasever/os/$basearch/ 17 http://mirrors.aliyuncs.com/centos/$releasever/os/$basearch/ 18 http://mirrors.cloud.aliyuncs.com/centos/$releasever/os/$basearch/ 19 gpgcheck=1 20 gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7 21 22 #released updates 23 [updates] 24 name=CentOS-$releasever - Updates - mirrors.aliyun.com 25 failovermethod=priority 26 baseurl=http://mirrors.aliyun.com/centos/$releasever/updates/$basearch/ 27 http://mirrors.aliyuncs.com/centos/$releasever/updates/$basearch/ 28 http://mirrors.cloud.aliyuncs.com/centos/$releasever/updates/$basearch/ 29 gpgcheck=1 30 gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7 31 32 #additional packages that may be useful 33 [extras] 34 name=CentOS-$releasever - Extras - mirrors.aliyun.com 35 failovermethod=priority 36 baseurl=http://mirrors.aliyun.com/centos/$releasever/extras/$basearch/ 37 http://mirrors.aliyuncs.com/centos/$releasever/extras/$basearch/ 38 http://mirrors.cloud.aliyuncs.com/centos/$releasever/extras/$basearch/ 39 gpgcheck=1 40 gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7 41 42 #additional packages that extend functionality of existing packages 43 [centosplus] 44 name=CentOS-$releasever - Plus - mirrors.aliyun.com 45 failovermethod=priority 46 baseurl=http://mirrors.aliyun.com/centos/$releasever/centosplus/$basearch/ 47 http://mirrors.aliyuncs.com/centos/$releasever/centosplus/$basearch/ 48 http://mirrors.cloud.aliyuncs.com/centos/$releasever/centosplus/$basearch/ 49 gpgcheck=1 50 enabled=0 51 gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7 52 53 #contrib - packages by Centos Users 54 [contrib] 55 name=CentOS-$releasever - Contrib - mirrors.aliyun.com 56 failovermethod=priority 57 baseurl=http://mirrors.aliyun.com/centos/$releasever/contrib/$basearch/ 58 http://mirrors.aliyuncs.com/centos/$releasever/contrib/$basearch/ 59 http://mirrors.cloud.aliyuncs.com/centos/$releasever/contrib/$basearch/ 60 gpgcheck=1 61 enabled=0 62 gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
或者
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo