vMotion

vMotion

VMware VMotion enables the live migration of running virtual machines from one physical server to another with zero downtime, continuous service availability, and complete transaction integrity. It is transparent to users.

Port : TCP port 8000.

It is also known as Hot Migration/Live migration.

1. Host Maintainence

e.g.: While upgrading ESX hardware /ESX updates

2. Continuous VM operation

e.g.: Insufficient memory in VM’s

3. Better H/W Utilization

e.g: ESX host having insufficient resources.

How vMotion works?

• Users currently accessing VMA on ESX01
• Initiate Migration of VMA from ESX01 to ESX02 (While VMA is up and running)
• Pre-copy memory from ESX01 to ESX02.
• Logon going memory changes into a memory bitmap on ESX01.
• Quiesce VM on ESX01 and copy memory bitmap to ESX02.
• Copy VM’s remaining memory from ESX01.
• Start VMA on ESX02 and Delete VMA from ESX01.

Migration Types:

Benefits :
1.Hardware maintenance
2. Performance and optimizes resource usage
3.Load Balancing across physical
4. Disaster recovery

VMware Cross vCenter vMotion is a feature introduced in vSphere 6.0 that allows Virtual machines (VMs) to switch from one vCenter Server instance to another to change the compute, network, storage and management of the VM concurrently.

vMotion Network Configuration:

Configure the virtual networks on vMotion enabled hosts as follows:

• On each host, configure a VMkernel port group for vMotion.
• Ensure that virtual machines have access to the same subnets on source and destination hosts.
• If you are using standard switches for networking, ensure that the network labels used for virtual machine port groups are consistent across hosts. During a migration with vMotion, vCenter Server assigns virtual machines to port groups based on matching network labels.
• If you are using vSphere Distributed Switches for networking, ensure that source and destination hosts are members of all vSphere Distributed Switches that virtual machines use for networking.

vMotion virtual machine conditions and limitations apply:

• The source and destination management network IP address families must match. You cannot migrate a virtual machine from a host that is registered to vCenter Server with an IPv4 address to a host that is registered with an IPv6 address.
• If virtual CPU performance counters are enabled, you can migrate virtual machines only to hosts that have compatible CPU performance counters.
• You can migrate virtual machines with USB devices that are connected to a physical USB device on the host. You must enable the devices for vMotion.
• You cannot use migration with vMotion to migrate a virtual machine that uses a virtual device backed by a device that is not accessible on the destination host. For example, you cannot migrate a virtual machine with a CD drive backed by the physical CD drive on the source host. Disconnect these devices before you migrate the virtual machine.
• You cannot use migration with vMotion to migrate a virtual machine that uses a virtual device backed by a device on the client computer. Disconnect these devices before you migrate the virtual machine.

 vMotion in an environment without shared storage is subject to the following requirements and limitations:

■The hosts must be licensed for vMotion.

■The hosts must be running ESXi 5.1 or later.

■The hosts must meet the networking requirement for vMotion.

■The virtual machines must be properly configured for vMotion

■Virtual machine disks must be in persistent mode or be raw device mappings (RDMs).

■The destination host must have access to the destination storage.

■When you move a virtual machine with RDMs and do not convert those RDMs to VMDKs, the destination host must have access to the RDM LUNs.

■Consider the limits for simultaneous migrations when you perform a vMotion migration without shared storage. This type of vMotion counts against the limits for both vMotion and Storage vMotion, so it consumes both a network resource and 16 datastore resources.

Limits on Simultaneous Migrations in the vSphere Web Client

Network Limits for Migration with vMotion
Operation	ESX/ESXi Version	Network Type	Maximum Cost
vMotion	3.x, 4.0	1GigE and 10GigE	2
vMotion	4.1, 5.0, 5.1, 5.5	1GigE	4
vMotion	4.1, 5.0, 5.1, 5.5	10GigE	8

 

Datastore Limits and Resource Costs for vMotion and Storage vMotion
Operation	ESX/ESXi Version	Maximum Cost Per Datastore	Datastore Resource Cost
vMotion	3.x, 4.0	8	1
vMotion	4.1, 5.0, 5.1, 5.5	128	1
Storage vMotion	3.x, 4.0	8	1
Storage vMotion	4.1, 5.0, 5.1, 5.5	128	16

 

Host Migration Limits and Resource Costs for vMotion, Storage vMotion, and Provisioning Operations
Operation	ESX/ESXi Version	Derived Limit Per Host	Host Resource Cost
vMotion	3.x, 4.0	2	4
vMotion	4.1, 5.0, 5.1, 5.5	8	1
Storage vMotion	3.x, 4.0, 4.1, 5.0, 5.1, 5.5	2	4
vMotion Without Shared Storage	5.1, 5.5	2	4
Other provisioning operations	3.x, 4.0, 4.1, 5.0, 5.1, 5.5	8	1

How many VMs can vMotion live migrate at once?
4-8, depending on the network bandwidth When VMware vMotion debuted, it migrated one VM at a time. Now at vSphere 5.1, vMotion can move multiple VMs concurrently, four vMotion operations per host on a 1 Gbps connection or eight on a 10 Gbps connection

What’s the maximum network latency time allowed when vMotioning a running VM between ESXi hosts?
5 milliseconds Unless you’re operating a high-latency vMotion network, latency between hosts should not exceed 5 milliseconds round-trip time. The VM could fail to migrate if vMotion experiences high latency.

Certain enterprises operate multiple geographical sites within one vSphere environment with VMware vSphere Metro Storage Cluster. What maximum network latency time does Metro vMotion allow round-trip between hosts?
10 milliseconds 

To support Metro vMotion, an available option with vSphere Enterprise Plus, round-trip network latency must be at or below 10 milliseconds between sites. Metro vMotion also demands at least 622 Mbps network bandwidth, configured with redundant links

Does a DMZ network meet vMotion requirements?
No, VM data is vMotioned in plain text During vMotion, the memory and disk contents of a VM will pass, in clear text, across the network. For this reason, vMotion should never occur in an unsecure network, such as the DMZ. VMware admins also must effectively control administrative rights with vMotion, lest someone vMotion a mission-critical VM to an unsecured server.

++You need to upgrade your vSphere infrastructure from v5 to v5.5. You have the following products in this infrastructure:

– 6 ESXi hosts
– vCenter
– VUM(Update Manager)
– 77 VM’s

In which order would you upgrade the various parts?

Ans : 1. vCenter
2. VUM
3. ESXi
4. VMs