MagnetoDB/specs/monitoring-api

MagnetoDB monitoring api
Launchpad: monitoring-api

The API for exposing usage statistic for users, external monitoring or billing tools.

Specification status
Obsolete moved to https://review.openstack.org/#/c/130239/ and https://review.openstack.org/#/c/130801/

Problem Description
As a magnetodb user I need to know how much data I have in table As a magnetodb administrator I need to know now much space is used with user's table As a accountant department I need to know how big user's table is in order to create a bill

Proposed Change
Response example: {item_count: 3000, size: 1003432}
 * 1) Introduce monitoring API available on the same port as data API by path /monitoring/*
 * 2) implement REST method for list of tables  /{tenant_id}/monitoring/tables
 * 3) table usage details /{tenant_id}/monitoring/table/{table_name}

Alternatives
Implement as part of data API. However it gives access to data itself for monitoring tools.

Security Impact

 * authorization is performed by user's token
 * authorization can be performed by token with specific role with permission to call monitoring API
 * MagnetoDB API node should have access to Jolokia HTTP endpoint

Notifications Impact
None

Other End User Impact
None

Performance Impact
Now we have POC for count items in table (https://review.openstack.org/#/c/118557/), but this implementation is very expensive (we scan all our data to get one counter). So we need change concept and use Cassandra JMX to get approximate number of items and also size of CF on disk.

Other Deployer Impact

 * Jolokia component is used for collecting data from Cassandra
 * Cassandra start script should be updated with jolokia-jvm-agent
 * MagnetoDB API node should have access to Jolokia HTTP endpoint

Developer Impact
None

Implementation
Current concept:
 * 1) at Cassandra node we run JMX-HTTP bridge agent (Jolokia).
 * 2) Client goes to MagnetoDB with REST-like interface (.../{tenant_id}/monitoring/table/{table_name}),
 * 3) MagnetoDB goes to Jolokia agent via HTTP, get JMX-metrics from Cassanra and returns them to client

Assignee(s)
Primary assignee: ominakov

Other contributors: achudnovets SpyRay

Work Items

 * 1) Define Monitoring API on wiki.
 * 2) Write interface for API.
 * 3) Implement calls from MagnetoDB to Jolokia agent.

Dependencies
Devstack integraion update

Documentation Impact

 * Monitoring API section should be added here http://magnetodb.readthedocs.org/en/latest/api_reference.html
 * deploment guide should be updated http://magnetodb.readthedocs.org/en/latest/admin_guide.html#installation-guide