In the preceding chapter, we looked at how identities are managed in OpenStack and how to authenticate to an OpenStack cluster. In this chapter, we will start to gather the resources necessary to launch an instance. The first resource we will work with is the image that an instance will use as its disk image when it is launched. Glance is the image management component in OpenStack. In this chapter, we'll look at how to register images with the image registry and how to build a custom cloud image.