Hot restart

• The new process fully initializes itself (loads the configuration, does an initial service discovery and health checking phase, etc.) before it asks for copies of the listen sockets from the old process. The new process starts listening and then tells the old process to start draining.

• An example restarter/parent process written in Python is included in the source distribution. This parent process is usable with standard process control utilities such as monit/runit/etc.

Envoy’s default command line options assume that only a single set of Envoy processes is running on a given host: an active Envoy server process and, potentially, a draining Envoy server process that will exit as described above. The --base-id or options may be used to allow multiple, distinctly configured Envoys to run on the same host and hot restart independently.

This feature is not supported on Windows.

By default, Envoy uses reuse_port sockets on Linux for better performance. This feature workers correctly during hot restart because Envoy passes each socket to the new process by worker index. Thus, no connections are dropped in the accept queues of the draining process.

Attention