1. Check if the server has swap configured
swapon -s
If nothing is shown, that means no swap is enabled.
free -m
If swap is 0, that means no swap is enabled.
2. Create a swap file
sudo fallocate -l 4G /swapfile
3. Change file permission to make sure the swap file can only be accessed by root
sudo chmod 600 /swapfile
4. Setup swap
sudo mkswap /swapfile
5. Enable swap
sudo swapon /swapfile
6. Verify swap
swapon -s
free -m
7. Make the swap File Permanent
sudo vim /etc/fstab
#add this line to the bottom
/swapfile swap swap sw 0 0
Reference:
https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-centos-7