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📦 Persistent Package Installation

MOS is designed to run from a compressed, read-only root filesystem (rootfs). Any changes made to the system via apt install or similar commands will be lost after a reboot, as the root filesystem is rebuilt from the compressed image on every startup.

To install additional packages that persist across reboots, MOS provides a dedicated directory for optional Debian packages.

📂 Package Directory​

Place your .deb packages in the following directory:

/boot/optional/packages

Packages placed here will be automatically installed during system startup before services are started.

note
  • Only .deb packages are supported
  • Packages must be compatible with the MOS base system (Devuan Linux)
  • Dependencies are not automatically resolved — ensure all required dependencies are either pre-installed on MOS or also placed in this directory

🔧 How to Add Packages​

Step 1: Download the Package​

Use apt download to obtain a .deb package without installing it:

apt download <package-name>

This will download the .deb file to the current directory.

Example:

apt download htop

This creates a file like htop_3.2.2-2_amd64.deb in the current directory.

tip

If the package has dependencies that are not already present on MOS, download them as well:

apt download <package-name> && apt download <dependency1> <dependency2>

Step 2: Copy to /boot/optional/packages​

Move or copy the downloaded .deb file(s) to the persistent package directory:

cp *.deb /boot/optional/packages/
warning
  • Do not extract or modify the .deb files
  • Place only valid .deb packages in this directory
  • The /boot partition must have sufficient free space

Step 3: Reboot​

After placing the packages in the directory, reboot the system:

reboot

During startup, MOS will automatically install all .deb packages found in /boot/optional/packages.

❌ What Does NOT Work​

Running apt install directly will install the package into the running root filesystem, but these changes will be lost on the next reboot:

# This will NOT persist after reboot!
apt install htop

This is because MOS reconstructs the root filesystem from the compressed base image on every boot. Only packages in /boot/optional/packages are reinstalled automatically.

✅ Best Practices​

DoDon't
Use apt download to obtain .deb filesUse apt install for persistent installations
Place .deb files in /boot/optional/packagesModify the running root filesystem expecting persistence
Verify package compatibility with MOSInstall packages with complex dependency trees without checking
Reboot after adding packagesExpect immediate availability without reboot

⚠️ Limitations​

  • No automatic dependency resolution — you must ensure all dependencies are available
  • Only .deb format is supported (no .rpm, source builds, or other package formats)
  • No package manager tracking — packages installed this way are not tracked by dpkg in the running system; they are reinstalled on every boot

✅ Summary​

  • Persistent packages go to /boot/optional/packages
  • Use apt download to fetch .deb files
  • Reboot to apply installations
  • Direct apt install does not persist

For system packages that must survive reboots, always use /boot/optional/packages.

Parts of this documentation were created with the assistance of AI tools. All AI-generated content has undergone review, but it may still contain inaccuracies, omissions, or outdated information.