What is OpenStack

To get a better understanding, let's start with the type of cloud computing. Depending on the type of service provided, cloud computing has the following three landing methods:

1. Iaas (infrastructure as a service) from which users can request hardware or virtual hardware, including bare metal or virtual machines, and then install the operating system or other applications on top.

2, PaaS (Platform-as-a-service), the user can apply to a installation of the operating system and support the application to run the required runtime software such as a physical machine or virtual machine, and then install other applications on the top, but can not modify the pre-installed operating system and running environment.

3, SaaS (software-as-a-service), users can use the network to lease a number of software, rather than purchase, the more common mode is to provide a set of account password.

OpenStack is an IaaS. In July 2010, Rackspace and NASA collaborated to contribute the Rackspace cloud file platform code and the Nebula Platform code, and released the Openstack,openstack from the Apache license open source. The first version of OpenStack, codenamed Austin, is named after Rackspace's Texas capital, Texas, and plans to release a new version every few months, followed by a-to-Z sequence named after 26 letters. The first edition only has Swift and Nova two projects.

In February 2011, the OpenStack community released the Bexar version, the second version of OpenStack, with the addition of glance to provide mirroring services.

In April 2011, the OpenStack community released a more stable version of Cactus, but this version has no new projects.

In September 2011, OpenStack released its fourth version of Diablo, and the version of OpenStack was updated every six months, respectively, during the spring and autumn of the year.

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OpenStack currently covers seven core components, namely compute (Compute), Object Storage (Storage), authentication (identity), user interface (Dashboard), block storage (blocks Storage), Network and mirroring Services (image service). Each component is a collection of multiple services, and a service means a process that is running.

The Compute (Nova) Compute is the Nova, which provides virtual machine services on demand, such as creating virtual machines or making thermal migrations to virtual machines.

Object Storage (Swift) it allows you to store or retrieve objects, or it allows you to store or retrieve files, and it can manage large amounts of unstructured data in a low-cost way.

Identity (Keystone) provides authentication and authorization for all OpenStack services, tracks users and their permissions, and provides a list of available services and APIs.

DashBoard (Horizon) provides a modular Django-based interface for all OpenStack services, with the ability to do most of the work for both end-users and operators, such as starting virtual machines, assigning IP addresses, dynamic migrations, and so on.

Block Storage (Cinder) provides blocks storage services

Network (Neutron) is used to provide networking services that allow users to create their own virtual networks and connect to various network device interfaces.

ImageService (Glance) provides a virtual machine image storage, query, and retrieval service that provides a mirror service for a Nova virtual machine by providing a directory and repository of virtual disk images.

The following is an example of creating a virtual machine to illustrate how each component works with each other. The user first touches the interface, which is horizon. With the simple interface operation on Horizon, a request to create a virtual machine is sent to the OpenStack system back end. Now that you want to start a virtual machine, you must specify what type of virtual machine operating system it is, and you must download the boot image for the virtual machine to start using, and this will be done with glance, while the image managed by glance is likely to be stored on swift. So you need to interact with Swift to get the required image files.

When creating a virtual machine, it is naturally necessary for cinder to provide the block service and neutron to provide the network Service so that the virtual machine has volume can be used, can be assigned to the IP address and external network connection, After that, the access to the virtual machine resource is Keystone certified before it can continue. At this point, all of OpenStack's core components are involved in this creation of the virtual machine.

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What is OpenStack