VMware Interview Questions & Answers -VMware Fault Tolerance

Transcription

VMware Interview Questions & Answers -VMware Fault Tolerance
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 technology
What are requirements and Limitattions 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
Validate that
Validate that
Validate that
Validate that
Validate that
Validate that
Validate that
Fault Tolerancelogging NIC speed is at least 1000 Mbps.
power management is supported on the host
Fault Tolerance logging is enabled.
VMotion NIC speed is at least 1000 Mbps.
all the hosts in the cluster have the same build for Fault Tolerance
the host hardware supports Fault Tolerance.
VMotion is enabled.
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.
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
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.
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.
Graphics Thanks toVMware.com
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
Clone
Template
Clone creates an exact copy of a running Virtual
Machine at the time of cloning process
Template acts as a baseline image with the predefined
configuration as per organization standards
Cloning a virtual machine creates a exact duplicate
copy of the virtual machine with the same configuration
and installed software without performing any
additional settings.
Create a template to create a master image of a
virtual machine from which you can deploy multiple
virtual machines
You can create a clone of existing installed and
Configured running virtual machine by right clicking
the VM and Clone.
You can create a template by converting a virtual machine
to a template, cloning a virtual machine to a template, or cloning
another template
VM clones are best suited in test and development
environments where you want to create, test and work
with exact copies of production servers without
disturbing production servers by creating clone of the
production virtual machine.
Templates are best suited for production environments where you
want the mass deployment of virtual machines along with the
installed OS and basic software, configured policy as per
the security policy of your organization as a base Machine.
Once template is deployed, you can install software depend
on the role of the server like IIS,Database
VM Clones are not suited for mass deployment of
Virtual Machines
Templates are best suited for Mass Deployment of Virtual
Machines
We Cannot Convert back the Cloned Machine
You can convert the template back to virtual machine to update
the base template with the latest released patches and updates
and to install or upgrade any software and again convert back
to template to be used for deployment of virtual machines
with latest patches.
Cloned Virtual Machine Can be powered on
Templates cannot be powered on
You cannot Clone a Virtual Machine if you have
connected directly to ESX/ESXi host using vSphere
Client
You cannot create a template of a Virtual Machine if you
have connected directly to ESX/ESXi host using vSphere Client
You can customize the guest operating system of the
clone to change the virtual machine name, network
settings, and other properties. This prevents conflicts
that can occur if a virtual machine and a clone with
identical guest operating system settings are deployed
simultaneously.
Clone of a virtual machine can be created when the
virtual machine is powered on
You can also Customize the guest operating system while
deploying from template
Convert virtual Machine to template cannot be performed,
when Virtual machine is powered on. Only Clone to Template
can be performed when VM is powered on
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
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?
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?
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.
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?
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 the HA Slots are Calculated?
I have written a post about how the HA slots are calculated.
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.
What is use of Host Monitoring status in HA cluster?
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
For More HA related Advanced options, Please refer my blog post
How the "Percentage of cluster resources reserved as failover spare capacity" admission control policy
works?
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?
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.
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
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 is VST , EST & VGT?
Please refer my blog post on VST , EST & 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
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
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 bytes:35475848 (33.8 MiB) TX bytes:402120 (392.6 KiB)
Interrupt:145
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
RX bytes:35895750 (34.2 MiB) TX bytes:0 (0.0 b)
Interrupt:137
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
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 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
link/ether 00:0c:29:85:0d:8a 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
link/ether 00:50:56:4f:45:b1 brd ff:ff:ff:ff:ff:ff
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
Uplinks
vSwitch1
64
3
64
1500 vmnic2,vmnic1
PortGroup Name
VM-10.0.0 subnet 0
0
vmnic2,vmnic1
VM-192.168.0 subnet 0
0
vmnic2,vmnic1
vSwitch2
64
4
64
1500 vmnic3
Uplinks
PortGroup Name
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
========================================================================
=
[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
========================================================================
=
[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
vmnic2 02:03.00 e1000
Up 1000Mbps Full 00:0c:29:85:0d:8a 1500 Intel Corporation 82545EM Gigabit
vmnic3 02:04.00 e1000
========================================================================
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.
======================================================================
vswitch3
64
1
64
1500
Uplinks
PortGroup Name
========================================================================
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.
========================================================================
=
Uplinks
vswitch3
64
1
64
1500
PortGroup Name
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
4. 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
•
ESX servers should have exact similar network & network names
storage.
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.

VMware Interview Questions & Answers -VMware Fault Tolerance

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VMware Interview Questions &amp; Answers -VMware Fault Tolerance

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VMware Interview Questions & Answers -VMware Fault Tolerance