yum 报错信息

yum被锁定无法使用，错误信息：

[root@cdms ~]# yum install -y lrzsz

Loaded plugins: product-id, refresh-packagekit, security, subscription-manager
Updating certificate-based repositories.
Existing lock /var/run/yum.pid: another copy is running as pid 3030.
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...
Another app is currently holding the yum lock; waiting for it to exit...

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

解决方法：

[root@cdms ~]# rm -rf /var/run/yum.pid              #来强行解除锁定，然后你的yum就可以运行了

[root@cdms ~]# yum install -y lrzsz
Loaded plugins: product-id, refresh-packagekit, security, subscription-manager
Updating certificate-based repositories.
dvd                                                                                | 4.0 kB     00:00 ...
dvd/primary_db                                                                     | 2.5 MB     00:00 ...
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package lrzsz.i686 0:0.12.20-27.1.el6 will be installed
--> Finished Dependency Resolution

问题：
使用yum install somexx -y的时候，执行到
Installed products updated.

报如下错误：
ERROR:dbus.proxies:Introspect error on :1.261:/org/freedesktop/PackageKit: dbus.exceptions.DBusException: org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.
Unable to send message to PackageKit

问题排查：

因为是两台不同的机器同时指向同一个YUM源，其中一台机器已经通过yum install xx -y命令成功安装所需软件，而另外一台却不行，可以排除不是YUM源的问题，也不是网络的问题，那肯定是本机的问题了，
查看日志发现PackageKit这个词频繁出现，所以目标定位在这个PackageKit上面，查阅得知PackageKit是一款新的Linux包管理器，但是既然这边包这个错误，删除之是否可行？

问题解决
yum remove PackageKit* -y //删除该管理器