VMware is the leader in Virtualization and Cloud Computing technologies and also providing solutions in the field of network and desktop virtualization. VMware has changed the tech world from physical to software based virtual world.
Due to implementation of virtual environment to consolidate the hardware infrastructure, the demands of subject matter experts are increasing day by day in the market. To manage and maintain organization’s business, an experience workforce is required, and to choose the top talent from the market for growing an organization’s business, professionals are selected via many technical and HR processes.
Along with the HR processes, technical interviews are also conducted to assess the abilities of a professional in the field of virtualization for continues business process.
Following are 40 scenario based interview questions and answers for experience IT administrators (up to 5 years’ experience) on data center virtualization technology that may be asked to assess the candidate’s technical and hands-on expertise.
- An administrator wants to connect ESXi host directly from vSphere Web Client. Which ports are required for this purpose?
Normally vSphere Web Client is used to connect vCenter Server and VClient is used to connect ESXi hosts. But vSphere Web Client can also be used to connect vCenter Server, but for this purpose you will need 443 TCP, 902 TCP and UDP, and 903 TCP ports to be opened from Security Profile.
- Clock time of an ESXi 6.x host is not correct. What should an administrator do to correct this issue?
To correct the time on ESXi host, modify the time for the host using the vSphere client and, correct the NTP settings in the /etc/ntp.conf file.
- An administrator wants to shutdown the host using ESXi host. Which option would be used in Direct Console User Interface to perform this task?
To shutdown the host for Direct Console User Interface (DCUI), administrator will press F12 Key.
- An administrator can access ESXi host via vCenter Server using vSphere Web Client but unable to access directly via VClient. What should he do to access ESXi host directly?
If ESXi host connected to vSphere Web Client is being accessed and can’t be accessed directly, we should check that Lockdown is not enabled. If it enabled, we should be disabled. Because if Lockdown is enabled, ESXi hosts can only be accessed via vCenter Server, you cannot directly access any host.
- An administrator wants to use the VMware Certificate Authority (VMCA) as an Intermediate Certificate Authority (CA). He already replaces the Root Certificate and Machine Certificates (Intermediate CA)
What should he do next?
After replacing root certificate and machine certificate (intermediate CA), following two steps are needed to perform.
- Replace Solution User certificates (Intermediate CA)
- Replace the VMware Directory Service certificate.
6. If Strict Lockdown Mode is enabled on an ESXi host, which action should an administrator perform to allow ESXi Shell or SSH access for users with administrator privileges?
Administrator will add the users to Exception Users and enable the service to allow ESXi Shell or SSH access.
- SSO is an important component of vCenter Server. Which SSO component issues Security Assertion Markup Language tokens?
VMware Security Token Service component of SSO grants SAML tokens.
- What valid Identity Source is used to configure vCenter Single Sign-On?
OpenLDAP is a valid Identity Source for configuring vCenter SSO.
- What happens to the files contained on shared storage When a Content Library is deleted?
When Content Library is deleted, all stored files in content library will be deleted.
- What is the maximum number of vCPUs are required for a VM in vSphere 6.0?
Maximum 128 vCPUs can be allocated to a VM vSphere 6.0.
- A windows domain user can be logged into vSphere using vSphere Web Client. What are the requirements to be met for this feature to be available and functional?
An administrator can allow users to login to vSphere Web Client using Windows session authentication. For this purpose, Install the vSphere Web Client Integration browser plug-in on each computer from where a user will sign in. The users must be signed into Windows using Active Directory user accounts. And, administrator must create a valid Identity Source in Single Sign-On for the users’ domain.
- An administrator wants to clone a virtual machine using the vSphere Client. Which explains why the Clone option is missing?
To clone a VM can be perform from vCenter Server either you connected via vSphere Web Client or VClient. If you are directly connected to an ESXi host, you cannot perform cloning of a VM.
- What will happen if the .nvram file is deleted accidently from a VM?
.nvram file is used to store the BIOS state of a VM. If it deleted for some reason, then, .nvram file will be created again when the virtual machine is powered on.
- An administrator wants to connect the vSphere 5.5 Client to ESXi 6.x host. What will occur?
If administrator tries to connect the vSphere 5.5 Client to ESXi 6.x host, the operation will prompt the administrator to run a script to upgrade the vSphere Client.
- Which one of secondary Private VLANs (PVLANs) type can send packets to Isolated PVLAN?
Promiscuous type of PVLAN can communicate and send packets to an Isolated PVLAN.
- What sample roles are provided by default when vCenter is installed?
When vCenter is installed, Virtual machine user and Network Administrator roles are provided.
- What will happen when all paths down (APD) event occurs for the software FCoE storage?
If all paths down event occurs, Spanning Tree Protocol is enabled on the network ports.
- What methods are available for upgrade a host from ESXi 5.x to ESXi 6.x?
vSphere Update Manager (VUM), esxcli command line tool, and vSphere Auto Deploy can be used to upgrade.
- What administrator should do before upgrading virtual machine hardware?
Before upgrading a VM hardware, we should create a backup or snapshot of the VM, should upgrade VMware Tools to the latest version, and verify that the VM is stored VMFS or NFS datastore.
- vCenter Server upgradation fails at the vCenter Single Sign-On installation. What should do to complete the upgrade process?
Before upgrading vCenter Server, verify that the VMware Directory service can stop by manually restarting it. If it stopped manually, then you can start upgradation process of vCenter Server.
- What prerequisites should be considered before upgrading the vCenter Server Appliance?
In case of upgradation of vCenter Server Appliance (vCSA) or after fresh installation, Client Integration Plugin (CIP) will be installed in both cases.
- After deploying a PSC, vCenter Server is not being installed and shows the following error:
Could not contact Lookup Service. Please check VM_ssoreg.log.
If this error appears then verify that the clocks on the host machines running the PSC, vCenter Server, and the vSphere Web Client are synchronized with each other. And also ensure that there is no firewall blocking port 7444 between the PSC and vCenter Server.
- An administrator installed Windows Server 2008 and want to install vCenter Server on it but failed when installing on a Windows virtual machine?
vCenter Server installation requires 64bit Windows OS to install. If you try to install it on Windows Server 2008, it would not be installed and installation will be failed. vCenter Server will be installed in Windows Server 2008 R2 or higher Windows OS.
- What is the minimum Virtual Hardware version required for vFlash Read Cache?
vFlash Read Cache was first in vSphere 5.5, and the minimum Virtual Hardware version for vSphere 5.5 is version 10.
- ESXi host is added in vCenter Server but not responding in vSphere Web Client. If this issue occurs due to firewall, which port should be opened?
If administrator sees no response of added ESXi 6.x host in vCenter Server, and the issue is caused by network firewall blocking traffic. Then he should check that port 902 (UDP) is not blocked by firewall. If it happens, enable the port from Security Profile by using vSphere Web Client by selecting said ESXi host in vCenter Server.
- If a VM is unexpectedly powered off. Which VM logs files should be considered to troubleshoot the issue?
If it happens, administrator should check vmware.log and hostd.log log files to troubleshoot the issue.
- Why a VM appeared as orphaned VM?
If a VM appears in orphaned state, this could cause a VMware High Availability host failure has occurred. And the virtual machine was unregistered directly on the ESXi host.
- While upgrading an ESXi 5.5 host to ESXi 6.x, following error appears: MEMORY_SIZE
What does this require to do?
It indicates insufficient memory on the ESXi host to complete the upgrade process of an ESXi host from ESXi 5.5 to ESXi 6.x.
- To remove a host from a vSphere Distributed Switch (vDS), following error message is observed:
The resource ’10’ is in use
Before removing vDS, it is ensured that VMkernel network adapters on the vDS are not in use. If any of resource of vDS is being used, then above mentioned error message with resource ID will appear.
- An administrator wants to monitor network traffic and tries to capture network traffic for a VM, but cannot see the expected traffic in the packet capture tool. What should he do to resolve the problem?
If administrator needs to capture network traffic for a VM, he should Enable Promiscuous Mode on the relevant port group. Then he can capture the network traffic by using any networking traffic capturing tool.
- A vSAN Cluster is created with six nodes along with the fault domain, and three of them moved into fault domain. One-member node of fault domain fails. What will happen with the remaining two nodes exist in fault domain?
When a member node of fault domain fails, the remaining two fault domain members will be treated as failed.
- At which level a vSAN Fault Domain configured?
Fault domain is configured at vSAN Cluster level and nodes will be added in this domain. If any member node fails due to any reason, remaining members of fault domain will also be considered as fail.
- It is observed that a VM storage activity on an ESXi 6.x host is negatively affecting a VM storage activity on another host that is accessing the same VMFS Datastore. Which action would mitigate the issue?
To control the storage activity of a VM to affecting another VM’s storage activity, Storage IO Control (SIOC) should be enabled. Storage I/O Control provides much needed control of storage I/O and should be used to ensure that the performance of your critical VMs are not affected by VMs from other hosts when there is contention for I/O resources.
- While upgrading an ESXi host from 5.5to 6.0, administrator runs the following command:
esxcli software vib list –rebooting-image
What will be shown by this command?
This command will show all active VIBs (vSphere Installation Bundle). VIB is is a collection of files like tarball or zip that packaged into a single archive to facilitate distribution.
- To troubleshoot a CPU performance issues of a VM, which counters will be used to demonstrate CPU contention?
To test the performance of an ESXi host in the form of memory, CPU, and network utilization, ESXTOP tool is used. It is a very good tool available for VMware administrators to troubleshoot the performance issues. For configuring ESXTOP, you’ll need vSphere Client and putty and SSH session should be enabled. For CPU performance testing, %RDY, %MLMTD, and %CSTP counters are used.
- An administrator tries to run esxtop by enabling SSH and using putty to troubleshoot CPU performance issues, but no output displayed. How to resolve this issue?
To display output in ESXTOP, press f and place an asterisk next to each field that should be displayed.
- An administrator wants to monitor VMs on a host using vCenter Server and send notifications when memory usage crosses 80%. What should an administrator do in vCenter Server to accomplish this?
To monitor VM’s memory usage that reaches 80%, vCenter Server alarm will be created that will monitor VM’s memory usage and set an action to email the notification.
- An administrator created a DRS cluster and it became unbalanced. What are likely causes to become unbalanced?
DRS cluster can become unbalance when Affinity rules are preventing VMs from being moved. And a device is mounted to a VM is preventing vMotion from one host on another.
- An IT administrator configured two vCenter Servers within a PSC, and needs to grant a user privileges that can access all environments. What access level is required to access all the environment?
To access multiple vCenter Servers within a PSC, it requires Global Permission to access all environments.
- An administrator created 10 ESXi 6.x hosts via Auto Deploy for a new Test/Dev cluster and all hosts are configured to obtain their IP address via DHCP. Which DCUI option should the administrator use to renew the DHCP lease for the hosts?
To renew the DHCP lease for the hosts, “Reset Management Network” of Direct Console User Interface (DCUI) option is used.
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