vantage-docs/docs/reference/agent-config.md

id, title, sidebar_label

id	title	sidebar_label
agent-config	Agent configuration	Agent config

The agent reads no environment variables. Everything is in one YAML file.

Location

Platform	Path
Linux	/etc/vantage/config.yaml
Windows	%ProgramData%\vantage\config.yaml

Directory 0700, file 0600. The install script sets both.

Contents

server_url: "vantage.yourdomain.com:9090"
server_id: "<uuid>"
pre_reg_token: "<token>" # removed after the first successful Register()
agent_token: "" # written by the agent after Register()
poll_interval: 30s
tls: true

Field	Meaning
server_url	host:port of the gRPC endpoint. Comes from the server's GRPC_HOST
server_id	The identity issued when the enrolment was created
pre_reg_token	Single-use, one hour. Cleared once registration succeeds
agent_token	The permanent credential, written by the agent itself
poll_interval	How often the agent polls for key state. Default 30s
tls	Whether to use TLS. Leave true

:::danger This file is the credential agent_token is plaintext here and nowhere else the control plane holds only its SHA-256. Anyone who can read this file can act as this agent. That is why it is 0600 and the directory is 0700. :::

Startup sequence

1. Load the config
2. pre_reg_token present → register → save agent_token,
   clear pre_reg_token, reconnect
3. Start: command stream · hourly update check · inventory · monitors
4. Enter the key poll loop

The poll loop

1. Ask the control plane for the desired key state, reporting the
   agent version
2. Non-Linux hosts stop here Windows agents register and heartbeat only
3. Diff the desired keys against /root/.ssh/authorized_keys;
   unchanged → write nothing
4. Changed → write a temp file, rename it over the real one, chmod 0600

Service management

Linux

Unit at /etc/systemd/system/vantage-agent.service, Restart=always, running as root.

systemctl status vantage-agent
systemctl restart vantage-agent
journalctl -u vantage-agent -f

Windows

A service registered through NSSM, or installed by the MSI that CI builds.

Get-Service vantage-agent
Restart-Service vantage-agent

Command-line flags

vantage-agent -generate-key

Generates a keypair locally. Normal operation takes no flags.

Moving an agent to a new control plane

Change server_url, clear agent_token, set a fresh pre_reg_token from a new enrolment, and restart. The old control plane still holds a server record that will go offline; delete it there.

Uninstalling

systemctl disable --now vantage-agent
rm -f /usr/local/bin/vantage-agent /etc/systemd/system/vantage-agent.service
rm -rf /etc/vantage
systemctl daemon-reload

Keys already written to authorized_keys remain on disk the agent is no longer running to remove them. Revoke first if that matters.