In this blog, we will talk about some top VMware scenario based interview questions and answers for the profile of the VMware Administrator which are commonly asked in an interview. It will help you build confidence and get a step closer to your dream job. Most of these questions are shared by the candidates who appeared in the interview for the VMware Admin profile.
Top VMware scenario based interview questions and answers
Scenario 1: A Customer/User reported that their Virtual Machine is not reachable. What action will you take to fix this issue?
Answer: First, ask for the virtual machine Name/IP/FQDN and run ping the VM to observe the status. Log in to the relevant vCenter and find the VM. Check the status of VM and detail such as IP address and DNS in vCenter console. You should check for the correct network adapter. If VM is in a hung state, then try to reset/reboot it. That is the possible action you can take in this case.
Scenario 2: We are failing to take a Snapshot for the virtual machine. Why?
Answer. There could be many reason for failing the snapshot for a virtual machine. First, There is not enough space to store the data in the datastore. Second, Virtual machine is already engaged is any process such as backup or deletion of old snapshot so wait till the current task is completed.
Third, Virtual machine with RDM(Raw Device Mapping) is not ready for any snapshot. You should remove the RDM then proceed with the snapshot. Check the limits or number of snapshot, which is 32 for a virtual machine in a row, more than this not possible.
Scenario 3:. Explained snapshot creation process?
Answer. You can refer our blogpost What Is Virtual Machine Snapshots And Its Best Practices
Scenario 4: In the case of hardware failure in your ESXi hypervisor, what things first need to perform?
Answer. During the hardware failure, We first evacuate all the virtual machines to other hosts and put the host in maintenance mode in vSphere. We will check the iLO/iDRAC management console for the exact hardware that is failed and request a replacement from the Datacenter operation team.
If it has causes Purple Screen Of Death(PSOD), will fetch the logs and open a case with VMware.
Scenario 5: How do you get an ESXi logs?
Ans. There are many ways to fetch the logs for an ESXi.
- Right click on the host in vSphere inventory -> Export System Logs
- You can download the logs from iLO/iDRAC management console.
- Once the ESXi is online, take SSH with the help of putty. Navigate the VMkernel summary, ESXi host agent log, VMkernel warnings, and VMkernal logs.
Scenario 6:. What if you are not able to expand your datastore?
Answer. If we are not able to expand the datastore then there cou;d be below issue:
- You do not have required permission to perform the task.
- You have selected the wrong Datastore/LUN. Check that.
- You are at right datastore and LUN but still unable to do any task because the Storage team did not presented the LUN yet.
Scenario 7:. What if your vCenter server goes offline?
Answer. When vCenter Server is offline, the main disadvantage is we lose the full-featured functionality of the vSphere Web Client until vCenter Server is back online. All existing VMs will be running fine. However, you can not provision new VMs. The DRS will not work also. However, HA will work fine. FT will work for one failure, and dvSwitch will work fine but can not make changes to it. You may refer to the below articles for more insight:
- vCenter is down – impact on VMware infrastructure.
- Mastering VMware
- What if my VirtualCenter server crashes?
Scenario 8: What would happen if we add the same VLAN Id to two Virtual machine adapter?
Ans. There should not be any issue. We can assign the same VLAN ID to one or multiple port groups. But in a critical production environment we always separate different types of communication.
Scenario 9:. What if we put security profile of ESXi in strict lockdown mode?
Ans. In strict lockdown mode, the DCUI service is stopped. If the connection to vCenter Server is lost and the vSphere Web Client is no longer available, the ESXi host becomes unavailable unless the ESXi Shell and SSH services are enabled and Exception Users are defined.
Scenario 10. How an administrator can connect with VMware ESXi console?
Answer: To connect an ESXi through web client, you need to paste FQDN or IP address in the browser and hit enter. It will show the ESXi web client login screen where you can login using root credentials. Also make sure you below port opened to set up communication between ESXi and vCenter server.
- 443 TCP
- 902 TCP
- 903 UDP and TCP ports
Scenario 11: Let suppose a user deleted the .nvram file. How would you recover it?
Answer: After a reboot of the VM, it will restore the .nvram file.
Scenario 12: Can you upgrade ESXi 5.x to 6.x directly from the VUM?
Answer: We may have to use a two-step upgrade method if it fails directly from ESXi 5.x to 6.x. In a two-step upgrade, we have to first update the ESXi 5.x U1 to the latest Un than from Un to 6.x. where n is the last version of the update.
Scenario 13: What do you understand by orphaned VM?
Answer: During the vSphere HA failover when one host is failed, VM start migrating to other host and restart it. But sometime it fails to register itself to other host during failover and become orphaned. We call these VM as orphaned VM.
Scenario 14: DRS failed to balance the cluster resources, Why?
Answer: Because sometimes the affinity rules prevent VM to migrate to another host in the cluster. It causes the DRS cluster to unbalance.