Swap

Because a Linux system requires swap to function properly install zram-init. To keep it simple, it will utilise RAM to store compressed swap.

Install it with:

# apk add zram-init
# rc-update add zram-init default

zram-init can be configured in /etc/conf.d/zram-init. The amount of devices and the size of zram can be changed here, for example:

num_devices=1

# swap - 500M

#size0=512
size0=`LC_ALL=C free -m | awk '/^mem:/{print int($2/4)}'`

Now the size of the swap device will be one fourth of the ram size. Reboot the computer or restart the service to check if it works.

Also be sure to read the ArchWiki for more information.