Commit ca683 is not backwards compatible.

The commit ca683cb9e27bae76424a687bc6c3af5a73c501b9 is not backwards compatible. The last section of the commit

4. Modified the Health Checker and redefined the meaning initial_interval_secs.

has serious, unintended consequences.

Consider the following health check config:

      initial_interval_secs: 10
      interval_secs: 5
      max_consecutive_failures: 1

On the 0.16.0 executor, no health checking will occur for the first 10 seconds. Here the earliest a task can cause failure is at the 10th second.

On master, health checking starts right away which means the task can fail at the first second since max_consecutive_failures is set to 1.

This is not backwards compatible and needs to be fixed.

I think a good solution would be to revert the meaning change to initial_interval_secs and have the task transition into RUNNING when max_consecutive_successes is met.

An investigation shows initial_interval_secs was set to 5 but the task failed health checks right away:

D1011 19:52:13.295877 6 health_checker.py:107] Health checks enabled. Performing health check.
D1011 19:52:13.306816 6 health_checker.py:126] Reset consecutive failures counter.
D1011 19:52:13.307032 6 health_checker.py:132] Initial interval expired.
W1011 19:52:13.307130 6 health_checker.py:135] Failed to reach minimum consecutive successes.