Chapter 4. Red Hat Enterprise Virtualization Hosts

Hosts are the physical servers on which the virtual machines run. A Host is a compact, full-featured virtualization platform for quickly and easily deploying and managing virtualized guests. Full virtualization is provided by using a loadable Linux kernel module called Kernel-based Virtual Machine (KVM). KVM can concurrently host multiple virtualized guests running either Windows or Linux operating systems. Virtualized guests run as individual Linux processes and threads on the host machine and can be managed remotely using the Red Hat Enterprise Virtualization Manager. A Red Hat Enterprise Virtualization environment has one or more hosts attached to it.
Alternatively, host is also called hypervisor. Both Red Hat Enterprise Virtualization Hypervisors and Red Hat Enterprise Linux hosts interact with the rest of the virtualized environment in the same way. Red Hat Enterprise Virtualization Manager handles both Red Hat Enterprise Virtualization Hypervisors and Red Hat Enterprise Linux hosts with the KVM hypervisor, delivering leading performance and scalability for virtual machines on a stable and secure platform for their most mission-critical workloads. This section describes how set up and manage the host types that can be used in the Red Hat Enterprise Virtualization platform.

4.1. Managing Hosts

A host is a physical 64-bit server with the Intel VT or AMD-V extensions running any of the following:
  • Red Hat Enterprise Linux 6.1 or later AMD64/Intel 64 version

    Note

    Support is still ongoing for Red Hat Enterprise Linux 5.4 and 5.5 that already belong to existing Clusters. However, the Red Hat Enterprise Virtualization Guest Agent is now included in the virtio serial channel, whereas before it was in a separate channel. As a result, the Guest Agent installed on Windows guests on Red Hat Enterprise Linux hosts that are upgraded from version 5 to 6 lose connection to the Manager.
A physical host on the Red Hat Enterprise Virtualization platform:
  • Must belong to only one cluster in the system. For more information on clusters, refer Section 2.2, “Clusters”.
  • Must have CPUs that support the AMD-V™ or Intel VT® hardware virtualization extensions.
  • Must have CPUs that support all functionality exposed by the virtual CPU type selected upon cluster creation.
  • Can have a maximum of 128 physical CPUs.
  • Can have a maximum of 1 TB RAM.
  • Can have an assigned system administrator with system permissions.
The Red Hat Enterprise Virtualization Hypervisor has various security features enabled. Security Enhanced Linux (SELinux) and the iptables firewall are fully configured and on by default.
Administrators can receive the latest security advisories from the Red Hat Enterprise Virtualization watch list. Subscribe to the Red Hat Enterprise Virtualization watch list to receive new security advisories for Red Hat Enterprise Virtualization products by email. Subscribe by completing this form:
Red Hat Enterprise Virtualization platform uses various network ports for management and other virtualization features. These ports must be open on a Red Hat Enterprise Linux 6.1 host or higher. For a full list of ports, see Red Hat Enterprise Virtualization Installation Guide.

4.1.1. Hosts Properties

The Hosts tab provides a graphical view of all the hosts in the system. The following properties of the host are displayed on the Hosts tab, and on the New and Edit dialog boxes. The Network Interfaces tab is described in Section 4.1.2.2, “Managing Host Network Interfaces”.
Host Details Pane

Figure 4.1. Host Details Pane


Table 4.1. Hosts Properties

Field/Tab
Description/Action
Data Center
The selected data center.
Host Cluster
The selected host cluster. All hosts in a cluster must be of the same architecture.
Name
The host name. Provide a descriptive name.
Address
The IP address, or resolvable hostname of the host (provided during installation).
Root Password
The password of the designated host; used during installation of the host.
Power Management Address
The address of the remote access card (RAC) on the host. The password of the designated host; used during installation of the host.
Power Management User Name
A valid User Name for the OOB management.

4.1.2. Host Operations

4.1.2.1. Adding Hosts

Hosts must be correctly installed before you can add them to the Red Hat Enterprise Virtualization platform. Before adding hosts ensure that they have been configured correctly with a name and IP address.

Note

There is no need to configure Network Bridge, as this is automatically created on the hypervisor and exists to allows Virtual Machines to interact with the network as if they were using physical NICs.
Once added to the Administration Portal, hosts must be either approved or activated from the Hosts tab on Red Hat Enterprise Virtualization Manager.

Important

If you re-install Red Hat Enterprise Virtualization Manager, you must remove the hosts to enable them to be reconnected with the correct ssh keys for the new installation of Red Hat Enterprise Virtualization Manager. In contrast, if you upgrade Red Hat Enterprise Virtualization Manager, the hosts remain connected, and no action is required from you.
4.1.2.1.1. Prerequisites
Before you can add a host to Red Hat Enterprise Virtualization platform, ensure the following criteria have been met.
  • The host hardware is Red Hat Enterprise Linux certified. Refer to https://hardware.redhat.com/ to confirm that the server has Red Hat certification.

    Important

    The Red Hat Enterprise Virtualization platform only supports 64-bit processors with the Intel VT or AMD-V extensions. Only the AMD64/Intel 64 version of Red Hat Enterprise Linux 6.1 and higher is compatible for use with Red Hat Enterprise Virtualization platform.
  • If you are using VLAN, the network VLAN should be configured for access to the Red Hat Enterprise Virtualization Manager.
  • If a host is to be highly available, and have power management, out-of-band management must be set up and configured correctly. In most instances, this requires the presence of a remote access card (RAC) in the host.
  • The BIOS in the host has Intel VT or AMD-V activated.
  • Red Hat Enterprise Virtualization Hypervisor or Red Hat Enterprise Linux Host has been installed with either of the supported operating systems. For detailed information on installation, including how to install multiple hosts, install from networks, or other advanced features, refer to the appropriate installation documents. Refer Appendix H, Additional References.
  • The host has a resolvable hostname or static IP address.
  • A data partition with a minimum size of 25 GB is recommended to provide temporary storage.
4.1.2.1.2. Adding Red Hat Enterprise Virtualization Hypervisor Hosts
If you have not yet installed your Red Hat Enterprise Virtualization Hypervisor Host(s) then you must do so before you can attach them to the Red Hat Enterprise Virtualization Manager. Information on installing Red Hat Enterprise Virtualization Hypervisors is contained in the Red Hat Enterprise Linux — Hypervisor Deployment Guide and Red Hat Enterprise Virtualization Installation Guide. Once you have followed the instructions in these guides to install the Red Hat Enterprise Virtualizations you are ready to attach them to the Red Hat Enterprise Virtualization Manager.
During the installation of the Red Hat Enterprise Virtualization Hypervisor, the configuration script prompts for the IP address, or fully qualified domain name, of the Red Hat Enterprise Virtualization Manager. If the correct address is provided, the Red Hat Enterprise Virtualization Hypervisor host automatically contacts the manager and is added to the list of hosts shown in the Administration Portal. At this point while the manager knows of the hypervisor it must still be manually approved before it is ready for use. To approve a newly-configured hypervisor:
  1. In the Hosts tab, select the newly-configured host. This host will display a status of "Pending Approval".
  2. Click the Approve button.
The approval process is a hand shake between the Management server and the host. On successful conclusion of this process the host's status changes to Up. The host is now certified and is part of the Red Hat Enterprise Virtualization platform.
If you didn't provide a valid Red Hat Enterprise Virtualization Manager IP address, or fully qualified domain name, when you installed the hypervisor host then it must be added using the Add Host dialog. To do this you will need to know the IP address of the hypervisor and the password which was set on the RHEV-M screen when it was configured. See Section 4.1.2.1.4, “To Add a Host” for further information.
4.1.2.1.3. Adding Red Hat Enterprise Linux Hosts
Red Hat Enterprise Virtualization also supports hosts running Red Hat Enterprise Linux AMD64/Intel 64 version. This section describes the preparatory steps for installing the Red Hat Enterprise Linux host, as well as the steps to manually add the host to the Red Hat Enterprise Virtualization platform.
Adding a host can take some time, as the following steps are completed by the platform: virtualization capability checks, installation of packages, creation of bridge and a reboot of the host. Use the Details pane to monitor the handshake process as the host and management system establish a connection.
Red Hat Enterprise Virtualization 3.0 supports Red Hat Enterprise Linux, version 6.1 and higher as hosts.
4.1.2.1.3.1. Preparing Red Hat Enterprise Linux Hosts
To ensure a smooth and successful integration of Red Hat Enterprise Linux Hosts and Red Hat Enterprise Virtualization platform, prepare the host carefully according to the instructions in this section.

Procedure 4.1. Directions:

  1. Install Red Hat Enterprise Linux

    Ensure that Red Hat Enterprise Linux is correctly installed and configured on the physical host. Refer to the Red Hat Enterprise Linux Installation Guide for more information. Only the Base package group is required. All other packages can be removed or not selected.

    Important — Provide Access to Authentication Files

    If you are using proprietary directory services or standard directory services with no access to authentication files for user management, the vdsm package will fail to create the required system user. The authentication files required by the useradd command must be accessible to the installer. Red Hat Directory Server (RHDS) recommends a security policy with a mixture of local files and LDAP. Following this recommendation will resolve this issue.

    Note — DNS Configuration

    It is recommended that all Red Hat Enterprise Linux hosts have a fully resolvable network address. This includes having valid forward and reverse lookups for each host's address available in DNS.
  2. Configure VLANs

    If you are using VLAN, ensure that VLANs are configured for access to the Red Hat Enterprise Virtualization Manager.
  3. Check Red Hat Network Subscriptions

    Ensure the host is correctly subscribed to the Red Hat Enterprise Virt Management Agent (v 6 x86_64) channel in Red Hat Network, also referred to as rhel-x86_64-rhev-mgmt-agent-6, on Red Hat Network. If you do not have the appropriate subscription entitlements, contact Red Hat Customer Service.
    1. If the machine has not already been registered with Red Hat Network, run the rhn_register command as root to register it. To complete registration successfully you will need to supply your Red Hat Network username and password. Follow the onscreen prompts to complete registration of the system.
      # rhn_register
    2. You must now add a subscription to the Red Hat Enterprise Virt Management Agent (v 6 x86_64) channel to the machine. To add the channel subscription to the system from the Red Hat Network web interface:
      1. Log on to Red Hat Network (http://rhn.redhat.com).
      2. Click Systems at the top of the page.
      3. Select the system to which you are adding channels from the list presented on the screen, by clicking the name of the system.
      4. Click Alter Channel Subscriptions in the Subscribed Channels section of the screen.
      5. Select the Red Hat Enterprise Virt Management Agent (v 6 x86_64) channel from the list presented on the screen, then click the Change Subscription button to finalize the change.
  4. Open firewall ports

    Red Hat Enterprise Virtualization platform uses a number of network ports for management and other virtualization features.
    The following steps configure iptables to open the required ports. These steps replace any existing firewall configuration with that required for Red Hat Enterprise Virtualization Manager. If you have existing firewall rules with which this configuration must be merged then you must manually edit the rules defined in the iptables configuration file, /etc/sysconfig/iptables.
    1. Remove and existing firewall rules.
      # iptables --flush
    2. Add the ports required by Red Hat Enterprise Virtualization Manager to the iptables rules.
      # iptables --append INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
      # iptables --append INPUT -p icmp -j ACCEPT
      # iptables --append INPUT -i lo -j ACCEPT
      # iptables --append INPUT -p tcp --dport 22 -j ACCEPT
      # iptables --append INPUT -p tcp --dport 16514 -j ACCEPT
      # iptables --append INPUT -p tcp --dport 54321 -j ACCEPT
      # iptables --append INPUT -p tcp -m multiport --dports 5634:6166 -j ACCEPT
      # iptables --append INPUT -p tcp -m multiport --dports 49152:49216 -j ACCEPT
      # iptables --append INPUT -j REJECT --reject-with icmp-host-prohibited
      # iptables --append FORWARD -m physdev ! --physdev-is-bridged -j REJECT --reject-with icmp-host-prohibited
      

      Note

      The provided iptables commands add firewall rules to accept network traffic on a number of ports. These include:
      • port 22 for SSH,
      • ports 5634 to 6166 for guest console connections,
      • port 16514 for libvirt virtual machine migration traffic,
      • ports 49152 to 49216 for VDSM virtual machine migration traffic, and
      • port 54321 for the Red Hat Enterprise Virtualization Manager.
    3. Save the modified rules.
      # service iptables save
    4. Ensure that the iptables service is configured to start on boot and has been restarted, or started for the first time if it wasn't already running.
      # chkconfig iptables on
      # service iptables restart
      
  5. Configure sudo access

    The Red Hat Enterprise Virtualization Manager makes use of sudo to perform operations as root on the host. The default configuration stored in /etc/sudoers contains values to allow this. If this file has been modified since Red Hat Enterprise Linux installation these values may have been removed. As root run visudo to ensure that the /etc/sudoers contains the default configuration values. Where it does not they must be added.
    # Allow root to run any commands anywhere 
    root    ALL=(ALL)   ALL
    
  6. Enable SSH access for root

    The Red Hat Enterprise Virtualization management daemon accesses host machines via SSH. To do this it logs in as root with an encrypted key for authentication. To ensure that SSH is configured and root is able to use it to access the system follow these additional steps.

    Warning

    The first time the Red Hat Enterprise Virtualization Manager is connected to the host it will install an authentication key. In the process it will overwrite any existing keys which exist in /root/.ssh/authorized_keys.
    1. These steps assume that the openssh-server package is installed on the system. Where the package is not present use yum to install it.
      # yum install openssh-server
    2. Use chkconfig to verify which run-levels SSH is enabled at.
      # chkconfig --list sshd
      sshd			0:off	1:off	2:on	3:on	4:on	5:on	6:off
      
      It is expected that the SSH daemon shows as on for run-levels 3, 4, and 5. This is the default configuration.
      If the configuration on the host differs use chkconfig to enable it for the required run-levels. The /etc/init.d/sshd script can then be used to ensure the service is currently started.
      # chkconfig --level 345 sshd on
      # /etc/init.d/sshd start
      
      To verify this operation as successful run chkconfig --list sshd again and check the output. It should now show the daemon as on at run-level 3, 4, and 5.
    3. In Red Hat Enterprise Linux the default SSH daemon configuration allows remote login by the root user. This is also a requirement for the Red Hat Enterprise Virtualization Manager to successfully access the machine. In some cases administrator's may have disabled this ability.
      To check whether or not this is the case search the /etc/ssh/sshd_config for the value PermitRootLogin. This must be done while logged in as root.
      # grep PermitRootLogin /etc/ssh/sshd_config
      PermitRootLogin no
      
      Where PermitRootLogin is set to no the value must be changed to yes. To do this edit the configuration file.
      # vi /etc/ssh/sshd_config
      
      Once the updated configuration file has been saved the SSH daemon must be told to reload it.
      # /etc/init.d/sshd reload
      Reloading sshd:                                            [  OK  ]
      
    The root user should now be able to access the system via SSH.
Result:
You can now add the correctly installed and configured Red Hat Enterprise Linux host to the Red Hat Enterprise Virtualization platform.
4.1.2.1.4. To Add a Host
Before adding a host, ensure you have the correct IP and password of the host. Once you have entered the requisite details, the following steps are completed by the platform:
  • Virtualization capability checks.
  • Installation of requisite packages.
  • Creation of bridge.
  • Reboot of the host.
The process of adding a new host can take some time; the progress can be followed in the Events pane.
  1. Click the Hosts tab. The Hosts tab displays a list of all hosts in the system.
  2. Click the New button. The New Host dialog box displays.
    New Host Dialog Box

    Figure 4.2. New Host Dialog Box


    Enter the following details in the General tab:
    • Data Center: Select the appropriate data center from the drop-down menu that you want to assign to the new host.

      Note

      A default data center is displayed; change the default only if you are sure that another data center can be used.
    • Host Cluster: The cluster to which the host belongs (select from the drop-down list).
    • Name: A descriptive name for the host.
    • Address: The IP address, or resolvable hostname of the host (provided during installation).
    • Root password: the password of the designated host; used during installation of the host.
  3. Click the Power Management tab.
    New Host Power Management

    Figure 4.3. New Host Power Management


  4. Enable Power Management: Select this check box to turn out-of-band (OOB) power management on. If selected, the information for the following fields must also be provided:
    • The Address of the host. This is usually the address of the remote access card (RAC) on the host.
    • A valid User Name for the OOB management.
    • A valid, robust Password for the OOB management.
    • The Type of the OOB management device. Select the appropriate device from the drop down list.

      Table 4.2. Types of OOB management devices

      alom Sun ALOM
      apc APC
      bladecenter IBM Bladecenter Remote Supervisor Adapter
      drac5 Dell Remote Access Controller for Dell computers
      eps Entry-Level Power Supply Specification
      ilo HP Integrated Lights Out standard
      ipmilan Intelligent Platform Management Interface
      rsa IBM Remote Supervisor Adaptor
      rsb Fujitsu-Siemens RSB management interface
      wti WTI PowerSwitch
      Cisco_ucs Cisco Systems

    • Depending on the Type selected, any or all of the following fields display on the Power Management tab.
      • Click Secure to use SSH to connect to OOB management.
      • The Port to connect to OOB management.
      • Enter the Slot if a Blade server is being configured.
      • Enter any Options that are needed for the SSH command.
  5. Click the Test button to test the operation of the OOB management solution. Alerts, if any, appear on the Alerts panel. The Alerts panel displays on the bottom right corner of the screen. If there are existing alerts, the alert text changes color to brighter red.
    Alerts Tab

    Figure 4.4. Alerts Tab


    Note

    The Alerts panel can be resized by using the Expand/Collapse button, or dragging the border upwards/downwards.

    Important

    Red Hat Enterprise Virtualization recommends the configuration of power management on the hosts. Power management enables the system to fence a troublesome host using an additional interface.

    Important

    If the host is required to be Highly Available, power management must be enabled and configured. Setting up power management for hosts is described in detail later in this guide. Refer Section 13.3.1, “Setting the Parameters for Fencing”.
  6. Click OK.
    The new host displays in the list of hosts with a status of "Installing". Once installation is complete, the status of the newly added host is Pending Approval. The host must be activated for the status to change to Up.

Note

View the process of the host installation on the Details pane.
4.1.2.1.5. Activating a Host
After a host has been added, or an existing host has been taken down for maintenance, it needs to be activated before it can be used. Red Hat Enterprise Linux 6.1 and higher hosts need to be activated after being added or upgraded.
  1. In the Hosts tab, select the host to be activated.
  2. Click the Activate button.
The host status changes to Up. Virtual machines can now run on the host.

4.1.2.2. Managing Host Network Interfaces

The Network Interfaces tab on the Details pane of a host allows you to define the attachment of the logical network in the Administration Portal to the physical network interface cards (or NICs) of the host. This is a simple operation in which you attach one or more of the host's physical network interface cards (NICs) to a predefined logical network in the cluster.

Note

New logical networks cannot be defined at the host level.
The management and storage subnets are defined by default in the cluster. Typically, eth0 is allocated to the management network interface (which displays as RHEVM) and eth1 is allocated to the storage network interface (which may display as data). The Administration Portal automatically detects the attached subnets and networks, so all that is required is to match the logical network name to the correct subnet.
Each host can support up to 32 interfaces, and these are grouped by logical networks. If the default settings are not correct, or more subnets need to be added, the Network Interfaces tab can be used to make changes.
4.1.2.2.1. Editing Network Interfaces
You can edit the host NICs and the network using the Network Interfaces tab on a host's Details pane.
4.1.2.2.1.1. Editing Host Network Interfaces
The Network Interfaces tab displays the name, network name, address, MAC address, speed, and link status for each interface. The Edit, Edit Management Network, Bond/Unbond, Detach and Save Network Configuration buttons enable you to manage host NICs.
  1. Click the Hosts tab. A list of hosts displays. Select the appropriate host. The Details pane displays.
  2. Click the Maintenance button to migrate all virtual machines to alternative hosts, and place the host into maintenance. The Status field of the host changes to Preparing for Maintenance, followed by Maintenance. The icon changes to indicate that the host is in maintenance mode.
  3. Click the Network Interfaces tab on the Details pane. The Network Interfaces tab displays the list of NICs on the host, their address and other specifications. Select the NIC that you want to edit.
  4. Click the Edit/Add VLAN button. The Edit Network Interface dialog box displays.
    Host Edit Network Interface dialog box

    Figure 4.5. Host Edit Network Interface dialog box


    • To attach the NIC to a different logical network, select a different Network from the list of available logical networks.
    • Select the network setting of None, DHCP, or Static. For Static setting, provide the IP, Subnet and Default Gateway information for the host.
    • Select the Check Connectivity check box if necessary.
    • Click OK.
4.1.2.2.1.2. Editing Management Network
The Network Interfaces tab displays the name, network name, address, MAC address, speed, and link status for each interface. In the course of editing the host NICs, it may be necessary to check or edit the Management Network Interface.

Important

Communication between the Management Server and the host is via the management interface. Changing the properties of the management interface may cause the host to become unreachable.
  1. Click the Hosts tab. A list of hosts displays. Select the appropriate host. The Details pane displays.
  2. Click the Maintenance button to migrate all virtual machines to alternative hosts, and place the host into maintenance. The Status field of the host changes to Preparing for Maintenance, followed by Maintenance. The icon changes to indicate that the host is in maintenance mode.
  3. Click the Network Interfaces tab on the Details pane. The Network Interfaces tab on the Details pane that displays the list of NICs on the host, their address and other specifications. Select the appropriate management NIC that you want to edit.
  4. Click the Edit Management Network button. The Edit Management Network dialog box displays.
    Edit Management Network Dialog Box

    Figure 4.6. Edit Management Network Dialog Box


    • To attach the RHEVM management network to a different NIC, select a different interface from the Interface drop-down list of available NICs.
    • Select the network setting from None, DHCP or Static. For Static setting, provide the IP, Subnet and Default Gateway information for the host.
    • Select the Check Connectivity check box if necessary.
    • Select the Save network configuration check box to make the changes persistent, since changes done to the Networking configuration are temporary until explicitly saved.
    • Click Close.
4.1.2.2.2. Configuring Network Interfaces
After editing the NICs to ensure that the physical NICs connect to the logical networks, some further configuration may be necessary. For example, you may want to aggregate links, separate bonded links, or even detach NICs from the network. When the host is correctly configured and linked to the RHEVM network, you may want to save the network configuration.
4.1.2.2.2.1. Bonding network interfaces
Network bonding (also known as link aggregation, NIC bonding) consists of aggregating multiple network interfaces into a single logical bonded interface that correspond to a single IP address. Network bonding uses multiple network cables/ports in parallel to increase the link speed beyond the limits of any one single cable or port, and to increase the redundancy for higher availability. Red Hat Enterprise Virtualization conforms to what used to be clause 43 of IEEE 802.3-2005 Ethernet standard, usually referred to by its working group name of "IEEE 802.3ad".
Red Hat Enterprise Virtualization platform allows bonding of several NICs on a host. For example, if a host has four NICs but only two logical networks, two of the NICs can be bonded together using 802.3ad protocol to create a single channel. This channel can be mapped to a single logical network providing a higher bandwidth. To bond host NICs follow the below mentioned procedure:

Note

Ensure that the NICs have been configured correctly across the network, that is, configure your routers accordingly.
  1. Click the Hosts tab. A list of hosts displays. Select the appropriate host. The Details pane displays.
  2. Click the Maintenance button to migrate all virtual machines to alternative hosts, and place the host into maintenance. The Status field of the host changes to Preparing for Maintenance, followed by Maintenance. The icon changes to indicate that the host is in maintenance mode.
  3. Click the Network Interfaces tab on the Details pane that displays the list of NICs on the host, their address and other specifications.
  4. Select the multiple NICs that are to be bonded together.

    Important

    You cannot bond between NICs if the status for all is “UP” (The status arrow in the beginning is Green). To use the Bond feature, at least one NIC should be down (The status arrow in the beginning is Red).
  5. Click the Bond button. The Bond Network Interface dialog box displays.
    Bond Network Interface Dialog Box

    Figure 4.7. Bond Network Interface Dialog Box


    • To create a bonded interface select a Bond Name from the list.
    • Select the network setting from None, DHCP or Static. For Static setting, provide the IP, Subnet Mask and Default Gateway information for the host.
    • Select the Check Connectivity check box if necessary.
    • Select the Save network configuration check box to make the changes persistent, since changes done to the Networking configuration are temporary until explicitly saved.
    • Click OK.
4.1.2.2.2.2. Detaching NICs
The Network Interfaces tab displays the name, network name, address, MAC address, speed, and link status for each interface. In the course of editing the host NICs, it may be necessary to detach a particular NIC.
  1. Click the Hosts tab. A list of hosts displays. Select the appropriate host. The Details pane displays.
  2. Click the Maintenance button to migrate all virtual machines to alternative hosts, and place the host into maintenance. The Status field of the host changes to Preparing for Maintenance, followed by Maintenance. The icon changes to indicate that the host is in maintenance mode.
  3. Click the Network Interfaces tab on the Details pane that displays the list of NICs on the host, their address, and other specifications.
  4. Select the NIC (or NICs) to be detached, and click the Detach button. The Detach Network Interface dialog box displays.
    Detach Network Interface Dialog Box

    Figure 4.8. Detach Network Interface Dialog Box


  5. The dialog box lists the NICs selected for detachment.
  6. Click OK to confirm the detachment.
4.1.2.2.2.3. Saving Host Network Configuration
When the host is correctly configured and linked to the network, you may want to save the network configuration.
  1. Click the Hosts tab. A list of hosts displays. Select the appropriate host. The Details pane displays.
  2. Click the Maintenance button to migrate all virtual machines to alternative hosts, and place the host into maintenance. The Status field of the host changes to Preparing for Maintenance, followed by Maintenance. The icon changes to indicate that the host is in maintenance mode.
  3. Click the Network Interfaces tab on the Details pane that displays the list of NICs on the host, their address, and other specifications.
  4. Click the Save Network Configuration button.
  5. The host network configuration is saved and the following message is displayed on the task bar: “Network Changes were saved on host <Hostname>."

4.1.3. Hosts Entities

The General tab on the Details pane provides information on an individual host, including hardware and software versions, and whether updates are available (in the case of Hypervisor hosts).
  1. Click the Hosts tab. If the host you want to view is not displayed, perform a search (see Section 1.2, “Search”).
    A list of hosts displays. Select the appropriate host. The Details pane displays. The Details pane displays general information, network interface information and virtual machine information.
  2. Click the General tab. The General tab displays the following information:
    • Version Information for OS, Kernel, KVM, VDSM, and SPICE.
    • Host type for example iSCSI Initiator Name.
    • Active VMs.
    • Status of Memory Page Sharing (Active/Inactive) and Automatic Large Pages(On/Off).
    • CPU information like number of CPUs attached, CPU name and type, total Physical Memory allocated to the selected host, Swap Size, and Shared Memory proportion.
    • In addition, if an updated version of the host is available, an Alert appears.

4.1.3.1. Viewing Virtual Machines on Hosts

The Virtual Machines tab on the Details pane provides information on virtual machines running on the host.
  1. Click the Hosts tab. A list of hosts displays. Select the appropriate host. The Details pane displays.
  2. Click the Virtual Machines tab on the Details pane. A list of virtual machines running on the host displays. This includes both virtual servers and virtual desktops. Virtual machines can be scheduled to run on the approved host. The list also displays cluster, network and display information.
  3. You can Suspend, Shut down and Migrate a virtual machine from this tab.

4.1.3.2. Viewing Network Interfaces on Hosts

The Network Interfaces tab on the Details pane provides information about logical and physical networks of the host.
  1. Click the Hosts tab. A list of hosts displays. Select the appropriate host. The Details pane displays.
  2. Click the Network Interfaces tab on the Details pane. A list of virtual machines running on the host displays. This allows you to define the attachment of the logical network in the Administration Portal to the physical network interface cards (or NICs) of the host. The Network Interfaces tab is discussed in detail in Section 4.1.2.2, “Managing Host Network Interfaces”.

4.1.3.3. Viewing Network Host Hooks

The Host Hooks tab on the Details pane provides information about logical and physical networks of the host.
  1. Click the Hosts tab. A list of hosts displays. Select the appropriate host. The Details pane displays.
  2. Click the Host Hooks tab on the Details pane. Hooks can be implemented to execute scripts when key events are triggered. When called, a hook executes the scripts in /usr/libexec/vdsm/hooks/hook-name/ in alphabetical order. The Host Hooks tab displays information about Event, Script, and Property name and value. More information about VDSM Hooks can be found in Appendix B.

4.1.3.4. Viewing Permissions on Hosts

The Permissions tab on the Details pane provides information about user roles and their inherent permissions.
  1. Click the Hosts tab. A list of hosts displays. Select the appropriate host. The Details pane displays.
  2. Click the Permissions tab on the Details pane. The Permissions tab displays a list of users, their roles, and their inherited permissions.

4.1.3.5. Viewing Events on Hosts

The Events tab on the Details pane provides information about an important or unusual event.
  1. Click the Hosts tab. A list of hosts displays. Select the appropriate host. The Details pane displays.
  2. Click the Events tab on the Details pane. The Events tab displays information about any important events that a system administrator should know about, such as problems with storage or notifications that have been sent to users for unexpected events, such as when virtual machines are unexpectedly shut down.

4.1.4. Host Troubleshooting

4.1.4.1. Maintaining Hosts

You can use the Administration Portal to complete many host maintenance tasks. For example, you may have to change the network configuration details of the host, or the cluster to which it belongs. All virtual machines are migrated automatically, however the migration increases the load on the network and on other hosts. If a large number of virtual machines are running on the host (that is to be moved into maintenance mode), the migration of the virtual machines may take a considerable amount of time.

Warning

Maintaining hosts may involve the shut down, de-activation and restart of the physical host. Moving hosts into Maintenance must be planned and considered carefully.
4.1.4.1.1. Moving a Host into Maintenance Mode
Hosts must occasionally be brought down for maintenance. Red Hat Enterprise Virtualization platform attempts to migrate all the virtual machines running on the host to other hosts automatically. In some instances this may not be possible, and you may have to manually migrate or shut down a virtual machine, before the host can be placed in maintenance. Follow the below mentioned steps to move a host into maintenance mode:
  1. Click the Hosts tab. A list of hosts displays. If the host you want to edit is not displayed, perform a search (see Section 1.2, “Search”).
  2. Select the appropriate host. The Details pane displays information about the host.
  3. Click the Maintenance button to migrate all virtual machines to alternative hosts, and place the host into maintenance. The Maintenance Host(s) dialog box appears. Click OK.
    Host Details Pane

    Figure 4.9. Host Details Pane


  4. The Status field of the host changes to Preparing for Maintenance, followed by Maintenance. The icon changes to indicate that the host is in maintenance.
  5. Perform any required tasks. When the host is ready to be reactivated, click the Activate button to bring the host back up.
    The Status field of the host changes to Up.

Note

If Red Hat Enterprise Virtualization Manager is unable to communicate with and control the host, its status displays Non-responsive.
4.1.4.1.2. Upgrading Hosts
Hosts must be upgraded over the course of their deployment. A host should be moved to maintenance mode before being upgraded.
Red Hat Enterprise Linux hosts can be upgraded using the yum update like any Red Hat Enterprise Linux system.
For more information on upgrading Red Hat Enterprise Virtualization hosts, see the Hypervisor Deployment Guide Chapter 6. Upgrading Red Hat Enterprise Virtualization Hypervisors.
4.1.4.1.3. Editing Host Details
You can edit the details of a host, such as its name or network configuration. You can also change the cluster to which the host belongs.
Before changing the cluster that the host belongs to, you must first place it into maintenance mode (see Section 4.1.4.1.1, “Moving a Host into Maintenance Mode”). Follow this procedure to edit host details:

Warning

Maintaining hosts may involve the shut down, de-activation and restart of the physical hosts. If any virtual machines are running on the host, be aware that you may lose data and configuration details if the virtual machine have not been shut down. Moving hosts into maintenance must be carefully planned and executed with due care and consideration.
  1. Click the Hosts tab. A list of hosts is displayed. If the host you want to edit is not displayed, perform a search (see Section 1.2, “Search”).
  2. Select the host that you want to edit. Click the Edit button. The Edit Host dialog box opens.
    Edit Host Dialog Box

    Figure 4.10. Edit Host Dialog Box


  3. Edit the details as required (see Section 4.1.2.1.3, “Adding Red Hat Enterprise Linux Hosts”). Click Save to save the changes.
    The details of the host are updated in the Hosts tab, and the status changes appropriately.
4.1.4.1.4. Customizing Hosts
You can assign user defined tags to objects and aggregate these objects into a group; for example you can create a group of hosts running in a department or location.

To tag a host:

  1. Click the Hosts tab.
    A list of hosts is displayed. If the host you want to edit is not displayed, perform a search (see Section 1.2, “Search”).
  2. Select the appropriate host, and click the Assign Tags button.
    The Assign Tags dialog box opens. It displays a list of available tags.
  3. Select the required tags.
  4. Click Close.
The tagged host displays in the result of searches for the assigned tag.
4.1.4.1.4.1. Deleting a Physical Host
Hosts that are no longer being used by the Red Hat Enterprise Virtualization platform can be permanently removed. Deleting unused hosts saves system resources, as existing hosts are checked (or pinged) at fixed intervals. Ensure that any virtual machines are migrated off the host, or shut down if they are no longer required. Follow this procedure to delete a host:
  1. Click the Hosts tab. If a host that you want to delete is not displayed, perform a search (see Section 1.2, “Search”). Select the host to be deleted.
  2. Place the host into Maintenance mode (see Section 4.1.4.1.1, “Moving a Host into Maintenance Mode”).
  3. Click the Remove button. A confirmation message displays.
  4. Click OK. The host is removed from Red Hat Enterprise Virtualization platform and deleted from the Hosts tab.

4.1.5. Hosts Permissions

While the superuser or system administrator of the platform has the full range of permissions, a Host Administrator is a system administration role for a specific host only. This is a hierarchical model, it means that the Data Center Administrator and the Cluster Administrator have permissions to manage the hosts. This is useful in an enterprise where there are multiple hosts, perhaps running specific sets of virtual machines, each of which require their own system administrators. A Host Administrator has permissions for the assigned host only, not for all hosts in the cluster.

To assign a system administrator role for a host:

  1. Click the Hosts tab.
    A list of hosts displays. If the required host is not visible, perform a search (see Section 1.2, “Search”).
  2. Select the host that you want to edit, 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.
    Hosts Permissions

    Figure 4.11. Hosts Permissions


  3. 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.
  4. Select the check box of the user to be assigned the permissions. Scroll through the Assign role to user list and select HostAdmin.
    Assign HostAdmin Permission

    Figure 4.12. Assign HostAdmin Permission


  5. 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 Chapter 5, Users.
You can also change the system administrator of a host, 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 Hosts tab. A list of hosts displays. If the required host is not visible, perform a search (see Section 1.2, “Search”).
  2. Select the required host 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. The Super User, Data Center Administrator and Cluster Administrator, if any, will display in the Inherited Permissions tab. However, none of these higher level roles can be removed.
  3. Select the check box of the appropriate user.
  4. Click Remove. The user is removed from the Permissions tab.