yum 安装软件时，报错：No package XXX av

1234[root@localhost ~]``# yum -y install redis``Loaded plugins: fastestmirror``No package redis available.``Nothing to ``do

配置一台CentOS 7.x或RHEL 7.x的系统使用Fedora EPEL repos和第三方软件包安装各种软件包。请注意，这些软件包没有正式获得任何的CentOS或Red Hat的支持，但提供了许多流行的包和应用程序。

显示以上错误，有以下2种原因：

1、dns问题；

2、镜像连接错误；

DNS问题

首先测试下网络连接，如果ping不通，需要设置下DNS。

123

[root@localhost ~]``# ping www.baidu.com``XXXXXXXXXXXXXXXXX``[root@localhost ~]``# echo "nameserver 8.8.8.8">>/etc/resolv.conf

再次ping即可ping通了。

镜像连接错误问题

具体原因：使用yum搜索某些rpm包，找不到包是因为CentOS是RedHat企业版编译过来的，去掉了所有关于版权问题的东西。安装EPEL后可以很好的解决这个问题。EPEL(Extra Packages for Enterprise Linux )即企业版Linux的扩展包，提供了很多可共Centos使用的组件，安装完这个以后基本常用的rpm都可以找到。

Method #1 » 从企业版Linux库配置包中安装扩展包。（推荐）

| 123456789101112131415161718192021222324252627282930313233343536 | [root@localhost ~]``# sudo yum install epel-release``Loaded plugins: fastestmirror, langpacks``Loading mirror speeds from cached hostfile``Resolving Dependencies``--> Running transaction check``---> Package epel-release.noarch 0:7-5 will be installed``--> Finished Dependency Resolution Dependencies Resolved ================================================================================`` ``Package Arch Version Repository Size``================================================================================``Installing:`` ``epel-release noarch 7-5 extras 14 k Transaction Summary``================================================================================``Install 1 Package Total download size: 14 k``Installed size: 24 k``Is this ok [y``/d/N``]: y``Downloading packages:``epel-release-7-5.noarch.rpm | 14 kB 00:01 ``Running transaction check``Running transaction ``test``Transaction ``test succeeded``Running transaction`` ``Installing : epel-release-7-5.noarch 1``/1`` ``Verifying : epel-release-7-5.noarch 1``/1 Installed:`` ``epel-release.noarch 0:7-5 Complete! | | --------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |

Method #2 » 从dl.fedoraproject.org安装扩展包。

1.使用wget命令下载epel-release：

[root@localhost ~]``# cd/tmp``[root@localhost ~]``# wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm ls*.rpm

或者通过wiki查找到对应版本的epel后，再下载：

123

[root@localhost ~]``# wget http://dl.fedoraproject.org/pub/epel/7/x86_64/epel-release-7-5.noarch.rpm``或``[root@localhost ~]``# wget http://mirrors.ustc.edu.cn/fedora/epel/7/x86_64/epel-release-7-5.noarch.rpm //中国科学技术大学镜像

2.安装：

1[root@localhost ~]``# sudo yum install epel-release-7.noarch.rpm

注意：