Nova and Glance from OpenStack.

Nova and Glance are the components of the Openstack. Openstack is a private cloud. Open source cloud platforms are playing an increasingly significant role in cloud computing. These systems have been undergoing rapid development cycles. OpenStack has grown approximately 10 times in code size since its inception two and a half years ago. Openstack has the following components in total. 1. Horizon. 2. Nova. 3. Cinder. 4. Quantum. 5. Glance. 6. Swift. 7. Keystone.

We will be diving into the role of the glance and nova in Openstack.

Nova

Nova is the OpenStack project that provides a way to provision compute instances (aka virtual servers). Nova supports creating virtual machines, bare-metal servers (through the use of ironic), and has limited support for system containers. Nova runs as a set of daemons on top of existing Linux servers to provide that service. In AWS it is known as EC2. In other words, it is responsible for providing the ram and processing power to our instance.

Glance

The Image service (glance) project provides a service where users can upload and discover data assets that are meant to be used with other services. This currently includes images and metadata definitions.

Glance image services include discovering, registering, and retrieving virtual machine (VM) images. Glance has a RESTful API that allows querying of VM image metadata as well as retrieval of the actual image. VM images made available through Glance can be stored in a variety of locations from simple filesystems to object-storage systems like the OpenStack Swift project.

Conclusion

From the above description, we came to know that Nova is a compute service responsible for creating virtual machine instances and managing their life cycle, as well as managing the hypervisor of choice. And Glance allows querying of VM image metadata as well as retrieval of the actual image. Glance Image is nothing but ready to use operating system image which can be used on our nova instance.