ovsvswitchd

ovs-vswitchd (commonly written as ovs-vswitchd) is the Open vSwitch userspace daemon that implements the switching behavior of an Open vSwitch instance. It manages the logical components of a virtual switch, including bridges, ports, and the flow rules that determine how packets are forwarded. The daemon coordinates with the Open vSwitch kernel datapath (or, in older configurations, a userspace datapath) and with external controllers via the OpenFlow protocol.

As part of the Open vSwitch architecture, ovs-vswitchd handles the control plane tasks for a virtual switch. It programs the datapath with flow entries, enforces bridging logic, and provides features such as VLAN handling, tunneling (for example VXLAN or GRE), quality of service, and port bonding. It interacts with the controller plane to receive or push flow configurations and uses the Open vSwitch database (OVSDB) to store and synchronize configuration data.

Configuration and operation in production typically involve the OVSDB server and the ovs-vsctl command-line utility. ovs-vswitchd reads its runtime configuration from files such as /etc/openvswitch/ovs-vswitchd.conf.xml and from OVSDB. The kernel datapath, managed by ovs-vswitchd, provides the fast path for packet forwarding, while ovs-vswitchd handles policy, management, and dynamic updates.

Open vSwitch and ovs-vswitchd are widely used in virtualized and cloud environments, including platforms like OpenStack and software-defined networking deployments, where programmable switching, multi-tenant isolation, and portable virtualization networks are required.