When creating a Managed Start/Stop plan, you have the following options:
Start & Stop, Single Action (default)
Start & Stop, Separate Actions
Start Only
Stop Only
What is the difference between the "Single Action" and "Separate Actions" options?
Under the hood, Managed Start/Stops will create standard Skeddly actions: "Start EC2 Instances" and "Stop EC2 Instances".
The "Start EC2 Instances" action will start zero or more EC2 instances and has the option to stop those same EC2 instances after a specified period of time.
The "Stop EC2 Instances" action will stop zero or more EC2 instances and has the option to restart those same EC2 instances after a specified period of time.
When choosing the "Start & Stop, One Action" option, Skeddly will create a "Start EC2 Instances" action that will stop the same EC2 instances later.
When choosing the "Start & Stop, Separate Actions", Skeddly will create a "Start EC2 Instances" action and a "Stop EC2 Instances" action.
Why does this matter? Two reasons:
1. Skeddly cost
When using the optional stop option in the "Start EC2 Instances" action, we don't charge for the stop. But when using two separate actions, we'll charge for both the start and stop.
2. Re-evaluation of the EC2 instances
When using the single action, the matching EC2 instances are not re-evaluated at the stop time. So if an EC2 instance was started in the morning, it will be stopped in the evening. When using separate actions, EC2 instances are matched at both start and stop time.
Most people choose the single action option because of the lower cost.