When you run hexo g on any web instances, like on AWS or Azure, you might get the following error:

(node:3568) ExperimentalWarning: The fs.promises API is experimental
INFO  Validating config
INFO  Start processing
Killed

Solution:

This might be caused by running out of memory, try to run the following command:

free -m 
dd if=/dev/zero of=/swap bs=4096 count=1572864
mkswap /swap
swapon /swap
echo "LABEL=SWAP-sda /swap swap swap defaults 0 0" >> /etc/fstab