..
      Copyright 2021 Red Hat, Inc. All rights reserved.

      Licensed under the Apache License, Version 2.0 (the "License"); you may
      not use this file except in compliance with the License. You may obtain
      a copy of the License at

          http://www.apache.org/licenses/LICENSE-2.0

      Unless required by applicable law or agreed to in writing, software
      distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
      WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
      License for the specific language governing permissions and limitations
      under the License.

=========================
Monitoring Load Balancers
=========================

Introduction
============

Octavia provides multiple ways to monitor your load balancers. You can query
statistics via the Octavia API or directly from your load balancer.

This guide will discuss the various options available to monitor your Octavia
load balancer.

Monitoring Using the Octavia API
================================

Octavia collects key metrics from all load balancers, including load balancers
built with third party provider drivers that support collecting statistics.
Octavia aggregates these statistics and makes them available via the Octavia
API. Load balancer statistics are available at the load balancer or listener
level.

.. _OpenStack Client: https://docs.openstack.org/python-openstackclient/latest/

Load balancer statistics can be queried using the `OpenStack Client`_.

.. code-block:: bash

   $ openstack loadbalancer stats show <lb id>

   +--------------------+-----------+
   | Field              | Value     |
   +--------------------+-----------+
   | active_connections | 0         |
   | bytes_in           | 2236722   |
   | bytes_out          | 100973832 |
   | request_errors     | 0         |
   | total_connections  | 3606      |
   +--------------------+-----------+

Individual listener statistics can also be queried using the
`OpenStack Client`_.

.. code-block:: bash

   $ openstack loadbalancer listener stats show <listener id>

   +--------------------+-------+
   | Field              | Value |
   +--------------------+-------+
   | active_connections | 0     |
   | bytes_in           | 89    |
   | bytes_out          | 237   |
   | request_errors     | 0     |
   | total_connections  | 1     |
   +--------------------+-------+

Load balancer statistics queried via the Octavia API include metrics for all
listener protocols.

Monitoring with Prometheus
==========================

Some provider drivers, such as the Octavia amphora driver, provide a prometheus
endpoint. This allows you to configure your Prometheus infrastructure to collect
metrics from Octavia load balancers.

To add a Prometheus endpoint on an Octavia load balancer, create a listener
with a special protocol ``PROMETHEUS``. This will enable the endpoint as
``/metrics`` on the listener. The listener supports all of the features of an
Octavia load balancer, such as allowed_cidrs, but does not support attaching
pools or L7 policies. All metrics will be identified by the Octavia object
ID (UUID) of the resources.

.. note:: Currectly UDP and SCTP metrics are not reported via Prometheus
          endpoints when using the amphora provider.

To create a Prometheus endpoint on port 8088 for load balancer lb1, you would
run the following command.

.. code-block:: bash

   $ openstack loadbalancer listener create --name stats-listener --protocol PROMETHEUS --protocol-port 8088 lb1
   +-----------------------------+--------------------------------------+
   | Field                       | Value                                |
   +-----------------------------+--------------------------------------+
   | admin_state_up              | True                                 |
   | connection_limit            | -1                                   |
   | created_at                  | 2021-10-03T01:44:25                  |
   | default_pool_id             | None                                 |
   | default_tls_container_ref   | None                                 |
   | description                 |                                      |
   | id                          | fb57d764-470a-4b6b-8820-627452f55b96 |
   | insert_headers              | None                                 |
   | l7policies                  |                                      |
   | loadbalancers               | b081ed89-f6f8-48cb-a498-5e12705e2cf9 |
   | name                        | stats-listener                       |
   | operating_status            | OFFLINE                              |
   | project_id                  | 4c1caeee063747f8878f007d1a323b2f     |
   | protocol                    | PROMETHEUS                           |
   | protocol_port               | 8088                                 |
   | provisioning_status         | PENDING_CREATE                       |
   | sni_container_refs          | []                                   |
   | timeout_client_data         | 50000                                |
   | timeout_member_connect      | 5000                                 |
   | timeout_member_data         | 50000                                |
   | timeout_tcp_inspect         | 0                                    |
   | updated_at                  | None                                 |
   | client_ca_tls_container_ref | None                                 |
   | client_authentication       | NONE                                 |
   | client_crl_container_ref    | None                                 |
   | allowed_cidrs               | None                                 |
   | tls_ciphers                 | None                                 |
   | tls_versions                | None                                 |
   | alpn_protocols              | None                                 |
   | tags                        |                                      |
   +-----------------------------+--------------------------------------+

Once the ``PROMETHEUS`` listener is ``ACTIVE``, you can configure Prometheus to
collect metrics from the load balancer by updating the prometheus.yml file.

.. code-block:: yaml

   [scrape_configs]
   - job_name: 'Octavia LB1'
     static_configs:
     - targets: ['192.0.2.10:8088']

For more information on setting up Prometheus, see the
`Prometheus project web site <https://prometheus.io/>`_.

.. note:: The metrics exposed via the ``/metrics`` endpoint will use a
          custom Octavia namespace.

You can connect `Grafana <https://grafana.com>`_ to the
`Prometheus <https://prometheus.io>`_ instance to provide additional graphing
and dashboard capabilities. A Grafana dashboard for Octavia load balancers is
included in the etc/grafana directory of the Octavia code.
