# Configuring Watcher

This document is continually updated and reflects the latest available code of the Watcher service.

## Service overview

The Watcher system is a collection of services that provides support to optimize your IaaS platform. The Watcher service may, depending upon configuration, interact with several other OpenStack services. This includes:

- the OpenStack Identity service (keystone) for request authentication and to locate other OpenStack services.

- the OpenStack Telemetry service (ceilometer) for collecting the resources metrics.

- the time series database (gnocchi) for consuming the resources metrics.

- the OpenStack Compute service (nova) works with the Watcher service and acts as a user-facing API for instance migration.

- the OpenStack Bare Metal service (ironic) works with the Watcher service and allows to manage power state of nodes.

- the OpenStack Block Storage service (cinder) works with the Watcher service and as an API for volume node migration.

The Watcher service includes the following components:

- `watcher-decision-engine`: runs audit on part of your IaaS and return an action plan in order to optimize resource placement.

- `watcher-api`: A RESTful API that processes application requests by sending them to the watcher-decision-engine over RPC.

- `watcher-applier`: applies the action plan.

- python-watcherclient: A command-line interface (CLI) for interacting with the Watcher service.

- watcher-dashboard: An Horizon plugin for interacting with the Watcher service.

Additionally, the Watcher service has certain external dependencies, which are very similar to other OpenStack services:

- A database to store audit and action plan information and state. You can set the database back-end type and location.

- A queue. A central hub for passing messages, such as RabbitMQ.

Optionally, one may wish to utilize the following associated projects for additional functionality:

- watcher metering: an alternative to collect and push metrics to the Telemetry service.

## Install and configure prerequisites

You can configure Watcher services to run on separate nodes or the same node. In this guide, the components run on one node, typically the Controller node.

This section shows you how to install and configure the services.

It assumes that the Identity, Image, Compute, and Networking services have already been set up.

### Configure the Identity service for the Watcher service

1. Create the Watcher service user (eg `watcher`). The service uses this to authenticate with the Identity Service. Use the `KEYSTONE_SERVICE_PROJECT_NAME` project (named `service` by default in devstack) and give the user the `admin` role:

   >     $ keystone user-create --name=watcher --pass=WATCHER_PASSWORD \
   >       --email=watcher@example.com \
   >       --tenant=KEYSTONE_SERVICE_PROJECT_NAME
   >     $ keystone user-role-add --user=watcher \
   >       --tenant=KEYSTONE_SERVICE_PROJECT_NAME --role=admin

   or (by using python-openstackclient 1.8.0+)

   >     $ openstack user create  --password WATCHER_PASSWORD --enable \
   >       --email watcher@example.com watcher \
   >       --project=KEYSTONE_SERVICE_PROJECT_NAME
   >     $ openstack role add --project KEYSTONE_SERVICE_PROJECT_NAME \
   >       --user watcher admin

2. You must register the Watcher Service with the Identity Service so that other OpenStack services can locate it. To register the service:

   >     $ keystone service-create --name=watcher --type=infra-optim \
   >       --description="Infrastructure Optimization service"

   or (by using python-openstackclient 1.8.0+)

   >     $ openstack service create --name watcher infra-optim \
   >       --description="Infrastructure Optimization service"

3. Create the endpoints by replacing YOUR_REGION and `WATCHER_API_[PUBLIC|ADMIN|INTERNAL]_IP` with your region and your Watcher Service’s API node IP addresses (or FQDN):

   >     $ keystone endpoint-create \
   >     --service-id=the_service_id_above \
   >     --publicurl=http://WATCHER_API_PUBLIC_IP:9322 \
   >     --internalurl=http://WATCHER_API_INTERNAL_IP:9322 \
   >     --adminurl=http://WATCHER_API_ADMIN_IP:9322

   or (by using python-openstackclient 1.8.0+)

   >     $ openstack endpoint create --region YOUR_REGION
   >       watcher public http://WATCHER_API_PUBLIC_IP:9322

   >     $ openstack endpoint create --region YOUR_REGION
   >       watcher internal http://WATCHER_API_INTERNAL_IP:9322

   >     $ openstack endpoint create --region YOUR_REGION
   >       watcher admin http://WATCHER_API_ADMIN_IP:9322

### Set up the database for Watcher

The Watcher service stores information in a database. This guide uses the MySQL database that is used by other OpenStack services.

1. In MySQL, create a `watcher` database that is accessible by the `watcher` user. Replace WATCHER_DBPASSWORD with the actual password:

       # mysql

       mysql> CREATE DATABASE watcher CHARACTER SET utf8;
       mysql> GRANT ALL PRIVILEGES ON watcher.* TO 'watcher'@'localhost' \
       IDENTIFIED BY 'WATCHER_DBPASSWORD';
       mysql> GRANT ALL PRIVILEGES ON watcher.* TO 'watcher'@'%' \
       IDENTIFIED BY 'WATCHER_DBPASSWORD';

## Configure the Watcher service

The Watcher service is configured via its configuration file. This file is typically located at `/etc/watcher/watcher.conf`.

You can easily generate and update a sample configuration file named watcher.conf.sample by using these following commands:

    $ git clone https://opendev.org/openstack/watcher.git
    $ cd watcher/
    $ tox -e genconfig
    $ vi etc/watcher/watcher.conf.sample

The configuration file is organized into the following sections:

- `[DEFAULT]` - General configuration

- `[api]` - API server configuration

- `[database]` - SQL driver configuration

- `[keystone_authtoken]` - Keystone Authentication plugin configuration

- `[watcher_clients_auth]` - Keystone auth configuration for clients

- `[watcher_applier]` - Watcher Applier module configuration

- `[watcher_decision_engine]` - Watcher Decision Engine module configuration

- `[oslo_messaging_rabbit]` - Oslo Messaging RabbitMQ driver configuration

- `[ceilometer_client]` - Ceilometer client configuration

- `[cinder_client]` - Cinder client configuration

- `[glance_client]` - Glance client configuration

- `[nova_client]` - Nova client configuration

- `[neutron_client]` - Neutron client configuration

The Watcher configuration file is expected to be named `watcher.conf`. When starting Watcher, you can specify a different configuration file to use with `--config-file`. If you do not specify a configuration file, Watcher will look in the following directories for a configuration file, in order:

- `~/.watcher/`

- `~/`

- `/etc/watcher/`

- `/etc/`

Although some configuration options are mentioned here, it is recommended that you review all the available options so that the watcher service is configured for your needs.

1. The Watcher Service stores information in a database. This guide uses the MySQL database that is used by other OpenStack services.

   Configure the location of the database via the `connection` option. In the following, replace WATCHER_DBPASSWORD with the password of your `watcher` user, and replace DB_IP with the IP address where the DB server is located:

       [database]
       ...

       # The SQLAlchemy connection string used to connect to the
       # database (string value)
       #connection=<None>
       connection = mysql+pymysql://watcher:WATCHER_DBPASSWORD@DB_IP/watcher?charset=utf8

2. Configure the Watcher Service to use the RabbitMQ message broker by setting one or more of these options. Replace RABBIT_HOST with the IP address of the RabbitMQ server, RABBITMQ_USER and RABBITMQ_PASSWORD by the RabbitMQ server login credentials

       [DEFAULT]

       # The default exchange under which topics are scoped. May be
       # overridden by an exchange name specified in the transport_url
       # option. (string value)
       control_exchange = watcher

       # ...
       transport_url = rabbit://RABBITMQ_USER:RABBITMQ_PASSWORD@RABBIT_HOST

3. Watcher API shall validate the token provided by every incoming request, via keystonemiddleware, which requires the Watcher service to be configured with the right credentials for the Identity service.

   In the configuration section here below:

   - replace IDENTITY_IP with the IP of the Identity server

   - replace WATCHER_PASSWORD with the password you chose for the `watcher` user

   - replace KEYSTONE_SERVICE_PROJECT_NAME with the name of project created for OpenStack services (e.g. `service`)

         [keystone_authtoken]

         # Authentication type to load (unknown value)
         # Deprecated group/name - [DEFAULT]/auth_plugin
         #auth_type = <None>
         auth_type = password

         # Authentication URL (unknown value)
         #auth_url = <None>
         auth_url = http://IDENTITY_IP:5000

         # Username (unknown value)
         # Deprecated group/name - [DEFAULT]/username
         #username = <None>
         username=watcher

         # User's password (unknown value)
         #password = <None>
         password = WATCHER_PASSWORD

         # Domain ID containing project (unknown value)
         #project_domain_id = <None>
         project_domain_id = default

         # User's domain id (unknown value)
         #user_domain_id = <None>
         user_domain_id = default

         # Project name to scope to (unknown value)
         # Deprecated group/name - [DEFAULT]/tenant-name
         #project_name = <None>
         project_name = KEYSTONE_SERVICE_PROJECT_NAME

4. Watcher’s decision engine and applier interact with other OpenStack projects through those projects’ clients. In order to instantiate these clients, Watcher needs to request a new session from the Identity service using the right credentials.

   In the configuration section here below:

   - replace IDENTITY_IP with the IP of the Identity server

   - replace WATCHER_PASSWORD with the password you chose for the `watcher` user

   - replace KEYSTONE_SERVICE_PROJECT_NAME with the name of project created for OpenStack services (e.g. `service`)

         [watcher_clients_auth]

         # Authentication type to load (unknown value)
         # Deprecated group/name - [DEFAULT]/auth_plugin
         #auth_type = <None>
         auth_type = password

         # Authentication URL (unknown value)
         #auth_url = <None>
         auth_url = http://IDENTITY_IP:5000

         # Username (unknown value)
         # Deprecated group/name - [DEFAULT]/username
         #username = <None>
         username=watcher

         # User's password (unknown value)
         #password = <None>
         password = WATCHER_PASSWORD

         # Domain ID containing project (unknown value)
         #project_domain_id = <None>
         project_domain_id = default

         # User's domain id (unknown value)
         #user_domain_id = <None>
         user_domain_id = default

         # Project name to scope to (unknown value)
         # Deprecated group/name - [DEFAULT]/tenant-name
         #project_name = <None>
         project_name = KEYSTONE_SERVICE_PROJECT_NAME

5. Configure the clients to use a specific version if desired. For example, to configure Watcher to use a Nova client with version 2.1, use:

       [nova_client]

       # Version of Nova API to use in novaclient. (string value)
       #api_version = 2.56
       api_version = 2.1

6. Create the Watcher Service database tables:

       $ watcher-db-manage --config-file /etc/watcher/watcher.conf create_schema

7. Start the Watcher Service:

       $ watcher-api &&  watcher-decision-engine && watcher-applier

## Configure Nova compute

Please check your hypervisor configuration to correctly handle instance migration.

## Configure Measurements

You can configure and install Ceilometer by following the documentation below :

1. https://docs.openstack.org/ceilometer/latest

The built-in strategy ‘basic_consolidation’ provided by watcher requires “compute.node.cpu.percent” and “cpu” measurements to be collected by Ceilometer. The measurements available depend on the hypervisors that OpenStack manages on the specific implementation. You can find the measurements available per hypervisor and OpenStack release on the OpenStack site. You can use ‘ceilometer meter-list’ to list the available meters.

For more information: https://docs.openstack.org/ceilometer/latest/admin/telemetry-measurements.html

Ceilometer is designed to collect measurements from OpenStack services and from other external components. If you would like to add new meters to the currently existing ones, you need to follow the documentation below:

1. https://docs.openstack.org/ceilometer/latest/contributor/measurements.html#new-measurements

The Ceilometer collector uses a pluggable storage system, meaning that you can pick any database system you prefer. The original implementation has been based on MongoDB but you can create your own storage driver using whatever technology you want. For more information : https://wiki.openstack.org/wiki/Gnocchi

## Configure Nova Notifications

Watcher can consume notifications generated by the Nova services, in order to build or update, in real time, its cluster data model related to computing resources.

Nova emits unversioned(legacy) and versioned notifications on different topics. Because legacy notifications will be deprecated, Watcher consumes Nova versioned notifications.

> - In the file `/etc/nova/nova.conf`, the value of driver in the section `[oslo_messaging_notifications]` can’t be noop, and the value of notification_format in the section `[notifications]` should be both or versioned

>       [oslo_messaging_notifications]
>       driver = messagingv2

>       ...

>       [notifications]
>       notification_format = both

## Configure Cinder Notifications

Watcher can also consume notifications generated by the Cinder services, in order to build or update, in real time, its cluster data model related to storage resources. To do so, you have to update the Cinder configuration file on controller and volume nodes, in order to let Watcher receive Cinder notifications in a dedicated `watcher_notifications` channel.

> - In the file `/etc/cinder/cinder.conf`, update the section `[oslo_messaging_notifications]`, by redefining the list of topics into which Cinder services will publish events

>       [oslo_messaging_notifications]
>       driver = messagingv2
>       topics = notifications,watcher_notifications

> - Restart the Cinder services.

## Workers

You can define a number of workers for the Decision Engine and the Applier.

If you want to create and run more audits simultaneously, you have to raise the number of workers used by the Decision Engine:

    [watcher_decision_engine]

    ...

    # The maximum number of threads that can be used to execute strategies
    # (integer value)
    #max_workers = 2

If you want to execute simultaneously more recommended action plans, you have to raise the number of workers used by the Applier:

    [watcher_applier]

    ...

    # Number of workers for applier, default value is 1. (integer value)
    # Minimum value: 1
    #workers = 1

this page last updated: 2026-05-26 14:30:00

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