10.6. Explanation of Settings and Controls in the New Host and Edit Host Windows

10.6.1. Host General Settings Explained

These settings apply when editing the details of a host or adding new Red Hat Enterprise Linux hosts and Satellite host provider hosts.

The General settings table contains the information required on the General tab of the New Host or Edit Host window.

Table 10.1. General settings

Field NameDescription

Host Cluster

The cluster and data center to which the host belongs.

Use Foreman/Satellite

Select or clear this check box to view or hide options for adding hosts provided by Satellite host providers. The following options are also available:

Discovered Hosts

  • Discovered Hosts - A drop-down list that is populated with the name of Satellite hosts discovered by the engine.
  • Host Groups -A drop-down list of host groups available.
  • Compute Resources - A drop-down list of hypervisors to provide compute resources.

Provisioned Hosts

  • Providers Hosts - A drop-down list that is populated with the name of hosts provided by the selected external provider. The entries in this list are filtered in accordance with any search queries that have been input in the Provider search filter.
  • Provider search filter - A text field that allows you to search for hosts provided by the selected external provider. This option is provider-specific; see provider documentation for details on forming search queries for specific providers. Leave this field blank to view all available hosts.

Name

The name of the host. This text field has a 40-character limit and must be a unique name with any combination of uppercase and lowercase letters, numbers, hyphens, and underscores.

Comment

A field for adding plain text, human-readable comments regarding the host.

Hostname

The IP address or resolvable host name of the host. If a resolvable hostname is used, you must ensure that all addresses that the hostname is resolved to match the IP addresses, IPv4 and IPv6, used by the management network of the host.

Password

The password of the host’s root user. Set the password when adding the host. The password cannot be edited afterwards.

Activate host after install

Select this checkbox to activate the host after successful installation. This is enabled by default and required for the hypervisors to be activated successfully.

After successful installation, you can clear this checkbox to switch the host status to Maintenance. This allows the administrator to perform additional configuration tasks on the hypervisors.

Reboot host after install

Select this checkbox to reboot the host after it is installed. This is enabled by default.

Note

Changing the kernel command line parameters of the host, or changing the firewall type of the cluster also require you to reboot the host.

SSH Public Key

Copy the contents in the text box to the /root/.ssh/authorized_hosts file on the host to use the Manager’s SSH key instead of a password to authenticate with a host.

Automatically configure host firewall

When adding a new host, the Manager can open the required ports on the host’s firewall. This is enabled by default. This is an Advanced Parameter.

SSH Fingerprint

You can fetch the host’s SSH fingerprint, and compare it with the fingerprint you expect the host to return, ensuring that they match. This is an Advanced Parameter.

10.6.2. Host Power Management Settings Explained

The Power Management settings table contains the information required on the Power Management tab of the New Host or Edit Host windows. You can configure power management if the host has a supported power management card.

Table 10.2. Power Management Settings

Field NameDescription

Enable Power Management

Enables power management on the host. Select this check box to enable the rest of the fields in the Power Management tab.

Kdump integration

Prevents the host from fencing while performing a kernel crash dump, so that the crash dump is not interrupted. In Red Hat Enterprise Linux 7.1 and later, kdump is available by default. If kdump is available on the host, but its configuration is not valid (the kdump service cannot be started), enabling Kdump integration will cause the host (re)installation to fail. If this is the case, see Section 10.7.4, “fence_kdump Advanced Configuration”.

Disable policy control of power management

Power management is controlled by the Scheduling Policy of the host’s cluster. If power management is enabled and the defined low utilization value is reached, the Manager will power down the host machine, and restart it again when load balancing requires or there are not enough free hosts in the cluster. Select this check box to disable policy control.

Agents by Sequential Order

Lists the host’s fence agents. Fence agents can be sequential, concurrent, or a mix of both.

  • If fence agents are used sequentially, the primary agent is used first to stop or start a host, and if it fails, the secondary agent is used.
  • If fence agents are used concurrently, both fence agents have to respond to the Stop command for the host to be stopped; if one agent responds to the Start command, the host will go up.

Fence agents are sequential by default. Use the up and down buttons to change the sequence in which the fence agents are used.

To make two fence agents concurrent, select one fence agent from the Concurrent with drop-down list next to the other fence agent. Additional fence agents can be added to the group of concurrent fence agents by selecting the group from the Concurrent with drop-down list next to the additional fence agent.

Add Fence Agent

Click the + button to add a new fence agent. The Edit fence agent window opens. See the table below for more information on the fields in this window.

Power Management Proxy Preference

By default, specifies that the Manager will search for a fencing proxy within the same cluster as the host, and if no fencing proxy is found, the Manager will search in the same dc (data center). Use the up and down buttons to change the sequence in which these resources are used. This field is available under Advanced Parameters.

The following table contains the information required in the Edit fence agent window.

Table 10.3. Edit fence agent Settings

Field NameDescription

Address

The address to access your host’s power management device. Either a resolvable hostname or an IP address.

User Name

User account with which to access the power management device. You can set up a user on the device, or use the default user.

Password

Password for the user accessing the power management device.

Type

The type of power management device in your host. Choose one of the following:

  • apc - APC MasterSwitch network power switch. Not for use with APC 5.x power switch devices.
  • apc_snmp - Use with APC 5.x power switch devices.
  • bladecenter - IBM Bladecenter Remote Supervisor Adapter.
  • cisco_ucs - Cisco Unified Computing System.
  • drac5 - Dell Remote Access Controller for Dell computers.
  • drac7 - Dell Remote Access Controller for Dell computers.
  • eps - ePowerSwitch 8M+ network power switch.
  • hpblade - HP BladeSystem.
  • ilo, ilo2, ilo3, ilo4 - HP Integrated Lights-Out.
  • ipmilan - Intelligent Platform Management Interface and Sun Integrated Lights Out Management devices.
  • rsa - IBM Remote Supervisor Adapter.
  • rsb - Fujitsu-Siemens RSB management interface.
  • wti - WTI Network Power Switch.

For more information about power management devices, see Power Management in the Technical Reference.

Port

The port number used by the power management device to communicate with the host.

Slot

The number used to identify the blade of the power management device.

Service Profile

The service profile name used to identify the blade of the power management device. This field appears instead of Slot when the device type is cisco_ucs.

Options

Power management device specific options. Enter these as 'key=value'. See the documentation of your host’s power management device for the options available.

For Red Hat Enterprise Linux 7 hosts, if you are using cisco_ucs as the power management device, you also need to append ssl_insecure=1 to the Options field.

Secure

Select this check box to allow the power management device to connect securely to the host. This can be done via ssh, ssl, or other authentication protocols depending on the power management agent.

10.6.3. SPM Priority Settings Explained

The SPM settings table details the information required on the SPM tab of the New Host or Edit Host window.

Table 10.4. SPM settings

Field NameDescription

SPM Priority

Defines the likelihood that the host will be given the role of Storage Pool Manager (SPM). The options are Low, Normal, and High priority. Low priority means that there is a reduced likelihood of the host being assigned the role of SPM, and High priority means there is an increased likelihood. The default setting is Normal.

10.6.4. Host Console Settings Explained

The Console settings table details the information required on the Console tab of the New Host or Edit Host window.

Table 10.5. Console settings

Field NameDescription

Override display address

Select this check box to override the display addresses of the host. This feature is useful in a case where the hosts are defined by internal IP and are behind a NAT firewall. When a user connects to a virtual machine from outside of the internal network, instead of returning the private address of the host on which the virtual machine is running, the machine returns a public IP or FQDN (which is resolved in the external network to the public IP).

Display address

The display address specified here will be used for all virtual machines running on this host. The address must be in the format of a fully qualified domain name or IP.

10.6.5. Network Provider Settings Explained

The Network Provider settings table details the information required on the Network Provider tab of the New Host or Edit Host window.

Table 10.6. Network Provider settings

Field NameDescription

External Network Provider

If you have added an external network provider and want the host’s network to be provisioned by the external network provider, select one from the list.

10.6.6. Kernel Settings Explained

The Kernel settings table details the information required on the Kernel tab of the New Host or Edit Host window. Common kernel boot parameter options are listed as check boxes so you can easily select them.

For more complex changes, use the free text entry field next to Kernel command line to add in any additional parameters required. If you change any kernel command line parameters, you must reinstall the host.

Important

If the host is attached to the Manager, you must place the host into maintenance mode before making changes. After making the changes, reinstall the host to apply the changes.

Table 10.7. Kernel Settings

Field NameDescription

Hostdev Passthrough & SR-IOV

Enables the IOMMU flag in the kernel so a virtual machine can use a host device as if it is attached directly to the virtual machine. The host hardware and firmware must also support IOMMU. The virtualization extension and IOMMU extension must be enabled on the hardware. See Configuring a Host for PCI Passthrough. IBM POWER8 has IOMMU enabled by default.

Nested Virtualization

Enables the vmx or svm flag so virtual machines can run within virtual machines. This option is a Technology Preview feature: It is intended only for evaluation purposes. It is not supported for production purposes. To use this setting, you must install the vdsm-hook-nestedvt hook on the host. For details, see Enabling nested virtualization for all virtual machines and Enabling nested virtualization for individual virtual machines

Unsafe Interrupts

If IOMMU is enabled but the passthrough fails because the hardware does not support interrupt remapping, you can consider enabling this option. Note that you should only enable this option if the virtual machines on the host are trusted; having the option enabled potentially exposes the host to MSI attacks from the virtual machines. This option is only intended to be used as a workaround when using uncertified hardware for evaluation purposes.

PCI Reallocation

If your SR-IOV NIC is unable to allocate virtual functions because of memory issues, consider enabling this option. The host hardware and firmware must also support PCI reallocation. This option is only intended to be used as a workaround when using uncertified hardware for evaluation purposes.

Blacklist Nouveau

Blocks the nouveau driver. Nouveau is a community driver for NVIDIA GPUs that conflicts with vendor-supplied drivers. The nouveau driver should be blocked when vendor drivers take precedence.

SMT Disabled

Disables Simultaneous Multi Threading (SMT). Disabling SMT can mitigate security vulnerabilities, such as L1TF or MDS.

FIPS mode

Enables FIPS mode. For details, see Section D.4, “Configuring FIPS hosts using the Manager”.

Kernel command line

This field allows you to append more kernel parameters to the default parameters.

Note

If the kernel boot parameters are grayed out, click the reset button and the options will be available.

10.6.7. Hosted Engine Settings Explained

The Hosted Engine settings table details the information required on the Hosted Engine tab of the New Host or Edit Host window.

Table 10.8. Hosted Engine Settings

Field NameDescription

Choose hosted engine deployment action

Three options are available:

  • None - No actions required.
  • Deploy - Select this option to deploy the host as a self-hosted engine node.
  • Undeploy - For a self-hosted engine node, you can select this option to undeploy the host and remove self-hosted engine related configurations.