Chapter 3. Troubleshooting the OpenStack Image Service

Glance is the code name for the OpenStack image service. This service is responsible for the functionality that allows users to discover virtual machine images, register new images, and retrieve existing images. Glance provides a RESTful API, which also powers the command-line interface and the image functionality in the Horizon Dashboard.

In this chapter, we will systematically walk you through the troubleshooting layers, which are as follows:

• Glance services
• The Glance database
• The Glance authentication
• The Glance API
• The Glance command-line client
• Glance logging and configuration
• Common errors

Glance is made up of several components. There is an API service and a registry service included in Glance. Each of these services need to be running for Glance to work properly. Glance also requires a database such as MySQL or Postgres. Finally, Glance supports several storage backends, where images are physically stored. The backend you use is configurable in glance-api.conf.