The docker has supported healthcheck. It is useful for application
container.
Zun may integrate these options.
--health-cmd Command to run to check health
--health-interval Time between running the check
--health-retries Consecutive failures needed to report unhealthy
--health-timeout Maximum time to allow one check to run
In zun, the four parameter are cmd, interval, retries, timeout.
Partial-Implements: blueprint support-healthycheck
Change-Id: I2f9f48aef17f0d92835db13c6112550bda5e31bf
c18105dea5