Context
I want to host public-facing applications on a server in my home, without compromising security. I realize containers might be one way to do this, and want to explore that route further.
Requirements
I want to run applications within containers such that they
- Must not be able to interfere with applications running on host
- Must not be able to interfere with other containers or applications inside them
- Must have no access or influence on other devices in the local network, or otherwise compromise the security of the network, but still accessible by devices via ssh.
Note: all of this within reason. I understand that sometimes there may be occasional vulnerabilities, like in kernel for example, that would eventually get fixed. Risks like this within reason I am willing to accept.
What I found so far
- Running containers in rootless mode: in other words, running the container daemon with an unprivileged host user
- Running applications in container under unprivileged users: the container user under which the container is ran should be unprivileged
- Networking: The container’s networking must be restricted. I am still not sure how to do this and shall explore it more, but would appreciate any resources.
Alternative solution
I have seen bubblewrap presented as an alternative, but it seems like it is not intended to be used directly in this manner, and information about using it for this is scarce.
I think the container piece is probably the least of your concerns here honestly. The biggest thing you’ll want to focus on is the ingress networking layer, but that won’t really be any different than if you were running the app normally. Generally exposing ports from your home network to the internet is not a great idea, and you try to use something like cloudflare or get a cheap cloud VPS with a reverse proxy connected to the container host via VPN.
But for general container security practice, what you mentioned is good. You could also look at the Docker CIS Benchmark for more good security practices. And container scanning tools like trivy or anchore syft/grype to identify vulnerabilities in your containers. But again this is secondary to the networking layer in my opinion.