Skip to content

c0m4r/kula

image

K U L A

Lightweight, self-contained Linux® server monitoring tool.

Go Go JS JS License: GPL v3

👀 Demo | 🐋 Docker Hub

Zero dependencies. No external databases. Single binary. Just deploy and go.

image

📦 What It Does

Kula collects system metrics every second by reading directly from /proc and /sys, stores them in a built-in tiered ring-buffer storage engine, and serves them through a real-time Web UI dashboard and a terminal TUI.

Metric What's Collected
CPU Total usage (user, system, iowait, irq, softirq, steal) + core count
Load 1 / 5 / 15 min averages, running & total tasks
Memory Total, free, available, used, buffers, cached, shmem
Swap Total, free, used
Network Per-interface throughput (Mbps), packets/s, errors, drops; TCP errors/s, resets/s, established connections; socket counts
Disks Per-device I/O (read/write bytes/s, reads/s, writes/s IOPS); filesystem usage
System Uptime, entropy, clock sync, hostname, logged-in user count
Processes Running, sleeping, blocked, zombie counts
Self Kula's own CPU%, RSS memory, open file descriptors
Thermal CPU and Disk temperatures

🪩 How It Works

                    ┌──────────────────────────────────────────────┐
                    │              Linux Kernel                    │
                    │     /proc/stat  /proc/meminfo  /sys/...      │
                    └──────────────────┬───────────────────────────┘
                                       │ read every 1s
                                       ▼
                              ┌──────────────────┐
                              │    Collectors    │
                              │  (cpu, mem, net, │
                              │   disk, system)  │
                              └────────┬─────────┘
                                       │ Sample struct
                          ┌────────────┼────────────┐
                          ▼            ▼            ▼
                   ┌────────────┐  ┌────────┐  ┌──────────┐
                   │  Storage   │  │  Web   │  │   TUI    │
                   │  Engine    │  │ Server │  │ Terminal │
                   └─────┬──────┘  └───┬────┘  └──────────┘
                         │             │ 
              ┌──────────┼─────────┐   └───────────┐  HTTP + WebSocket
              ▼          ▼         ▼               ▼
          ┌─────────┬─────────┬─────────┐  ┌───────────────┐
          │ Tier 1  │ Tier 2  │ Tier 3  │  │   Dashboard   │
          │   1s    │   1m    │   5m    │  │   (Browser)   │
          │ 250 MB  │ 150 MB  │  50 MB  │  └───────────────┘
          └─────────┴─────────┴─────────┘
             Ring-buffer binary files
             with circular overwrites

Storage Engine

Data is persisted in pre-allocated ring-buffer files per tier. Each tier file has a fixed maximum size — when it fills up, new data overwrites the oldest entries. This gives predictable, bounded disk usage with no cleanup needed.

  • Tier 1 — Raw 1-second samples (default 250 MB)
  • Tier 2 — 1-minute metrics aggregation (Avg/Min/Max) (default 150 MB)
  • Tier 3 — 5-minute metrics aggregation (Avg/Min/Max) (default 50 MB)

HTTP server

The HTTP server on backend exposes a REST API and a WebSocket endpoint for live streaming. Authentication is optional - when enabled, it uses Argon2id hashing with salt and session cookies. It is worth adding that Kula truly respects your privacy. It works on closed networks and does not make any calls to external services.

Dashboard

The frontend is a single-page application embedded in the binary. Built on Chart.js with custom SVG gauges, it connects via WebSocket for live updates and falls back to history API for longer time ranges. Features include:

  • Interactive zoom with drag-select (auto-pauses live stream)
  • Focus mode to display only specific charts of interest
  • Configurable Y-axis bounds (Manual limits or Auto-detect)
  • Per-device selectors for Network, Disk I/O, and Thermal monitoring
  • Grid / stacked list layout toggle
  • Alert system for clock sync, low entropy, and system overload
  • Modern aesthetics with light/dark theme support

💾 Installation

Kula was built to have everything in one binary file. You can just upload it to your server and not worry about installing anything else because Kula has no dependencies. It just works out of the box! It is a great tool when you need to quickly start real-time monitoring.

Example installation methods for amd64 (x86_64) GNU/Linux.

Check Releases for ARM and RISC-V packages.

Guided installation

KULA_INSTALL=$(mktemp)
curl -o ${KULA_INSTALL} -fsSL https://kula.ovh/install
echo "f0c064b20d23c948a4569a35cfe65589a36a497aa0d9037413c6e452471355dd ${KULA_INSTALL}" | sha256sum -c || rm -f ${KULA_INSTALL}
bash ${KULA_INSTALL}
rm -f ${KULA_INSTALL}

Quick

wget https://github.com/c0m4r/kula/releases/download/0.8.3/kula-0.8.3-amd64.tar.gz
echo "f0e9c99b309d89414eec8e5a65792afbef7f1ee7c8353bfab4c72a4682979777 kula-0.8.3-amd64.tar.gz" | sha256sum -c || rm -f kula-0.8.3-amd64.tar.gz
tar -xvf kula-0.8.3-amd64.tar.gz
cd kula
./kula

Docker

Temporary, no persistent storage:

docker run --rm -it --name kula --pid host --network host -v /proc:/proc:ro c0m4r/kula:latest

With persistent storage:

docker run -d --name kula --pid host --network host -v /proc:/proc:ro -v kula_data:/app/data c0m4r/kula:latest
docker logs -f kula

Debian / Ubuntu (.deb)

wget https://github.com/c0m4r/kula/releases/download/0.8.3/kula-0.8.3-amd64.deb
echo "53ea1623dc85a57919baf1ade5fdc512022cd2630149a93a827616a02437ed60 kula-0.8.3-amd64.deb" | sha256sum -c || rm -f kula-0.8.3-amd64.deb
sudo dpkg -i kula-0.8.3-amd64.deb
systemctl status kula

RHEL / Fedora / CentOS / Rocky / Alma (.rpm)

wget https://github.com/c0m4r/kula/releases/download/0.8.3/kula-0.8.3-x86_64.rpm
echo "9c3a4d3c53e11544a51b7161e9887b15fff7dcd334c6bb648e98f7ab8db80109 kula-0.8.3-x86_64.rpm" | sha256sum -c || rm -f kula-0.8.3-x86_64.rpm
sudo rpm -i kula-0.8.3-x86_64.rpm
systemctl status kula

Arch Linux / Manjaro (AUR)

wget https://github.com/c0m4r/kula/releases/download/0.8.3/kula-0.8.3-aur.tar.gz
echo "85cb8c7aa7b637be82cdfcf1a9a06f91c7458bb37e00d7a00f605f0ee2590bca kula-0.8.3-aur.tar.gz" | sha256sum -c || rm -f kula-0.8.3-aur.tar.gz
tar -xvf kula-0.8.3-aur.tar.gz 
cd kula-0.8.3-aur
makepkg -si

Build from Source

git clone https://github.com/c0m4r/kula.git
cd kula
bash addons/build.sh

💻 Usage

Quick Start

# 1. Copy and edit config (optional)
cp config.example.yaml config.yaml

# 2. Start the server
./kula serve
# Dashboard at http://127.0.0.1:8080

# 3. Or use the terminal UI
./kula tui

# 4. Inspect storage
./kula inspect

Authentication (Optional)

# Generate password hash
./kula hash-password

# Add the output to config.yaml under web.auth

Service Management

Init system files are provided in addons/init/:

# systemd
sudo cp addons/init/systemd/kula.service /etc/systemd/system/
sudo systemctl enable --now kula

# OpenRC
sudo cp addons/init/openrc/kula /etc/init.d/
sudo rc-update add kula default

# runit
sudo cp -r addons/init/runit/kula /etc/sv/
sudo ln -s /etc/sv/kula /var/service/

⚙️ Configuration

All settings live in config.yaml. See config.example.yaml for defaults.


🧰 Development

# Lint + test suite
bash ./addons/check.sh

# Build dev (Binary size: ~14MB)
CGO_ENABLED=0 go build -o kula ./cmd/kula/

# Build prod (Binary size: ~9MB, xz: ~3MB)
CGO_ENABLED=0 go build -trimpath -ldflags="-s -w" -buildvcs=false -o kula ./cmd/kula/

Updating Dependencies

To safely update only the Go modules used by Kula to their latest minor/patch versions, and prune any unused dependencies:

go get -u ./...
go mod tidy

Testing & Benchmarks

# Run unit tests with race detector
go test -race ./...

# Run the full storage benchmark suite (default: 3s per bench)
bash addons/benchmark.sh

# Shorter run for quick iteration
bash addons/benchmark.sh 500ms

# Python scripts formatter and linters
black addons/*.py
pylint addons/*.py
mypy --strict addons/*.py

Cross-Compile

bash addons/build.sh cross    # builds amd64, arm64, riscv64

Debian / Ubuntu (.deb)

bash addons/build_deb.sh
ls -1 dist/kula-*.deb

Arch Linux / Manjaro (AUR)

bash addons/build_aur.sh
cd dist/aur && makepkg -si

RHEL / Fedora / CentOS / Rocky / Alma (.rpm)

bash addons/build_rpm.sh
ls -1 dist/kula-*.rpm

Docker

bash addons/docker/build.sh
docker compose -f addons/docker/docker-compose.yml up -d

📖 License

GNU Affero General Public License v3.0


🫶 Attributions