| Summary: | [RFE][ceilometer]: improve the ceilometer central agent | ||
|---|---|---|---|
| Product: | Red Hat OpenStack | Reporter: | Stephen Gordon <sgordon> |
| Component: | openstack-ceilometer | Assignee: | Eoghan Glynn <eglynn> |
| Status: | CLOSED NOTABUG | QA Contact: | Shai Revivo <srevivo> |
| Severity: | unspecified | Docs Contact: | |
| Priority: | high | ||
| Version: | unspecified | CC: | jruzicka, marius.borze, markmc, nbarcet, pbrady, yeylon |
| Target Milestone: | --- | Keywords: | FutureFeature |
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| URL: | https://blueprints.launchpad.net/ceilometer/+spec/central-agent-improvement | ||
| Whiteboard: | upstream_milestone_none upstream_status_not-started upstream_definition_obsolete | ||
| Fixed In Version: | Doc Type: | Enhancement | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2015-08-10 14:00:41 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Bug Depends On: | |||
| Bug Blocks: | 799011, 1038706 | ||
|
Description
Stephen Gordon
2013-12-05 16:21:38 UTC
To clarify, the main focus of this RFE is the ability to horizontally scale the ceilometer-central agent. Currently, such scale-out is not possible without duplicating the polling of the public REST APIs from which the central agent generates sample data. Such duplication would add unnecessary traffic on the message bus, result in duped samples in the metering store and potentially lead ultimately to double-charging the user. Horizontal scale-out is not possible currently because there is no co-ordination mechanism to divide the workload among multiple central agents (unlike say the partitioned alarm evaluator). So the focus of the implementation will be rebasing the central agent on some co-ordination protocol, with the intention that this would be sufficiently general to be implemented in Oslo[1] and shared among several services. Tooz[2] was one potential concrete protocol considered as the underpinnings for the generic synchronization service. In terms of testing these improvements to the central agent, the key would be to spin up multiple instances of the agent and then check for effective duplication in the samples gathered for the meters for which the central is responsible for gathering. For example, the image meter should be gathered once for every existing image glance in every polling period (default 600s). The samples observed being more frequent that the interval defined in the pipeline.yaml would suggest duplication, hence a lack of correct support for horizontal scaling. Depending on the detailed mechanism used for co-ordination, testing should also assert that the pool of central agents can be grown and shrunk dynamically without causing duplication or starvation of any meters. [1] https://blueprints.launchpad.net/oslo/+spec/service-sync [2] https://github.com/stackforge/tooz This was implemented via another RFE. |