Welcome to the OpenStack Instances module. By the end of this module, you should be able to describe how to create and manage OpenStack instances. An OpenStack administrator creates and manages three primary constructs: Project—it is an organization unit in the cloud to which users are assigned. For example, in OpenStack Compute, a project owns virtual machines. Users—they are assigned to a project and perform tasks based on the roles defined. Roles—these are actions a user can perform and are assigned to a user-project pair. In OpenStack Compute, the important constructs are: Images— it refers to the virtual machine images. Multiple formats are supported. Flavors—it is the compute, memory, and storage capacity of compute instances. Volume—it is a detachable block storage device attached to one compute instance. Network—it is a virtual network attached to one or more instances. Instances—it refers to a virtual machine created in OpenStack compute. Projects are organizational units in OpenStack to which users are assigned. They own resources such as virtual machines in compute. Projects are also called as tenants. You can access them on the Horizon Web UI from the Identity > Projects workspace. This page is used to create project, delete project, manage members, or switch between projects. To define a project, click "Create Project." Define a project name, description, project members, and user role, and optionally, project groups. Users are accounts that are members of one or more projects. The roles define the actions that users can perform. You assign roles to user-project pairs. You access it from the Identity > Users workspace. This page enables you to view existing users, create new users, delete users, view role assignment, and more. To create a user, define the username, email, password, project, and role to be assigned to the user. Roles define the actions that users can perform. A role is assigned to a project user pair. You access roles from the Identity > Roles workspace. You create or manage virtual machines from the Project > Compute > Images workspace. You can also create globally available images from the Admin > Compute > Images workspace. Define the image name, browse for the image file, and define image requirements and metadata. In OpenStack, Flavors define the compute, memory, and storage capacity of Nova computing instances. It is an available hardware configuration for a server and defines the size of a virtual server that can be launched. You access it from the Admin > Compute > Flavors workspace. This page enables you to create, update, or delete a Flavor. Define vCPUs, RAM, and disk space when creating a Flavor. Select the projects where you want to use the Flavor. OpenStack implements virtual networks by defining multiple networks for tenant virtual machines. Networks are created within projects for connectivity between instances. Project networks are fully isolated. Network isolation and overlay technologies supported are: Flat— all instances are on the same network. There is no VLAN tagging or network segregation. VLAN—project networks are created using VLAN IDs mapping into VLANs present on the physical network. Generic Routing Encapsulation (or GRE) and virtual extensible LAN (or VXLAN)— these are encapsulation protocols to create overlay networks. A networking router is required to enable traffic flow outside a project network. Networks are of two types; project and provider networks. Provider networks offer Layer 2 (or L2) connectivity to instances that map to existing L2 networks in the data center, typically VLAN, to identify and separate them. Routed provider networks offer Layer 3 (or L3) connectivity to instances and map to existing L3 networks in the data center. Essentially, the network maps to multiple L2 segments and a router gateway is attached to the routed provider network to route traffic between the L2 segments or externally. Self-service networks are virtual networks created within OpenStack that use virtual routers to interact with provider and external networks. The diagram displayed illustrates a self-service network. It mostly uses overlay protocols such as VXLAN or GRE, and the communication with provider networks happens through source Network Address Translation (or NAT) on virtual routers. Manage a network from Project > Network > Networks. Define a network name to create a network. You can attach a network to an existing subnet or create another subnet. Virtual machine instances are managed from the Project > Compute > Instances workspace. You can use this page to launch an instance or perform actions against an existing instance, such as reboot an instance, shut it off, attach volumes, change configuration, and more.