View source for APT-CACHER-NG - Base Config

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== Installation ==

=== Debian / Ubuntu ===

Install the package from the official repositories:

 <nowiki>
sudo apt update
sudo apt install apt-cacher-ng</nowiki>

The service is automatically started after installation.

Check service status:

 <nowiki>
systemctl status apt-cacher-ng</nowiki>

Enable it at boot:

 <nowiki>
sudo systemctl enable apt-cacher-ng</nowiki>

=== RHEL / Rocky / AlmaLinux ===

Enable EPEL and install:

 <nowiki>
sudo dnf install epel-release
sudo dnf install apt-cacher-ng</nowiki>

Start and enable the service:

 <nowiki>
sudo systemctl start apt-cacher-ng
sudo systemctl enable apt-cacher-ng</nowiki>

== Directory Layout ==

Default paths (may vary by distribution):

* Configuration: <code>/etc/apt-cacher-ng/</code>
* Main configuration file: <code>/etc/apt-cacher-ng/acng.conf</code>
* Cache storage: <code>/var/cache/apt-cacher-ng/</code>
* Logs: <code>/var/log/apt-cacher-ng/</code>

Cache directory structure example:

* <code>deb/</code> – cached Debian/Ubuntu packages
* <code>ubuntu/</code> – Ubuntu repositories
* <code>security.ubuntu.com/</code>
* <code>partial/</code> – incomplete downloads

== Core Configuration ==

Edit the main configuration file:

 <nowiki>
sudo nano /etc/apt-cacher-ng/acng.conf</nowiki>

=== Cache Directory ===

 <nowiki>
CacheDir: /var/cache/apt-cacher-ng</nowiki>

=== Listening Port ===

Default port is '''3142''':

 <nowiki>
Port:3142</nowiki>

=== Bind Address ===

Restrict listening interface:

 <nowiki>
BindAddress: 0.0.0.0</nowiki>

For localhost only:

 <nowiki>
BindAddress: 127.0.0.1</nowiki>

== Client Configuration ==

=== Using APT Proxy Configuration ===

Create a proxy configuration file on the client:

 <nowiki>
sudo nano /etc/apt/apt.conf.d/02proxy</nowiki>

Content:

 <nowiki>
Acquire::http::Proxy "http://APT_CACHER_IP:3142";
Acquire::https::Proxy "http://APT_CACHER_IP:3142";</nowiki>

Example:

 <nowiki>
Acquire::http::Proxy "http://192.168.1.10:3142";</nowiki>

Test:

 <nowiki>
sudo apt update</nowiki>

== HTTPS and SSL Handling ==

apt-cacher-ng does '''not decrypt HTTPS''', but tunnels it.

Ensure HTTPS support is enabled (default):

 <nowiki>
PassThroughPattern: .*</nowiki>

HTTPS repositories benefit from metadata caching but not from package-level deduplication.

== Supported Repositories ==

apt-cacher-ng supports:

* Debian
* Ubuntu
* Linux Mint
* Kali Linux
* Proxmox
* Docker APT repositories
* Custom APT repositories

Example custom repository rewrite:

 <nowiki>
Remap-myrepo: file:custom_mirror /myrepo</nowiki>

== Pre-Fetching Packages ==

Pre-download packages to warm the cache:

 <nowiki>
sudo apt-cacher-ng -c /etc/apt-cacher-ng/acng.conf</nowiki>

Or from a client:

 <nowiki>
sudo apt install --download-only linux-image-generic</nowiki>

== Cache Maintenance ==

=== Check Cache Usage ===

 <nowiki>
du -sh /var/cache/apt-cacher-ng</nowiki>

=== Expire Old Packages ===

Manual expiration:

 <nowiki>
sudo apt-cacher-ng -c /etc/apt-cacher-ng/acng.conf -e</nowiki>

=== Clear Cache Completely ===

 <nowiki>
sudo systemctl stop apt-cacher-ng
sudo rm -rf /var/cache/apt-cacher-ng/*
sudo systemctl start apt-cacher-ng</nowiki>

== Logging and Monitoring ==

Log files:

* <code>apt-cacher.log</code>
* <code>apt-cacher.err</code>
* <code>apt-cacher.debug</code>

Tail logs in real time:

 <nowiki>
tail -f /var/log/apt-cacher-ng/apt-cacher.log</nowiki>

Web interface (read-only):

 <nowiki>
http://APT_CACHER_IP:3142/acng-report.html</nowiki>

== Security Hardening ==

=== Restrict Access ===

Firewall example:

 <nowiki>
sudo ufw allow from 192.168.1.0/24 to any port 3142</nowiki>

Bind only to internal IP:

 <nowiki>
BindAddress: 192.168.1.10</nowiki>

=== Protect Administrative Pages ===

 <nowiki>
AdminAuth: admin:strongpassword</nowiki>

== Performance Tuning ==

Increase file descriptor limit:

 <nowiki>
ulimit -n 65535</nowiki>

Adjust worker threads:

 <nowiki>
MaxConThreads: 50</nowiki>

Using SSD-backed storage for the cache significantly improves performance.

== Integration with Containers ==

Example Docker run:

 <nowiki>
docker run -d \
  -p 3142:3142 \
  -v /var/cache/apt-cacher-ng:/var/cache/apt-cacher-ng \
  apt-cacher-ng</nowiki>

Dockerfile APT proxy usage:

 <nowiki>
RUN echo 'Acquire::http::Proxy "http://host.docker.internal:3142";' \
    > /etc/apt/apt.conf.d/02proxy</nowiki>

== Troubleshooting ==

=== Clients Do Not Use Cache ===

* Verify proxy configuration on client
* Inspect logs:

 <nowiki>
grep CONNECT /var/log/apt-cacher-ng/apt-cacher.log</nowiki>

=== Permission Errors ===

Fix ownership:

 <nowiki>
sudo chown -R apt-cacher-ng:apt-cacher-ng /var/cache/apt-cacher-ng</nowiki>

Restart service:

 <nowiki>
sudo systemctl restart apt-cacher-ng</nowiki>

=== Port Already in Use ===

Check port usage:

 <nowiki>
sudo ss -tulpn | grep 3142</nowiki>

Change port if required:

 <nowiki>
Port:3143</nowiki>

=== Corrupted Cache ===

Clean and rebuild partial cache:

 <nowiki>
sudo systemctl stop apt-cacher-ng
sudo rm -rf /var/cache/apt-cacher-ng/partial/*
sudo systemctl start apt-cacher-ng</nowiki>

== Useful Links ==

* https://www.unix-ag.uni-kl.de/~bloch/acng/
* https://wiki.debian.org/AptCacherNg
* https://help.ubuntu.com/community/Apt-Cacher-NG
* https://github.com/apt-cacher-ng/apt-cacher-ng
* https://manpages.debian.org/apt-cacher-ng