WangLu's Notes

I've been running a few containers for several years. They were all running under rootless Docker with a single user. Initially, I planned to  migrate the containers to VMs , but I couldn't get a stable workflow after about two months of effort. Later,  gVisor caught my attention , and I decided to migrate to Podman with gVisor instead. The new plan is to run each container with  --userns=auto  and use Quadlet for systemd integration. This approach provides better isolation and makes writing firewall rules easier. I'm now close to migrating all my containers. Here are a couple of rough edges I'd like to share. Network Layout I compared  various networking options  and spent a few hours trying the one-interface-per-group approach before giving up. I settled on a single macvlan network and decided to use static IP addresses for my containers. To prevent a randomly assigned IP address from conflicting with a predefined one, I allocated a large IP range for my ...

I want to filter the outgoing network traffic for all of my containers based on a set of rules. For example: Some containers should be blocked from accessing the internet entirely. Some containers should have unrestricted internet access. Some containers should be able to access the internet, but not a specific list of URLs. Some containers should only be allowed to access a specific list of URLs. To manage this, I will define logical policy groups and assign each container to one. As a general rule, only DNS and HTTP/HTTPS traffic will be permitted. Option 1: A Proxy for Each Policy Group Imagine Container A is only allowed to access  www.google.com . Here’s how this approach would work: Create an Nginx (or  socat ) container that listens on port 443 and acts as a reverse proxy for  www.google.com . Place both the Nginx proxy and Container A into an  internal  container network. Within this network, add  www.google.com  as a network alias for the Ngin...

For the last few days, I've been experimenting with Podman. My goal was to get a feel for the setup, create a minimal yet scalable environment for a few containers, and identify potential problems early on. Here are my notes from this experience. [Updates 2025-09-21] Added more networking options and other information. Quadlet Quadlet  allows you to define containers, networks and more using a syntax similar to systemd. This includes helpful features like drop-in overrides and templates. The framework is tightly integrated with systemd, and Quadlet actually generates real systemd units. This means I can directly write systemd options in my Quadlet files. One of the biggest benefits I've found is how easy Quadlet makes it to set up socket activation. This allows me to place some containers in an internal network or even without a network at all. Hardening Defaults Let's say I have a group of Systemd and Quadlet units, all named in the format of  xyz-* . My goal is to define ...