CLI Overview

Introduction to nats-server command-line interface

The nats-server command-line interface provides a flexible way to start and configure NATS server instances. You can specify options directly via command-line flags or use a configuration file for more complex setups.

Basic Usage

nats-server [options]

Start a NATS server with default settings:

nats-server

This starts the server listening on 0.0.0.0:4222 with auto-generated server name.

Common Usage Patterns

Starting with Custom Port

nats-server -p 4223

Using a Configuration File

nats-server -c /etc/nats/nats-server.conf

Testing Configuration

Validate your configuration file without starting the server:

nats-server -c /etc/nats/nats-server.conf -t

Enable JetStream with Custom Storage

nats-server -js -sd /var/lib/nats

Enable Monitoring

nats-server -m 8222

Access monitoring interface at http://localhost:8222

Debug Mode with Logging

nats-server -D -l /var/log/nats-server.log

Configuration File vs CLI Flags

You can configure NATS server using either CLI flags or a configuration file:

• CLI Flags: Quick setup, ideal for development and testing
• Configuration File: Better for production, supports complex configurations including clusters, accounts, and authorization

CLI flags take precedence over configuration file settings. You can combine both approaches:

nats-server -c nats.conf -D -p 4223

This loads nats.conf but overrides the port to 4223 and enables debug mode.

Help and Version

Display Help

nats-server -h
nats-server --help

Show Version

nats-server -v
nats-server --version

TLS Help

nats-server --help_tls

Common Flag Combinations

Production Server with Monitoring

nats-server -c /etc/nats/nats-server.conf -P /var/run/nats-server.pid -m 8222 -l /var/log/nats-server.log

Development with Debug and Trace

nats-server -DV -p 4222

JetStream with Monitoring and Logging

nats-server -js -sd /data/jetstream -m 8222 -l /var/log/nats.log

Clustered Server

nats-server -c cluster.conf --cluster nats://0.0.0.0:6222 --routes nats://node1:6222,nats://node2:6222

Next Steps

• Server Options - Complete reference of server CLI flags
• Logging Options - Configure logging and debugging
• Signals - Signal handling and process management