Chapter 2. Managing Data Centers

The data center is the highest level virtual entity for all physical and logical resources within a managed virtual environment. The data center contains the following physical resources; CPU resources in the form of clusters and hosts; network resources in the form of logical networks and physical NICs, and storage resources in the form of storage domains. These resources are available to the virtual machines running in the data center. This section describes how to create and manage data centers, clusters and networking so that you can effectively set up the physical infrastructure for your virtual environment. Your Red Hat Enterprise Virtualization environment may contain several data centers with a complex topology of clusters, hosts, and networks; or it can consist of a single data center that uses the default data center provided by Red Hat Enterprise Virtualization. When you are setting up the physical infrastructure, as the administrator you should understand the set up and maintenance needs of the virtual machines that you intend to run in the data center. For example, consider whether some virtual machines will require dedicated resources, or can be migrated freely across hosts; whether you will need to set up desktop pools or clusters of servers; whether some machines can be expected to have consistent or varying workloads.
Data Centers

Figure 2.1. Data Centers


In all instances, it is assumed that you have successfully installed the Red Hat Enterprise Virtualization Manager, and have fulfilled the prerequisites as detailed in the Installation Guide and Quick Start Guide
All resources from a data center, cluster, networks, hosts, through to storage and permissions provide default values when working in flat mode; while tree mode ensures that the resource is located in the correct hierarchy. This guide assumes the use of tree mode, unless the flat mode is specified. For a brief overview of terminology, see Section 2, “Red Hat Enterprise Virtualization Resources”.

2.1. Data Centers

A data center is a logical entity that defines the set of physical and logical resources used in a managed virtual environment, consider it a container with clusters of hosts, virtual machines, storage and networks. Though Red Hat Enterprise Virtualization contains a default data center at installation, you can set up additional data centers. All data centers are managed from the single Administration Portal. For example, an organization may have different data centers for different physical locations, business units, or for reasons of security. It is recommended that you do not remove the default data center, instead set up new appropriately named data centers.
Data Center Objects

Figure 2.2. Data Center Objects


2.1.1. Data Center Properties

Data Centers can be defined, managed and viewed using the Data Centers tab on the Red Hat Enterprise Virtualization Manager Administration Portal.
Data Center Tab

Figure 2.3. Data Center Tab


The table below describes the properties of a data center as displayed in the New Data Center and Edit Data Center dialog boxes. Missing mandatory fields and invalid entries are outlined in red when you click OK to close the dialog box. In addition, field prompts indicate the expected values or range of values.

Table 2.1. Data Center Properties

Field/Tab
Description/Action
Name
The name of the data center. This must be a unique name with any combination of uppercase or lowercase letters, numbers, hyphens and underscores. Maximum length is 40.
Description
The description of the data center. While this is not a mandatory field, it is recommended.
Type
Any one of, NFS, iSCSI, FCP or Local Storage. This cannot be changed after creation without significant disruption and high possibility of data loss. The type of data domain dictates the type of the data center. All storage in a data center must be of one type only. For example, if iSCSI is selected as the type, only iSCSI data domains can be attached to the data center.
Compatibility Level
The version of the Red Hat Enterprise Virtualization, either 2.2 or 3.0. When you upgrade to a new version, it is necessary to upgrade the hosts, and then the clusters, and finally the data center. After upgrading the Manager, the hosts, clusters and data centers may still be in the earlier version. Ensure that you have upgraded all the hosts, then the clusters, before you upgrade the Compatibility Level of the data center.

2.1.2. Data Centers Operations

You can create, edit and configure a data center from the Administration Portal from the Data Centers tab.

To create a data center from the Data Centers tab :

  1. Click New > New Data Center.
    Enter the properties in the New Data Center dialog box and click OK.
  2. The Guide Me dialog box displays the configuration tasks that must be completed before the data center can be activated. See Section 1.1.2, “Using the Guide Me facility”. Click Configure Later to close the dialog box.
  3. The new data center displays in appropriate search results or lists of data centers, with a status of Uninitialized. An uninitialized data center requires further configuration, for example, storage domains must be attached to it. Either click the Configure Storage button on the Guide Me dialog box or select the new data center in the list, and click the Storage tab in the Details pane. You can define existing storage for the data center, or attach existing storage domains to the data center.

To configure a new data center using the Guide Me dialog box:

  1. Select the required data center from the Tree panel, and click the Guide Me button on the Data Centers tab.
  2. The Guide Me dialog box displays the configuration tasks that must be completed before the data center can be activated. To set up a data center, a number of tasks must be completed in sequence. You can perform this manually, by using the various tabs and dialog boxes, or you can use the Guide Me dialog boxes, which provide sequential, context-sensitive steps that lead to a complete and accurate configuration. The Guide Me dialog box prompts you to complete the required tasks; because it is context sensitive it only displays the actions that are appropriate to the resource that is being configured. If you are configuring a new data center, the dialog box prompts you to configure clusters, hosts, and storage. In addition, you can attach an ISO library as an option.
    New Data Center Guide Me Dialog Box

    Figure 2.4. New Data Center Guide Me Dialog Box


  3. Click each of the buttons in order, and follow the prompts and dialog boxs to set up all the required objects for the data center. Configuring clusters, hosts and storage are described in detail later in this document.
  4. Click Configure Later to close the dialog box.
The Guide Me dialog box can also be accessed from the Guide Me button on the resource toolbar.

2.1.3. Data Centers Related Entities

To configure the data center, the related objects that belong to the data center also need to be set up. The Storage, Logical Networks, Clusters and Permissions tabs on the Details pane of a selected data center enable you to correctly define the objects in the data center, where they are to be stored, and how they are to work together.
Data Centers Storage Entities
A data center requires storage domains to be attached to it. Use data domains to store images and data of the virtual machines, an ISO domain to store the images used to install and run the virtual machines, and optionally an export domain to export virtual machines and templates from one data center to another.

Table 2.2. Data Centers Storage Tab Properties

Field/Tab
Description/Action
Domain Name
The name of the storage domain.
Domain Type
Either ISO, data or export domain. While ISO domains can be shared across data centers, data domains cannot be shared. An export domain can only be attached to only one data center at a time.
Status
Either Active or Inactive.
Free Space, Used Space and Total Space
The amount of hard drive space on the storage domain that is available or used, or the total amount of hard drive space.

Data Center Logical Network Entities
The logical networks that are required for the virtual machines to communicate to hosts and storage, and for the Manager to communicate with all entities need to be defined for a data center.

Table 2.3. Data Center Logical Network Tab Properties

Field/Tab
Description/Action
Name
The name of the network belonging to the data center.
Description
The description of the network belonging to the data center.

Data Center Clusters Entities
The clusters in a data center are the migration domains for virtual machines. The ability to migrate virtual machines from one host to another in a cluster is a key feature of virtualization. In an upgrade, the clusters need to be upgraded before the data center can work in the upgraded version.

Table 2.4. Data Center Clusters Tab Properties

Field/Tab
Description/Action
Name
The name of the clusters belonging to the data center.
Compatibility
Compatibility Version- Either 2.2 or 3.0. When you upgrade to a new version, it is necessary to upgrade the hosts, and then the clusters. After upgrading the Manager, the hosts, clusters and data centers may still be in the earlier version. Ensure that you have upgraded all the hosts, before you upgrade the Compatibility Level of the cluster.
Description
The description of the cluster.

Data Center Permissions Entities
The users who have permissions to work in the data center, and their roles determine who can work in a data center, and what operations they can carry out.

Table 2.5. Data Center Permissions Tab Properties

Field/Tab
Description/Action
User
The user name of an existing user in Directory Services.
Role
The role of the user. The role is a combination of user, permission level, and object. Roles can be default or customized roles.
Inherited Permissions
The hierarchical permissions available to the user.

2.1.4. Data Centers Troubleshooting

The Data Centers tab enables you to track problems or change the properties or entities attached to a data center. You can use the Events tab on the Details pane to view a complete list of events to track down possible errors.
If the data center has an Active status, you can only edit the Name, Description and Compatibility Level of the data center. If it is Inactive, you can also change the storage Type.

To edit a data center from the Tree panel:

  1. Select the required data center and click the Edit button on the Data Centers tab.
  2. Change the properties in the Edit Data Center dialog box and click Save.

Important

If you have changed the Storage type (of an inactive data center only), ensure that you define the storage domains for the data center.
Using the Event Tab to Troubleshoot
The Events tab for the data center, displays all events that occur in the system, for that selected data center. The types of events that appear in the Events tab are audits, warnings, and errors. In addition, the names of the user, host, virtual machine, and/or template involved in the event are listed. This makes it possible to determine the cause of the event. Select the data center in the Tree pane, and then click the Events tab. This will enable you to identify the problem objects, and take corrective action.
The Events Tab

Figure 2.5. The Events Tab


Removing or Re-initializing a Data Center
Data centers can be removed entirely from the platform, or they can be reinitialized. Both actions are irreversible and should not be undertaken without careful consideration. Data Centers that are not in use can be permanently removed. Deleting unused data centers saves system resources, as existing hosts are checked (or pinged) at fixed intervals. Data centers can only be removed if there are no running hosts within any cluster belonging to the data center.

Note

The clusters, hosts and storage domains are not removed, and can be allocated to a different data center.

To remove a data center:

  1. Click the Data Centers tab.
  2. If the required data center is not visible, perform a search (see Section 1.2, “Search”).
  3. Select the data center to be removed. Ensure that there are no running hosts in any cluster. You can use the Remove button or right-click on the data center and select Remove.
  4. Click the Remove button.
    A message prompts you to confirm removal.
  5. Click OK. The data center is deleted and is no longer displayed on the Data Centers tab.
Data Centers that are not in use can be reinitialized. All data, connections and virtual machines are removed, and the data center is available to be set up again. Data centers can only be reinitialized if there are no running hosts within any cluster belonging to the data center.

Warning

The storage domains are initialized, and all existing data is removed.

To reinitialize a data center:

  1. Click the Data Centers tab.
  2. If the required data center is not visible, perform a search (see Section 1.2, “Search”).
  3. Select the data center to be reinitialized. Ensure that there are no running hosts in any cluster. Right-click on the data center and select Reinitialize Data Center.
  4. A warning message displays and prompts you to confirm initialization. You are also prompted to select a new storage domain for the data center.
    Data Center Re-Initialize Dialog Box

    Figure 2.6. Data Center Re-Initialize Dialog Box


  5. Select the Approve Operation checkbox.
    The storage domain is initialized and all objects removed from it. This includes all virtual machine images, templates and snapshots. You can now set up the data center again, attaching the initialized, or a new storage domain.

Warning

Removal and initialization of data centers are destructive and irreversible operations.

2.1.5. System Permissions

The system administrator, as the superuser, can manage all aspects of the platform, that is, data centers, storage pools, users, roles and permissions by default; however more specific administrative roles and permissions can be assigned to other users. For example, the enterprise may need a data center administrator for a specific data center, or a particular cluster may need an administrator. All system administration roles for physical resources have a hierarchical permission system. For example, a data center administrator will automatically have permission to manage all the objects in that data center, storage, cluster and hosts; while a cluster administrator can manage all objects in the particular cluster.
While the system administrator of the data center has the full range of permissions, a data center administrator is a system administration role for a specific data center only. This is a hierarchical model, and means that if a user is assigned the data center administrator role for a data center, all objects in the data center can be managed by the user. The data center administrator role permits the following actions:
  • Creation and removal of specific clusters.
  • Addition and removal of hosts, virtual machines, pools.
  • Permission to attach users to virtual machines within a single data center.
This is useful in a data center where there are multiple data center, each of which require their own system administrators. A data center administrator has permissions for the assigned data center only, not for all data centers in the system.

To assign a system administrator role to a data center:

  1. Click the Data Center tab. A list of data centers displays. If the required data center is not visible, perform a search (see Section 1.2, “Search”).
    Select the required data center, and click the Permissions tab on the Details pane. The Permissions tab displays a list of users and their current roles and permissions, if any.
  2. Click Add to add an existing user. The Add Permission to User dialog box displays. Enter a Name, or User Name, or part thereof in the Search text box, and click Go. A list of possible matches display in the results list.
  3. Select the check box of the user to be assigned the permissions. Scroll through the Assign role to user list and select DataCenterAdmin.
    Assign DataCenterAdmin Permission

    Figure 2.7. Assign DataCenterAdmin Permission


  4. Click OK. The name of the user displays in the Permissions tab, with an icon and the assigned Role.

Note

You can only assign roles and permissions to existing users. See (see Chapter 5, Users).
You can also change the system administrator of a data center, by removing the existing system administrator, and adding the new system administrator, as described in the previous procedure.

To remove a system administrator role:

  1. Click the Data Center tab. A list of data centers displays. If the required data center is not visible, perform a search (see Section 1.2, “Search”).
  2. Select the required data center and click the Permissions tab from the Details pane.
    The Permissions tab displays a list of users and their current roles and permissions, if any.
  3. Select the check box of the appropriate user.
  4. Click Remove. The user is removed from the Permissions tab. As this is hierarchical, the user will also be removed from the clusters, hosts and other objects.