ROS Parameter Server

A shared key-value store in ROS 1 that holds global configuration values any node can read or write.

The Parameter Server is a mechanism in ROS 1: the ROS master (roscore) maintains a globally shared key-value dictionary, and nodes read and write entries in it over the network — things like control gains, a camera's topic name, or a robot's physical dimensions. Parameters are typically loaded in bulk from launch files or YAML files, and can also be viewed or changed from the command line with rosparam. It's meant for static configuration that rarely changes, not high-frequency data. ROS 2 removed the global parameter server; instead, each node declares and holds its own parameters, accessed via ros2 param, with callbacks that can fire when a parameter changes. Note that distributed machine learning has an unrelated concept with the same name, referring to servers that store model parameters during training — that's a different thing.

ExampleA launch file uses rosparam to load pid.yaml, so the control node reads gains such as /arm_controller/kp on startup.

Also called

Parameter Server, rosparam

Related

Robot Operating System · Robot Operating System 2 · ROS Master (roscore) · Node (ROS) · Launch File · Topic (ROS)

Sources

ROS Wiki: Parameter Server
ROS 2 文档：About parameters (Chinese)