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KVM live migration to resolve performance issues
This article covers how to use KVM live migration to achieve load balancing which is important in a server virtualization system to maintain server performance.
Migration enables an administrator to move a virtual machine instance from one compute host to another. A typical scenario is planned maintenance on the source host, but migration can also be useful to redistribute the load when many VM instances are running on a specific physical machine.
Kernel-based Virtual Machine (KVM) is an open source virtualization technology built into Linux.
Specifically, KVM lets you turn #Linux into a #hypervisor that allows a host machine to run multiple, isolated virtual environments called guests or virtual machines (VMs).
Live migration of virtual machines is necessary when you need to achieve high-availability setups and load distribution.
The #KVM hypervisor has been a powerful alternative to Xen and VMware in the Linux world for several years.
To make the virtualization solution suitable for enterprise use, the developers are continually integrating new and useful features.
An example of this is live migration of virtual machines (VMs).
Live #migration involves:
The instance keeps running throughout the migration.
This is useful when it is not possible or desirable to stop the application running on the instance.
Live migrations can be classified further by the way they treat instance storage:
1. Shared storage-based live migration. The instance has ephemeral disks that are located on storage shared between the source and destination hosts.
2. Block live migration, or simply block migration. The instance has ephemeral disks that are not shared between the source and destination hosts. Block migration is incompatible with read-only devices such as CD-ROMs and Configuration Drive (config_drive).
3. Volume-backed live migration. Instances use volumes rather than ephemeral disks.
Block live migration requires copying disks from the source to the destination host.
It takes more time and puts more load on the network. Shared-storage and volume-backed live migration does not copy disks.
KVM hypervisor How it Works
This article will guide you on how the KVM #hypervisor works. Basically, KVM is a type-2 hypervisor (installed on top of another OS, in this case some flavor of #Linux).
It runs, however, like a type-1 hypervisor and can provide the power and functionality of even the most complex and powerful type-1 hypervisors, depending on the tools that are used with the KVM package itself.
KVM (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware containing virtualization extensions (Intel VT or AMD-V).
Using KVM, one can run multiple virtual machines running unmodified Linux or Windows images.
1. The main difference between Type 1 vs. Type 2 hypervisors is that Type 1 runs on bare metal and Type 2 runs on top of an operating system.
2. Each hypervisor type also has its own pros and cons and specific use cases.
3. Xen is better than #KVM in terms of virtual storage support, high availability, enhanced security, virtual network support, power management, fault tolerance, real-time support, and virtual CPU scalability.
4. A Type 1 hypervisor takes the place of the host operating system.
5. Type 1 hypervisors are highly efficient because they have direct access to physical hardware.
6. This also increases their security, because there is nothing in between them and the CPU that an attacker could compromise.
OnApp Cloud
This article will guide you on OnApp cloud. You will also learn about its dashboard and features.
OnApp Enterprise is a complete on-premises cloud solution for SMBs and enterprises.
It makes private and hybrid cloud easier to manage and easier to scale.
OnApp clouds can be created on almost any commodity x64 infrastructure, and across heterogeneous compute and storage hardware.
The features of OnApp cloud comprise of:
1. Public, private & hybrid cloud, plus VPS
2. Xen, KVM & VMware, plus Amazon EC2
3. Storage, backup and disaster recovery
4. Smart servers & bare metal servers
5. Global cloud & CDN through OnApp federation
6. CPU, disk, IOPS,RAM, servers, networks & more
OnApp is used:
i. By Telcos, MSPs and other service providers to create, manage and sell their own IaaS cloud products - either using their own datacenter infrastructure, third party infrastructure or hyperscale infrastructure.
ii. OnApp is used by hosts, telcos, MSPs, CDN vendors and other service providers to sell public/private/hybrid cloud services; and by enterprises for on-premise private & hybrid public/private cloud.
LXC container vs VM
This article will deal with the differences between LXC container and VM as well as which to choose. VMs are the best choice if you need to host multiple applications in the same environment for multiple purposes. LXC containers are preferred in cases where you have a single-purpose application environment.
KVM is hardware-level virtualization with its own kernel instance.
This allows the user to boot their own operating system of choice with no underlying or base OS.
And since each server is its own instance, they can be migrated without having to reboot.
Advantages to LXC:
1. It is easier to maintain and has very little overhead on deployment compared to a virtual machine. This allows for a much more lightweight cloud environment with LXC.
2. Containers also have a faster startup and stop speed, making them much more efficient overall.
3. Multiple containers can be deployed on the host system, where VMs are heavier on resources.
Manage KVM guest virtual machines via virsh commands
This article will guide you on how to use to manage KVM guest virtual #machines using virsh #commands.
virsh is a command line utility for managing virsh guest domains/virtual machines and the #hypervisor.
Linux list a KVM vm guest using #virsh command.
The main command interface used to control both Solaris xVM and guest domains is the virsh command. virsh provides a generic and stable interface for controlling virtualized operating systems.
Many virsh commands act asynchronously. This means that the system prompt can return before the operation has completed.
#KVM lets you turn Linux into a hypervisor that allows a host machine to run multiple, isolated virtual environments called guests or virtual machines (VMs).
To log into VM with Virsh, simply:
1. Open a shell prompt or login using ssh.
2. Login to a host server called server1.
3. Use the virsh console command to log in to a running VM called 'centos7' type: virsh console centos7.
The virsh destroy #command initiates an immediate ungraceful shutdown and stops the specified guest virtual machine.
Using virsh destroy can corrupt guest virtual machine file systems.
Use the virsh destroy command only when the guest virtual machine is unresponsive.
Reset Windows Administrator Password from Hyper-V
This article will guide you on steps to reset the forgotten #Windows Administrator password from Hyper-V using an #ISO file.
Microsoft's Hyper-V virtualization can greatly reduce cost of operations. By purchasing a few very powerful #servers you can virtualize all or most of your entire infrastructure while reducing the cost of #hardware and maintenance.
To Reset Lost Admin Password for Hyper-V Virtual #Machine:
1. Select the administrator account, then click the Reset Password button to reset the password to blank.
2. Click the Restart button to reboot the virtual machine, you are able to log in to the administrator account with a blank password.
Azure PowerShell context objects How to manage them
This article will guide you on how to manage #Azure #PowerShell #context #objects. Azure PowerShell context objects are to hold subscription and authentication information.
Azure PowerShell is basically an extension of #Windows PowerShell. It lets Windows PowerShell users control Azure's robust functionality. From the command line, Azure PowerShell programmers use preset scripts called cmdlets to perform complex tasks like provisioning virtual #machines (#VMs) or creating #cloud services.
To select Azure subscription in PowerShell:
1. Enter Login-AzAccount and hit enter, then provide your user id and password.
2. Get-AzureSubscription (this will give you the list of subscription).
3. Select-AzureRmSubscription -SubscriptionId xxxxx-xxxxx-xxxxxx-xxxx (this way you can set which particular subscription you want to use).
Add Glance Cloud images to OpenStack
This article will guide you on steps to add #Glance #Cloud images to #OpenStack with different #Linux distributions which enables users to discover, register, and retrieve virtual machine images.
After images are created they should be registered in Openstack Glance - #image operation service.
Upload Image Into Glance:
1. Replace <NAME> with the name that users will refer to the disk image by.
2. Replace <IMAGE_FILE> with the local path to the image file to upload.
Deploy Node js Application to DigitalOcean Server
This article will guide you on how to deploy node.js application to #DigitalOcean Server.
To Deploying #Node . js application to DigitalOcean — Setting up the #server:
1. Getting familiar with Digital Ocean and creating your first #droplet.
2. Setting up #SSH and connecting to your server from your local #machine.
3. Setting up a simple Express.js web-server in local machine.
4. Using #Git to deploy your code to server.
Steps to Deploy Virtual Machines in RHEV Environment
This article will guide you on how to #deploy #virtual #machines in the #RHEV environment and also on #Linux and #Windows virtual machines.
A Virtual Machine (#VM) is a compute resource that uses software instead of a physical computer to run programs and deploy apps. One or more virtual "guest" #machines run on a physical "host" machine.
The main purpose of VMs is to operate multiple operating systems at the same time, from the same piece of hardware. Without virtualization, operating multiple systems — like Windows and Linux — would require two separate physical units.
The two basic types of virtual machines are process and system VMs:
1. A process virtual machine allows you to run a single process as an application on a host machine.
2. A system virtual machine is a fully virtualized #VM designed to be a substitute for a physical machine.
Your virtual machine internet connection goes through your computer and through your router. So they can track your router's #IP address, and possibly track you down at least to your city, if not to individual street or house.
Standard and Production Checkpoints in Hyper-V
This article will guide on how to choose between #Standard or #production #checkpoints in Hyper-V. We also look into the various aspects of standard and production checkpoints.
Hyper-V checkpoints allow IT #administrators to easily save the existing state of a virtual machine before any changes are made so that if a problem crops up due to the changes, the VM can revert to its previous state. A #snapshot of the virtual machine #memory state is not taken when using a production checkpoint.
To Change checkpoints to production or standard checkpoints:
1. In Hyper-V Manager, right-click the virtual machine and click Settings.
2. Under the Management section, select Checkpoints.
3. Select either production checkpoints or standard checkpoints.
Guide to install Red Hat Enterprise Linux 7 3
This article will guide you on the step by step process to install Red Hat Enterprise Linux 7.3. This involves completing the “Installation Summary” window along with the installation of #VMware #Workstation and creation of a virtual machine.
Red Hat® Enterprise Linux® is the world's leading enterprise #Linux platform. * It's an open source operating system (#OS). It's the foundation from which you can scale existing apps—and roll out emerging technologies—across bare-metal, virtual, container, and all types of cloud environments.
Virtual Machines (VMs) in oVirt 4 0 Environment
This article will guide you on the steps to create a Virtual Machines (#VMs) in oVirt 4.0 Environment.
The #oVirt engine acts as the control center for oVirt environments. The engine enables admins to define #hosts and #networks, as well as to add storage, create VMs and manage user permissions. Included in the oVirt engine is a graphical user interface (GUI), which manages oVirt #infrastructure resources.
To Create a Virtual Server:
i. Access the Virtual Server class tab in the Class #Manager.
ii. Click the Add Virtual Server link.
iii. Specify the name of the virtual server, its connections, and the URL Hosts. ...
iv. Click OK and then Apply to save and apply your changes.
To to Create Virtual Machines (VMs) in oVirt 4.0 Environment:
1. Create new Data Center.
2. Configure Cluster for Data Center.
3. Add Host or oVirt Node to above created data center & cluster.
4. Creating Storage #Domains.
5. Upload #ISO files to ISO Storage Domain.
6. Create Virtual Machine.
Monitor Azure virtual machines with RDP
This article will guide you on how to monitor virtual #machines #RDP using Azure.
You can View performance directly from an Azure VM:
1. In the #Azure portal, select Virtual Machines.
2. From the list, choose a #VM and in the #Monitoring section choose Insights.
3. Select the #Performance tab.
Using Kill Commands In Linux
This article will guide you on how to use Kill #Commands In #Linux. Here, you will learn several ways to #terminate a running process. However, one should exercise caution to prevent incorrectly terminating a #process that should not be killed.
The #kill -9 command sends a SIGKILL signal indicating to a service to shut down immediately. An unresponsive program will ignore a kill command, but it will shut down whenever a kill -9 command is issued.
Monitoring VMware with Nagios XI
This article will guide you on the steps to Monitor VMware with #Nagios.
To Monitor the VMware host
i. Enter the Address, Username and Password of your #ESX / #ESXi host.
ii. Select Monitor the #VMware #Host.
iii. Click Next to go to Step 2.
iv. On step 2 you will configure all of the options for #monitoring.
Process to install node js Windows
This article will guide you on how to install Node.js and verify its installation. Additionally, you will also learn how to uninstall it. #Node . js is a runtime environment that allows software developers to launch both the #frontend and #backend of web apps using #JavaScript. Although JS underpins all the processes for app assembly, as a backend #development #environment, Node. js, differs from the frontend environment.
Cloning existing KVM virtual machine images on Linux
This article will guide you on how to use the virt-clone command which provides a number of options to clone a #KVM #VM. You can use the virt-sysprep if you need to clone the VM and make/reset anything inside the guest #OS.
Selecting the number of vCPUs and Cores for a Virtual Machine
This articles will guide you when selecting the number of vCPUs and Cores for a Virtual Machine which depends on the operating system used and some other factors.
Basically, When Selecting the Number of #vCPUs and #Cores for a Virtual Machine, you can use all CPU #resources allocated to a virtual machine, it must see one 8 core #processor, 2 vCPUs with 4 cores each or 1 vCPU with 4 cores in two threads instead of 8 vCPUs.
Detecting Memory Overcommit in the Guest OS
This article will guide you on how to go about detecting Memory Overcommit in the Guest #OS.
#Memory overcommit is a #hypervisor feature that allows us to allocate to virtual #machines more memory than is available on a physical #host.
Install and Configure Free VMware Hypervisor
This article will guide you on the process to Configure Free VMware Hypervisor, to create a virtual #machine, and install a guest operating system.
“VMware vSphere Hypervisor #VMware #vSphere #Hypervisor is a free product that provides a simple and easy way to get started with #virtualization at no cost.
Match Windows Disks to VMWare VMDK Files
This article will guide you on the steps to match #windows #disks to #VMWare #VMDK files.
Resizing the Nagios VM disk size for CentOS 7
This article will guide you on the process to resize the #Nagios #VM #disk size.
Invalid State of a Virtual Machine on VMWare ESXi
This article will guide you on the steps to resolve the Invalid State of a Virtual Machine on VMWare #ESXi error which relates to #orphaned virtual machines.
A virtual machine can show up as invalid or orphaned in these situations. After a vMotion or #VMware DRS migration. After a VMware HA #host failure occurs, or after the #ESX host comes out of maintenance mode. A virtual machine is deleted outside of vCenter Server. #vCenter Server is restarted while a migration is in progress.
Extending Disk Space with LVM
To increase the size of a logical volume, use the lvextend command. When you extend the logical volume, you can indicate how much you want to extend the volume, or how large you want it to be after you extend it. The following command extends the logical volume /dev/myvg/homevol to 12 gigabytes.
Using Differencing Disks in Hyper-V for Quick VM Deployment
This article will guide you on the steps to use Differencing Disks in Hyper-V for Quick VM Deployment provides digital storage space for securing critical data.
VMWare vCenter Self-Signed Certificate Warning
This article will guide you on the steps to remove VMWare vCenter Self-Signed Certificate Warning.
Managing password expiration settings in VMWare vSphere
This article will guide you on the steps to manage the password expiration settings in VMWare vSphere.
How to access VMFS Datastore from Linux Windows and ESXi
This tutorial will help you on the process to access VMFS datastore from Linux, Windows, and ESXi.
Backup Hyper V Virtual Machines
This article will guide you on how to perform backup of Hyper-V Virtual Machines and how it works.
VMWare how to find VMS by IP or MAC address
This tutorial will guide you on how to easily find VMS by IP or mac address.
Steps to kill an unresponsive Virtual Machine
This article will guide you through the steps to kill an unresponsive Virtual Machine in VMWare ESXi.
Set up SNMP VMWare ESXi 5 5
This article will guide you on the steps to follow to configure SNMP VMWare ESXi 5.5.
System logs on ESXi host are stored on Non Persistent Storage
This article will help to fix VMWare warning message "System logs on ESXi host are stored on Non-Persistent Storage".
Windows Server error The disk is offline because of a policy set by an administrator
This article will help to fix Windows Server error : The disk is offline because of a policy set by an administrator which relates to SAN Policy
Installing Hyper-V Role in Windows 10 VM under VMWare ESXi
This article will guide you on the steps to follow to install Hyper-V Role in Windows 10 VM under VMWare ESXi.
Fix Hyper V VM Stuck in the Stopping Starting State
Basically, if our virtual machine running on Hyper-V is stuck for some reason, the only way out is to forcibly kill the process responsible for this VM on the host OS.
vCenter installation on ESXi Host
This article will guide you on how to install vCenter Server on a physical server or a virtual machine running Windows.
Failed to initialize a valid firewall backend
This article will guide you on how to fix error ‘failed to initialize a valid firewall backend’ which is triggered in the process of creating Virtual Machines on KVM using Libvirt.
Vmware virtual machine disks consolidation is needed error
This guide will help you to fix the warning error experienced in the process of deleting a snapshot, the snapshot VMDK files or logs have not been deleted correctly.
Tips to fix unable to unmount delete VMFS Datastore the resource is in use
This guide will help to fix VMWare error "unable to unmount/delete vmfs datastore: the resource is in use" which occurs when trying to remove an empty VMFS Datastore in VMWare vSphere.
Vmware operation failed to upload to datastore
This guide will help you to fix errors ecountered while trying to upload or copy files to the VMFS Datastore in VMware vSphere (6.7) using the “Upload Files” button in the vSphere Client interface.
Solution to error VMWare virtual machine disks consolidation is needed
This article will help you to fix the warning error "VMWare: virtual machine disks consolidation is needed" experienced when trying to delete a snapshot, the snapshot VMDK files or logs have not been deleted correctly.
KVM Installation on CentOS 7
This article will guide you through the process of installing kernel-based virtual machine (KVM) on your CentOS 7 machine.
Fix Unable to access file since it is locked error on vmware
This article will guide you through the steps you need to take to fix the VMWare "Unable to access a file since it is locked" error by restarting the Management Agent or ESXi host.
Fix no such device error when using ethtool
Ethtool is a great utility for Linux kernel-based operating system which helps to display and modify some important parameters of network interface controllers and their device drivers.
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