Apt Cacher NG

Apt-Cacher NG: Bandwidth Discipline for the Home Lab

The Instructor's Perspective

If you have more than two Linux systems on your network, you are wasting bandwidth. Every time you run apt update && apt upgrade, you’re pulling the same bits from the internet. Apt-Cacher NG is a caching proxy that keeps those bits local. It’s faster for you and more polite to the mirror owners.

Why use it?

• Speed: Installing a new package on your 5th LXC container will be near-instant.
• Efficiency: Drastically reduces your external bandwidth usage.
• Reliability: If the external repo is temporarily down or slow, you might already have what you need.

The PACE Plan for Updates

Update Reliability

P (Primary): Local Apt-Cacher NG instance. A (Alternate): Direct connection to official mirrors (bypass the proxy). C (Contingency): Secondary local cache or a sibling node with the packages already downloaded. E (Emergency): Sneakernet - Use a USB drive with .deb files or a full local repository mirror.

Basic Setup (The NetYeti Way)

1. Install: sudo apt install apt-cacher-ng
2. Configure Clients: On your other Linux systems, create a file at /etc/apt/apt.conf.d/00aptproxy:

   Acquire::http::Proxy "http://<your-cacher-ip>:3142";

3. Monitor: Access the web interface at http://<your-cacher-ip>:3142/acng-report.html to see your “Hit Rate.”

Check for Understanding

• If your Apt-Cacher NG server goes down, can your clients still update? (Hint: Check your Alternate plan).
• Why do we use a dedicated configuration file in apt.conf.d instead of modifying the main apt.conf?

---

Related: The Stack, Linux