Stabilizer

Native memory monitoring and application protection for Ubuntu 26.04 / Linux 7.0+.

Built with Rust, GTK4 and libadwaita. A small user-session agent keeps policies active while the main window is closed. No Electron, WebView, root daemon, telemetry or independent process killer.

Русский · Español · License · Contributing

Features

• English, Spanish and Russian UI, tray and status messages; persistent language selection.
• Live RAM, available memory, swap and memory-pressure (PSI) statistics.
• Per-application cgroup accounting including child processes.
• Persistent priorities: Protected, High, Normal.
• Optional soft memory limits, reversible changes and verified cgroup attributes.
• Session protection for D-Bus and GNOME Shell, with explicit effectiveness status.
• Native system tray: click for a live summary, double/middle-click support depends on the desktop; use Open Stabilizer in the menu to open the main window.
• The agent is excluded from systemd-oomd candidates and automatically restarted after an unexpected termination when running in its dedicated systemd user unit.
• Local, atomic settings storage and a bounded history of policy actions.

Download and install

Get the amd64 .deb and checksum from Releases.

sha256sum -c stabilizer_0.1.0_amd64.deb.sha256
sudo apt install ./stabilizer_0.1.0_amd64.deb

Open Stabilizer in the applications menu. Select English, Español or Русский in the header to change the interface and tray language. The initial language follows the system locale, falling back to English. The background agent starts through D-Bus activation; it is also configured to start at the next login. Closing the window frees GUI resources while the tray and policies remain active.

Supported runtime: Ubuntu 26.04, Linux >= 7.0, systemd >= 259, cgroups v2. The initial release is tested on amd64 with the default Ubuntu GNOME session. Other Debian-based distributions are not supported by version 0.1. GNOME requires the Ubuntu AppIndicators extension (enabled in the standard Ubuntu session) for the tray. The agent still works if the tray host is unavailable.

What protection means

Protected excludes a verified eligible cgroup from systemd-oomd selection. High asks oomd to prefer other eligible candidates. This does not prevent the kernel OOM killer, a manual kill, a session shutdown, or a program's own crash. Root administrators and the owning user can deliberately stop the service:

systemctl --user stop stabilizer-agent.service

Crash recovery does not undo an explicit systemd stop. Stabilizer is not an unremovable or tamper-proof service. Low-memory recovery still requires enough resources to restart the agent. The development unit is named stabilizer-agent-dev.service.

Preferences are not recursive. Version 0.1 does not claim effective protection for nested cgroups or indivisible OOM ancestor groups. It checks ownership and ancestor policies; root-owned monitoring may ignore user preferences. The UI shows unconfirmed protection instead of promising safety in these cases.

A soft memory limit can slow an application and create memory pressure. It is therefore unavailable for protected applications. No hard memory limit or automatic app termination is enabled by Stabilizer.

Build

On Ubuntu 26.04 with Rust >= 1.92:

sudo apt install build-essential pkg-config libgtk-4-dev libadwaita-1-dev python3
cargo build --locked -j 2
cargo run --locked --bin stabilizer
./scripts/build-deb.sh

A development launch creates a dedicated user unit for the sibling agent binary, so that tray monitoring and crash recovery work without installing the package. To stop it: systemctl --user stop stabilizer-agent-dev.service.

Read-only diagnostics:

cargo run --locked --no-default-features --bin stabilizer-agent -- --check
cargo run --locked --no-default-features --bin stabilizer-agent -- --once

stabilizer --demo displays sample data with system actions disabled.

Tests

cargo fmt --check
cargo clippy --locked --all-targets -- -D warnings
cargo test --locked --no-default-features
python3 scripts/live-smoke.py --release
python3 scripts/tray-smoke.py
python3 scripts/language-smoke.py

The live smoke scripts require a real Ubuntu user session and no running Stabilizer agent. They operate on dedicated temporary services only. They never fill the host RAM or change GNOME/D-Bus policies. CI compiles and tests inside an Ubuntu 26.04 container; it does not claim to validate a real GNOME session or OOM victim selection under exhausted host memory.

State and uninstall

Settings: ${XDG_STATE_HOME:-$HOME/.local/state}/stabilizer/state.json (0600). No application command lines or network telemetry are collected. Installed desktop-entry names and executable paths are used locally to identify groups.

Remove policies in the Rules tab before uninstalling if you want to restore managed settings immediately. Changes made by other tools are preserved. Stop the agent and uninstall the package using the system package manager. User state is retained; already-applied runtime settings may remain until the affected unit ends if you uninstall without removing its rules first.

License

Source-available, not OSI-approved Open Source. The Stabilizer Source-Available License 1.0 — No Resale allows personal and internal business use, modification, and free redistribution. Selling copies, paid sublicensing, or including original or modified copies in a paid software product/bundle requires separate written permission. Paid support and installation work remain permitted when the software itself is free.

Dependencies retain their original licenses; see third-party notices.