Explore information related to hypervisor


OnApp Boot from ISO


This article covers how to boot from ISO on Onapp. OnApp allows uploading your custom bootable ISOs for recovery purposes. These could be different images for Windows/Linux/FreeBSD or any additional software. As a cloud administrator, you can limit user's ability to upload and manage ISOs by permissions and in buckets. You can boot virtual servers from your own ISOs or the ISOs that are uploaded and made publicly available by other users. 


If your cloud deployment is not a fresh installation, make sure to enable the following permissions for your Admin and other roles as appropriate:

  • Any action on ISOs - the user can take any action on ISOs.
  • Create a new ISO - the user can create a new ISO.
  • Destroy any ISO - the user can delete any ISO (own, user, and public).
  • Destroy own ISO - the user can only delete own ISO .
  • Destroy user ISO - the user can delete ISOs created by any user, but not public ISOs .
  • Make any ISO public - the user can make public any ISO available to all users.
  • Make own ISO public - the user can make public own ISOs only.
  • Make user ISO public - the user can make public ISOs created by any user .
  • Create and manage own ISOs - the user can create and edit/delete/view own ISOs.
  • Manage all ISOs - the user can manage own/user/public ISOs.
  • Create and manage user ISOs - the user can view/create/edit/delete ISOs created by any user.
  • See all ISOs - the user can view all ISOs in the cloud.
  • See own ISOs - the user can only view the ISOs created by themselves.
  • See all public ISOs - the user can view all public ISOs.
  • See user ISOs - the user can view the ISOs created by any user in the cloud.
  • Update any ISO - the user can edit any ISO in the cloud.
  • Update own ISO - the user can only edit own ISO.
  • Update user ISO - the user can edit  the ISOs created by any user in the cloud.


By default ISOs are available only to those users who uploaded them. These ISO images are available in the My ISOs tab. 

To make your ISO public and accessible for all users:

  • Go to your Control Panel > Cloud > Templates > ISO List menu.
  • Click My ISOs tab.
  • Click the Actions button next to the ISO you want to make public, then select Make public.
  • Confirm the window that pops up.
  • When you make a user ISO public, it is moved to the System ISOs tab.

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Shrink VMDK Virtual Disk Size on VMWare ESXi - Do it Now ?


This article covers how to shrink VMDK Virtual Disk Size on VMWare ESXi.
By default, VMware creates "growable" disks that grow larger in size as you add data.

Unfortunately, they don't automatically shrink when you remove data.
You'll need to clean up or compact your disks to actually free up space on your hard drive.

VMware Workstation also allows you to create snapshots, which contain a complete "snapshot" of a virtual machine's state at the point in time you created them.
These can take a lot of space if the virtual machine has changed significantly since then.
You can free up additional space by deleting snapshots you no longer need.

1. To view the snapshots for a virtual machine, select the virtual machine in VMware Workstation and click VM > Snapshot > Snapshot Manager.
2. To delete a snapshot you no longer need, right-click it in the Snapshot Manager window and select "Delete". It will be removed from your computer.
3. You won't be able to restore your virtual machine to that previous point in time after deleting the snapshot, of course.

Before we try to shrink the virtual disk files, we should try to remove any unneeded files from the virtual machine to free space.

For example, on Debian-based VMs, you can run:

$ apt-get clean

To clear out the local repository of retrieved package files.
Next, run the command below to fill the unused space with zeros:

cat /dev/zero > zero.fill;sync;sleep 1;sync;rm -f zero.fill


Free Disk Space In VMware Workstation

In VMware Workstation, first power off the virtual machine you want to compact. You can't complete this process if it's powered on or suspended.
1. Select the virtual machine you want to compact in the main window and click VM > Manage > Clean Up Disks.
2. The tool will analyze the selected virtual machine's disk and show you how much space you can reclaim.
To reclaim the space, click "Clean up now".
If no space can be freed, you'll see a "Cleanup is not necessary" message here instead.

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USB device passthrough to Hyper-V - How to get this done


This article covers how to perform Hyper-V USB Passthrough. A USB passthrough is referenced when a keyboard has female USB ports for other devices to be plugged into the keyboard. USB passthroughs requires more than one USB port to be used by the keyboard in order to pass the USB through to the PC, often requiring an additional connection to the host system for powered ports.


What does Hyper-V USB passthrough Mean?

Hyper-V USB passthrough functionality allows you to access the USB device from within a virtual machine. There is a way to enable USB passthrough on Hyper-V for a memory stick, but you’ll have to use Windows storage subsystem.


Known issues with Hyper-V USB device passthrough organized with native methods:

1. Platform restrictions: said methods rely upon Windows storage subsystem so using them to set up Hyper-V USB passthrough on Linux (or any other OS that’s not Windows) is out of question, sadly.

2. An extremely limited list of supported devices: for the native methods to work, your USB peripheral must be recognized as a “Mass Storage Device”. No exceptions.

3. No sharing: once your device is set in passthrough mode, you can access it only from the guest OS. That’s why using these methods to permanently connect a USB to Hyper-V is definitely not the best idea.

4. Poor choice for a cloud: with these methods, the USB device is always locked to a specific host PC while there's no way to anchor a cloud-based Hyper-V guest system or preestimate where it's going to run for your next session.


Advantages of using RDP for Hyper-V USB passthrough:

1. Works for literally any hypervisor you can name;

2. Instant access to USB devices, once RDP connection is up;

3. Group Policy feature for overall control;

4. All USB devices plugged into your host PC are accessible from a virtual machine.


To enable USB device in Hyper-V with the Enhanced Session Mode:

1. On a host computer, you go to the Hyper-V Manager, right-click the name of the host and choose Hyper-V Settings.

2. In the Setting window, you will see the Server and User sections. Select Enhanced Session Mode Policy in the Server section and allow the enhanced session mode by checking the corresponding box.

3. Now, choose "Enhanced Session Mode" in the User section and check the “Use enhanced session mode” box.

4. Click OK and the changes will be saved.


To allow Hyper-V access to attached USB devices:

1. Start the Hyper-V Manager and double-click the name of your virtual machine.

2. In the pop-up window, click “Show Options” to configure your VM’s future connections.

3. After that, go to the tab “Local resources” and click “More” in the section “Local devices and resources”.

4. Then, check the boxes “Other supported Plug and Play devices” and “Devices that I plug in later”. Hit OK.

5. If you want this configuration to be saved for all future connections, check the corresponding box in the “Display” tab. Click “Connect” to implement the changes.

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Virtuozzo VS Hyper-V - Which is better


This article covers some comparison between Virtuozzo VS Hyper-V. 

Hyper-V and Virtuozzo are both popular VPS platforms used by a large number of web hosting providers for the provisioning of Windows VPS hosting services, with Virtuozzo being favoured for Windows Server 2003 VPS hosting and Hyper-V being the most reliable solution for Windows Server 2008 VPS hosting services.


Advantages of using Virtuozzo over Hyper-V include:

1. Direct Linux support – Virtuozzo can be installed on their Windows or Linux VPS hosting nodes, and although Hyper-V can be used for the hosting of virtual machines running Linux it is only available for use on Windows Server 2008.

2. Web based control panel (Parallels Power Panel) – the Parallels Power Panel will allow users to manage their Linux or Windows VPS hosting server from a web based interface meaning that if they aren't in a situation where they can access their VPS server via Remote Desktop then they can use the Power Panel to restart their VPS server if necessary or to kill any services or processes which may be overloading their VPS server’s resources.

3. Separate application – the fact that Virtuozzo is a separate application which can be installed on top of the operating system can have its advantages in some cases, for example if a web hosting providers wishes to discontinue using a server for VPS server hosting then all they have to do is uninstall the application from their server, although in most cases it is advised to do an OS reload anyway to ensure that you have a blank canvas to start with.


Advantages of using Hyper-V over Virtuozzo:

1. Cost – with Virtuozzo VPS hosting web hosting providers have to pay for the cost of the Virtuozzo application and the cost of the operating system license, but because Hyper-V is part of the Windows Server 2008 operating system they will only need to pay for the operating system license – this can help to reduce the costs of Hyper-V VPS hosting services and as the cost of the operating system falls, prices will fall further and will eventually meet Virtuozzo Windows Server 2003 hosting services when it comes to price which will mean that people will gradually move over to using Windows Server 2008 VPS hosting.

2. Reliability – as Hyper-V is part of the Window Server 2008 operating system, web hosting providers are able to guarantee reliable Windows Server 2008 VPS server hosting services.

3. Native support for Windows Server 2008 – although Virtuozzo may have support for Windows Server 2008, it hasn’t been able to offer the most reliable of Windows Server 2008 VPS hosting services.

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The URI Failed to Connect to the Hypervisor - Fix it now


This article covers methods to resolve hypervisor error. The error message is misleading about the actual cause. This error can be caused by a variety of factors, such as an incorrectly specified URI, or a connection that is not configured.


To fix THE URI FAILED TO CONNECT TO THE HYPERVISOR:

1. Incorrectly specified URI

When specifying qemu://system or qemu://session as a connection URI, virsh attempts to connect to host names system or session respectively. This is because virsh recognizes the text after the second forward slash as the host.

Use three forward slashes to connect to the local host. For example, specifying qemu:///system instructs virsh connect to the system instance of libvirtd on the local host.

When a host name is specified, the QEMU transport defaults to TLS. This results in certificates.


2. Connection is not configured

The URI is correct (for example, qemu[+tls]://server/system) but the certificates are not set up properly on your machine. For information on configuring TLS, see Setting up libvirt for TLS available from the libvirt website.

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Troubleshoot KVM Virtualization Problem


This article covers how to troubleshoot KVM virtualization problem.


Log file locations and tools used to track down #KVM #problems are:
1. $HOME/.virtinst/virt-install.log – virt-install tool log file.
2. $HOME/.virt-manager/virt-manager.log – virt-manager tool log file.
3. /var/log/libvirt/qemu/ – Log files for each running virtual machine. If centos is virtual machine name, than log file is /var/log/libvirt/qemu/centos.log.

You can use the grep and other Linux tools to view this files:
# tail -f /var/log/libvirt/qemu/freebsd.log
# grep something $HOME/.virtinst/virt-install.log
$ sudo tail -f /var/log/libvirt/qemu/openbsd.log

Hyper-V backups can fail for any number of reasons, but there are some things to look for when backups don’t work the way that they are supposed to.
When backups fail, the first thing that you should do is to check the backup logs in an effort to learn more about the problem.
Specifically, you need to determine if the problem is confined to a particular host, a particular virtual machine, or perhaps related to the backup target itself.

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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.

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Managing Hypervisor with OnApp


This article will guide you on OnApp which is a complete cloud management software. Basically, OnApp is one of the popular #software for managing hypervisors.

Hypervisors support the creation and management of virtual machines (#VMs) by abstracting a computer's software from its hardware. 

OnApp is a complete Infrastructure-as-a-Service solution for cloud providers, #CDN providers, telcos, carriers, MSPs and enterprises. 

With #OnApp, you can manage all of your #IT through a single pane of glass: orchestration, management, scaling, backups, DR, RBAC, governance, metering, chargeback and provisioning – for VMs, containers, apps and bare metal – across multiple sites, in one UI.

Hypervisors make virtualization possible by translating requests between the physical and virtual resources.


OnApp can simplify infrastructure management, automate your datacenter, maximize your investments in hardware, and deliver intuitive, secure cloud services to customers, partners and employees.

1. Easy to deploy: OnApp includes a complete suite of cloud orchestration, management and provisioning tools, fully integrated into one platform. 

2. Easy to use: OnApp includes a fully customizable, selfservice control panel that streamlines workload management, and uses intuitive wizards and GUI controls to make cloud management and provisioning as simple and efficient as possible. 

3. Highly scalable: OnApp clouds feature autoscaling as standard, enabling individual servers to scale vertically and horizontally based on configurable thresholds. 

4. Highly available: OnApp clouds are secure, self-healing and extremely resilient, with multiple backup schema, automatic hypervisor failover, High Availability support, and disaster recovery options for real-time remote replication and restore.

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Working with Production checkpoint in Hyper-V 2016


This article will guide you on how to change the checkpoints in Hyper-V. 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. 

Virtual machine checkpoints (formerly known as virtual machine #snapshots) capture the state, data, and #hardware #configuration of a running virtual machine. 

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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.

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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.

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