How to seed a single standalone Vault instance with filesystem backend?

As opposed to HA deployment I want to use Vault using docker on a single Single Board Computer. The idea is, I am trying to use packer to create an image for a Single Board Computer with docker engine installed and I want to seed Vault container with some credentials like database stuff and environment variables.

How will I be able to provide such information as bootstrapping initialization where I will have to unseal, add the information and seal the vault back again?

Does this hold true, even when I am not planning to use the SBCs in a swarm mode. I mean AFAIK raft is generally used in Docker Swarm mode. I just want to provision my SBCs with some default secrets and maybe once I get some good understanding I can keep these secrets rolling in a timely fashion

This is just a docker run … not a swarm definition.
Also swarm doesn’t enter your original question since you don’t want HA, which means a single container. As long as your data and config volumes are not tied into the run then they’ll be available to the next container you attach to it in case of a restart. How you setup your external volumes across a swarm (n number of nodes) is up to you and your setup.