Setup Apt-Cacher NG as a caching proxy server in your homelab and configure your other Linux hosts to use it
If your homelab has more than a few servers or VMs running Debian-based distributions, it makes sense to set up a package caching proxy on one of your servers. This guide will show how to set that up, configure your other Linux hosts, and optionally how to use Ansible to automate configuring those other hosts.
Table of Contents
About Apt-Cacher NG
Apt-Cacher NG is a caching proxy that lets a Debian-based server cache any upgrades downloaded from the official repositories when using the apt upgrade command. Your other Linux servers can then download those upgrades from that cache, greatly speeding up their own upgrade process. It’s quick and easy both to setup the cache server and to configure a client use it.
Installing and configuring the cache proxy server
To install Apt-Cacher NG just use the package manager:
sudo apt update && sudo apt install apt-cacher-ng -y
sudo systemctl start apt-cacher-ng && sudo systemctl enable apt-cacher-ng
If you’re accessing the official repositories via HTTPS (which is probably the case), then you should also make Apt-Cacher-NG use HTTPS. Just be aware it will use HTTPS to download from the repositories, but HTTPS is NOT possible between Linux hosts. (Not that it’s necessary within your own homelab anyway.)
Open the file at /etc/apt-cacher-ng/acng.conf with a text editor, find and uncomment this line:
PassThroughPattern: .*
Save and close the file, then restart Apt-Cacher NG:
sudo systemctl restart apt-cacher-ng
Now that the cache server is set up, let’s tell other Linux hosts to use it.
Configure a Linux host to use the cache server
On another Linux host, create this file:
touch /etc/apt/apt.conf.d/01proxy
Now copy & paste the below into it, using your own cache server’s IP address:
Acquire::http::Proxy "http://192.168.0.250:3142";
That’s it. Now when you update, it should pull from the cache server. You can verify this by using this command on the cache server:
cat /var/log/apt-cacher-ng/apt-cacher.log
The output should show the other host downloading from the cache server:
1740793422|I|714|192.168.0.100|secdeb/dists/bookworm-security/InRelease
1740793422|O|48232|192.168.0.100|secdeb/dists/bookworm-security/InRelease
1740793437|I|15812|192.168.0.100|debrep/dists/bookworm/InRelease
1740793437|O|102|192.168.0.100|debrep/dists/bookworm/InRelease
1740793437|I|675|192.168.0.100|debrep/dists/bookworm-updates/InRelease
1740793437|O|55714|192.168.0.100|debrep/dists/bookworm-updates/InRelease
1740793440|I|394558|192.168.0.100|secdeb/pool/updates/main/o/openh264/libopenh264-7_2.3.1+dfsg-3+deb12u1_amd64.deb
1740793440|O|393430|192.168.0.100|secdeb/pool/updates/main/o/openh264/libopenh264-7_2.3.1+dfsg-3+deb12u1_amd64.deb
1740793440|I|2384518|192.168.0.100|secdeb/pool/updates/main/x/xorg-server/xserver-common_21.1.7-3+deb12u9_all.deb
1740793440|O|2383385|192.168.0.100|secdeb/pool/updates/main/x/xorg-server/xserver-common_21.1.7-3+deb12u9_all.deb
1740793440|I|2389946|192.168.0.100|secdeb/pool/updates/main/x/xorg-server/xserver-xorg-legacy_21.1.7-3+deb12u9_amd64.deb
1740793440|O|2388824|192.168.0.100|secdeb/pool/updates/main/x/xorg-server/xserver-xorg-legacy_21.1.7-3+deb12u9_amd64.deb
1740793451|I|3721758|192.168.0.100|secdeb/pool/updates/main/x/xorg-server/xserver-xorg-core_21.1.7-3+deb12u9_amd64.deb
1740793451|O|3720630|192.168.0.100|secdeb/pool/updates/main/x/xorg-server/xserver-xorg-core_21.1.7-3+deb12u9_amd64.deb
Using Ansible to automate configuration of multiple hosts
If you only have a few Linux hosts, you can easily add the 01proxy conf file using SCP a few times.
sudo scp /etc/apt/apt.conf.d/01proxy user@other-host:/etc/apt/apt.conf.d/01proxy
This can be tedious with more than a few hosts, though. If you’re the kind of madlad that runs a dozen or more Linux servers or VMs, it might be more desirable to use Ansible to automate the configuration change everywhere. However, you have to use Ansible from a host that already has SSH access to every other host it will push configuration changes to, and if you don’t it’s probably more trouble than it’s worth. In my case, I was already using Ansible in my network, so it made sense to leverage it for this. (If you use infrastructure-as-code solution like Chef, Puppet or Saltstack, you should use them instead.)
First, if you don’t yet have Ansible, add it’s repository and install it. (We’ll be installing ansible-core which is a smaller, minimal package. If you want you can install the full ansible package instead, but this playbook does not require it.)
sudo apt-add-repository ppa:ansible/ansible
sudo apt install ansible-core -y
Create a new directory to house the Ansible playbook and related files. Copy the 01proxy file into the directory then go into it.
mkdir apt-proxy
sudo cp /etc/apt/apt.conf.d/01proxy apt-proxy/01proxy
cd apt-proxy
Here we’ll create three more files. First, the Ansible configuration file, ansible.cfg.
[defaults]
inventory = hosts.yaml
ansible_python_interpreter=/usr/bin/python3
timeout=30
[ssh_connections]
pipelining = true
Now the inventory file, hosts.yaml. Make sure to add all your other Linux hosts (besides the cache server) here, and the right IPs and users for each host.
---
all:
hosts:
server1:
ansible_user: chandler
ansible_host: 192.168.0.100
server2:
ansible_user: monica
ansible_host: 192.168.0.105
vm1:
ansible_user: debian
ansible_host: 192.168.1.20
vm2:
ansible_user: debian
ansible_host: 192.168.1.25
vm3:
ansible_user: ubuntu
ansible_host: 192.168.1.30
Finally, the playbook itself, name it whatever you want. I’ll call it run.yaml.
---
- name: Add apt-proxy to hosts
hosts: all
become: true
tasks:
- name: Copy the apt-cacher-ng client config
copy:
src: files/01proxy
dest: /etc/apt/apt.conf.d/01proxy
mode: "0644"
- name: Update all installed packages
apt:
update_cache: yes
upgrade: safe
name: "*"
state: latest
- name: Clean cache & remove unnecessary dependencies
apt:
autoclean: yes
autoremove: yes
purge: yes
The above playbook is dead simple, all it does it copy the 01proxy file into the /etc/apt/apt.conf.d directory, then check for updates. It will do this on all hosts you list in the inventory file.
When you’re ready to run the playbook, use this command:
ansible-playbook run.yaml
You’ll see some output as the playbook carries out its tasks, and if there’s any errors it will clearly say so and cancel. Once it finishes up, check apt-cacher.log again on the caching server and you should see all the hosts pulling from it, assuming they had upgrades to download and install.