Flux Agent

The agent is the worker component of Serverless Fabric. It receives function deployments from Flux (the control plane) over gRPC, executes them natively under cgroups v2 memory limits, and reports node metrics back for autoscaling decisions.

Each agent runs as root to manage cgroups. Functions are deployed to /home/flux-runner/apps/ and execute as the unprivileged flux-runner system user.

Install from .deb

Download the latest release from GitHub Releases:

sudo dpkg -i flux-agent_*.deb

The package creates the flux-runner user, installs a systemd service, and places an example config at /etc/flux-agent/agent.yaml.example.

Manual Setup

Create flux-runner User

sudo useradd -r -m -s /bin/bash flux-runner

Build and Install

CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -ldflags="-s -w" -o flux-agent .
sudo install -Dm755 flux-agent /usr/local/bin/flux-agent

Configuration

Copy example.agent.yaml to agent.yaml and edit:

agent_id: agent-1
port: 50051
max_concurrency: 10
redis_addr: redis://localhost:6379

When agents are provisioned by Flux, mTLS certificates are automatically generated and uploaded during SSH bootstrap — no manual cert setup is needed.

Run

# Directly
sudo ./flux-agent

# Or via systemd (after .deb install)
sudo cp /etc/flux-agent/agent.yaml.example /etc/flux-agent/agent.yaml
# edit agent.yaml
sudo systemctl enable --now flux-agent

The agent self-registers with Flux by calling POST /nodes/register on startup.

gRPC Services

RPC	Description
RegisterFunction	Stores function metadata on this agent
DeployFunction	Receives a zip archive and extracts it to the function's app directory
ExecuteFunction	Runs the function handler with cgroup isolation and returns output
HealthCheck	Liveness probe used by Flux's health poller
ReportNodeStatus	Returns CPU, memory, active tasks, and uptime for autoscaling