[MESOS-3485] Make hook execution order deterministic

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Component/s: modules
• Story Points: 3
• Assignee: haosdent
• Reporter: Felix Abecassis
• Shepherd: Niklas Quarfot Nielsen
• Created: 21/Sep/15 23:55
• Updated: 29/Apr/19 09:25
• Resolved: 19/Jan/16 10:20

Description

Currently, when using multiple hooks of the same type, the execution order is implementation-defined.

This is because in src/hook/manager.cpp, the list of available hooks is stored in a hashmap<string, Hook*>. A hashmap is probably unnecessary for this task since the number of hooks should remain reasonable. A data structure preserving ordering should be used instead to allow the user to predict the execution order of the hooks. I suggest that the execution order should be the order in which hooks are specified with --hooks when starting an agent/master.

This will be useful when combining multiple hooks after MESOS-3366 is done.