MISC interview question collection

What will happen if vCenter server fails?

1:-DRS will not work.

2:-HA works, but we can’t make HA related changes. New powered on VMs will not be protected

3:-FT works for one failure. New secondary vm will not be created

4:-Dvswitch works, but we can’t make changes

5:- vMotion or SvMotion will fail

Where to find different VMware ESXi Host log files?

è/var/log/hostd.log: Host management service logs, including virtual machine and host Task and Events, communication with the vSphere Client and vCenter Server vpxa agent, and SDK connections.

  è/var/log/hostd-probe.log: Host management service responsiveness checker





è/var/log/vmkernel.log: Core VMkernel logs, including device discovery, storage and networking device and driver events, and virtual machine startup.
è/var/log/vmkwarning.log: A summary of Warning and Alert log messages excerpted from the VMkernel logs.
è/var/log/vmksummary.log: A summary of ESXi host startup and shutdown, and an hourly heartbeat with uptime, number of virtual machines running, and service resource consumption

When an ESXi 5.1 / 5.5 host is managed by vCenter Server 5.1 and 5.5, two components are installed, each with its own logs:

è/var/log/vpxa.log: vCenter Server vpxa agent logs, including communication with vCenter Server and the Host Management hostd agent.

è/var/log/fdm.log: vSphere High Availability logs, produced by the fdm service.

è /root/vmkernel-log.date     virtual machine kernel core file

è/var/log/shell.log: ESXi Shell usage logs, including enable/disable and every command entered.

Check VM log:
èvmfs/volume/<vm name> vmware.log

è/var/log/sysboot.log: Early VMkernel startup and module loading.

è/var/log/boot.gz: A compressed file that contains boot log information and can be read using zcat /var/log/boot.gz|more.

è/var/log/syslog.log: Management service initialization, watchdogs, scheduled tasks and DCUI use.

How to troubleshoot following Esxi Host problems?

• An ESXi/ESX host shows as Not Responding in VirtualCenter or vCenter Server
• An ESXi/ESX host shows as Disconnected in vCenter Server
• Cannot connect an ESXi/ESX host to vCenter Server
• Virtual machines on an ESXi/ESX host show as grayed out in vCenter Server
• When attempting to add an ESXi/ESX host to vCenter Server, you see an error similar to:
  
  Unable to access the specified host, either it doesn't exist, the server software is not responding, or there is a network problem

ESXi

1.   Verify that the ESXi host is in a powered ON state.

2.  Verify that the ESXi host can be re-connected, or if reconnecting the ESXi host resolves the issue.

3.  Verify that the ESXi host is able to respond back to vCenter Server at the correct IP address. If vCenter Server does not receive heartbeats from the ESXi host, it goes into a not responding state.

4.  Verify that network connectivity exists from vCenter Server to the ESXi host with the IP and FQDN. 

5. Verify that you can connect from vCenter Server to the ESXi host on TCP/UDP port 902

6.  Verify if restarting the ESXi Management Agents resolves the issue. 

7.  Verify if the hostd process has stopped responding on the affected ESXi host.

8.  The vpxa agent has stopped responding on the affected ESXi host.

9.  Verify if the ESXi host has experienced a Purple Diagnostic Screen

10.            ESXi hosts can disconnect from vCenter Server due to underlying storage issues.

 Remember this while troubleshooting:-

From the Direct Console User Interface (DCUI):

1.   Connect to the console of your ESXi host.

2.  Press F2 to customize the system.

3.  Log in as root.

4.  Use the Up/Down arrows to navigate to Restart Management Agents.

Note: In ESXi 4.1 and ESXi 5.0, 5.1, 5.5 and 6.0 this option is available under Troubleshooting Options.

5.  Press Enter.

6.  Press F11 to restart the services.

7.  When the service restarts, press Enter.

Press Esc to log out of the system

From the Local Console or SSH:

1.   Log in to SSH or Local console as root.

Run these commands:

/etc/init.d/hostd restart
/etc/init.d/vpxa restart

How to collect core dump file from Esxi 5.x environment?

• Collecting VMkernel coredumps from ESXi 5.x
  
  During startup of an ESXi 5.x host, the startup script /usr/lib/vmware/vmksummary/log-bootstop.sh checks the defined Dump Partition for new contents. If new content is found, an entry is written to the /var/log/vmksummary.log file citing bootstop: Core dump found.
  
  You can collect logs from an ESXi host either by running vm-support at the command line or by using ExportDiagnostic Data from the vSphere Client. Both methods invoke the vm-support script, which checks the defined Dump Partition for new contents. If new content is found, it is temporarily placed in a vmkernel-zdump file in /var/core/ before being compressed in the vm-support output.
  
  Determine the device identifiers for the core partition(s) by running the command:
  
  esxcfg-dumppart –t

1.   Change to a directory with sufficient space to store the core dump file.

For example:

cd /vmfs/volumes/DatastoreName/

Note: A core dump file will normally be between 100 and 300 MB in size. Be sure to select a location with sufficient free space.

2.  Dump the partition contents to a file by running the command:

esxcfg-dumppart --copy --devname "/vmfs/devices/disks/identifier" --zdumpname /vmfs/volumes/datastore1/filename.1

For example:

esxcfg-dumppart --copy --devname "/vmfs/devices/disks/mpx.vmhba2:C0:T0:L0:2" --zdumpname /vmfs/volumes/datastore1/filename.1

VMware P2V conversion checklist using VMware converter?

1.Disable UAC (User access control) for Windows
2.To eliminate DNS problems, use IP addresses instead of host names.
3.Do not choose vendor specific Diagnostic Partitions while conversion. 
4.Convert directly to an ESXi host instead of vCenter Server.






5.Make sure there is at least 500MB of free space on the machine being converted.
6.Shut down any unnecessary services, such as SQL, antivirus programs, and firewalls..
7.Run a check disk on the volumes before running a conversion.
8.  Ensure that these services are enabled:-

o  Workstation Service.

o  Server Service.

o  TCP/IP NetBIOS Helper Service.

o  Volume Shadow Copy Service.

9.Check that the appropriate firewall ports are opened
10.Ensure that you are not using GPT on the disk partition
11.In Windows XP, disable Windows Simple File Sharing. 
12.Unplug any USB, serial/parallel port devices from the source system.





13.NIC's that are statically configured to be at a different speed or duplex
14.  If the source server contains a hard drive or partition larger than 256GB, ensure that the destination datastores block size is 2MB, 4MB, or 8MB, and not the default 1MB size. The 1MB default block size cannot accommodate a file larger than 256GB.
15.Clear any third-party software from the physical machine that could be using the Volume Shadow Copy Service (VSS).

 16.Disable mirrored or striped volumes

How vSphere 5.x Differs from vSphere 4.x?

vSphere 5.x is a major upgrade from vSphere 4.x.

The following changes from vSphere 4.x affect vSphere installation and setup.

1>Service Console is removed.
2>ESXi does not have a graphical installer
3>vSphere Auto Deploy and vSphereESXi Image Builder CLI
4>Changes in the ESXiinstallation and upgrade process
5>Installer caching
6>Changes to partitioning of host disks
7>VMware vCenter Server Appliance
8>vSphere Web Client
9>vCenter Single Sign On