Snappy is a software deployment and package management system designed by Canonical that can be used to install the same packages on various distributions. Snaps work in vpsAdminOS containers with some extra configuration.
To run snap in a container, it has to have access to FUSE:
osctl ct devices add <id> char 10 229 rwm /dev/fuse
Install squashfuse, e.g. for Ubuntu containers:
ct exec <id> apt install fuse squashfuse
Also make sure that you have directory
ct exec <id> mkdir -p /lib/modules