logMaster

A self-hosted systemd journal log viewer with Authentik SSO authentication.

Overview

logMaster consists of two independent Flask/Gunicorn applications:

logMaster/
├── server/ # Web UI — Authentik OIDC auth, service tabs, log rendering
└── daemon/ # Log API — queries journalctl and returns JSON

Browser ──OIDC──► Authentik
│
▼
server (port 5000)
│ POST /logs (shared secret)
▼
daemon (port 5001)
│ subprocess
▼
journalctl

The server authenticates users via Authentik and renders log data in a browser UI. The daemon runs on any systemd host, exposes a single authenticated HTTP endpoint, and pipes requests into journalctl. Multiple daemons can be configured — one per host — each mapped to a set of services in config.json.

---

Prerequisites

Requirement	Notes
Python 3.11+	Both components
systemd	Daemon host must run systemd (Linux only)
Authentik	Any reachable Authentik instance
rsync	Used by setup.sh --install-service

---

Quick Start

1. Daemon

cd daemon
./setup.sh # create venv, install deps, copy .env.example → .env
nano .env # set LOG_API_SHARED_SECRETsource .venv/bin/activate
python daemon.py # dev server on port 5001

2. Server

cd server
./setup.sh # create venv, install deps, copy .env.example → .env
nano .env # fill in Authentik + shared secret values
nano config.json # add your servicessource .venv/bin/activate
python server.py # dev server on port 5000

---

Service Configuration

server/config.json defines which services appear as tabs in the UI.

{
"services": [
{
"name": "Nginx",
"service_name": "nginx.service",
"address": "http://192.168.1.10:5001"
},
{
"name": "Postgresql",
"service_name": "postgresql.service",
"address": "http://192.168.1.11:5001"
}
]
}

Field	Description
name	Display name shown in the tab bar
service_name	Exact systemd unit name passed to journalctl -u
address	URL of the daemon instance that hosts this service

The config is loaded once at server startup. Restart the server after editing it.

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Systemd Deployment

Install both components as systemd services on their respective hosts.

Daemon host

cd daemon
sudo ./setup.sh --install-service

Server host

cd server
sudo ./setup.sh --install-service

Both scripts copy files to /root/logMaster/{daemon,server}/, install the service unit, and start it immediately.

After any update, copy the new files and run:

systemctl restart logMasterDaemon # on the daemon host
systemctl restart logMasterServer # on the server host

Tail logs:

journalctl -u logMasterDaemon -f
journalctl -u logMasterServer -f

---

Authentik Setup

1. In Authentik, go to Applications → Providers → Create → OAuth2/OpenID Provider.
2. Set the redirect URI to match AUTHENTIK_REDIRECT_URI in server/.env:

   http://your-host:5000/callback
   

3. Copy the Client ID and Client Secret into server/.env.
4. Create an Application linked to the provider and note the application slug — this is the value used in AUTHENTIK_CLIENT_ID.

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Environment Variables

See server/.env.example and daemon/.env.example for full reference.

server/.env

Variable	Required	Description
APP_SECRET_KEY	Yes	Flask session signing key — use a long random string
AUTHENTIK_BASE_URL	Yes	Base URL of your Authentik instance, e.g. https://auth.example.com
AUTHENTIK_CLIENT_ID	Yes	OAuth2 application slug from Authentik
AUTHENTIK_CLIENT_SECRET	Yes	OAuth2 client secret from Authentik
AUTHENTIK_REDIRECT_URI	Yes	Must match the redirect URI registered in Authentik
LOG_API_SHARED_SECRET	Yes	Must match the daemon's value
LOG_API_URL	No	Fallback daemon URL if a service has no address (default: http://127.0.0.1:5001)
APP_PORT	No	Port to bind (default: 5000)
FLASK_DEBUG	No	Set true for development only (default: false)

daemon/.env

Variable	Required	Description
LOG_API_SHARED_SECRET	Yes	Shared secret — must match the server's value
LOG_API_PORT	No	Port to bind (default: 5001)
FLASK_DEBUG	No	Set true for development only (default: false)

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Security Notes

• The shared secret is the only authentication mechanism on the daemon endpoint. Use a strong random value and keep it out of version control.
• The daemon validates the systemd unit name against a strict regex (^[\w.\-]+$) before passing it to journalctl — no shell interpolation is used.
• Both systemd services run with NoNewPrivileges, PrivateTmp, and ProtectSystem=strict.
• The daemon runs as root to access the journal. If you prefer an unprivileged user, add them to the systemd-journal group and remove the User=root line from the service file.