Chapter 2. Red Hat Virtualization Components
2.1. Red Hat Virtualization Manager
The Red Hat Virtualization Manager provides a graphical user interface and a RESTful API to manage the resources of the Red Hat Virtualization environment. In a standalone Manager environment, the Manager is installed on a Red Hat Enterprise Linux 7 physical machine, or a virtual machine hosted in a separate environment. In a self-hosted engine environment, the Manager is installed as a virtual machine hosted on self-hosted engine nodes in the same environment it manages.
Native high availability for the Manager is only available in a self-hosted engine environment. At least two self-hosted engine nodes are required for high availability.
See: Administration Guide
Hosts, also known as hypervisors, are the physical servers on which virtual machines run. Full virtualization is provided by using a loadable Linux kernel module called Kernel-based Virtual Machine (KVM). KVM can concurrently host multiple virtual machines running either Windows or Linux operating systems. Virtual machines run on the host machine and are managed remotely by the Red Hat Virtualization Manager.
Red Hat Virtualization supports two types of host: Red Hat Virtualization Host and Red Hat Enterprise Linux. You can use either or both in your Red Hat Virtualization environment, depending on your requirements.
Red Hat recommends that you install at least two hosts and attach them to the Red Hat Virtualization environment. If you attach only one host, you cannot access features such as migration and high availability.
- Red Hat Virtualization Host (RHVH)
- Red Hat Virtualization Host is a minimal operating system based on Red Hat Enterprise Linux, built for easy management, easy maintenance, and simple deployment. It is distributed as an ISO file from the Customer Portal and contains only the packages required for the machine to act as a host.
- Red Hat Enterprise Linux
- Red Hat Enterprise Linux servers with the appropriate subscriptions attached can be used as hosts. These hosts are more customizable than RHVH.
See: Hosts in the Administration Guide.
Setting up storage and attaching it to your Red Hat Virtualization environment is a prerequisite before you can start creating end-user virtual machines. Red Hat Virtualization has three types of storage domains; however, only the data domain is now fully supported:
- The data domain contains all the data associated with virtual machines. The data domain supports all storage types that are supported for use with Red Hat Virtualization. See Storage Types in the Planning and Prerequisites Guide. For information on uploading to a data domain, see Uploading Images to a Data Storage Domain in the Administration Guide.
- The ISO domain is a deprecated storage domain type that was used to store ISO files for installing a virtual machine operating system or additional applications, such as the Windows guest agents and drivers. Virtual machine images can now be uploaded to data domains instead. For information on uploading to an ISO domain, see The ISO Uploader Tool in the Administration Guide.
- The export domain is a deprecated storage domain type that was used as a temporary storage repository for moving images between data centers and Red Hat Virtualization environments. This is now done by importing data storage domains.
The ISO and export domains only support file-based storage types (NFS, POSIX, or GlusterFS). The ISO domain supports local storage when used in a local storage data center.
See: Storage in the Administration Guide.
2.4. Data Warehouse
The Red Hat Virtualization Manager includes a data warehouse that collects monitoring data about hosts, virtual machines, and storage. Data Warehouse, which includes a database and a service, must be installed and configured along with the Manager setup, either on the same machine or on a separate server.
The Red Hat Virtualization installation creates two databases:
The Manager database (
engine) is the primary data store used by the Red Hat Virtualization Manager. Information about the virtualization environment like its state, configuration, and performance are stored in this database.
The Data Warehouse database (
ovirt_engine_history) contains configuration information and statistical data which is collated over time from the Manager database. The configuration data in the Manager database is examined every minute, and changes are replicated to the Data Warehouse database. Tracking the changes to the database provides information on the objects in the database. This enables you to analyze and enhance the performance of your Red Hat Virtualization environment and resolve difficulties.
To calculate an estimate of the space and resources the
ovirt_engine_history database will use, use the RHV Manager History Database Size Calculator tool. The estimate is based on the number of entities and the length of time you have chosen to retain the history records.
See: Data Warehouse Guide
2.5. Metrics Store
Metrics Store collects logs and metrics from Red Hat Virtualization. The data is transferred from Red Hat Virtualization to OpenShift where it is stored and aggregated in Elasticsearch and saved in indexes. The data can then be analyzed and visualized in Kibana.
- Elasticsearch is a distributed, RESTful search and analytics engine that lets you perform and combine many types of searches.
- Kibana is an open source analytics and visualization platform designed to work with Elasticsearch. You can easily perform advanced data analysis and visualize your data in a variety of charts and tables.
2.6. Networking in Red Hat Virtualization
Operations such as storage, host management, user connections, and virtual machine connectivity all rely on a well-planned and well-configured network to deliver optimal performance. Setting up networking is a vital prerequisite for a Red Hat Virtualization environment. Planning for your projected networking requirements and implementing your network accordingly is much simpler than discovering your networking requirements through use and altering your network configuration retroactively.
Red Hat Virtualization separates network traffic by defining logical networks. Logical networks define the path that a selected network traffic type must take through the network. They are created to isolate network traffic by functionality or to virtualize a physical topology.
The ovirtmgmt logical network is created by default and labeled as the Management network. The ovirtmgmt logical network is intended for management traffic between the Red Hat Virtualization Manager and hosts. You can define additional logical networks to segregate:
- General virtual machine traffic
- Storage-related traffic (such as NFS or iSCSI)
- Virtual machine migration traffic
- Virtual machine display traffic
- Gluster storage traffic
See: Logical Networks in the Administration Guide.