用yum安装rz时到问题

安装sz/rz时，

运用yum install lrzsz -y

结果出现

Another app is currently holding the yum lock; waiting for it to exit..

可能是系统升级正在运行，yum在锁定状态中

显示yum

# ps aux|grep yum

 root    2614  0.0  4.2 347060 43196 pts/0    T    17:07   0:01 /usr/bin/python /usr/bin/yum install lrzsz -y
root      2656  0.0  1.9 320240 19896 pts/0    T    17:13   0:00 /usr/bin/python /usr/bin/yum install lrzsz -y

kill -s 9 2614
如果KILL不死，用
#rm -f /var/run/yum.pid
然后继续使用yum


若出现
http://mirrors.163.com/centos/6.5/os/i386/Packages/mlocate-0.22.2-4.el6.i686.rpm: [Errno 14] PYCURL ERROR 6 - "Couldn't resolve host 'mirrors.163.com'"Trying other mirror.
是DNS服务器错误。于是修改一下 /etc/resolv.conf
添加一个nameserver 8.8.8.8完成
即是 cat resolv.conf 
nameserver 8.8.8.8
nameserver 172.28.1.26 
nameserver 172.28.1.28