If an app hangs

After a deploy, the proxy tests only that an instance accepts TCP connections.

After a deploy, the proxy tests one thing: the instance accepts TCP connections.

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Ferry uses the path of the health check (--health) only while a deploy starts new instances. After that, the proxy tests only the TCP connection.

An app that hangs with an open port keeps its traffic. Ferry does not see the problem.

What to do

Make your app exit when it cannot serve. Docker then restarts the container, as for each crash.

To see the restarts of each instance, use this command:

Terminal

ferry status api

When a container crashes

Docker starts a crashed container again, and the proxy uses the other instances during that time.

If ferryd stops

When ferryd stops, your containers continue to run. Public traffic, cron runs and deploys stop.