VMware NSX Interview Questions
VMware NSX Interview Questions
Q. What is Service Console?
The service console is developed based up on Redhat Linux Operating system, it is used to manage the VMKernel
Q. What are the basic commands to troubleshoot connectivity between vSphere Client /vCenter to ESX server?
service mgmt–vmware restart (restarts host agent(vmware–hostd) on vmware esx server)
service vmware-vpxa restrat (restarts Vcenter agent service)
service network restart (restarts management networks on ESX)
Q. What is vCenter Agent?
VC agent is an agent installed on ESX server which enables communication between VC and ESX server. This Agent will be installed on ESX/ESXi will be done when you try to add the ESx host in Vcenter.
Q. What is the command used to restart SSH, NTP & Vmware Web access?
It is very important to understand the command to start and stop services. So i have covered basic service restart command in the below VMware interview questions.
Service sshd restart
Service ntpd restart
Service vmware–webaccess restart
Q. What are the types of Ports groups in ESX/ESXi?
There are 3 types of port groups in ESX
- Service console port group
- VMkernel Port group
- Virtual machine port group
There are only 2 types of port group in ESXi
- Vmkernel Port group
- Virtual Machine Port group
Q. What is VMKernel ?
VMWare Kernel is a Proprietary kernel of vmware and is not based on any of the flavors of Linux operating systems, .VMkernel requires an operating system to boot and manage the kernel. A service console is being provided when VMWare kernel is booted. Only service console is based up on Redhat Linux OS not VMkernel.
Q. What is the use of Service Console port ?
Service console port group required to manage the ESX server and it acts as the management network for the ESX. vCenter/vSphere Client uses the service console IP’s to communicate with the ESX server. This is one of the frequently asked VMware interview questions.
Q. What is the use of VMKernel Port ?
Vmkernel port is used by ESX/ESXi for vmotion, ISCSI & NFS communications. ESXi uses Vmkernel as the management network since it don’t have service console built with it.
Q. What is the use of Virtual Machine Port Group?
Virtual Machine port group is used by Virtual machine communication.
Q. How Virtual Machine communicates to another servers in Network ?
All the Virtual Machines which are configured in VM Port Group are able to connect to the other machines on the network. So this port group enables communication between vSwitch and Physical Switch by the use of uplink (Physical NIC) associated with the port group.
Q. What is the default number of ports configured with the Virtual Switch?
When the time of Virtual switch created, Vswitch is created with 56 ports by default. We can extend the no of ports by editing the vswitch properties.
Q. What are the different types of Partitions in ESX server?
VMware Interview Questions – Network Security
Q. What is MAC Address changes?
All the virtual machines nics are provide with the MAC address at the time of creation and it is stored in .VMX file. If the packet doesn’t match with the MAC address as same as in the .VMX file , it does not allow incoming traffic to the VM by setting this option as reject.
If it is set as Accept,ESX accepts requests to change the effective MAC address to other than the MAC address save din the .VMX file.
Q. What are the Traffic Shaping policies available in the vSwitch?
Understanding the usecases of Traffic shaping policies are very important part of VMware interview questions. Traffic shaping policies are disabled by default. There are 3 different traffic shaping policy setting
- Average Bandwidth
- Peak Bandwidth
- Burst Size
Q. What are the Load balancing policies available in vswitch?
- Route based on the originating virtual switch port ID
- Route based on source MAC hash
- Route based on IP hash
- Route based on the originating virtual switch port ID – Chooses an uplink based on the virtual port where the traffic entered the virtual switch. The traffic will be always send with that same uplink until that particular uplink is failed and failed over to another NIC.
- Route based on source MAC hash – Choose an uplink based on a hash of the source Ethernet MAC address.The traffic will be always send with that same uplink until that particular uplink is failed and failed over to another NIC.
- Route based on IP hash – Choose an uplink based on a hash of the source and destination IP addresses of each packet.
Q. What is Forged Transmits?
Which is same as the Mac Address changes setting but it worked for the outgoing traffic but the MAC address changes setting is for incoming traffic.
Q. What is a VLAN?
A VLAN is the Virtual LAN which is used to broke down the Broadcast traffic into many logical groups. Basically, one physical switch comprise of one broadcast domain. VLAN used to separate the one broadcast domain into many small pieces to separate the networks within the broadcast domain.
Q. What are the types of VLAN tagging in Vsphere?
There are 3 types of VLAN tagging available in Vsphere.
- Virtual Switch Tagging (VST)
- External Switch Tagging (EST)
- Virtual Guest Tagging (VGT)
Q. What is VST , EST & VGT?
Please refer my blog post on VLAN tagging
Q. What are the security options available for ESX vswitch?
Promiscuous Mode – Reject
MAC Address changes – Accept
Forged Transmits – Accept
Q. What is Promiscuous Mode?
If the promiscuous mode set to Accept, all the communication is visible to all the virtual machines, in other words all the packets are sent to all the ports on vSwitch. It can be useful when you are running virtual machines with network sniffers to capture packet in that network.
Q. What are the types for Network Failover Detection settings?
Link Status only
Link Status only – Relies solely on the link status provided by the network adapter. This detects failures, such as cable pulls and physical switch power failures, but it cannot detect configuration errors, such as a physical switch port being blocked by spanning tree or misconfigured to the wrong VLAN or cable pulls on the other side of a physical switch.
Beacon Probing – Sends out and listens for beacon probes — Ethernet broadcast frames sent by physical adapters to detect upstream network connection failures — on all physical Ethernet adapters in the team. In addition to link status, to determine link failure. This detects many of the failures which are not detected by Link Status.