yum安装指定路径和配置文件出错

错误提示如下

[root@newings yum.repos.d]# yum -c /etc/yum.conf --installroot=/usr/local/wget install wget -y
Loaded plugins: fastestmirror
Determining fastest mirrors
 * base: mirrors.aliyun.com
 * extras: mirrors.aliyun.com
 * updates: mirrors.aliyun.com
http://mirrors.aliyun.com/centos/%24releasever/os/x86_64/repodata/repomd.xml: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
http://mirrors.aliyuncs.com/centos/%24releasever/os/x86_64/repodata/repomd.xml: [Errno 12] Timeout on http://mirrors.aliyuncs.com/centos/%24releasever/os/x86_64/repodata/repomd.xml: (28, 'connect() timed out!')
Trying other mirror.
http://mirrors.cloud.aliyuncs.com/centos/%24releasever/os/x86_64/repodata/repomd.xml: [Errno 14] PYCURL ERROR 6 - "Couldn't resolve host 'mirrors.cloud.aliyuncs.com'"
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: base. Please verify its path and try again

解释下两个参数

-c /etc/yum.com #指定Yum配置文件地址
--installroot=/usr/local/wget #指定所安装软件的路径

该错误是由于$releasever和$basearch这两个变量中任何一个无法识别都会出现上面的错误，所以在配置yum源的时候首先要确认这两个变量是否存在。

如果变量不存在就用数字6和i386/x86_64代替。

我的配置如下

[base]
name=CentOS-6 - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/6/os/x86_64/
        http://mirrors.aliyuncs.com/centos/6/os/x86_64/
        http://mirrors.cloud.aliyuncs.com/centos/6/os/x86_64/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
 
#released updates 
[updates]
name=CentOS-6 - Updates - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/6/updates/x86_64/
        http://mirrors.aliyuncs.com/centos/6/updates/x86_64/
        http://mirrors.cloud.aliyuncs.com/centos/6/updates/x86_64/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
 
#additional packages that may be useful
[extras]
name=CentOS-6 - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/6/extras/x86_64/
        http://mirrors.aliyuncs.com/centos/6/extras/x86_64/
        http://mirrors.cloud.aliyuncs.com/centos/6/extras/x86_64/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
 
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-6 - Plus - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/6/centosplus/x86_64/
        http://mirrors.aliyuncs.com/centos/6/centosplus/x86_64/
        http://mirrors.cloud.aliyuncs.com/centos/6/centosplus/x86_64/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
 
#contrib - packages by Centos Users
[contrib]
name=CentOS-6 - Contrib - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/6/contrib/x86_64/
        http://mirrors.aliyuncs.com/centos/6/contrib/x86_64/
        http://mirrors.cloud.aliyuncs.com/centos/6/contrib/x86_64/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6