I came across Kubernetes a few times while looking for a simple way to manage infrastructure and deployments for over 50 PHP applications. And every time, I came to the conclusion that it wasn't the right tool for the job.
Flight then runs the composer command (composer install) and release commands in the release directory on all servers.
As previously explained, this causes PHP to read the application files from the release directory rather than the symlink.
When the server receives an app deployment request, it initiates the release process in the same way that the flight app:release command does.