Existing lock /var/run/yum.pid: another copy is running as pid XXXX. Another app is currently holding the yum lock; waiting for it to exit..

When you are searching / installing the RPM and if you ever come across the below exception, 

[root@dhcp-ptp2-10-177-154-84 yum.repos.d]# yum search libaio
Loaded plugins: langpacks
Existing lock /var/run/yum.pid: another copy is running as pid 3339.
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: PackageKit
    Memory :  25 M RSS (429 MB VSZ)
    Started: Wed Jul  6 14:52:53 2016 - 02:30 ago
    State  : Sleeping, pid: 3339
Another app is currently holding the yum lock; waiting for it to 

Follow the below steps.

cd /var/run/ and you could see a file "yum.pid". Just delete it and try again. Now you can seach / install the RPM.

Not able to install RPM through "yum" utility?

I am trying to search / install rpm through yum utility, when I am searching for it am getting the below exception.

[root@dhcp-blr-kkm-itpark-10fl-10-184-29-195 /]# yum search libaio-devel-0.3.109-12.el7-i686

Loaded plugins: langpacks

http://public-yum.oracle.com/repo/OracleLinux/OL7/UEKR3/x86_64/repodata/repomd.xml: [Errno 14] curl#7 - "Failed connect to public-yum.oracle.com:80; No route to host"

Trying other mirror.

To over come this situation, follow the below steps.

1. Export your Proxy as follows.

[root@dhcp-blr-kkm-itpark-10fl-10-184-29-195 /]# export http_proxy="http://www-XXXXXXXXXX.com:80"

[root@dhcp-blr-kkm-itpark-10fl-10-184-29-195 /]# yum search libaio-devel-0.3.109-12.el7-i686

Loaded plugins: langpacks

ol7_UEKR3                                                                                                                                                                     | 1.2 kB  00:00:00

  2. go to /etc/yum.repos.d/ -> vi public-yum-ol7.repo and edit the below two entries from 0 to 1.

Now try the same.

How to bring your VM in network?

Open your Oracle VM Virtualbox, Select the respective VM -> Right Click, Settings -> Network and enable as follows.

Then logon to your VM, open your browser and give your proxy details.

Now I could connect to the internet. 

Configure Networking in Oracle Linux 7.1

Usually, when I would be creating a new VM (eg. Oracle Linux 5.x, 6.x) I used to get an IP address by default.
Today, I configured Oracle Linux 7.1 in my Oracle VM where as I didn't get the IP address. It stops me to proceed further.

If I do "ifconfig" in my terminal, I will be getting as shown below.

To configure the same, follow the steps given in the below link.
https://blogs.oracle.com/devops/entry/test

Not able to ping the Virtual Machine (Guest OS) from your local machine?

Check whether your eth0 interface is up or not (you can check by running ifconfig) in your guest OS. If not bring it up as follows: 

ifconfig eth0 <-Guest OS IP address-> netmask <-Guest OS Subnet Mask-> up

Find the screen shot below:

 

 

If it is running, just restart it as shown in the above screen shot.