I am using fsl-image-qt5 build , but on trying to renew ip with dhclient, I see that the command is missing.
Do I need to install with rpm (is that possible) ? or is there another way to achieve it ?
You should have busybox on the target which provides the 'udhcpc' tool which should do just what you need.
udhcpc -i eth0
Retrieving data ...