ATTEMPTS=0 means don't run the checks. Useful if you want to skip the checks and can be overridden by DOKKU_CHECKS_ATTEMPTS
ATTEMPTS=1 means run only once
- Specify how long to wait before running first check
- Specify timeout for each check
- Check specific hosts, e.g. http://signin.example.com
- Check both HTTP and HTTPS resources
This change makes Dokku start up the new container, run a set of checks
against it, and only switch traffic over to the new containers if all
checks complete successfully. No requests are dropped during the switch
over.
To specify checks, add a CHECKS file to the root of your project
directory. This is a text file with one line per check. Empty lines and
lines starting with # are ignored.
A check is a relative URL and may be followed by expected content from
the page, for example:
/about Our Amazing Team
Even if you don’t use any checks, this change will prevent downtime
during switching from old to new container.
See: https://labnotes.org/zero-downtime-deploy-with-dokku/
