remote-svc-ctrl

An EPICS IOC that monitors and controls systemd services, exposing their status as Process Variables (PVs). Supports both local and remote (via SSH) service management.

This can be particularly useful for managing acquisition/control services on vendor provided systems, such as the Dectris camserver service for Pilatus3 detectors, or the xspd remote control service from X-Spectrum.

Features

• Poll systemctl status and publish service state as EPICS PVs
• Start, stop, and restart services via Channel Access
• Monitor over SSH for services running on remote hosts
• Phoebus operator screen included

PVs

Given a prefix like XF:28ID-CT{Svc:MyApp}, the IOC exposes:

PV Suffix	Type	Description
Unit	stringIn	Systemd unit name
Desc	stringIn	Unit description
LoadState	mbbIn	Load state (loaded, not-found, masked, error, bad-setting)
UnitFile	stringIn	Path to the unit file
Enabled	mbbIn	Enable state (enabled, disabled, static, masked, ...)
ActiveState	mbbIn	Active state (active, reloading, inactive, failed, ...)
SubState	mbbIn	Sub-state (running, dead, exited, failed, ...)
Since	stringIn	Timestamp when the service entered its current state
MainPID	longIn	Main process ID
Tasks	longIn	Number of tasks
Memory	stringIn	Memory usage
CPU	stringIn	CPU usage
CGroup	stringIn	Control group
Start	boolOut	Write 1 to start the service
Stop	boolOut	Write 1 to stop the service
Restart	boolOut	Write 1 to restart the service

The LoadState, ActiveState, and SubState PVs enter a MAJOR alarm when the service is in a failure state (e.g. failed, not-found, error).

Usage

# Monitor a local service
remote-svc-ctrl "XF:28ID-CT{Svc:MyApp}" my-app.service

# Monitor a service on a remote host via SSH
remote-svc-ctrl "XF:28ID-CT{Svc:MyApp}" my-app.service --host user@server

Operator Screen

A Phoebus .bob screen is provided in op/service_ctrl.bob. Open it with the macro PREFIX set to your IOC's PV prefix.

Development

uv sync                             # Install dependencies
uv run pytest                       # Unit tests
uv run pre-commit run --all-files   # Linting and formatting

Requirements

• Python >= 3.11
• pythonSoftIOC >= 4.7.0
• systemctl available on the target host
• SSH key-based auth configured for remote hosts