What is Distributed Resources Scheduler (DRS)

Here i will let you know all about DRS

1. What is DRS

2. DRS Resources management capabilities.

a.Initial Placement

b.Load Balancing

c.Power Management (DPM)

3. DRS Pre-requisites

4. DRS Automation Level

5. Using HA and DRS together

Lets start with

Q. What is Distributed Resources Scheduler (DRS)

DRS is enabled in a cluster. A DRS cluster is managed by vCenter Server and has these resources management capabilities.

  1. ) Initial Placement
  2. ) Load Balancing
  3. ) Power Management (DPM)

Lets discuss about these above point.

  1. Initial Placement:- when you first Power ON virtual machine in the cluster, DRS either places the VM on an appropriate host or sends a recommendation.
  2. Load Balancing:- DRS continuously monitors the distribution and usage of CPU and Memory resources for all Hosts (ESXi) and VMs in the cluster. DRS compares the resource usage defined by the migration threshold and then performs or recommends for VMs migration accordingly.
  3. Power Management (DPM):- when DPM is enabled in a DRS cluster, DRS compares the cluster level and hosts level capacity to the demands of the clusters virtual machines. if a host1 which is underutilized, evacuate all the VMs to some other host2 and host1 made powered off or standby power mode. once the demand or usage grows the VMs distributed across the hosts on the fly without any downtime and the standby host will be powered back ON.

Note : Generally we do not use this DPM option in Production environment.


DRS Cluster Pre-requisites:-

  1. DRS works with vMotion so if the VMs meet vMotion requirements this would be best.
  2. To use DRS for load balancing the hosts in a cluster must be in a vMotion network.
  3. Hosts must use shared storage (VMFS data store or NFS data store)
  4. Place the disks on a shared storage that is accessible by source and destination hosts.
  5. Ensure that the shared storage must have sufficient space to store all virtual disks for your VMs.


DRS Cluster Automation Level:-

  • Manual:- When you power on a VM, DRS displays a list of recommended hosts on which to place the VMs. when the cluster becomes unbalanced, DRS displays recommendations for virtual machine migration.
  • Partially Automated:- When you powered on the VM, DRS auto place the VMs to the best suited host. When cluster becomes unbalanced, DRS displays recommendations for VM migration.
  • Fully Automated:- When you power on the VM, DRS auto place the VMs to the best suited host. when cluster becomes unbalanced, DRS migrates the VMs from over utilized to underutilized hosts to ensure a balanced use of cluster resources.

Using HA and DRS Together:-


  • HA closely intergraded with DRS. When a failure occurs, HA first checks whether resources are available on that destination host for the failover. if the resources are not available then HA asks DRS to accommodate for these resources. For Example: A VM that has been assigned a large CPU and memory reservation that results in fragmentation resources i.e. inefficient use of resources throughout the cluster. vSphere HA requests but can’t be guaranteed, defragmentation of resources to accommodate for the VMS resource requirements.
  • DRS flatters shares and limits on virtual machine before failover. This flattening process ensures that VMs get the resources that they are entitled to if they would have been failed over to the correct resource pool cause in the earlier versions the VMs failed over to the Root Resources Pool even if it is available in the other child resources pools.

Configuring vSphere HA, Admission Control, Datastore Heart beating

Here i will let you know about Configuring vSphere HA

  1. Admission Control and Admission Control Policy.
  2. VM Options.
  3. VM Monitoring.
  4. Datastore Heart beating.

1. Admission Control:– In this admission control we have two settings.

i) Enable: Disallows the VMs to be Power ON that violates the availability constraints.

ii) Disable: Allow VM to be powered ON that violate the availability constraints.

  Over-commitment in a vSphere HA- Enabled cluster:-

When admission control setting is set to allow VMs to be powered ON even if they violate availability constraints, you could be in a situation where there is more physical RAM/Memory allocated to VMs than actually exists. This situation is called over-commitment which can lead to poor performance of VMs. Yes your VMs will start but after the host gets massed out, the whole system & all VMs will slow down dramatically. This will increase the amount of time that HA will take to recover the VMs. In normal situation HA will take up-to 20-30 Mints to recover could end up being an hour or even more.

If it is set to Enable:

HA will block the VMs to be Power ON if the cluster is already at the limit of the capacity it could support if one of the ESXi host in the cluster failed (one host out of four identical hosts is equal to 25% of the cluster capacity) as we have already set, the HA will prevent the VMs to be powered on that violate availability constraints because it has resources to protect and HA ensure you that it has sufficient resources preserved for protecting VMs in the event of failure.

In contrary if it is set to Disable:

HA will allow the VMs to be Powered ON even if it violate availability constraints & it continuous to powering IN the VMs until all the cluster resources are allocated. In this case in the event of failure of any ESXi host it may happen that some VMs would not be able to be Power ON because of insufficient resources to power ON all the VMs. HA allowed you to exceed the availability constraints of the cluster.

2. Admission Control Policy

Specify the type of policy that admission control should enforce.

○ Host failure the cluster tolerates: 1

○ Percentage of cluster resources reserved as failover spare capacity:  25% CPU

25% Memory

○ Specify failover Hosts: Hosts failover(Advanced option)

3. Configuring Virtual Machine Options:

When a cluster Host fails HA tries to restart VMs ON the remaining hosts in the cluster. There are cluster default settings & VM settings. Cluster settings can be overrides for a specific VM. We can set as high, low, medium & disabled for a specific VM to be restarted.

Virtual Machine Monitoring: VM monitoring restarts individual VMs if the VMware tools heartbeat are not received within a set of time. Application monitoring restarts the individual VMs if their VMware tools application heartbeat is not received within a set of time. You can set as VM monitoring only or VM & application monitoring.

4. Restart Priority and Order

In vSphere 5.0 new types of virtual machines have been introduced called as Agent virtual machines. These virtual machines typically offers a “Services” to other VMs. This is why these agent VMs have the highest priority to get powered ON as other regular VMs may dependent on them. Example: if agent VM a vSheild Endpoint VM which offers antivirus services to other VMs. Prioritization is done by each host and not globally. Each host that has been requested to initiate restart of VM will restart all the top priority VMs before attempting to restart any other VMs. If in case top priority VMs fails to restart it will retried after a delay. In the meantime, HA will continue powering ON the remaining VMs. Keep in mind that some VMs are dependent on agent VMs. You should document that which regular VM is dependent on which agent VM and also document the process to start-up these services in the right order if automatic restart of agent VM fails.

Besides Agent VM, HA prioritizes the other VM in the following way:

  1. Agent Virtual Machine.
  2. FT secondary VM
  3. VM configured with a restart priority of high.
  4. VM configured with a restart priority of Medium.
  5. VM configured with a restart priority of Low.

It is noted that HA will not place any VMs on the host if the required number of Agent VMs are not running on the host at the time placement is done.

HA Failure Scenario: Host, Guest OS, Application:

1) Host Failure Scenario: HA is able to determine whether the ESXi host is isolated from the network or has crashed. Isolation refers to an ESXi host that does not see N/W traffic coming from the host to the cluster or is separated from management network. If host is crashed then HA is responsible to restart the VMs that were running on the failed host on the remaining hosts that are running perfectly in the cluster.

In every cluster downtime depends on how long it takes whatever is running to restart when the virtual machine is failed over.

2) Guest operating system failure scenario: The HA agent in each individual host monitors VMware tools in each VM running on the host. When the VMs stop sending heartbeats, the guest OS is reset. The VM stays on the same host.

3) Application failure scenario: The agent on each host monitors the application heartbeat running in each VM. When the application fails, the VM on which the application as running is restarted on the same host. Application monitoring requires a third party application monitoring agent designed to work with VM application monitoring.

#Introducing And Working with Storage DRS

Here i will let you know about Storage DRS (SDRS)

SDRS is Automated to perform storage utilization balancing. This balancing is not only based on only space utilization but also based on I/O load balancing.

Closely Related Concepts b/w DRS and SDRS:-

  1. DRS uses cluster of hosts and SDRS used cluster of datastores.
  2. DRS can perform both initial placement and manual & outgoing balancing, SDRS also performs initial placement of VMDK’s and ongoing balancing of VMDK’s.
  3. DRS offers affinity and antiaffinity rules and SDRS also offers VMDK’s affinity and antiaffinity rules.


Guidelines for datastores that are combined to a datastore cluster:-

  1. Datastores of different sizes and I/O capacities can be combined in a datastore cluster. different arrays and venders can be combined together in a cluster. however you cannot be combined NFS and VMFS data store.
  2. All the hosts attached to the datastore in a datastore cluster must be running ESXi 5.x or later. In the earlier versions cannot connected to a datastore in the datastore cluster.
  3. Datastores shared Across multiple datacenters are not supported for SDRS.

# SDRS Automation Level:-

SDRS offers two predefined automation levels

1) No automation ( Manual Mode ) &

2) fully automated.

1.) No automation ( Manual Mode ):-

SDRS will generate recommendations for initial placement and for storage migrations based on the configured space and I/O thresholds. Initial placement recommendation occurs when you create a new VM (Thus a new Virtual disk), add a virtual disk to a VM or clone a VM or template. SDRS presents a list of initial placement recommendations whenever a new VD is created.

Recommendation for SDRS migrations are noted in two different ways.

  1. An alarm is generated
  2. The monitor

SDRS tab of datastore cluster will list the current SDRS recommendation and give you the option to apply those recommendations i.e initial the storage vMotion migration.

2.) Fully Automated:-

It will automatically initiate the storage vMotion migrations instead of generating recommendations for the administrator to approve.

In this case you can see:-

Use the monitor- SDRS tab of the datastore cluster to view the history of SDRS actions by selecting the history button at the top of the SDRS tab.

Note: Where to see DRS recommendation list?

It is unusual to see DRS make any recommended list of migrations by selecting the cluster in teh inventory and then select DRS tab.

From the monitor – DRS tab, the RUN DRS Now button allows you to agree with any pending DRS recommendations and initiate a migration.

In manual DRS automation the recommendation list is display in DRS tab – Recommendations you can see the list.

All About High Availability (HA),Requirements,fundamental components,Configuring

Here i will tell you All about

High Availability (HA),Requirements,fundamental components,Configuring

  1. Define HA and its Requirements.
  2. Components of HA with Diagram.
    • vCenter Server
    • Hostd and VPXA
    • FDM Agent
  3. Explain the fundamental components
      • Files for both Master and Slave.
      • Explain protectedlist file.
      • Responsibilities of Master and Slave Agents.
      • Election process of Master.
      • Master/ Slave Agents.
        • a) Remote files and b)  Local files
      • Datastore Heartbeating.
      • Election process of datastores for heartbeating.
      • Administration selection configuration for datastore heartbeating.
      • Isolated and partitioned network with diagram.
      • Virtual machine protection and unprotected workflow.
  4. Configuring vSphere HA
    • Admission control and over commitment in HA enabled cluster.
    • Admission control policy.
    • VM options.
    • VM Monitoring.
    • VM Restart Priority and Order.
  5. HA failure Scenarios
    • Host failure scenarios.
    • Guest Operating System failure scenario.
    • Application failure scenarios.
  6. Components of HA
      • vCenter Server
      • Hostd and VPXA
      • FDM Agent or HA Agent


vCenter Server:- vCenter is responsible for many tasks in respect with HA

  • Deploying and configuring HA agents.
  • Protection of VMs
  • Communicates cluster configuration changes to the Master host.

Hostd and VPXA:-

Host D is the most crucial component of an ESXi host and VPXA is a management agent of vCenter both are installed in an ESXi .FDM agent relies on host D agent to get the information about the list of all the VMs that are registered to that host if in case host d is not operational FDM agent stops/pauses all the functions and waits till the host D agent becomes available and operational.

FDM agent:-

FDM stands for Fault Domain Manager that replaced AAM i.e. (Automatic Availability Manager) which was there in the earlier versions of vSphere 5.0 FDM uses the concept of agent running on an ESXi host and is separate and decoupled from vCenter server management agent i.e. VPXA. The FDM offers multiple improvements over AAM are as follows:-

  1. FDM supports master and slave architecture and doesn’t rely on primary / secondary host designations.
  2. It supports IPV6.
  3. FDM addresses the issues of network partitioning and network isolation.
  4. FDM uses both management network and storage devices for communication.

Explain the following fundamental concepts

  1. Master / Slave agents.
  2. Heart beating.
  3. Isolated and partitioned network.
  4. Virtual Machine protection

1. Master and Slave Agents :-

Once the HA is enabled in a cluster ,HA agents participate in the election of the master and once the master is elected all the other hosts having the management connectivity with it are considered as slaves connected to that master. Master is also elected in the situations given below :-

  • Fails
  • Disconnected from vCenter.
  • Isolated or partitioned network
  • If the master is in maintenance mode or in standby mode.
  • If HA is reconfigured in a cluster

The master host election takes about 15 secs and is conducted using UDP port. HA won’t react to any failure during the master election once the master is elected failures occur during or after is taking care by master.

Master is responsible for the following tasks

  • Monitors the slave hosts and will restart the VMs in the event of slave host failure.
  • Monitors the VMs power state that are protected by HA if the protected VMs failed, HA will restart the VMs.
  • Master manages the list of protected VMs in the cluster and also update the list each time the user initiates power ON and power OFF operation. These are requested by vCenter server to protect and unprotect the VMs.
  • vCenter notifies and informs the master about the changes of the cluster configuration.
  • Master sends the heartbeat to the slave hosts so that the slaves know the master is alive.
  • vCenter typically communicates with the master only in some circumstances vCenter has to communicate with the slave hosts.
  • When master is Isolated or Partitioned from the network or master informs vCenter that slave hosts are not reachable.

Slaves responsibilities are as follows 

  • Slaves monitors the VMs power state/ running state of all the protected VMs that are running locally and if any changes occur ,slave will inform it to the master host.
  • Slave host monitors the master health status. If the master fails, the slave participates in the election of the new master host.

Election process of Master

The host that is participating in the election process having greatest number of datastores connected will be elected as master but if in case there are more than one or more host having the equal number of datastores connected then the one having the greatest Managed Object ID (MOID) will be chosen. This is done Lexically, means 99 beats 100 as 9 is greater than 1. You can see the HA host status in the summary tab.

After the master is elected, all the other hosts that are having management network connectivity with it will setup a single, secured , encrypted TCP connection to the master. This secured connection is SSL based. Typically the slaves do not communicate with each other unless reelection of a master needs to take place . When the master is elected , the master will try to acquire the ownership all of the datastores that it can directly access or can access by proxying requests to one of the slave hosts connected to it  through  the management network .It does this by locking a file called “protected list”.

What is protectedlist File?

Master uses this file to store the inventory. It stores the list of all the protected VMs by HA and it also stores the CPU reservation information and memory overhead .The master distributes this protected list file to all the datastores that are in use by the VMs in the cluster.

Protected list naming format and location of the file :-

/<root of datastore>/vSphere HA/<cluster specific directory>/Protected list

How cluster specific directory is constructed :-

<UUID of vCenter server>-<number part of MOID>-<8 char string>-<name of the running vCenter Server>

What happens if master fails or isolated from the network?

If the master fails the lock will expire and the new master will relock the file if the datastore is accessible to that new master. Master will release the lock from the file in the datastore to ensure that the new master will relock the file and can determine what all the VMs are protected by HA by reading the file .If the master fails and becomes isolated from the network, the restart of the VMs will be delayed until a new master has been elected.

The process of reelection of the master is as follows :-

If in case slave does not receive any network heartbeat ,the slaves will try to reelect the master .The new master will re-lock the protected list file and will get all the information after which it will initiate the restart of the VMs accordingly within 10 secs.

What happens if slave host fails or isolated from the network?

          Master will determine which VMs need to be restarted and when the VMs need to be restarted , the master is responsible for VMs placement and use placement engine that will try to distribute the VMs to be restarted across all the available hosts.

Files for both Master and Slave :-

Master and Slave use files not only to store the VMs state but also as a communication mechanism. Like protectedlist file used by the master to store the list of protected VMs similarly these files are created by both master and slave.

Remote Files :-It is stored in the shared datastore and not locally. Remote files are “PoweredON” files  that are stored in per host. “PoweredON” files are not for only tracking power ON state for the VMs but also for informing the master or notifies the master that the slave host is isolated from the network .If the file contains 0 means host is not isolated from the network and if carries 1 then host is isolated from the network .The master inform the vCenter about the isolation of the hosts.

Local Files :- when HA is configured for the host , host will store the specific information about its cluster locally .Each host including master stores some specific data locally. These files are not human readable.

  • ClusterConfig
  • Compactlist
  • Hostlist
  • Vmmetadata
  • cfg

2. Heartbeating :-

          Datastore heartbeating enables a master to determine whether the host has failed or isolated from the network.

           By default HA selects two datastores for haertbeating , you can configure for more than two datastores for heartbeating but it is highly not recommended from the advanced option .Let vCenter deal with this operation .vCenter uses selection algorithm to select the datastore heartbeat that are visible to all the hosts. Datastore selection process gives preference to the following :-

  • Datastore that are visible to all of the hosts or if not as many as possible.
  • VMFS datastore rather than NFS datastore.
  • Datastores that comes from different LUNs or NFS.

HA provides three different settings for administrator to select the datastore for heartbeating :-

  • Automatically select the datastore accessible from the host and manual selection of datastore from only the preferred list is disabled.
  • Use datastore from only the preferred list and if any of the datastore becomes unavailable HA will not perform any HA datastore heartbeating through a different datastore.
  • Use the datastores from the preferred list and complement automatically if needed .This means use from the preferred list first but if any of the datastore becomes unavailable then it can choose a different datastore that are available until the datastore from the preferred list becomes available.

3. Isolated Versus Partitioned Network :-

          HA uses management network as well as storage device for communication .When master cannot communicate with the slaves across management network, HA uses datastore heartbeating to determine whether the host has failed or isolated from the network . Here the functionality of isolated and partitioned network role comes into play :-

Partitioned Network:-

Where one or more slaves cannot communicate with the master across management network even though they have still the connectivity with the other slaves. In this case HA uses datastore heartbeating to determine whether the hosts are still alive or the master need to take the appropriate action to protect the VMs running on the partitioned hosts or need to initiate an election of a new master within the partitioned network. Lets say you have four segments in your network, each partitioned segment will elect its own master in your cluster which means you will be having four masters in your network. When the network is corrected any of the four master will take over the role and responsible for the cluster again.

Isolated Network :-

          Where one or more hosts have lost all the management network connectivity is called as Isolated network. Isolated hosts neither can communicate with the master host nor can communicate with the slave hosts.In this slave hosts uses datastore heartbeat to notify the master that it is isolated. Slave hosts uses the special binary file i.e. HOST-X-PowerON file to notify the master .The master can then take the appropriate action to protect the VMs.

4. Virtual Machine Protection :-

  • The virtual machine protection workflow and VM unprotected workflow is given below. For VM protection and unprotected both must be updated on protectedlist file.
  • VM protection process has been change in vSphere 5.0 but in the earlier versions of vSphere was handled by vpxd which was notified by AAM(Automatically Availability Manager) through a vpxa module called vmap. Vpxd is a vCenter server agent that is installed on vCenter itself and vpxa is the management agent of vCenter which is installed on each host. In vSphere 5 the protection of VMs is the ultimate responsibility of vCenter server.
  • When the state of a VM changes , vCenter server will direct the master to protect or unprotect the VM, in other words the master is directed by the vCenter to enable or disable the HA protection for the VMs. Protection is only guaranteed when the master has committed the change of state to disk.

What is vCenter Server Services and features

Here i will tell you all about:

  1. What is vCenter Server
  2. vCenter Services
  3. vCenter Features
  4. JVM Memory
  5. Single Sign ON (SSO)
  6. VI Client
  7. VPXD (vCenter Server)
  8. Host d
  9. VPXA

#introducing vCenter Server:-

vCenter is a centralized management system (console) or an application Server for managing ESXi Hosts, VM’s, Datastore, clusters, alerts etc. vCenter acts as a proxy that performs tasks on the individual host (ESXi) that have been added as a member of vCenter Server installation. In vSphere 5.5 VMware includes vCenter server licensing in every kit & every edition of vSphere, underscoring the importance of vCenter server. The various editions that are offered by VMware includes vCenter server standard, Essentials and Foundation. While VMware has various other products, where vCenter is generally the central integration point tying them all together. Software such as vCloud Director, vCloud Automation Center (VCAC), vCenter Operations Manager & Site Recovery Manager, Update manager, Orchestrator they all depend on an instance of vCenter server.

  1. VMware vMotion
  2. Host Profiles
  3. VMHA
  4. Orchestrator
  5. V DRS
  6. VMware Update Manager

vCenter Services 

Core Services:- VM provisioning , Event logging, task scheduler, Alarms and Events, inventory, vAPP, Statistics and logging, Host and VM configuration.

Distributed Services:- vMotion, DRS, HA.

Additional Services:- Plug-in like update manager, vSheild zone, orchestrator, data recovery, storage monitoring, Hardware and Service status.

Database Interface:- Database connectivity. ( MS SQL )

ESXi Host Management:- ESXi Host mgmt.

Active directory Interface:- AD integration.

VMware VCMSDS:- Provides vCenter server (LDAP) directory Services.

VMware vSphere Profile Driven Storage Services.

VMware VSA Cluster Services 5.1:- A service that acts as a third cluster member in a VSA cluster with Two VSA cluster.

VMware Virtual Center Server:- Provides centralized mgmt of VM’s.

VMware virtual center mgmt web services:- Allows configurations of VMware vCenter mgmt services.

VMware vCenter orchestrator Server:- Hosts the vCenter orchestrator server.

VMware virtual center mgmt configuration:- A service for vCenter orchestrator, a workflow engine that can help administrator automate existing manual tasks.

VMware vCenter inventory Services:- Provides centralized inventory and search functions for VMware vCenter objects.

vCenter Single Sign ON


vCenter Server Features


  1. Resource Management for ESXi hosts & VMs
  2. VM Deployment
  3. Update Manager
  4. Templates Management
  5. Converter Enterprise
  6. Access Control (to AD)

vCenter Pre-Requisites:- 


  1. 2008 R2 or 64 Bit OS.
  2. Server must be in Domain.
  3. static IP and Host Name.
  4. Correct Date& Time.
  5. Create backend database.
  6. Determine licensing options.
  7. DNS Entry and resolve it from ESXi Host.
  8. Services Account for installation.

Note: Account that are using for installation must have:

i) log on as a service.

ii) Act as a part of an operating system.

iii) Member of Admin Group.

Hardware Requirement : Check VMware website.

Port Requirement (Check VMware website) Some ports are below:


  1. 80/443 :                                               For web access (HTTP,HTTPS).
  2. 8080/8443:                                         HTTP, HTTPS (for Web Services).
  3. 902:                                                       Heart beat, ESXi Mgmt, VM console.
  4. 389:                                                       For LDAP can be changed up to ( 1025-65535).
  5. 636:                                                       For linked mode can be changed up to (SSL)
  6. 60099:                                                  Web service change service notification port.
  7. 10443:                                                   vCenter inventory service HTTPS.
  8. 10109:                                                   vCenter inventory service Mgmt.
  9. 10111:                                                    vCenter inventory service linked mode.


Main Components which need to understand

  1. VI Client
  2. VPXD (vCenter Server)
  3. Host d
  4. VPXA



vCenter server and ESXi are accessed through VI client. vCenter server gives access to ESXi through VPXA. vCenter server agent VPXA process started on the host when the host is added to the vCenter server inventory. The VPXA vCenter server agent communicates with host agent Host D. The Host D is directly run on the host and it responsible for managing most of the operations on the host. It is aware with all the VM’s that are registered.

VPXA vCenter agent basically an intermediate b/w VPXD that runs on vCenter server and Host D that runs on Hosts. Host D Process is used to relay the tasks to perform on the host.

When you are logged into vCenter using VI client basically vCenter process commands through VPXA to Host D. which will update the vCenter database also but if you directly connect to ESXi host through Host D then the vCenter inventory database could not be updated.


Q. Explain JVM Memory and ephemeral port configuration?

JVM Memory:- vCenter server includes a service called VMware vCenter mgmt web services. This service required 1-4 GB of additional memory. To optimally configure web services, during installation you can specify the Maximum web services JVM memory in relation to the inventory size. For Ex. If you have small inventory (fewer less than 100 hosts and 1000 VM’s) select JVM size 1024 MB and if large inventory ( more than 400 host or 4000 VMs) the JVM size of 4096 MB.

Ephemeral Port configuration:- This option prevents the pool of available ephemeral ports from being exhausted in situations where vCenter will manage hosts on  which more than 2000 virtual machines will power on simultaneously.


Q. Explain vCenter single sign ON (SSO).

When administrator deploy multiple solutions in an environment, they often authenticated repeatedly with the same credentials used when they switched b/w various virtualization solution.

Administrators can sign on one rather than multiple times in vCenter server. SSO has multiple benefits:-

  1. It speeds up the operations and eases the authentication process.
  2. Supports for multiple identity sources, including multiple (AD) forests/Domains or mixed identity sources.
  3. Ability to trust each other without requiring authentication every time a solution is accessed.

SSO Features:-


  1. SSO server will auto discover all the vCenter 5.1 servers in the vSphere environment.
  2. vCenter 5.0 SSO servers require One Time Manual registration required.
  3. Users see all vCenter instances for Which they have permission.
  4. Linked mode is no longer needed for unified views of vCenter. If a user needs to share permission, roles or license.

Explain vCenter Serve Features


  1. VMware vSphere Web client:- Through this you can manage your virtual infra using any browser from anywhere in the world. (Port should be open from firewall end)
  1. Multi-hypervisor Management:- Provides simplified and integrated mgmt of VMware and hyper-V hosts.


  1. vCenter Server Single Sign On:- It eases/simplifies the administrator operation by allowing user to login once and then can access multiple instances of vCenter server and VMware vCloud director without further authentication.
  2. Inventory Search:- Have the entire vCenter inventory search including VMs, Hosts, Datastores, networks etc.
  3. Alerts and notifications:- You can configure alerts and notification like datastore and VM specific alarms that will trigger if anything happen.
  4. Host Profiles:- Simplify the process of configuring newly installed ESXi hosts, do not need to manually configure each host that takes a lot time.
  5. Resources Management for VMs:- Allocate CPU, Memory, Resources to VMs running on the Hosts. We can limit, share, reserve the resources for VMs.
  6. vSphere HA:- Automatically restart the VMs from the failed host to another available host in the cluster.
  7. Patch Management:- Using vSphere update manager we can perform patching to our ESXi hosts and Linux, Microsoft VMs.
  8. vCenter orchestrator:- Simplify management by automating more than 800 tasks using scripts and it also uses drag and drop interface.