Adding users to Distribution List in Exchange 2010

You need to be assigned permissions before you can perform this procedure. To see what permissions you need, see the "Distribution groups" entry in the Mailbox Permissions topic.

1. In the console tree, navigate to Recipient Configuration > Distribution Group.

2. In the result pane, select the distribution group to which you want to add a member.
3. In the action pane, under the distribution group name, click Properties.
4. In <Distribution Group> Properties, on the Members tab, click Add to open the Select Recipient dialog box.
5. In Select Recipient, click the recipient you want to add to the distribution group, and then click OK.

Note:

To add multiple recipients, hold down the CTRL key while selecting recipients.

6. Click OK to save your changes.

Bugzilla step by step installation

Installing Bugzilla-4.2 on CENTOS / FEDORA/ RHEL Linux

Step 1: update remi repository

#  rpm –Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-5.noarch.rpm

#  rpm –Uvh http://rpms.famillecollet.com/enterprise/remi-release-6.rpm

Step 2: yum update

            yum install perl-CPAN

yum install httpd mysql-server mod_perl mod_perl-devel httpd-devel graphviz patchutils gcc perl-DateTime perl-Template-Toolkit perl-Email-Send perl-Email-MIME perl-GD perl-Chart perl-Template-GD perl-GDGraph perl-GDTextUtil perl-PatchReader perl-MIME-tools perl-LDAP perl-Authen-SASL perl-RadiusPerl perl-SOAP-Lite perl-JSON-RPC perl-JSON-XS perl-Test-Taint perl-HTML-Scrubber perl-Email-MIME-Attachment-Stripper perl-Email-Reply perl-TheSchwartz perl-Daemon-Generic perl-Math-Random-Secure perl-YAML perl-Class-Inspector

Step 3: # restorecon –Rv /var/www/html/

Step 4: Now download latest bugzilla-4.2 tar file from the below link.

            Note: The downloaded bugzilla tar file should be moved to /var/www/html/ directory.

            

            # cd /var/www/html

            http://ftp.mozilla.org/pub/mozilla.org/webtools/bugzilla-4.2.tar.gz

            Now untar the downloaded bugzilla tar ball

            # tar zxf bugzilla-4.2.tar.gz

            # mv bugzilla-4.2 bugzilla4

            # chown –R 751 bugzilla4

            # chown root:apache –R bugzilla4

            # cd bugzilla4

            check for missing modules

# ./checksetup.pl --check-modules

To install all the missing modules just type the following:

            # /usr/bin/perl install-module.pl --all

           

            Recheck of missing modules

# ./checksetup.pl --check-modules

You can install missing modules one by one by the following methods –

1.      /usr/bin/perl install-module.pl <module name>

2.      # cpan

cpan>  install <module name>

3.      Perl –MCPAN –e ‘install “<module name>”’

# ./checksetup.pl

Note:  You would not be able to install the Encode : Detect module but no need to worry, it is a optional module.

If all the necessary modules are installed properly, then it will ask to edit  ./localconfig file.

# vi ./localconfig

Search for $ db_pass=’ ’ line in localconfig file

Now put type a new password for mysql as shown below.

 $ db_pass=’your password for sql’

         

Step5: Modify /etc/my.cnf to increase bugzilla attachment size:

            # vi /etc/my.cnf

            Add the below line in my.cnf file

            max_allowed_packet=10M

Above will allow attachment size upto 10 mb, you can change the attachment size as per your requirements. 

Step 6: Creating My SQL database bugs for bugzilla server :

                    

            # service mysqld restart

            # mysql

sql> create database bugs;

        Query OK, 1 row affected (0.00 sec)

sql> GRANT SELECT, INSERT, UPDATE, DELETE, INDEX, ALTER, CREATE, LOCK TABLES,    CREATE TEMPORARY TABLES, DROP, REFERENCES ON bugs.* TO bugs@localhost IDENTIFIED BY ‘your password for  mysql’;

          Query OK, 0 rows affected (0.00 sec)

sql> FLUSH PRIVILEGES;

sql> quit;

Step 7: Setup the Administrative User for Bugzilla

Rerun checksetup.pl. It reconfirms that all the modules are present, and notices the altered localconfig file, which it assumes you have edited to your satisfaction. It compiles the UI templates, connects to the database using the ‘bugs’ user you created and the password you defined, and creates the ‘bugs’ database and the tables therein.

If all goes well, it will ask you for an email for the Bugzilla Administrator account and the password for that account.

$ ./checksetup.pl

Step 8: Add the following to the httpd.conf file. This assumes you installed Bugzilla in the default path.

#vi /etc/httpd/conf/httpd.conf

find, uncomment and edit the following two lines:

ServerAdmin  root@yoursystemhostname     (line no.262 of your httpd.conf file)

ServerName  yoursystemhostname:80            (line no.276 of your httpd.conf file)

Also find and uncomment the following line:

AddHandler cgi-script .cgi     (you can find this at line no. 799 of your httpd.conf file)

            Type the below two line at the end of httpd.conf file:

PerlSwitches -I/var/www/html/bugzilla -I/var/www/html/bugzilla/lib -w -T

PerlConfigRequire /var/www/html/bugzilla/mod_perl.pl

Step 9: Now restart Apache web server:

# service httpd restart

Step 10: Open port 80 in firewall table:

# iptables –A INPUT –p tcp --dport 80 –j ACCEPT

# service iptables save

Now you can see your running bugzilla server on

http://localhost/bugzilla

Note: If you are not able to see your bugzilla server on the browser, then just disabled the your system Firewall by entering setup command in the terminal window.
# setup

Select Firewall Configuration menu and disable the Firewall by removing the “ * ” symbol by pressing spacebar in that Enabled bracket, then press OK , Yes and Quit.

                                                                         OR

Go to System>Administration>Firewall and disable it.

Now type this in the browser window: http://localhost/bugzilla

I hope now your are able to see your bugzilla server home page.





Email configuration for Bugzilla Server: 

Open your bugzilla server ip address in your browser

http://localhost/bugzilla

Log in with bugzilla administrator email id and password which you have setup during the installation.

After login click on Administration tab, then click Parameters, then click Email (on the left hand side menu) and change the following fields:

Mailfrom : your bugzillaserver email id (not bugzilla administrator email)

Smtpserver : your outgoing mailserver address

Smtp_username : your bugzillaserver email id

Smtp_password : bugzillaserver email id password

Then click on Save Changes at the bottom of the page.

Now go to User Authentication menu and go to field createemailregexp (at the bottom of the page), this field is used to give access to a particular email domain address.

For example: .*@gmail.com

In the above example, bugzilla will allow only those email address to be created who have @gmail.com as a suffix.

Now you are good to go with Bugzilla Server. Enjoy. 

Top 10 exchange interview questions

10. Pretend I’m a manager, and explain DNS to me.

Windows is increasingly tied to domain name resolution, and the bigger your company gets, the thornier DNS problems become.  If they can verbalize how end users’ computers make DNS requests and how forwarders work, and then if they can toss in Active Directory, they’ve solved some enterprise problems.
Starting with a generic open-ended question like that tests a candidate’s communication skills, too.  Bonus points for making a tough concept seem easy.

9. What’s a Windows profile? When would you delete one, and what gets deleted?

If you’re looking for someone to do desktop support, they should have at least a vague idea of where the user’s data can be stored.  Bonus points if they can explain where common application settings are stored, what the Registry is, and how roaming profiles work.

8. When an end user says a file went missing, what do you do?

End users delete files all the time, but before you recover it from backup, first do a search on the drive to make sure they didn’t drag & drop it to another folder.  (Normally I don’t give interview answers here, but that one’s an exception.)  Then, after they explain that, I’d ask them to cover things like VSS snapshots, end user recovery in Explorer and how to restore from their favorite backup program.

7. How do you recover one SQL Server database or one Exchange mailbox?

Different backup systems have different ways of dealing with this, so I may not be able to vet their exact answer if I haven’t used the same backup system they’re using.  However, I can do a pretty good job of sniffing out when someone doesn’t understand the complexities involved.  If they shrug and just say “I click restore and it’s done,” then they’re bluffing.
For example, when restoring an Exchange mailbox, do you really want to pave over every email the user has received since the last backup?  Or does the user just need one or two important emails pulled out of the archive?

6. If you get hired and you can pick any laptop, what do you get?

I wanna see ‘em get all excited.  I wanna see ‘em giddy with glee at the thought of picking out their own shiny new hardware.  The more excited they get, the more I know systems administration is a way of life for them, not just a hobby.

5. What’s the first software you’d install?

Hardcore sysadmins have their own favorite tools they like to use.  Listen with an open mind, too – the more sysadmins you interview, the more cool tools you’ll discover.  If they mention a tool you haven’t used before, drill into it.  Find out why they use it and how it saves them time.  If it’s a tool they’re passionate enough to mention, then they can probably describe some underlying concepts and technologies involved, and it’ll give you more confidence that they know what they’re doing.

4. What do the letters PST mean to you?

I want to know if they’ve experienced the pains (both technical and legal) involved with these files.  How do they back up PST files if the end user leaves their laptop online all the time?  Are there any size concerns with PST files?  Is there a good way to use PSTs?

3. What’s PowerShell, and how do you feel about it?

I don’t necessarily need PowerShell experience (although it’s a big plus for Windows sysadmins) but I want to know that they’re at least vaguely aware of the concept and what it means.  Bonus points if they can relate scripting to the *nix world, and if they bring up Windows Core.

2. Are you involved with any local user groups?

Be it Windows or just a hardware hacker group, I love candidates who love communities.  I like seeing someone get so involved in what they do that they seek out other people who share similar interests.

1. What do you want to do next?

Windows systems administration is a cool gateway into a lot of different careers.  Do they want to manage Exchange?  Become a SQL Server DBA?  Go into management to be the next CIO?  Having a drive and a passion means they’ll try to do a better job so they can keep moving up the ladder.

Configuring SMTP mail relay with office 365

Most organizations have internal application servers and appliances that send emails to users or groups. Examples include copier/scanners and application servers, such as backup servers that notify admins of a completed or failed backup job.

If the organization has Exchange on-prem you would normally configure an internal relay receive connector in Exchange and configure the internal resources to send emails to Exchange. But what do you do when you've migrated all your mailboxes to Office 365 and have decommissioned your Exchange servers?

The solution is to install an IIS SMTP relay server in your internal network, configure it to accept email from specific IP addresses, and forward emails to Office 365. You can also configure the SMTP relay for external domains, if necessary.

Here's how to do it:

• Install the SMTP Server feature and its dependencies to a new or existing Windows server. This will be your relay server and your firewall needs to allow it to send SMTP traffic (TCP port 25) outbound to the Internet. I typically use the DirSync server, if there is one.

Adding the SMTP Server feature and its dependencies to Windows Server 2012

• Open Internet Information Services (IIS) 6.0 Manager to configure the SMTP relay.
• Configure the properties of [SMTP Virtual Server #1] as follows:
• On the Access tab:
• Authentication: Only Anonymous access is checked.
• Relay: Only the list below. Add IP addresses or ranges of servers allowed to relay.
• Note - It's important to only allow IP addresses you trust to relay through this server. Any IP address you enter here will be allowed to send emails on behalf of your domain.
• On the Messages tab:
• Adjust message size limits. The default message size limit is 2048 KB (2 MB).  You may want to change it to 10240 KB (10 MB) or more to allow for larger messages from copier/scanners, etc.
• On the Delivery Tab:
• Outbound Security: Anonymous access only and no TLS encryption.
• Outbound Connections: Port 25
• Advanced: Leave the Smart Host field blank
• Add new remote domains:
• Right-click Domains > New > Domain and add the domain(s) hosted in Exchange Online.
• If the relay server is allowed to relay emails to other external domains add a new *.com remote domain. Repeat for *.org, *.net, etc. as necessary.

Add Office 365 and other remote domains if required for external relay

• For properties of each domain hosted in Exchange Online:
• Check Allow incoming mail to be relayed to this domain
• Forward all mail to this smart host: smtp.office365.com
• Outbound Security: Check Anonymous access and TLS encryption
• For properties of all other remote domains (if any):
• Check Allow incoming mail to be relayed to this domain
• Outbound Security: Check Anonymous access and do not check TLS encryption.
• Restart IIS.  Be aware that whenever you restart IIS, the SMTP virtual server usually stays stopped – start it.

Notes/Troubleshooting:

• The SMTP Server feature can be added to any Windows 2003 or better server. I usually use the DirSync server if there is one.
• Unlike Exchange, TLS for IIS 6 SMTP servers is not opportunistic. If the virtual server or a remote domain is configured to use TLS email will not be sent if the remote domain does not support TLS. Office 365 offers TLS, so we can use it.
• The configuration above allows the IIS 6 SMTP server to send emails to the Internet for the remote domains configured, so you should add the public NAT IP address for this server to your existing SPF record to prevent non-delivery. Use http://whatismyip.com from the SMTP server to determine the NAT IP address.
• Monitor the %systemdrive%\Inetpub\mailroot\Queue folder to ensure that emails are being delivered.
• If emails are not being delivered to Office 365 users, test sending email via Telnet. The IP address may be blocked by an Exchange Online Protection (EOP) blocklist and you will see that response from EOP. If so, send a delist request from your Office 365 admin account to delist@messaging.microsoft.com letting them know the IP address that should be delisted. In my experience it takes up to 36 hours for Microsoft to delist it.
• If emails are not being delivered to external domains, ensure that you have a remote domain type (*.com, *.eu, etc.) configured for those email addresses.
• You can enable logging in the properties of the SMTP virtual server for further troubleshooting. Use the NCSA Common Log File Format. IIS does not automatically groom or delete logs like Exchange does, so turn logging off when you're done troubleshooting.
• The best practice is to create an A record in internal DNS for smtp.yourdomain.com using the SMTP relay server's IP, and configure all application servers and appliances to use that FQDN for email forwarding. That makes it easier to update in the future.

26 Vmware interview questions

1. What is a Hypervisor?

It is a program that allows multiple operating systems to share a single hardware host. Each operating system appears to have the host's processor, memory, and other resources all to itself. However, the hypervisor is actually controlling the host processor and resources, allocating what is needed to each operating system in turn and making sure that the guest operating systems (called virtual machines) cannot disrupt each other.

2. What is the hardware version used in VMware ESXi 5.5?

Version 10

Below is the table showing the different version of hardware used in different VMware products along with their release version

Virtual Hardware Version	Products
10	ESXi 5.5, Fusion 6.x, Workstation 10.x, Player 6.x
9	ESXi 5.1, Fusion 5.x, Workstation 9.x, Player 5.x
8	ESXi 5.0, Fusion 4.x, Workstation 8.x, Player 4.x
7	ESXi/ESX 4.x, Fusion 2.x/3.x Workstation 6.5.x/7.x,Player 3.x
6	Workstation 6.0.x
4	ACE 2.x, ESX 3.x, Fusion 1.x, Player 2.x
3 and 4	ACE 1.x, Player 1.x, Server 1.x, Workstation 5.x, Workstation 4.x
3	ESX 2.x, GSX Server 3.x

3. What is the difference between the vSphere ESX and ESXi architectures?

VMware ESX and ESXi are both bare metal hypervisor architectures that install directly on the server hardware.

Although neither hypervisor architectures relies on an OS for resource management, the vSphere ESX architecture relied on a Linux operating system, called the Console OS (COS) or service console, to perform two management functions: executing scripts and installing third-party agents for hardware monitoring, backup or systems management.

In the vSphere ESXi architecture, the service console has been removed. The smaller code base of vSphere ESXi represents a smaller “attack surface” and less code to patch, improving reliability and security.

4. What is a .vmdk file?

This isn't the file containing the raw data. Instead it is the disk descriptor file which describes the size and geometry of the virtual disk file. This file is in text format and contains the name of the –flat.vmdk file for which it is associated with and also the hard drive adapter type, drive sectors, heads and cylinders, etc. One of these files will exist for each virtual hard drive that is assigned to your virtual machine. You can tell which –flat.vmdk file it is associated with by opening the file and looking at the Extent Description field.

Follow the below link for more details

VMware files description

5. What are the different types of virtualization?

Server Virtualization – consolidating multiple physical servers into virtual servers that run on a single physical server.

Application Virtualization – an application runs on another host from where it is installed in a variety of ways. It could be done by application streaming, desktop virtualization or VDI, or a VM package (like VMware ACE creates with a player). Microsoft Softgrid is an example of Application virtualization.

Presentation Virtualization – This is what Citrix Met frame (and the ICA protocol) as well as Microsoft Terminal Services (and RDP) are able to create. With presentation virtualization, an application actually runs on another host and all that you see on the client is the screen from where it is run.

Network Virtualization – with network virtualization, the network is “carved up” and can be used for multiple purposes such as running a protocol analyzer inside an Ethernet switch. Components of a virtual network could include NICs, switches, VLANs, network storage devices, virtual network containers, and network media.

Storage Virtualization – with storage virtualization, the disk/data storage for your data is consolidated to and managed by a virtual storage system. The servers connected to the storage system aren’t aware of where the data really is. Storage virtualization is sometimes described as “abstracting the logical storage from the physical storage.

6. What is VMware vMotion and what are its requirements?

VMware VMotion enables the live migration of running virtual machines from one physical server to another with zero downtime.

VMotion lets you:

• Automatically optimize and allocate entire pools of resources for maximum hardware utilization and
• availability.
• Perform hardware maintenance without any scheduled downtime.
• Proactively migrate virtual machines away from failing or under performing servers.

Below are the pre-requisites for configuring vMotion

• Each host must be correctly licensed for vMotion
• Each host must meet shared storage requirements
• vMotion migrates the vm from one host to another which is only possible with both the host are sharing a common storage or to any storage accessible by both the source and target hosts. 
• A shared storage can be on a Fibre Channel storage area network (SAN), or can be implemented using iSCSI SAN and NAS.
• If you use vMotion to migrate virtual machines with raw device mapping (RDM) files, make sure to maintain consistent LUN IDs for RDMs across all participating hosts.

• Each host must meet the networking requirements
• Configure a VMkernel port on each host.
• Dedicate at least one GigE adapter for vMotion.
• Use at least one 10 GigE adapter if you migrate workloads that have many memory operations.
• Use jumbo frames for best vMotion performance.
• Ensure that jumbo frames are enabled on all network devices that are on the vMotion path including physical NICs, physical switches and virtual switches.

7. What is the difference between clone and template in VMware?

Clone

• A clone is a copy of virtual machine.
• You cannot convert back the cloned Virtual Machine.
• A Clone of a Virtual Machine can be created when the Virtual Machine is powered on
• Cloning can be done in two ways namely Full Clone and Linked Clone.
• A full clone is an independent copy of a virtual machine that shares nothing with the parent virtual machine after the cloning operation. Ongoing operation of a full clone is entirely separate from the parent virtual machine.
• A linked clone is a copy of a virtual machine that shares virtual disks with the parent virtual machine in an ongoing manner. This conserves disk space, and allows multiple virtual machines to use the same software installation.
• Cloning a virtual machine can save time if you are deploying many similar virtual machines. You can create, configure, and install software on a single virtual machine, and then clone it multiple times, rather than creating and configuring each virtual machine individually.

Template

• A template is a master copy or a baseline image of a virtual machine that can be used to create many clones.
• Templates cannot be powered on or edited, and are more difficult to alter than ordinary virtual 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 future deployment of Virtual Machines with the latest patches.
• Convert virtual Machine to template cannot be performed, when Virtual machine is powered on.  Only Clone to Template can be performed when the Virtual Machine is powered on.
• A template offers a more secure way of preserving a virtual machine configuration that you want to deploy many times.
• When you clone a virtual machine or deploy a virtual machine from a template, the resulting cloned virtual machine is independent of the original virtual machine or template.

8. What is promiscuous mode in Vmware?

• Promiscuous mode is a security policy which can be defined at the virtual switch or portgroup level
• A virtual machine, Service Console or VMkernel network interface in a portgroup which allows use of promiscuous mode can see all network traffic traversing the virtual switch.
• If this mode is set to reject, the packets are sent to intended port so that the intended virtual machine will only be able to see the communication.
• Example: In case you are using a virtual xp inside any Windows VM. If promiscuous mode is set to reject then the virtual xp won't be able to connect the network unless promiscuous mode is enabled for the Windows VM.

9. What is the difference between Thick provision Lazy Zeroed, Thick provision Eager Zeroed and Thin provision?

Thick Provision Lazy Zeroed

• Creates a virtual disk in a default thick format.
• Space required for the virtual disk is allocated when the virtual disk is created.
• Data remaining on the physical device is not erased during creation, but is zeroed out on demand at a later time on first write from the virtual machine.
• Using the default flat virtual disk format does not zero out or eliminate the possibility of recovering deleted files or restoring old data that might be present on this allocated space.
• You cannot convert a flat disk to a thin disk.

Thick Provision Eager Zeroed

• A type of thick virtual disk that supports clustering features such as Fault Tolerance.
• Space required for the virtual disk is allocated at creation time.
• In contrast to the flat format, the data remaining on the physical device is zeroed out when the virtual disk is created.
• It might take much longer to create disks in this format than to create other types of disks.

Thin Provision

• It provides on on-demand allocation of blocks of data.
• All the space allocated at the time of creation of virtual disk is not utilized on the hard disk, rather only the size with utilized data is locked and the size increases as the amount of data is increased on the disk.
• With thin provisioning, storage capacity utilization efficiency can be automatically driven up towards 100% with very little administrative overhead.

10. What is a snapshot?

A snapshot is a “point in time image” of a virtual guest operating system (VM). That snapshot contains an image of the VMs disk, RAM, and devices at the time the snapshot was taken. With the snapshot, you can return the VM to that point in time, whenever you choose. You can take snapshots of your VMs, no matter what guest OS you have and the snapshot functionality can be used for features like performing image level backups of the VMs without ever shutting them down.

11. What is VDI?

• VDI stands for Virtual Desktop Infrastructure where end user physical machine like desktop or laptop are virtualized due to which VMware described VDI as "delivering desktops from the data center”.
• Once VDI is used the end user connect to their desktop using a device called thin client.
• The end user can also connect to their desktop using VMware Horizon View installed on any desktop or mobile devices

12. What is VMware HA?

• VMware HA i.e. High Availability which works on the host level and is configured on the Cluster.
• A Cluster configured with HA will migrate and restart all the vms running under any of the host in case of any host-level failure automatically to another host under the same cluster.
• VMware HA continuously monitors all ESX Server hosts in a cluster and detects failures.
• VMware HA agent placed on each host maintains a heartbeat with the other hosts in the cluster using the service console network. Each server sends heartbeats to the others servers in the cluster at five-second intervals. If any servers lose heartbeat over three consecutive heartbeat intervals, VMware HA initiates the failover action of restarting all affected virtual machines on other hosts.
• You can set virtual machine restart priority in case of any host failure depending upon the critical nature of the vm.

NOTE: Using HA in case of any host failure with RESTART the vms on different host so the vms state will be interrupted and it is not a live migration

13. What is the difference between VMware HA and vMotion?

VMware HA is used in the event when any of the hosts inside a cluster fails then all the virtual machines running under it are restarted on different host in the same cluster.

Now HA is completely dependent on vMotion to migrate the vms to different host so vMotion is just used for the migration purpose between multiple hosts. vMotion also has the capability to migrate any vm without interrupting its state to any of the host inside cluster.

14. What is storage vMotion?

• Storage vMotion is similar to vMotion in the sense that "something" related to the VM is moved and there is no downtime to the VM guest and end users. However, with SVMotion the VM Guest stays on the server that it resides on but the virtual disk for that VM is what moves.
• With Storage vMotion, you can migrate a virtual machine and its disk files from one datastore to another while the virtual machine is running.
• You can choose to place the virtual machine and all its disks in a single location, or select separate locations for the virtual machine configuration file and each virtual disk.
• During a migration with Storage vMotion, you can transform virtual disks from Thick-Provisioned Lazy Zeroed or Thick-Provisioned Eager Zeroed to Thin-Provisioned or the reverse.
• Perform live migration of virtual machine disk files across any Fibre Channel, iSCSI, FCoE and NFS storage

15. What is VMware DRS and how does it works?

• Here DRS stands for Distributed Resource Scheduler which dynamically balances resource across various host under Cluster or resource pool.
• VMware DRS allows users to define the rules and policies that decide how virtual machines share resources and how these resources are prioritized among multiple virtual machines.
• Resources are allocated to the virtual machine by either migrating it to another server with more available resources or by making more “space” for it on the same server by migrating other virtual machines to different servers.
• The live migration of virtual machines to different physical servers is executed completely transparent to end-users through VMware VMotion
• VMware DRS can be configured to operate in either automatic or manual mode. In automatic mode, VMware DRS determines the best possible distribution of virtual machines among different physical servers and automatically migrates virtual machines to the most appropriate physical servers. In manual mode, VMware DRS provides a recommendation for optimal placement of virtual machines, and leaves it to the system administrator to decide whether to make the change.

16. What is VMware Fault Tolerance?

• VMware Fault Tolerance provides continuous availability to applications running in a virtual machine, preventing downtime and data loss in the event of server failures.
• VMware Fault Tolerance, when enabled for a virtual machine, creates a live shadow instance of the primary, running on another physical server.
• The two instances are kept in virtual lockstep with each other using VMware vLockstep technology
• The two virtual machines play the exact same set of events, because they get the exact same set of inputs at any given time.
• The two virtual machines constantly heartbeat against each other and if either virtual machine instance loses the heartbeat, the other takes over immediately. The heartbeats are very frequent, with millisecond intervals, making the failover instantaneous with no loss of data or state.
• VMware Fault Tolerance requires a dedicated network connection, separate from the VMware VMotion network, between the two physical servers.

17. In a cluster with more than 3 hosts, can you tell Fault Tolerance where to put the Fault Tolerance virtual machine or does it chose on its own?

You can place the original (or Primary virtual machine). You have full control with DRS or vMotion to assign it to any node. The placement of the Secondary, when created, is automatic based on the available hosts. But when the Secondary is created and placed, you can vMotion it to the preferred host.

18. How many virtual CPUs can I use on a Fault Tolerant virtual machine ?

vCenter Server 4.x and vCenter Server 5.x support 1 virtual CPU per protected virtual machine.

19. What happens if vCenter Server is offline when a failover event occurs?

When Fault Tolerance is configured for a virtual machine, vCenter Server need not be online for FT to work. Even if vCenter Server is offline, failover still occurs from the Primary to the Secondary virtual machine. Additionally, the spawning of a new Secondary virtual machine also occurs without vCenter Server.

20. What is the difference between Type 1 and Type 2 Hypervisor?

Type 1 Hypervisor

• This is also known as Bare Metal or Embedded or Native Hypervisor.
• It works directly on the hardware of the host and can monitor operating systems that run above the hypervisor.
• It is completely independent from the Operating System.
• The hypervisor is small as its main task is sharing and managing hardware resources between different operating systems.
• A major advantage is that any problems in one virtual machine or guest operating system do not affect the other guest operating systems running on the hypervisor.
• Examples: VMware ESXi Server, Microsoft Hyper-V, Citrix/Xen Server

Type 2 Hypervisor

• This is also known as Hosted Hypervisor.
• In this case, the hypervisor is installed on an operating system and then supports other operating systems above it.
• It is completely dependent on host Operating System for its operations
• While having a base operating system allows better specification of policies, any problems in the base operating system a ffects the entire system as well even if the hypervisor running above the base OS is secure.
• Examples: VMware Workstation, Microsoft Virtual PC, Oracle Virtual Box

21. How does vSphere HA works?
When we configure multiple hosts for HA cluster, a single host is automatically elected as the master host. The master host communicates with vCenter Server and monitors the state of all protected virtual machines and of the slave hosts. When you add a host to a vSphere HA cluster, an agent is uploaded to the host and configured to communicate with other agents in the cluster.

22. What are the monitoring methods used for vSphere HA?
The Master and Slave hosts uses two types of monitoring the status of the hosts

• Datastore Heartbeat
• Network Heartbeat

23. What are the roles of master host in vSphere HA?

• Monitoring the state of slave hosts. If a slave host fails or becomes unreachable, the master host identifies which virtual machines need to be restarted.
• Monitoring the power state of all protected virtual machines. If one virtual machine fails, the master host ensures that it is restarted. Using a local placement engine, the master host also determines where the restart should be done.
• Managing the lists of cluster hosts and protected virtual machines.
• Acting as vCenter Server management interface to the cluster and reporting the cluster health state.

24. How is a Master host elected in vSphere HA environment?
When vSphere HA is enabled for a cluster, all active hosts (those not in standby or maintenance mode, or not disconnected) participate in an election to choose the cluster's master host. The host that mounts the greatest number of datastores has an advantage in the election. Only one master host typically exists per cluster and all other hosts are slave hosts.

If the master host fails, is shut down or put in standby mode, or is removed from the cluster a new election is held.

25. If the vCenterserver goes down with a situation that it was pre configured with vSphere HA and DRS, so after power down will HA and DRS perform their task?
vSphere HA is not dependent on vCenterserver for its operations as when HA is configured it installs an agent into each host which does its part and is not dependent on vCenterserver. Also HA doesnot uses vMotion, it justs restarts the vms into another host in any case of host failure.

Further vSphere DRS is very much dependent on vCenterserver as it uses vMotion for its action for live migration of vms between multiple hosts so in case vCenterserver goes down the vMotion won't work leading to failure of DRS.

26. What is the use of vmware tools?
VMware Tools is a suite of utilities that enhances the performance of the virtual machine's guest operating system and improves management of the virtual machine. Without VMware Tools installed in your guest operating system, guest performance lacks important functionality. Installing VMware Tools eliminates or improves these issues:

• Low video resolution
• Inadequate color depth
• Incorrect display of network speed
• Restricted movement of the mouse
• Inability to copy and paste and drag-and-drop files
• Missing sound
• Provides the ability to take quiesced snapshots of the guest OS
• Synchronizes the time in the guest operating system with the time on the host
• Provides support for guest-bound calls created with the VMware VIX API