[custom-cron] Temporarily empty crontab on apply

[thbar]

While deploying custom-cron, I discovered that the crontab is emptied for a good minute during the chef run.

To verify this, monitor the output of :

$ watch -d -n 0.1 "crontab -l | tee | wc -l"

Then in another shell, run:

$ ey-core recipes upload --environment=YourEnv --file=cookbooks --apply

While a cron job should be written in a way that having a "miss" in the occurrences is not a problem, this behaviour increases the risk of mis-beat unnecessarily IMO.

Reporting this here and I'll also open a ticket at EY support.