[root@alwar ~]# cat /etc/resolv.conf

# Generated by NetworkManager

search localdomain

nameserver 8.8.8.8

add above nameserver entry if not there

su –

yum update kernel*

reboot

mkdir /media/VirtualBoxGuestAdditions

mount -r /dev/cdrom /media/VirtualBoxGuestAdditions

rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm

yum install gcc kernel-devel kernel-headers dkms make bzip2 perl

KERN_DIR=/usr/src/kernels/`uname -r`

export KERN_DIR

cd /media/VirtualBoxGuestAdditions

./VBoxLinuxAdditions.run

[root@localhost cdrom]# mkdir /shared_dir

mount -t vboxsf linux /shared_dir