High Availability for RedHat Virtualization Manager

Earlier, you have installed Red Hat Virtualization Manager in its standard deployment to a Red Hat Enterprise Linux system running on bare-metal hardware. Red Hat Virtualization Manager can also be installed as an appliance in a virtual machine that runs on a host in its own Red Hat Virtualization infrastructure. This self-hosted engine is configured as a highly available virtual machine, which can be migrated to, or restarted on, another host.

RHVM self-hosted engine

A self-hosted engine is a virtualized environment in which the engine (RHVM) runs on a virtual machine on the hosts managed by that engine. RHVM is deployed by a host, in parallel with the host configuration process. The virtual machine running the engine is configured to be highly available. If the host running the virtual machine goes into maintenance mode or fails unexpectedly, the virtual machine is migrated or restarted automatically on another host in the environment.

The primary benefit of the self-hosted engine is that it requires less hardware to deploy an instance of Red Hat Virtualization, as the engine runs as a virtual machine and not on physical hardware. Additionally, the engine is automatically configured to be highly available, rather than requiring a separate cluster.

At least two hosts are required to support the high availability feature for self-hosted RHVM. Those hosts are the self-hosted engine hosts. The self-hosted engine may be installed using a host running Red Hat Enterprise Linux 7.4 or on a version of RHVH based on Red Hat Enterprise Linux 7.4. The engine must use the following procedure for installation. Manual installation of the self-hosted engine into a virtual machine in order to implement this is not supported.

Prerequisites

The following prerequisites must be met before starting a deployment of RHVM self-hosted engine on RHVH:

  • The host must be freshly installed with RHVH. It must be correctly registered and entitled to get software and updates. The Performance Profile in the System subtab of the Cockpit user interface must be set to virtual-host. The host’s /var/tmp directory must have at least 5 GB free.
  • Fully-qualified domain names for the host and RHVM must be prepared in DNS, and forward and reverse DNS lookups must properly resolve.
  • You must have at least 60 GB of network storage available for a shared storage domain dedicated to the RHVM appliance, which will be created during configuration. You must also have additional network storage available for a data domain for regular virtual machines. You should add this to the self-hosted engine’s data center as soon as deployment is complete. If you use iSCSI storage, do not use the same target for both storage domains.

WARNING: Red Hat strongly recommends that you have additional active data storage domains available in the same data center as the self-hosted engine environment. If you deploy the self-hosted engine in a data center with only one active data storage domain, and if that data storage domain is corrupted, you will be unable to add new data storage domains or to remove the corrupted data storage domain. You will have to redeploy the self-hosted engine.

Installation prerequisites for Red Hat Enterprise Linux 7.4 are similar, although you also need to install the cockpit-ovirt-dashboard or ovirt-hosted-engine-setup packages, depending on which tool you intend to use to install the self-hosted engine.

Installing RHVM self-hosted engine

The self-hosted engine may be installed with either the Cockpit user interface on the host, or by using the hosted-engine command. Each installation method requires different packages. Using the Cockpit user interface requires the cockpit-ovirt-dashboard package. Using the hostedengine command requires the installation of the ovirt-hosted-engine-setup package.

The deployment starts differently depending on which tool you use.

To start the deployment of the self-hosted engine using the Cockpit user interface, log in to Cockpit at https://Self-Engine-Host-IP-Address:9090. Once logged in, click Virtualization, and select Hosted Engine. Check the Standard check box to perform a standard selfhosted engine installation, and click Start.

If you use the hosted-engine command, run the hosted-engine command with the option –deploy to start the installation.

[[email protected] ~]# hosted-engine --deploy

NOTE: Officially, Cockpit is the preferred installation method.

Using either tool, the deployment process prompts you to set some configuration options. Those questions include default values. RHV saves the answers to the /etc/ovirt-hostedengine/answers.conf file. RHV supports a custom file location using the –generate-answer=<file> argument. In the Cockpit user interface, to confirm each answer click the Next button.

Starting the Deployment

Enter Yes to start the self-hosted RHVM deployment.

During customization use CTRL-D to abort.
Continuing will configure this host for serving as hypervisor and create a VM
  where you have to install the engine afterwards.
Are you sure you want to continue? (Yes, No)[Yes]:

Downloading the RHVM Virtual Appliance

Enter Yes to download the RHVM Virtual Appliance.

The oVirt engine appliance is now required to deploy hosted-engine.
You could get oVirt engine appliance installing ovirt-engine-appliance rpm.
Do you want to install ovirt-engine-appliance rpm? (Yes, No) [Yes]:

Storage Configuration

Enter the storage type to use. Depending on the storage option you select, additional storage configuration options appear.

Please specify the storage you would like to use (glusterfs, iscsi, fc, nfs3, nfs4)[nfs3]:

Networking Configuration

Enter Yes to automatically configure iptables.

 iptables was detected on your computer, do you wish setup to configure it? (Yes, No)[Yes]:

Enter the NIC to use as a management bridge, and set the gateway.

Please indicate a nic to set ovirtmgmt bridge on: (eth1, eth0) [eth1]:
Please indicate a pingable gateway IP address [X.X.X.X]:

Virtual Machine Configuration

Select the available RHVM Virtual Appliance to deploy.

The following appliance have been found on your system:
[1] - The oVirt Engine Appliance image (OVA)
[2] - Directly select an OVA file
Please select an appliance (1, 2) [1]:

Enter either vnc or spice for the type of console to connect to the virtual machine console.

Please specify the console type you would like to use to connect to the VM (vnc, spice) [vnc]:

Enter Yes to run initial configuration for the RHVM virtual machine using cloud-init.

Would you like to use cloud-init to customize the appliance on the first boot (Yes, No)[Yes]?

Enter Generate to configure networking and the hostname. Run engine-setup with the answer file configuration options in the RHVM virtual machine. Enter Existing to use a custom cloud-init script:

Would you like to generate on-fly a cloud-init ISO image (of no-cloud type) or do
 you have an existing one (Generate, Existing)[Generate]?

Enter the FQDN for the RHVM virtual machine.

Please provide the FQDN you would like to use for the engine appliance.
Note: This will be the FQDN of the engine VM you are now going to launch.
It should not point to the base host or to any other existing machine.
Engine VM FQDN: (leave it empty to skip):

Enter the domain to use for the RHVM virtual machine.

Please provide the domain name you would like to use for the engine appliance.
 Engine VM domain: [lab.example.com]

Choose to automatically execute engine-setup when the RHVM first boots.

Automatically execute engine-setup on the engine appliance on first boot (Yes, No) [Yes]?

Choose to restart the RHVM virtual machine as a monitored service.

Automatically restart the engine VM as a monitored service after engine-setup (Yes, No)[Yes]?

Enter a password for the root user in the RHVM virtual machine.

Enter root password that will be used for the engine appliance (leave it empty to skip):
Confirm appliance root password:

Enter an SSH public key to configure password-less access to the root user in the RHVM virtual

Enter ssh public key for the root user that will be used for the engine appliance
 (leave it empty to skip):

Select whether to enable SSH access for the root user in the RHVM virtual machine.

Do you want to enable ssh access for the root user (yes, no, without-password)
 [yes]:

Enter the disk size and memory size for the RHVM virtual machine.

Please specify the size of the VM disk in GB: [50]:
Please specify the memory size of the VM in MB (Defaults to appliance OVF value):
 [4096]:

Select the CPU type and enter the number of virtual CPUs to be used by the RHVM virtual machine.

The following CPU types are supported by this host:
- model_SandyBridge: Intel SandyBridge Family
- model_Westmere: Intel Westmere Family
- model_Nehalem: Intel Nehalem Family
- model_Penryn: Intel Penryn Family
- model_Conroe: Intel Conroe Family
Please specify the CPU type to be used by the VM [model_SandyBridge]:

Note: If you expect to run the self-hosted engine on hosts with less-capable CPUs than the host performing the installation at some point in the future, choose a CPU family supported by those hosts.

Please specify the number of virtual CPUs for the VM [Defaults to appliance OVF
 value: 4]:

Enter a MAC address for the RHVM virtual machine.

You may specify a MAC address for the VM or accept a randomly generated default
 [00:16:3e:77:b2:a4]:

Enter the method to configure an IP address for the RHVM virtual machine. If you select Static, you need to provide the IP address.

How should the engine VM network be configured (DHCP, Static)[DHCP]?

Provide hostname resolution configuration.

Please provide a comma-separated list (max3) of IP addresses of domain name
 servers for the engine VM Engine VM DNS (leave it empty to skip):
Add lines for the appliance itself and for this host to /etc/hosts on the engine
 VM? Note: ensuring that this host could resolve the engine VM hostname is still
 up to you (Yes, No)[No]

Configuring the Self-hosted Engine

Enter a password for the admin user in the internal profile to access the administration portal.

Enter engine admin password:
Confirm engine admin password:

Enter the SMTP configuration options for email notifications. Enter the hostname and port number for the SMTP server, the source email address, and a list of email addresses to receive those notifications.

Please provide the name of the SMTP server through which we will send
 notifications [localhost]:
Please provide the TCP port number of the SMTP server [25]:
Please provide the email address from which notifications will be sent
 [[email protected]]:
Please provide a comma-separated list of email addresses which will get
 notifications [[email protected]]:

Configuration Preview

Review the configuration settings, and start the installation.

Please confirm installation settings (Yes, No)[Yes]:

When deployment finishes, the RHVM virtual machine is running on the host. The self-hosted RHVM installation configures a data center, cluster, hosts, a virtual machine for the self-hosted RHVM virtual machine, and dedicated shared storage for its own use.

Operation and Maintenance

The self-hosted engine runs in its own data center and cluster. It is a recommended practice to run the self-hosted engine and other infrastructure services in a data center and cluster segregated from other Red Hat Virtualization workloads.

Only specific hosts are normally configured to run the self-hosted engine. You enable a host to run the self-hosted engine in Administration Portal by selecting the host from its entry on the Hosts tab, and accessing its Hosted Engine tab at the bottom of the interface. In that tab, select the Deploy radio button and click OK.

The hosted-engine command is used to reconfigure self-hosted engine and perform various administrative tasks, including switching the self-hosted engine hosts in and out of maintenance mode.

NOTE: It is possible to migrate an existing bare-metal RHVM deployment into a self-hosted engine.