Support out-of-cluster deployment (rpm/deb alongside remote agent)

[kitplummer]

Summary

peat-sidecar currently assumes Kubernetes deployment (Helm chart, sidecar container, PVC storage). It also needs to run as a standalone systemd service alongside the remote agent's rpm/deb install path for bare-metal and VM deployments.

Current State

• Binary is built as a single static Rust binary (target/release/peat-sidecar)
• Config is via CLI flags / env vars (already works outside K8s)
• Data dir defaults to /data/peat-sidecar (K8s-oriented path)
• Deployment assumes Helm + Docker (Dockerfile, chart/, zarf.yaml)
• No systemd unit file, no rpm/deb packaging, no FHS-compliant paths

Proposed Approach

1. FHS-Compliant Defaults

Add sensible defaults for non-K8s environments:

• Data dir: /var/lib/peat-sidecar (instead of /data/peat-sidecar)
• Config: /etc/peat-sidecar/config.yaml or env file at /etc/default/peat-sidecar
• Logs: stdout (systemd journal captures this)
• Socket: unix:///var/run/peat-sidecar.sock or tcp://127.0.0.1:50051

2. Systemd Unit File

[Unit]
Description=Peat Sidecar - CRDT mesh sync for UDS Remote Agent
After=network-online.target
Wants=network-online.target

[Service]
Type=simple
EnvironmentFile=-/etc/default/peat-sidecar
ExecStart=/usr/bin/peat-sidecar
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target

3. RPM/DEB Packaging

• Use cargo-deb for Debian packages
• Use cargo-rpm or nfpm for RPM packages
• Package includes: binary, systemd unit, default env file, man page (optional)
• Coordinate with remote agent's packaging so they can be installed together or as a dependency

4. Install Script (for non-package-manager environments)

Simple install.sh that:

• Copies binary to /usr/bin/
• Creates systemd unit
• Creates data dir with appropriate permissions
• Creates env file template
• Enables and starts the service

Testing

• CI builds rpm and deb artifacts
• Test install/uninstall cycle in a container (ubuntu, rocky)
• Verify sidecar starts, binds socket, and serves Connect RPC

References

• src/main.rs:39 — current default data dir (/data/peat-sidecar)
• Dockerfile — current container build
• Remote agent rpm/deb packaging (coordinate paths and dependencies)