Is it possible to display a static html page during dyno startup, similar to displaying a custom page on error or during maintenance mode?
My app's slug size is rather large and startup time can take close to 50 seconds. If possible, I'd like to display something for the user to see, rather than an empty page. If not, I'll address the large slug size directly to minimize startup time.
Thanks for any insights!
No, but you might consider taking a look at the preboot options instead. While there are some downsides (waiting several minutes for deploys to take effect) it does mean Heroku will wait until the new dynos are fully running and available before switching to them.
Preboot changes the standard dyno start behavior for web dynos. Instead of stopping the existing set of web dynos before starting the new ones, preboot ensures that the new web dynos are started (and receive traffic) before the existing ones are terminated. This can contribute to zero downtime deployments.
