OCA-H Sample Questions & Answers

vSGA is a feature that uses a native VMware driver to share a physical GPU's resources among multiple VMs. It is suitable for light 3D workloads, such as Windows Aero or office applications. It provides a lower level of performance and compatibility compared to NVIDIA GRID vGPU but can support a higher density of users per GPU for less demanding tasks.

When you store instant-clone replicas on a separate datastore, the Omnissa documentation requires that the replica datastore be accessible from all ESXi hosts in the cluster; only one separate replica datastore can be specified per pool, and the option is not available with vSAN datastores. Source: Omnissa Horizon 8 'Reducing Storage Requirements with Instant Clones'.

In the Horizon Console, the logical grouping of one or more Remote Desktop Session Host (RDSH) servers is called a 'Farm.' To create, manage, or view these groupings, the administrator must navigate to the Inventory > Farms section. Once a farm is created, it can then be used to create Application Pools or RDS Desktop Pools.

A Writable Volume is a dedicated, user-assigned virtual disk (VMDK or VHD) that attaches to a user's session. It captures and persists changes that would normally be lost on a non-persistent desktop, such as user-installed applications, profile settings, and other user-specific data. This provides a persistent experience on a non-persistent desktop.

During the customization phase each new instant clone powers on, gets an IP address from DHCP, and ClonePrep joins it to the domain. During a push-image, new clones are created while the old ones are still being replaced, so extra addresses are needed and the old leases have not yet expired. If the desktop VLAN's DHCP scope is exhausted, the new VMs get no address, cannot reach a domain controller, and customization times out. Enlarging the scope or shortening lease times fixes this. Source: Desktops and Applications in Horizon 8, 'Instant Clone Desktop Pools' (customization and domain join during initial power-on) and 'Instant Clone Image Publishing and Creation Workflow'.

The Horizon Connection Server integrates directly with the vCenter Server. vCenter is the management plane for the vSphere environment. Horizon leverages vCenter's APIs to perform all virtualization-related tasks, such as powering on VMs, creating clones (full, instant), taking snapshots, and managing the ESXi hosts and datastores where the desktops reside.

This is the correct multi-site architecture. Deploying independent pods in each datacenter avoids stretching the management plane over a high-latency WAN. Cloud Pod Architecture (CPA) federates these pods, and a global entitlement makes the application available across both sites. The Global Server Load Balancer (GSLB) is the key component that provides the single entry point and directs users to their nearest datacenter based on latency, while also handling failover if one site is unavailable.

Only one user is affected, so the cause has to be a per-user setting. The Sessions tab of a user account in Active Directory Users and Computers holds that user's Remote Desktop Services time-out settings: End a disconnected session, Active session limit, Idle session limit, and what to do when a limit is reached (disconnect or end the session) (Microsoft Learn: Manage user accounts in Active Directory Users and Computers). A published desktop on an RDS host is a Remote Desktop Services session, so an Active session limit of 1 hour with the disconnect action drops that one user every 60 minutes and leaves the session ready to reconnect. The Unified Access Gateway session timeout (sessionTimeout, default 36,000,000 ms, which is 10 hours) applies to every session through that appliance, and the RDS host's vSphere VM settings or its switch port would affect every user on that host, not one user.

A GSLB configured with geo-proximity policies resolves the single namespace to the nearest available region's pod entry point. A single global entitlement containing the pools from all three pods lets any pod in the federation broker a desktop from the nearest or next-available pod (default search order: local pod, local site, other sites). Stretched vSAN, Hybrid Linked Mode, and AD Sites and Services do not provide Horizon brokering, and Universal Broker is an alternative to CPA+GSLB rather than a component of it. Sources: Tech Zone Horizon 8 Architecture (Multi-site GSLB); Omnissa CPA - Finding and Allocating Desktops and Applications in the Pod Federation.

A GSLB configured with geo-proximity policies resolves the single namespace to the nearest available region's pod entry point. A single global entitlement containing the pools from all three pods lets any pod in the federation broker a desktop from the nearest or next-available pod (default search order: local pod, local site, other sites). Stretched vSAN, Hybrid Linked Mode, and AD Sites and Services do not provide Horizon brokering, and Universal Broker is an alternative to CPA+GSLB rather than a component of it. Sources: Tech Zone Horizon 8 Architecture (Multi-site GSLB); Omnissa CPA - Finding and Allocating Desktops and Applications in the Pod Federation.

The Horizon Connection Server acts as a broker, authenticating users and directing them to their entitled virtual desktops or applications. The actual virtual machines are hosted on vSphere ESXi hosts, which are managed by vCenter Server. The Connection Server manages the VDI environment but does not host the desktops themselves.

The -A option of vdmadmin administers Horizon Agent logging. Per the Horizon 8 Administration guide ('Configuring Logging in Horizon Agent Using the -A Option'), -getDCT creates a Data Collection Tool (DCT) bundle for the specified machine and -outfile names the local zip file, e.g. vdmadmin -A -d dtpool2 -m machine1 -getDCT -outfile C:\myfile.zip. -getlogfile copies a single named log file, -getloglevel only displays the current log level, and -list only lists the agent's log files.

Horizon Agent for Linux must be installed on the golden image. It communicates with Connection Server, and its ClonePrep customization renames each instant clone and joins it to Active Directory. The agent does not install the AD integration packages itself. You configure an offline domain join method on the image (SSSD, which is recommended for Ubuntu 20.04/22.04/24.04 and RHEL 8/9, or Samba/Winbind) and set OfflineJoinDomain in viewagent-custom.conf (Omnissa Horizon 8: 'Configure a Golden Image Linux VM for Instant Clones'). VMware Tools/open-vm-tools is a VM prerequisite but does not provide Horizon communication.

DEM personalizes only what its Flex configuration files define. In the Management Console you create config files with Create Config File > Windows Common Settings, which provides built-in definitions such as Wallpaper, Internet Explorer (Legacy) Personal Settings (favorites) and Microsoft Edge Chromium (Omnissa DEM Admin Guide). If no enabled config file covers wallpaper and browser favorites, FlexEngine does not export them at logoff, so they are lost when the non-persistent clone is discarded.

Omnissa defines a Cloud Pod Architecture site as a collection of well-connected pods in the same physical location, typically in a single data center, and CPA treats the pods in one site as equals. CPA assumes that pods in the same site are on the same LAN and that pods in different sites are on different LANs. Because WAN-connected pods are slower, CPA prefers desktops and applications in the local pod or site when it allocates them, and sites also support disaster recovery by placing data centers in different sites. A site is not an Active Directory boundary, a licensing region or a Unified Access Gateway setting. (Omnissa Horizon 8: Creating Cloud Pod Architecture Sites.)

Microsoft SQL Server is a supported platform for the Horizon event database (Oracle and PostgreSQL are also supported). Horizon does not include an embedded vPostgres event database, and MySQL and MongoDB are not supported. Source: Omnissa Horizon 8 Installation and Upgrade - Configure the Event Database in Horizon Console.