[AMBARI-9807] Store Configuration In Agent Memory For Alerts

• Type: Task
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.0.0
• Fix Version/s: 2.0.0
• Component/s: ambari-agent
• Epic Link: Alerts Redesign
• Assignee: Jonathan Hurley
• Reporter: Jonathan Hurley
• Created: 26/Feb/15 04:38
• Updated: 26/Feb/15 18:37
• Resolved: 26/Feb/15 16:49

Description

https://issues.apache.org/jira/browse/AMBARI-8885 fixes a problem where agents required a restart in order for the alert framework to pickup configuration changes.

Initially, alerts were designed so that they only received the parameters they requested. A single alert definition might only need a couple of values (such as hdfs-site/foo) as opposed to the entire configuration structure.

However, it seems like we're doing a lot of extra work to ensure that these values are kept current; alert definitions need to be rescheduled when a configuration changes so that its cached value can be updated.

It would be good to investigate (and implement if plausible) a way to store the entire configuration structure in memory and have it accessible to alerts (and any other part of the agent framework). This would allow us to:

• Remove the code that caches values in the alert jobs before they are schedule
• Remove the code the restarts jobs on configuration changes
• Have an up-to-date configuration structure that is easily accessible without the need to parse any files on-disk

The major concern would be that keeping such a large structure in memory could cause some kind of performance degradation or memory overhead that would be unacceptable.

Issue Links

• links to: Reviewboard