Installation

Note

Before the Stein release the placement code was in Nova alongside the compute REST API code (nova-api). Make sure that the release version of this document matches the release version you want to deploy.

Steps Overview

This subsection gives an overview of the process without going into detail on the methods used.

1. Deploy the API service

Placement provides a placement-api WSGI script for running the service with Apache, nginx or other WSGI-capable web servers. Depending on what packaging solution is used to deploy OpenStack, the WSGI script may be in /usr/bin or /usr/local/bin.

placement-api, as a standard WSGI script, provides a module level application attribute that most WSGI servers expect to find. This means it is possible to run it with lots of different servers, providing flexibility in the face of different deployment scenarios. Common scenarios include:

• apache2 with mod_wsgi

• apache2 with mod_proxy_uwsgi

• nginx with uwsgi

• nginx with gunicorn

In all of these scenarios the host, port and mounting path (or prefix) of the application is controlled in the web server’s configuration, not in the configuration (placement.conf) of the placement application.

When placement was first added to DevStack it used the mod_wsgi style. Later it was updated to use mod_proxy_uwsgi. Looking at those changes can be useful for understanding the relevant options.

DevStack is configured to host placement at /placement on either the default port for http or for https (80 or 443) depending on whether TLS is being used. Using a default port is desirable.

By default, the placement application will get its configuration for settings such as the database connection URL from /etc/placement/placement.conf. The directory the configuration file will be found in can be changed by setting OS_PLACEMENT_CONFIG_DIR in the environment of the process that starts the application. With recent releases of oslo.config, configuration options may also be set in the environment.

Note

When using uwsgi with a front end (e.g., apache2 or nginx) something needs to ensure that the uwsgi process is running. In DevStack this is done with systemd. This is one of many different ways to manage uwsgi.

This document refrains from declaring a set of installation instructions for the placement service. This is because a major point of having a WSGI application is to make the deployment as flexible as possible. Because the placement API service is itself stateless (all state is in the database), it is possible to deploy as many servers as desired behind a load balancing solution for robust and simple scaling. If you familiarize yourself with installing generic WSGI applications (using the links in the common scenarios list, above), those techniques will be applicable here.

2. Synchronize the database

The placement service uses its own database, defined in the placement_database section of configuration. The placement_database.connection option must be set or the service will not start. The command line tool placement-manage can be used to migrate the database tables to their correct form, including creating them. The database described by the connection option must already exist and have appropriate access controls defined.

Another option for synchronization is to set placement_database.sync_on_startup to True in configuration. This will perform any missing database migrations as the placement web service starts. Whether you choose to sync automaticaly or use the command line tool depends on the constraints of your environment and deployment tooling.

3. Create accounts and update the service catalog

Create a placement service user with an admin role in Keystone.

The placement API is a separate service and thus should be registered under a placement service type in the service catalog. Clients of placement, such as the resource tracker in the nova-compute node, will use the service catalog to find the placement endpoint.

See Configure User and Endpoints for examples of creating the service user and catalog entries.

Devstack sets up the placement service on the default HTTP port (80) with a /placement prefix instead of using an independent port.

Installation Packages

This section provides instructions on installing placement from Linux distribution packages.

Warning

These installation documents are a work in progress. Some of the distribution packages mentioned are not yet available so the instructions will not work.

The placement service provides an HTTP API used to track resource provider inventories and usages. More detail can be found at the placement overview.

Placement operates as a web service over a data model. Installation involves creating the necessary database and installing and configuring the web service. This is a straightforward process, but there are quite a few steps to integrate placement with the rest of an OpenStack cloud.

Note

Placement is required by some of the other OpenStack services, notably nova, therefore it should be installed before those other services but after Identity (keystone).

• Install and configure Placement from PyPI
• Install and configure Placement for openSUSE and SUSE Linux Enterprise
• Install and configure Placement for Red Hat Enterprise Linux and CentOS
• Install and configure Placement for Ubuntu
• Verify Installation