Add statistics gathering API for loadbalancer

https://blueprints.launchpad.net/octavia/+spec/stats-support

Problem description

Currently, Octavia does not support the gathering of loadbalancer statistics. This causes inconsistencies between the Octavia and Neutron-LBaaS APIs. Another point is that the statistics data we get from the Octavia API for the listener only reflects the first record for the listener in the Octavia database, since we’re supporting more topologies than SINGLE, this needs to be to fixed too.

Proposed change

Add one more data ‘request_errors’ to indicate the number of request errors for each listener, we can get this data from the stats of haproxy ‘ereq’.

Add a new module ‘stats’ to octavia.common with a class ‘StatsMixin’ to do the actual statistics calculation for both listener and loadbalancer. Make the mixin class as a new base class for octavia.api.v1.controllers.listener_statistics.ListenerStatisticsController, to make sure we get correct stats from Octavia API.

Add a new module ‘loadbalancer_statistics’ to octavia.api.v1.controllers with a class LoadbalancerStatisticsController to provide a new REST API for gathering statistics at the loadbalancer level.

Use evenstream to serialize the statistics messages from the octavia to neutron-lbaas via oslo_messaging, to keep consistent with neutron-lbaas API.

Alternatives

Update the ‘stats’ method in neutron-lbaas for octavia driver, allow the neutron-lbaas to get stats from octavia through REST API request, to keep consistent with neutron-lbaas API.

Data model impact

One new column for table listener_statistics will be introduced to represent request errors:

Field	Type	Null	Key	Default	Extra
request_errors	bigint(20)	NO		NULL

REST API impact

Add ‘request_errors’ in the response of list listener statistics:

Example List listener statistics: JSON response

{
    "listener": {
        "bytes_in": 0,
        "bytes_out": 0,
        "active_connections": 0,
        "total_connections": 0,
        "request_errors": 0
    }
}

Add a new API to list loadbalancer statistics

Lists loadbalancer statistics.

Request Type	GET
Endpoint	URL/v1/loadbalancers/{lb_id}/stats
Response Codes	Success	200
	Error	401, 404, 500

Example List loadbalancer statistics: JSON response

{
    "loadbalancer": {
        "bytes_in": 0,
        "bytes_out": 0,
        "active_connections": 0,
        "total_connections": 0,
        "request_errors": 0,
        "listeners": [{
            "id": "uuid"
            "bytes_in": 0,
            "bytes_out": 0,
            "active_connections": 0,
            "total_connections": 0,
            "request_errors": 0,
        }]
    }
}

Security impact

None

Notifications impact

None

Other end user impact

None

Performance Impact

None

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

li, chen <shchenli@cn.ibm.com>

Work Items

• Extend current stats collection for listener amphora

• Add module ‘stats’

• Add new API for gathering statistics at the loadbalancer level

• Update stats to neutron database

Dependencies

None

Testing

Function tests with tox.

Documentation Impact

Changes shall be introduced to the octavia APIs: see [1]

References

[1] https://docs.openstack.org/api-ref/load-balancer/v1/octaviaapi.html