VMware VSphere Interview Questions & Answers With ScreenShot

 

                      *   VMware Interview Questions & Answers   *

What is VMware Fault Tolerance? 

– VMware Fault Tolerance is a component of VMware VSphere and it provides continuous availability to applications by preventing downtime and data loss of Virtual machines in the event of ESX server failures.

What is the name of the technology used by VMware FT?
– VMware FT using a technology called vLockstep technolog

What are requirements and Limitations for ESX hosts & infrastructure components to run FT protected virtual machines in Vsphere 4 & 4.1?

Please refer my blog post on ESX Host -Infrastrcuture Requirements & Limitations for VMware Fault Tolerance to see the ESX requirements for VMware FT.

What are Requirements and Limitations for Virtual Machine to Enable FT ?

Please refer my blog post on Virtual Machine Requirements for VMware Fault Tolerance

How do i check my host for FT compatibility from vSphere client?

One way from vSphere client is to run the cluster complaince check from profile compliance tab of your cluster. The below checks as specified below will be performed as part of the compliance check.

Validate that Fault Tolerancelogging NIC speed is at least 1000 Mbps.
Validate that power management is supported on the host
Validate that Fault Tolerance logging is enabled.
Validate that VMotion NIC speed is at least 1000 Mbps.
Validate that all the hosts in the cluster have the same build for Fault Tolerance
Validate that the host hardware supports Fault Tolerance.
Validate that VMotion is enabled.
Validate that at least one shared datastore exists


Another way is to check the summary tab of the ESX/ESXi host, “Host Configured for FT” yes or NO.

If ” Host Configured for FT” is No. It will display the items required for that particular ESX for FT to work.

VMware VSphere Interview Questions & Answers With ScreenShot
What is FT Logging Traffic?

FT logging is the one of option in VMkernel port setting which is similar to enable vmotion option in the vmkernel port. when FT is enabled for the virtual machine, all the inputs (disk read.. wirte,etc..) of the primary virtual machine are recorded and sent to the secondary VM over via FT logging enabled VMkernel port.

How to Enable FT Logging in VMkernel Port?

GO the ESX host -> Configuration-> Networking -> Properties of Virtual switch with the VMkernel portgroup configured
Click on VMkernel Port -> click on Edit -> General tab -> select the Fault Tolerance Logging -> click on OK.

How do you configure or enable FT for the virtual machine ?

FT can be enabled only per virtual machine basis not at the cluster or ESX level.
Right-click the virtual Machine -> Fault Tolerance -> Turn on Fault Tolerance

VMware VSphere Interview Questions & Answers With ScreenShot

How does the FT enabled virtual machine will be differentiated with non FT VM’s in vSphere client?

FT Enabled Virtual machine will appear in Dark Blue colour as compared to non-protected virtual machines.


By default, Only Primary virtual machine will appear under the cluster and ESX host. To take a look at the secondary VM , Go to Virtual Machines tab of the Cluster or Host.

VMware VSphere Interview Questions & Answers With ScreenShot

How Does VMware Fault Tolerance Work?

When you enable Fault Tolerance for the virtual machine, a secondary virtual machine will be created to work with the primary virtual machine in which you have enabled FT. The primary and secondary virtual machine resides on a different ESX hosts in the cluster. Whatever the events or actions performed by the primary VM will be transmitted via
gigabit Ethernet network to be replayed by the secondary virtual machine using VLockstep technology. Eventhough both the primary and secondary virtual machines appear as a single entity and access a common disk, both running with the single IP address, MAc address but writes are only performed by the primary virtual machine.The primary and secondary virtual machines sends heartbeat between each other frequently with millisecond intervals to the check for the availability. If either of the virtual machine loses the heartbeat, other virtual machine will take over the primary virtual machine role immediately.

VMware VSphere Interview Questions & Answers With ScreenShot

What happens when you enabled Fault Tolerance for your virtual machine?

When you enable Fault Tolerance for the virtual machine, a secondary virtual machine (live shadow image of the primary) will be created to work with the primary virtual machine in which you have enabled FT. The primary and secondary virtual machine resides on a different ESX hosts in the cluster.

What will happen when the ESX host of primary VM failed?

When a failure is detected on the primary VM’s ESX host, the secondary virtual machine which is running on the another ESX server in the same cluster will takes the place of the first one with the least possible interruption of service.

If vCenter is down, will the FT work?

vCenter server is only required to enable FT on the virtual machine.once it is configured, vCenter is not required to be in online for FT to work. FT failover between primary and secondary will occure even if the vCenter is down.

How does Vmware FT differs from VMware HA?

1.VMware HA is enabled per cluster basis but FT is enabled per VM basis.
2. In case of ESX host failure, virtual machines in the failed host are restarted and powered-on on the other active hosts in HA cluster. So the restart duration of the virtual machine is the downtime for the virtual machine in HA cluster. But in FT enabled virtual machine, there is no downtime. In case of host failure, secondary VM will become primary and continuing the execution from the exact point where the primary VM is left off or failed. It happens automatically without data loss, without downtime and with a little delay. Users will not see any interruption.

How do you see the summary status of the FT enabled virtual machines in the ESX host from vsphere client?

Click on Summary tab of the ESX host -> Fault tolerance information and VM counts will be displayed

vmware

VMware VSphere Interview Questions & Answers With ScreenShot

What is VMware HA?
As per VMware Definition,
VMware® High Availability (HA) provides easy to use, cost effective high availability for applications running in virtual
machines. In the event of server failure, affected virtual machines are automatically restarted on other production
servers with spare capacity

What is AAM in HA?
AAM is the Legato automated availability management. Prior to vSphere 4.1, VMware’s HA is actually re engineered to
work with VM’s with the help of Legato’s Automated Availability Manager (AAM) software. VMware’s vCenter agent
(vpxa) interfaces with the VMware HA agent which acts as an intermediary to the AAM software. From vSphere 5.0, it
uses an agent called “FDM” (Fault Domain Manager).

What are pre-requites for HA to work?
1.Shared storage for the VMs running in HA cluster
2.Essentials plus, standard, Advanced, Enterprise and Enterprise Plus Licensing
3.Create VMHA enabled Cluster
4.Management network redundancy to avoid frequent isolation response in case of temporary network issues (preferred
not a requirement)

What is maximum number of primary HA hosts in vSphere 4.1?
Maximum number of primary HA host is 5. VMware HA cluster chooses the first 5 hosts that joins the cluster as primary
nodes and all others hosts are automatically selected as secondary nodes.

How to see the list of Primary nodes in HA cluster?
View the log file named “aam_config_util_listnodes.log” under /var/log/vmware/aam using the below command
cat /var/log/vmware/aam/aam_config_util_listnodes.log

VMware VSphere Interview Questions & Answers With ScreenShot
What is the command to restart /Start/Stop HA agent in the ESX host?
service vmware-aam restart
service vmware-aam stop
service vmware-aam start

Where to located HA related logs in case of troubleshooting?
/Var/log/vmware/aam

What the basic troubleshooting steps in case of HA agent install failed on hosts in HA cluster?
Below steps are are taken from my blog posts Troubleshooting HA
1. Check for some network issues
2. Check the DNS is configured properly
3. Check the vmware HA agent status in ESX host by using below commands service vmware-aam status
4. Check the networks are properly configured and named exactly as other hosts in the cluster. otherwise, you will get the below errors while installing or reconfiguring HA agent.
5. Check HA related ports are open in firewall to allow for the communication

Incoming port: TCP/UDP 8042-8045
Outgoing port: TCP/UDP 2050-2250
6. First try to restart /stop/start the vmware HA agent on the affected host using the below commands. In addition u can also try to restart vpxa and management agent in the Host.
service vmware-aam restart
service vmware-aam stop
service vmware-aam start
7. Right Click the affected host and click on “Reconfigure for VMWare HA” to re-install the HA agent that particular host.
8. Remove the affected host from the cluster. Removing ESX host from the cluster will not be allowed untill that host is put into maintenance mode.
9.Alternative solution for 3 step is, Goto cluster settings and uncheck the vmware HA in to turnoff the HA in that cluster and re-enable the vmware HA to get the agent installed.
10. For further troubleshooting , review the HA logs under /Var/log/vmware/aam directory.

What is the maximum number of hosts per HA cluster?
Maximum number of hosts in the HA cluster is 32

What is Host Isolation?
VMware HA has a mechanism to detect a host is isolated from rest of hosts in the cluster. When the ESX host loses its ability to exchange heartbeat via management network between the other hosts in the HA cluster, that ESX host will be considered as a Isolated.

How Host Isolation is detected?
In HA cluster, ESX hosts uses heartbeats to communicate among other hosts in the cluster.By default, Heartbeat will be sent every 1 second. If a ESX host in the cluster didn’t received heartbeat for for 13 seconds from any other hosts in the cluster, The host considered it as isolated and host will ping the configured isolation address(default gateway by default). If the ping fails, VMware HA will execute the Host isolation response.

What are the different types isolation response available in HA?

VMware VSphere Interview Questions & Answers With ScreenShot
Power off – All the VMs are powered off , when the HA detects that the network isolation occurs
Shut down – All VMs running on that host are shut down with the help of VMware Tools, when the HA detects that the network isolation occurs.If the shutdown via VMWare tools not happened within 5 minutes, VM’s power off operation will be executed. This behavior can be changed with the help of HA advanced options. Please refer my Post on HA Advanced configuration 

Leave powered on – The VM’s state remain powered on or remain unchanged, when the HA detects that the network isolation occurs.

How to add additional isolation address for redundancy?
By default, VMWare HA use to ping default gateway as the isolation address if it stops receiving heartbeat.We can add
an additional values in case if we are using redundant service console both belongs to different subnet.Let’s say we
can add the default gateway of SC1 as first value and gateway of SC2 as the additional one using the below value
1. Right Click your HA cluster
2. Goto to advanced options of HA
3. Add the line “das.isolationaddress1 = 192.168.0.1”
4. Add the line “das.isolationaddress2 = 192.168.1.1” as the additional isolation address
To know more about the Advanced HA Options

What is HA Admission control?
As per “VMware Availability Guide”,
VCenter Server uses admission control to ensure that sufficient resources are available in a cluster to provide failover
protection and to ensure that virtual machine resource reservations are respected.

What are the 2 types of settings available for admission control?

VMware VSphere Interview Questions & Answers With ScreenShot
Enable: Do not power on VMs that violate availability constraints
Disable: Power on VMs that violate availability constraints

What are the different types of Admission control policy available with VMware HA?
There are 3 different types of Admission control policy available.

VMware VSphere Interview Questions & Answers With ScreenShot
Host failures cluster tolerates
Percentage of cluster resources reserved as fail over spare capacity
Specify a fail over host.

How the Host Failures cluster tolerates admission control policy works?

VMware VSphere Interview Questions & Answers With ScreenShot5
Select the maximum number of host failures that you can afford for or to guarantee fail over. Prior vSphere 4.1,
Minimum is 1 and the maximum is 4.
In the Host Failures cluster tolerates admission control policy , we can define the specific number of hosts that can fail in the cluster and also it ensures that the sufficient resources remain to fail over all the virtual machines from that failed hosts to the other hosts in cluster. VMware High Availability(HA) uses a mechanism called slots to calculate both the available and required resources in the cluster for a failing over virtual machines from a failed host to other hosts
in the cluster.

What is SLOT?
As per VMWare’s Definition,
“A slot is a logical representation of the memory and CPU resources that satisfy the requirements for any powered-on virtual machine in the cluster.” If you have configured reservations at VM level, It influence the HA slot calculation. Highest memory reservation and highest CPU reservation of the VM in your cluster determines the slot size for the cluster.

How to Check the HA Slot information from vSphere Client?
Click on Cluster Summary Tab and Click on “Advanced Runtime Info” to see the the detailed HA slots information.

VMware VSphere Interview Questions & Answers With ScreenShot

What is use of Host Monitoring status in HA cluster?

VMware VSphere Interview Questions & Answers With ScreenShot

Let’s take an example, you are performing network maintenance activity on your switches which connects your one of th ESX host in HA cluster. 

what will happen if the switch connected to the ESX host in HA cluster is down?

It will not receive heartbeat and also ping to the isolation address also failed. so, host will think itself as isolated and HA will initiate the reboot of virtual machines on the host to other hosts in the cluster. Why do you need this unwanted situation while performing scheduled maintenance window.
To avoid the above situation when performing scheduled activity which may cause ESX host to isolate, remove the check box in ” Enable Host Monitoring” until you are done with the network maintenance activity.

How to Manually define the HA Slot size?
By default, HA slot size is determined by the Virtual machine Highest CPU and memory reservation. If no reservation is specified at the VM level, default slot size of 256 MHZ for CPU and 0 MB + memory overhead for RAM will be taken as slot size. We can control the HA slot size manually by using the following values.

There are 4 options we can configure at HA advanced options related to slot size

das.slotMemInMB – Maximum Bound value for HA memory slot size
das.slotCpuInMHz – Maximum Bound value for HA CPU slot Size
das.vmMemoryMinMB – Minimum Bound value for HA memory slot size
das.vmCpuMinMHz – Minimum Bound value for HA CPU slot size

How the “Percentage of cluster resources reserved as failover spare capacity” admission control policy works?

VMware VSphere Interview Questions & Answers With ScreenShot
In the Percentage of cluster resources reserved as failover spare capacity admission control policy, We can define the specific percentage of total cluster resources are reserved for failover.In contrast to the “Host Failures cluster tolerates admission control policy”, It will not use slots. Instead This policy calculates the in the way below

1.It calculates the Total resource requirement for all Powered-on Virtual Machines in the cluster and also calculates the total resource available in host for virtual machines.
2.It calculates the current CPU and Memory Failover capacity for the capacity.
3.If the current CPU and Memory Failover capacity for the cluster < configured failover capacity (ex 25 %)
4.Admission control will not allow to power on the virtual machine which violates the availability constraints.

How the “Specify a failover host” admission control policy works?

VMware VSphere Interview Questions & Answers With ScreenShot
In the Specify a failover host” admission control policy, We can define a specific host as a dedicated failover host. When isolation response is detected, HA attempts to restart the virtual machines on the specified failover host.In this Approach, dedicated failover hist will be sitting idle without actively involving or not participating in DRS load balancing.DRS will not migrate or power on placement of virtual machines on the defined failover host.

What is VM Monitoring status?
HA will usually monitors ESX hosts and reboot the virtual machine in the failed hosts in the other host in the cluster in case of host isolation but i need the HA to monitors for Virtual machine failures also. here the feature called VM monitoring status as part of HA settings.VM monitoring restarts the virtual machine if the vmware tools heartbeat didn’t received with the specified time using Monitoring sensitivity.

VMware VSphere Interview Questions & Answers With ScreenShot

What is Service Console?
The service console is developed based up on Redhat Linux Operating system, it is used to manage the VMKernel 

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)

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.

What is the command used to restart SSH, NTP & Vmware Web access?
Service sshd restart
Service ntpd restrat
Service vmware-webaccess restart

What are the types of Ports groups in ESX/ESXi?
There are 3 types of port groups in ESX
1.Service console port group
2.VMkernel Port group
3. Virtual machine port group
There are only 2 types of port group in ESXi
1. Vmkernel Port group
2.Virtual Machine Port group

What is VMKernel ?
VMWare Kernel is a Proprietary kernel of vmwareand 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.

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.

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.

What is the use of Virtual Machine Port Group?
Virtual Machine port group is used by Virtual machine communication.

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.

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.

What are the different types of Partitions in ESX server?
/ -root
Swap
/var
/Var/core
/opt
/home
/tmp

What are the security options available for ESX vswitch?
Promiscuous Mode – Reject
MAC Address changes – Accept
Forged Transmits – Accept

VMware VSphere Interview Questions & Answers With ScreenShot

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.

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.

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.

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.

What are the types of VLAN tagging in Vsphere?
There are 3 types of VLAN tagging available in Vsphere.
1.Virtual Switch Tagging (VST)
2.External Switch Tagging (EST)
3.Virtual Guest Tagging (VGT)

What are the Traffic Shaping policies available in the Vswitch?
Traffic shaping policies are disabled by default. There are 3 different traffic shaping policy setting
Average Bandwidth
Peak Bandwidth
Burst Size

VMware VSphere Interview Questions & Answers With ScreenShot

Average Bandwidth is defined in KBPS
Peak bandwidth is defined in KBPS
Burst Size is defined in Kilobytes

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

VMware VSphere Interview Questions & Answers With ScreenShot
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.

What are the types for Network Failover Detection settings?
Link Status only
Beacon Probing
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.
What is the command to check the IP address along with the detailed network cards assigned to the esx
server?
Ifconfig -a
Output appears like this
========================================================================
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:9365 errors:0 dropped:0 overruns:0 frame:0
TX packets:9365 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:8127714 (7.7 MiB) TX bytes:8127714 (7.7 MiB)
vmnic0 Link encap:Ethernet HWaddr 00:0C:29:85:0D:76
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:100772 errors:0 dropped:0 overruns:0 frame:0
TX packets:5103 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:35475848 (33.8 MiB) TX bytes:402120 (392.6 KiB)
Interrupt:145
vmnic1 Link encap:Ethernet HWaddr 00:0C:29:85:0D:80
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:105895 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:35894203 (34.2 MiB) TX bytes:0 (0.0 b)
Interrupt:129
vmnic2 Link encap:Ethernet HWaddr 00:0C:29:85:0D:8A
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:105908 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:35895750 (34.2 MiB) TX bytes:0 (0.0 b)
Interrupt:137
vmnic3 Link encap:Ethernet HWaddr 00:0C:29:85:0D:94
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:105690 errors:0 dropped:0 overruns:0 frame:0
TX packets:228 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:35883279 (34.2 MiB) TX bytes:13680 (13.3 KiB)
Interrupt:145
vswif0 Link encap:Ethernet HWaddr 00:50:56:4D:69:D1
inet addr:192.168.0.75 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:14893 errors:0 dropped:0 overruns:0 frame:0
TX packets:2575 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:966513 (943.8 KiB) TX bytes:230028 (224.6 KiB)
vswif1 Link encap:Ethernet HWaddr 00:50:56:4F:45:B1
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:11042 errors:0 dropped:0 overruns:0 frame:0
TX packets:30 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:717158 (700.3 KiB) TX bytes:1260 (1.2 KiB)
========================================================================
=
You can use “ip addr” command also to view the ip information
========================================================================
=
[root@ESXTEST1 etc]# ip addr
1: lo: mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
2: vmnic0: mtu 1500 qdisc noop qlen 1000
link/ether 00:0c:29:85:0d:76 brd ff:ff:ff:ff:ff:ff
3: vmnic1: mtu 1500 qdisc noop qlen 1000
link/ether 00:0c:29:85:0d:80 brd ff:ff:ff:ff:ff:ff
4: vmnic2: mtu 1500 qdisc noop qlen 1000
link/ether 00:0c:29:85:0d:8a brd ff:ff:ff:ff:ff:ff
5: vmnic3: mtu 1500 qdisc noop qlen 1000
link/ether 00:0c:29:85:0d:94 brd ff:ff:ff:ff:ff:ff
6: vswif0: mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:50:56:4d:69:d1 brd ff:ff:ff:ff:ff:ff
inet 192.168.0.75/24 brd 192.168.0.255 scope global vswif0
7: vswif1: mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:50:56:4f:45:b1 brd ff:ff:ff:ff:ff:ff
9: vswif2: mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:50:56:43:92:be brd ff:ff:ff:ff:ff:ff
inet 192.168.0.96/24 brd 192.168.0.255 scope global vswif2
========================================================================
=
what is the command to check the ESX vswitch details, port group and its ip address?
Esxcfg-vswitch -l
Outuput will appear like this:
========================================================================
=
[root@ESXTEST1 ~]# esxcfg-vswitch -l
Switch Name Num Ports Used Ports Configured Ports MTU Uplinks
vSwitch0 32 4 32 1500 vmnic0
PortGroup Name VLAN ID Used Ports Uplinks
Service Console 0 1 vmnic0
VMkernel 0 1 vmnic0
Switch Name Num Ports Used Ports Configured Ports MTU Uplinks
vSwitch1 64 3 64 1500 vmnic2,vmnic1
PortGroup Name VLAN ID Used Ports Uplinks
VM-10.0.0 subnet 0 0 vmnic2,vmnic1
VM-192.168.0 subnet 0 0 vmnic2,vmnic1
Switch Name Num Ports Used Ports Configured Ports MTU Uplinks
vSwitch2 64 4 64 1500 vmnic3
PortGroup Name VLAN ID Used Ports Uplinks
Service Console 2 0 1 vmnic3
Vmotion 0 1 vmnic3
========================================================================
=
From the above output,
we come to know that we have 3 virtual switches named vSwitch0,vSwitch1 and vSwitch2.
4 uplinks (physical nics in our esx server) Vmnic0,vmnic1,vmnic2,vmnic3.
vswitch0 constains 2 port group (Service Console & VMKernel), vSwitch1 contains 2 virtual machine port group (VM10.0.0
subnet & VM-192.168.0 subnet) and Vswitch2 contains 2 port group (Service Console 2 & Vmotion) port group.
What is command to get the information about Service console ports and its IP address assigned to it?
esxcfg-vswif -l
Output will appear like this:
========================================================================
=
[root@ESXTEST1 ~]# esxcfg-vswif -l
Name Port Group/DVPort IP Family IP Address Netmask Broadcast
Enabled TYPE
vswif0 Service Console IPv4 192.168.0.75 255.255.255.0 192.168.0.255
true STATIC
vswif1 Service Console 2 IPv4 192.168.0.78 255.255.255.0 192.168.0.255
false STATIC
========================================================================
=
what is the command to get the information about vmkernel ports and its ip address?
esxcfg-vmknic -l
Output will appear like this:
========================================================================
=
[root@ESXTEST1 ~]# esxcfg-vmknic -l
Interface Port Group/DVPort IP Family IP Address Netmask Broadcast MAC Address
MTU TSO MSS Enabled Type
vmk0 VMkernel IPv4 192.168.0.110 255.255.255.0 192.168.0.255
00:50:56:78:7e:73 1500 65535 true STATIC
vmk1 Vmotion IPv4 192.168.0.77 255.255.255.0 192.168.0.255
00:50:56:76:42:df 1500 65535 true S
========================================================================
=
what is the command to get the information about physical nics installed on ESX server?
esxcfg-vmknic -l
Output will appear like this:
========================================================================
=
[root@ESXTEST1 sbin]# esxcfg-nics -l
Name PCI Driver Link Speed Duplex MAC Address MTU Description
vmnic0 02:00.00 e1000 Up 1000Mbps Full 00:0c:29:85:0d:76 1500 Intel Corporation 82545EM Gigabit
Ethernet Controller (Copper)
vmnic1 02:02.00 e1000 Up 1000Mbps Full 00:0c:29:85:0d:80 1500 Intel Corporation 82545EM Gigabit
Ethernet Controller (Copper)
vmnic2 02:03.00 e1000 Up 1000Mbps Full 00:0c:29:85:0d:8a 1500 Intel Corporation 82545EM Gigabit
Ethernet Controller (Copper)
vmnic3 02:04.00 e1000 Up 1000Mbps Full 00:0c:29:85:0d:94 1500 Intel Corporation 82545EM Gigabit
Ethernet Controller (Copper)
========================================================================
What is command to add the new virtual switch named (vswitch3) to our ESX server?
[root@ESXTEST1 sbin]# esxcfg-vswitch -a vswitch3
Now vswitch3 is created without any port group.
======================================================================
Switch Name Num Ports Used Ports Configured Ports MTU Uplinks
vswitch3 64 1 64 1500
PortGroup Name VLAN ID Used Ports Uplinks
========================================================================
What is command to add the new port group named (mgmt)to vswitch (vswitch 3) ?
[root@ESXTEST1 sbin]# esxcfg-vswitch -A mgmt vswitch3
now port group “mgmt” is added.
========================================================================
=
Switch Name Num Ports Used Ports Configured Ports MTU Uplinks
vswitch3 64 1 64 1500
PortGroup Name VLAN ID Used Ports Uplinks
mgmt 0 0
========================================================================
=
How to add the service console port (vswif2) to our newly created port group “mgmt” with the ip addr
192.168.0.79 ?
[root@ESXTEST1 sbin]# esxcfg-vswif -a vswif2 -i 192.168.0.79 -n 255.255.255.0 -p “mgmt”
where i is the ip address, n is subnet mask p is to mentione the port group name
========================================================================
=
vswif2 mgmt IPv4 192.168.0.79 255.255.255.0 192.168.0.255
true STATIC
========================================================================
=
How to add the vmkernal port (vmk2) to our newly created port group “mgmt” with the ip addr
192.168.0.83?
[root@ESXTEST1 sbin]# esxcfg-vmknic -a -i 192.168.0.83 -n 255.255.255.0 -p “mgmt”
========================================================================
=
vmk2 mgmt IPv4 192.168.0.83 255.255.255.0 192.168.0.255 00:50:56:7b:bd:36 1500
65535 true STATIC
========================================================================
=
How to change the ip addresss of the existing service console “vswif2″?
nano /etc/sysconfig/network-scripts/ifcfg-vswif2.
Edit the file with your new id address ” 192.168.0.255″ then save and exit.
======================================================
DEVICE=vswif2
HOTPLUG=yes
MACADDR=00:50:56:43:92:be
ONBOOT=yes
PORTGROUP=mgmt
BOOTPROTO=static
BROADCAST=192.168.0.255
DHCPV6C=no
IPADDR=192.168.0.96
IPV6INIT=no
IPV6_AUTOCONF=no
NETMASK=255.255.255.0
======================================================
restart the network service for ip change to take effect:
[root@ESXTEST1 sysconfig]# service network restart
Shutting down interface vswif0: [ OK ]
Shutting down interface vswif2: [ OK ]
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface vswif0: [ OK ]
Another way is to connect to the console of the ESX server and at the shell prompt type in :esxcfg-vswif -d vswif2
This will delete the existing vswif0 and it will give the message about “nothing to flush”.
then type the below command
esxcfg-vswif -a vswif2 -p mgmt -i 192.168.0.97 -n 255.255.255.0
========================================================================
=
[root@ESXTEST1 etc]# esxcfg-vswif -d vswif2
Nothing to flush.
[root@ESXTEST1 etc]# esxcfg-vswif -a vswif2 -p mgmt -i 192.168.0.97 -n 255.255.255.0
[2011-09-17 19:35:46 ‘Vnic’ warning] Generated New MAC address, 00:50:56:43:92:be for vswif2
Nothing to flush.
========================================================================
=
How to change the ESX host name and default gateway?
edit the below file:
nano /etc/sysconfig/network
======================================
NETWORKING=yes
HOSTNAME=ESXTEST1.lab.com
GATEWAY=192.168.0.20
GATEWAYDEV=vswif0
IPV6_AUTOCONF=no
NETWORKING_IPV6=no
======================================
restart the network service for ip change to take effect:
[root@ESXTEST1 sysconfig]# service network restart
How to edit the ESX host file ?
nano /etc/hosts
Edit the file to make entry to your host file.
==========================================
127.0.0.1 localhost
::1 localhost
192.168.0.75 ESXTEST1.lab.com ESXTEST1
==========================================
How to edit the DNS entry of your ESX server?
nano /etc/resolv.conf
Edit the file to make changes or to make new entry of dns for your ESX server
========================
nameserver 192.168.0.20
search lab.com
=======================
what is the command to query the firewall ports ?
esxcfg-firewall – q
How to open the port in firewall (port no 8877, tcp, incoming , name: test3 ?
esxcfg-firewall -o 8877,tcp,in,test3
1.What is SvMotion?
Migration of a virtual machine files and disks from one datastore to another with Zero downtime.
2. What are the use cases of SvMotion ?

  • Migrating from Old storage to new storage systems or migrating to different vendor storage without
    downtime to VM’s.
    • Performing Scheduled activity like storage upgrades on the source Lun.
    • Converting VM disk type from Thick to Thin and Thin to Thick.
    • Migrating the critical virtual machines to high performance storage arrays to improve performance of virtual
    Machine.
    3. What are Pre-requisites for the SvMotion to Work?
    • ESX host in which virtual machine is running should have access to source and destination storage.
    • ESX host should have configured with the license for svMotion
  1. What are the Limitations of SvMotion?
    • Virtual machines with snapshots cannot be migrated using Storage vMotion.
    • Virtual machine with virtual compatibility RDM can be migrated with svMotion.If you convert the mapping file, a
    new virtual disk is created and the contents of the mapped LUN are copied to this disk.
    • For Physical compatibility RDM, only mapping file can be relocated.
    • Virtual Machines cannot be migrated while the VMware tools installation tools is in progress.
    • Virtual Machine should be in powered off state if you want to migrate the VM simultaneously to different host
    and storage.
    5. Steps involved in VMWare SvMotion ?
  • svMotion copies all the files expect virtual machine disk and create the directory as same the Virtual Machine
    name on the destination storage.
    • It uses Changed Block tracking to track the virtual machine disk. The change block tracking knows which region
    disk includes data. This data will be stored in bitmap and reside either in memory or in a file.
    • Pre-copies Virtual machine disk and swap file will start from the source to destination datastore as the first
    iteration. once it is completed, It only transfers the region which were modified or written after the first
    iteration.
    • ESX performs fast suspend and resume of the virtual Machine. The final changed regions will be copied to the
    destination before the virtual Machine is resumed on the destination datastore.
    • Virtual Machine will continue running on the destination datastore and source file and disk will be deleted.
    1.What is vMotion?
    Live migration of a virtual machine from one ESX server to another with Zero downtime . VMs disk files stay where
    they are (on shared storage)
    2. What are the use cases of vMotion ?
    • Balance the load on ESX servers (DRS
    • Save power by shutting down ESX using DPM
    • Perform patching and maintenance on ESX server (Update Manager or HW maintenance
    3. What are Pre-requisites for the vMotion to Work?
    • ESX host must be licensed for VMotion
    • ESX servers must be configured with vMotion Enabled VMkernel Ports.
    • ESX servers must have compatible CPU’s for the vMotion to work
    • ESX servers should have Shared storage (FB, iSCSI or NFS) and VM’s should be stored on that storage.
    • ESX servers should have exact similar network & network names
    4. What are the Limitations of vMotion?
    • Virtual machines configured with the Raw Device Mapping(RDM) for clustering features using vMotion
    • VM cannot be connected to a CD-ROM or floppy drive that is using an ISO or floppy image stored on a drive
    that is local to the host server. The device should be disconnected before initiating the vMotion.
    • Virtual Machine cannot be migrated with VMotion unless the destination swapfile location is the same as
    the source swapfile location. As a best practice, Place the virtual machine swap files with the virtual machine
    configuration file.
    • Virtual Machine affinity must not be set (aka, bound to physical CPUs).
    5. Steps involved in VMWare vMotion ?
  • A request has been made that VM-1 should be migrated (or “VMotioned”) from ESX A to ESX B.
    • VM-1’s memory is pre-copied from ESX A to ESX B while ongoing changes are written to a memory bitmap on
    ESX A.
    • VM-1 is quiesced on ESX A and VM-1’s memory bitmap is copied to ESX B.
    • VM-1 is started on ESX B and all access to VM-1 is now directed to the copy running on ESX B.
    • The rest of VM-1’s memory is copied from ESX A all the while memory is being read and written from VM-1 on
    ESX A when applications attempt to access that memory on VM-1 on ESX B.
    • If the migration is successful, VM-1 is unregistered on ESX A

 

Read More about : Microsoft’s New Data Center Sits at the Bottom of the Sea

Share it

Leave a Reply

Your email address will not be published. Required fields are marked *