How to Add Swap Space on Ubuntu 18.04 on Google Cloud. Swap Space is a space in Linux is used when the amount of physical memory (RAM) is full. If the system needs more memory resources and the RAM is full, inactive pages in memory are moved to the swap space.

Swap space can help machines with a small amount of RAM. In case you choose a VM instance with 600 MB RAM, then your memory will get exhausted and you will get cannot allocate memory.