VMware Basics Part 2

40. How many hosts can be managed by a cluster in vSphere 6.0?

A single cluster can manage maximum 64 hosts

41. How can maximum VMs be managed by a single cluster?

A single cluster can manage the maximum of 8000 VMs.

42. What is VVol?

Virtual Volume a new VM disk management concept introduced in vSphere 6.0 that enables array-based operations at the virtual disk level. VVol is automatically created when a virtual disk is created in a virtual environment for a VM.

43. How many licensing options for vSphere 6.0?

There are three licensing options for vSphere 6.0:

• Standard Edition: Contains 1 vCenter Server Standard license, up to 2 vCPUs for Fault Tolerance, vMotion, Storage vMotion, HA, VVols etc.
• Enterprise Edition: Same as Standard Edition additionally APIs for Array Integration and Multipathing, DRS, and DPM.
• Enterprise Plus: Includes all features of Standard and Enterprise Editions with additionally Fault Tolerance upto 4 vCPUs and 64GB of RAM. It also includes Distributed vSwitch and the most expensive licensing option of vSphere 6.0.

44. How much Maximum RAM can support vSphere 6.0?

It supports upto 12TB of RAM.

45. What is the Content Library?

Content Library is the central location point between two different geographical locations with vCenter Servers where you can store VM templates, ISO images, scripts etc. and share them between geographical locations

46. What are the main benefits of content libraries?

We create VM templates and can share on another geographical location of a company without creating again on other locations. It has many benefits such as sharing and consistency, storage efficiency, and secure subscription.

47. How many types of Content Libraries have?

It has three types:

1. Local: library of local control.
2. Published: local library which contents (VM templates, ISO images etc) for subscription.
3. Subscribed: A library which syncs with the published library
4. What are the requirements and limitations of Content Libraries?

A content library has the following requirements and limitations

• Single storage which can size upto 64TB
• Maximum of 256 items per library
• Sync occurs once every 24 hours

49. What is VMFS?

VMFS is a file system for a VM in VMware vSphere. VMFS is a datastore that responsible for storing virtual machine files. VMFS can also store large files which size can up to 64TB in vSphere 6.0

50. What is vSAN?

Virtual SAN is a software-defined storage first introduced in vSphere 5.5 and is fully integrated with vSphere. It aggregates locally attached storage of ESXi hosts which are part of a cluster and creates a distributed shared solution.

51. What is cold migration?

To move a powered-off VM from one host to another is called cold migration.

52. What is Storage vMotion?

To move a powered-on VM from one datastore to another is called Storage vMotion.

53. What are the different configuration options for VSAN?

There are two configuration options for  vSAN:

• Hybrid: Uses both flash-based and magnetic disks for storage. Flash are used for cashing, while magnetic disks are used for capacity or storage.
• All-Flash: Uses flash for both caching and for storage

54. Are there VSAN ready nodes are available in the market?

Yes, vSAN-ready such as VxRail 4.0 and 4.5 are available in the market. VxRail is the combination of min 3 servers which are part of a cluster and can scale up to 64 servers.

56. How are many maximum ESXi hosts allowed for vSAN?

       64 hosts are max allowed to configure a vSAN cluster.

57. How many disk groups and max magnetic disks are allowed in single disk group?

Maximum 5 disk groups are allowed on an ESXi host which is a part of a vSAN cluster and a maximum of 7 magnetic and 1 SSD per disk group is allowed.

58. How many types of storages can we use in our virtual environment?

• Direct Attached Storage
• Fiber Channel (FC)
• iSCSI
• Network Attached Storage (NAS)

59. What is NFS?

Network File System (NFS) is a file sharing protocol that ESXi hosts use to communicate with a NAS device. NAS is a specialized storage device that connects to a network and can provide file access services to ESXi hosts.

60. What is Raw Device Mapping (RDM)?

Raw Device Mapping (RDM) is a file stored in a VMFS volume that acts as a proxy for a raw physical device. RDM enables you to store virtual machine data directly on a LUN. RDM is recommended when a VM must interact with a real disk on the SAN.

61. What is iSCSI storage?

An iSCSI SAN consists of an iSCSI storage system, which contains one or more storage processors. TCP/IP protocol is used to communicate between host and storage array. an iSCSI initiator is configured with the ESXi host. an iSCSI initiator can be a hardware-based either dependent or independent and software-based known as iSCSI software initiator.

62. What is the format of iSCSI addressing?

It uses TCP/IP to configure.

63. What are iSCSI naming conventions?

iSCSI names are formatted in two different ways:

• the iSCSI qualified name (IQN)
• extended unique identifier (EUI)

64. What is vApp?

vApp is a container or group where more than one VM can be package and manage multi-tiered applications for specific requirements for example, Web server, database server, and application server can be configured as a vApp and can be defined their power-on and power-off sequence.

65. What settings can be configured for vApp?

We can configure several settings for vApp such as CPU and memory allocation, and IP allocation policy etc.

Miscellaneous

66. What is VMware DRS?

DRS stands for Distributed Resource Scheduler; that automatically balances available resources among various hosts by using cluster or resource pools. With the help of HA, DRS can move VMs from one host to another to balance the available resources among VMs.

67. What is share, limit, and reservation?

Share: A value that specifies the relative priority or importance of a VM access to given resource.

Limit: Consumption of a CPU cycle or host physical memory that cannot cross the defined value (limit).

68. What are the alarms why we use them?

An alarm is a notification which appears when an event occurs. Many default alarms exist for many inventory objects. Alarms can be created and modified using vSphere Web Client;

69. What are the hot-pluggable devices which can be added while VM is running?

We can add HDDs and NIC while VM is running.

70. What is a Template?

When a VM is converted into a format which can be used to create a VM with pre-defined settings is called a template. An installed VM can be converted into a template but it cannot be powered-on.

71. What is Snapshot?

To create a copy of a VM with the timestamp as a restore point is called a snapshot. Snapshots are taken when an upgrade or software installation is required. For better performance, a snapshot should be removed after a particular task is performed.

72. How to convert a physical machine into a VM?

Three steps are required to convert a physical machine to a VM:

• An agent needs to be installed on the Physical machine
• VI client needs to be installed with Converter Plug-in
• A server to import/export virtual machines

73. What is vMotion and what is the main purpose to use it in a virtual environment?

It is a very prominent feature of VMware vSphere used to live migrate running VMs from one ESXi host to another without any downtime. Datastores and ESXi hosts both can be used while vMotion.

74. What is the difference between a clone and a template?

A clone is a copy of a virtual machine. By cloning a VM, it will save time if multiple VMs with the same configurations are required to configure. While a template is a master copy of an image created from a VM which can be later used to create many clones. After converting a VM to a template, it can’t be powered-on or edited.

75. What monitoring method is used in vSphere HA?

• Network Heartbeat
• Datastore Heartbeat

76. How is master host elected in vSphere HA?

When HA is enabled in a cluster, all hosts take part in a selection process to be selected as a master host. A host which has the highest number of datastores mounted will be selected as a master host. All other hosts will remain slave hosts.

77. What is the purpose of VMware Tools?

It is a suite of utilities which are used to enhance the performance of a VM in the form of graphics, mouse/keyboard movement, network card, and other peripheral devices.

78. What is VMware DPM?

Stands for Distributed Power Management is a feature of VMware DRS is used to monitor required resources in a cluster. When the resources are decreases due to low usage, VMware DPM consolidates workloads and shut down the hosts which are not being used, and when resources are increased it automatically power on the un-used hosts.

79. What is the ESXi Shell?

It is a command-line interface is used to run repair and diagnostics of ESXi hosts. It can be accessed via DCUI, vCenter Server enable/disable, and via SSH.

80. How to run ESXTOP on ESXi host?

Enable SSH on ESX host. Open putty, type ESX host name.
Login via root access. Type ESXTOP

types of port binding:-

These three different types of port binding determine when ports in a port group are assigned to virtual machines:
• Static Binding
• Dynamic Binding
• Ephemeral Binding

Static binding:-
When you connect a virtual machine to a port group configured with static binding, a port is immediately assigned and reserved for it, guaranteeing connectivity at all times. The port is disconnected only when the virtual machine is removed from the port group. You can connect a virtual machine to a static-binding port group only through vCenter Server.
Note: Static binding is the default setting, recommended for general use.

Dynamic binding:-
In a port group configured with dynamic binding, a port is assigned to a virtual machine only when the virtual machine is powered on and its NIC is in a connected state. The port is disconnected when the virtual machine is powered off or the NIC of the virtual machine is disconnected. Virtual machines connected to a port group configured with dynamic binding must be powered on and off through vCenter.
Dynamic binding can be used in environments where you have more virtual machines than available ports, but do not plan to have a greater number of virtual machines active than you have available ports. For example, if you have 300 virtual machines and 100 ports, but never have more than 90 virtual machines active at one time, dynamic binding would be appropriate for your port group.
Note: Dynamic binding is deprecated from ESXi 5.0, but this option is still available in vSphere Client. It is strongly recommended to use Static Binding for better performance.

Ephemeral binding:-
In a port group configured with ephemeral binding, a port is created and assigned to a virtual machine by the host when the virtual machine is powered on and its NIC is in a connected state. When the virtual machine powers off or the NIC of the virtual machine is disconnected, the port is deleted.
You can assign a virtual machine to a distributed port group with ephemeral port binding on ESX/ESXi and vCenter, giving you the flexibility to manage virtual machine connections through the host when vCenter is down. Although only ephemeral binding allows you to modify virtual machine network connections when vCenter is down, network traffic is unaffected by vCenter failure regardless of port binding type.
Note: Ephemeral port groups must be used only for recovery purposes when you want to provision ports directly on host bypassing vCenter Server, not for any other case. This is true for several reasons:


Promiscuous Mode:-
■  Reject — Placing a guest adapter in promiscuous mode has no effect on which frames are received by the adapter.
■  Accept — Placing a guest adapter in promiscuous mode causes it to detect all frames passed on the vSphere standard switch that are allowed under the VLAN policy for the port group that the adapter is connected to.

MAC Address Changes :-
■  Reject — If you set the MAC Address Changes to Reject and the guest operating system changes the MAC address of the adapter to anything other than what is in the .vmx configuration file, all inbound frames are dropped.
If the Guest OS changes the MAC address back to match the MAC address in the .vmx configuration file, inbound frames are passed again.
■  Accept — Changing the MAC address from the Guest OS has the intended effect: frames to the new MAC address are received.

Forged Transmits:-
■  Reject — Any outbound frame with a source MAC address that is different from the one currently set on the adapter are dropped.
■  Accept — No filtering is performed and all outbound frames are passed.