Explore information related to vm
SolusVM: Cannot Allocate Memory Error – Best fix ?
This article covers the best way to tackle SolusVM: Cannot Allocate Memory Error. In fact, this error happens while booting KVM VPS in SolusVM. This error signifies that there is not enough free memory on the node.
PostgreSQL Error code 23505 - Fix it Now ?
This article covers methods to fix PostgreSQL Error code 23505 for our customers. This issue happens when you are trying to insert a value in a column that already exists there. If you have a sequencer on the field (like with a serial column type), it is likely out of sync with the table because you have done an insert and supplied a value (rather than letting the "default" mechanism handle it by getting the nextval from the sequencer). If this is the case, reset the sequencer with a setval statement to the max value of the field.
SolusVM error Unable to find ostemplate - Best Fixes ?
This article covers methods to resolve SolusVM errors for our customers.
To fix Unable to find ostemplate error:
Simply Re-install OS
$ vzctl reinstall <CTID> --ostemplate <template_name>
where <CTID> should be replaced with actual VPS CT ID and <template_name> should be replaced with the template name without ".tar.gz" part.
VMware error, Missing credentials for vCenter server - Fix it Now ?
This article covers methods to fix VMware errors for our customers. Basically, this guide provides information on troubleshooting common issues with logging in to the vSphere Web Client when using the Use Windows Session Credentials feature.
VMware error "Failed to build vmmon" - Fix it Now ?
This article covers method to resolve VMware error "Failed to build vmmon" for our customers. Linux for Workstation requires additional packages and steps in order to complete installation. The following steps have been tested on Fedora 28 and Fedora 29 but otherwise would be generally applicable to other Linux distributions. Please adjust for your specific version.
SolusVM blank page - Fix it Now ?
This article covers methods to resolve blank page in SolusVM due to a missing PHP extension.
SolusVM error "Connection Failed Debug Data: ERROR:4" - Fix it Now ?
This article covers method to resolve SolusVM error "Connection Failed Debug Data: ERROR:4".
Citrix XenServer internal error - Fix it Now ?
This article covers methods to fix Citrix XenServer internal error for our customers. This error occurs because the Control Domain (Dom0) on the XenServer which runs the VM, attaches the Virtual Disk Image (VDI) of the VM to Control Domain.
This attached disk is then operated by the Control Domain to perform the operations which has been initiated on the VM. As the operation fails, the VDI is still attached to the control domain through a Virtual Block Device (VBD) connection that needs to be destroyed.
SolusVM 'No bootable device' error - Fix it Now ?
This article covers methods to fix SolusVM 'No bootable device' error for our customers.
To fix this error:
- Log into SolusVM Master interface.
- Open Virtual Server and remove created VPS.
- Create a new VPS via SolusVM > Virtual Servers > Add Virtual Servers > KVM with HDD Space bigger than the size of the sum of the main partition and SWAP and SWAP bigger than the default value of the template - from the example above - HDD Space should be 22 GB and SWAP - 2000 MB.
SolusVM html5 and vnc consoles not working - Fix it Now ?
This article covers how to fix "Server disconnected (code:1006)". Basically, this error happens as a result of misconfiguration in the noVNC feature or when SSL settings required for NoVNC to work are not configured.
SolusVM slave connection error - Fix it Now ?
This article covers how to fix solusVM connection error. Basically, while accessing SolusVM Admin control panel users often receive different connection errors related to solusVM slave.
To fix Master SolusVM error:
1. Install repository:
$ yum install solusvm-release
2. shutdown lighttpd service:
$ service lighttpd stop
$ chkconfig lighttpd off
3. install nginx and legacy configuration file
$ yum install svmstack-nginx svmstack-nginx-legacy-slave-config
4. start new service
$ service svmstack-nginx restart
$ service svmstack-fpm restart
Migrate solusvm to proxmox – easy steps to implement this task ?
This article covers how to Migrate solusvm to proxmox.
To Migrate KVM VM's from SolusVM to Promox:
- Take LVM snapshot of currently running SolusVM KVM CentOS7 instance.
- dd the snapshot and copy it to the Proxmox Hypverisor.
- Create a new KVM on the Proxmox server with LVM disks the same size as the source.
- dd the raw snapshot image to the LVM device ie vm-VMID-disk-0.
- Boot the new VM with CentOS 7 rescue CD and fix device names, update initramfs, etc and reboot.
Linux passwd: authentication token manipulation error - Fix it Now ?
This article covers how to Fix "passwd: Authentication token manipulation error" in Linux. Basically, passwd: authentication token manipulation error in Linux occurs when we try to change the password via the passwd command.
To fix this error, simply Reboot the System by running the following command:
$ sudo reboot
Setting remote desktop drain mode on a Windows Server RDS host
This article covers how to set remote desktop drain mode on a Windows Server RDS host. Basically, setting remote desktop drain mode on a Windows Server RDS host can be easily performed with PowerShell. The Drain Mode is used when a server administrator needs to maintain a server (install Windows updates, configure or update apps) without affecting the availability of the entire RDS farm.
When you set the RDS host in drain mode state, the RDS host can no longer accept new connections but existing sessions continue working until users log out. You can monitor the status of the RDS host in Horizon Administrator.
To remove a Remote Desktop Session Host (Uninstall the RD Session Host Role Service) :
- Open Server Manager.
- In the left pane, expand Roles.
- Right-click Remote Desktop Services, and then click Remove Role Services.
- On the Select Role Services page, clear the Remote Desktop Session Host check box, and then click Next.
- On the Confirm Removal Selections page, click Remove.
Create Private Network Bridge on Proxmox VE 6 with NAT
This article covers how to create a Private Network Bridge on Proxmox.
To do this:
1. Enable paket forwarding in /etc/sysctl.conf on the Proxmox host
2. Edit /etc/network/interfaces on the ProxMox host, to get 10.10.10.0/24 for your containers, that route through eth0 of the ProxMox host
Code:
# network interface settings; autogenerated# Please do NOT modify this file directly, unless you know what
# you're doing.
#
# If you want to manage parts of the network configuration manually,
# please utilize the 'source' or 'source-directory' directives to do
# so.
# PVE will preserve these directives, but will NOT read its network
# configuration from sourced files, so do not attempt to move any of
# the PVE managed interfaces into external files!
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet static
address YOUR-PUBLIC-STATIC-IP/YOUR-PUBLIC-MASK
gateway YOUR-STATIC-GATEWAY
auto vmbr1
iface vmbr1 inet static
address 10.10.10.1
netmask 255.255.255.0
bridge_ports none
bridge_stp off
bridge_fd 0
post-up iptables -t nat -A POSTROUTING -s '10.10.10.0/24' -o eth0 -j MASQUERADE
post-down iptables -t nat -D POSTROUTING -s '10.10.10.0/24' -o eth0 -j MASQUERADE
3. Configure a container inside 10.10.10.0/24 - as an example using 10.10.10.2 .
Install Proxmox VE 6 on Debian Buster (Debian 10) - Step by Step Process ?
This article covers the installation of Proxmox VE 6 server on Debian 10 (Buster) Linux system. Please note that you need a 64-bit processor with support for the Intel 64 or AMD64 CPU extensions.
Visit Proxmox Documentation website for advanced configurations and to master Proxmox VE Administration.
To Access Proxmox VE web interface:
1. Connect to the Proxmox VE admin web interface on (https://youripaddress:8006).
2. Select "PAM Authentication" and authenticate with server's root user password.
3. And add your first network interface to it.
Dnsmasq DHCP Server in Proxmox – How to use for VMs IP ?
This article covers methods to install, configure and resolve matters relating to Dnsmasq DHCP Server in Proxmox. When creating the VM we just need to specify the MAC address for specific IP and than just use DHCP to get the assigned IP.
To Install the DHCP server, run the command:
$ apt install isc-dhcp-server
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.
Updating Windows VM Templates on VMWare with PowerShell - How to do it
This article covers how to update Windows VM Templates on VMWare.
The update process of a VM template on VMWare consists of the following stages:
1. A template from the Content Library is converted to a virtual machine.;
2. After starting it, an administrator logs on, installs approved Windows updates using WSUS, updates the required software;
3. After the updates have been installed, the VM is restarted, then turned of and converted back to the template.
Virtualization Restrictions in RedHat Linux with KVM
This article covers Virtualization Restrictions in RedHat Linux which are additional support and product restrictions of the virtualization packages.
The following notes apply to all versions of Red Hat Virtualization:
1. Supported limits reflect the current state of system testing by Red Hat and its partners. Systems exceeding these supported limits may be included in the Hardware Catalog after joint testing between Red Hat and its partners. If they exceed the supported limits posted here, entries in the Hardware Catalog are fully supported. In addition to supported limits reflecting hardware capability, there may be additional limits under the Red Hat Enterprise Linux subscription terms. Supported limits are subject to change based on ongoing testing activities.
2. These limits do not apply to Red Hat Enterprise Linux (RHEL) with KVM virtualization, which offers virtualization for low-density environments.
3. Guest operating systems have different minimum memory requirements. Virtual machine memory can be allocated as small as required.
Guest unable to reach host using macvtap interface - Fix it Now
This article covers how to fix the issue with guests unable to reach the host using macvtap interface.
This issue happens when A guest virtual machine can communicate with other guests, but cannot connect to the host machine after being configured to use a macvtap (also known as type='direct') network interface.
To resolve this error (guests unable to reach the host using macvtap interface), simply create an isolated network with libvirt:
1. Add and save the following XML in the /tmp/isolated.xml file. If the 192.168.254.0/24 network is already in use elsewhere on your network, you can choose a different network.
<network>
<name>isolated</name>
<ip address='192.168.254.1' netmask='255.255.255.0'>
<dhcp>
<range start='192.168.254.2' end='192.168.254.254' />
</dhcp>
</ip>
</network>
2. Create the network with this command: virsh net-define /tmp/isolated.xml
3. Set the network to autostart with the virsh net-autostart isolated command.
4. Start the network with the virsh net-start isolated command.
5. Using virsh edit name_of_guest, edit the configuration of each guest that uses macvtap for its network connection and add a new <interface> in the <devices> section similar to the following (note the <model type='virtio'/> line is optional to include):
<interface type='network'>
<source network='isolated'/>
<model type='virtio'/>
</interface>
6. Shut down, then restart each of these guests.
Since this new network is isolated to only the host and guests, all other communication from the guests will use the macvtap interface.
Boot a guest using PXE - Do it now
This article covers how to boot a guest using PXE. PXE booting is supported for Guest Operating Systems that are listed in the VMware Guest Operating System Compatibility list and whose operating system vendor supports PXE booting of the operating system.
The virtual machine must meet the following requirements:
1. Have a virtual disk without operating system software and with enough free disk space to store the intended system software.
2. Have a network adapter connected to the network where the PXE server resides.
A virtual machine is not complete until you install the guest operating system and VMware Tools. Installing a guest operating system in your virtual machine is essentially the same as installing it in a physical computer.
To use PXE with Virtual Machines:
You can start a virtual machine from a network device and remotely install a guest operating system using a Preboot Execution Environment (PXE).
You do not need the operating system installation media. When you turn on the virtual machine, the virtual machine detects the PXE server.
To Install a Guest Operating System from Media:
You can install a guest operating system from a CD-ROM or from an ISO image. Installing from an ISO image is typically faster and more convenient than a CD-ROM installation.
To Upload ISO Image Installation Media for a Guest Operating System:
You can upload an ISO image file to a datastore from your local computer. You can do this when a virtual machine, host, or cluster does not have access to a datastore or to a shared datastore that has the guest operating system installation media that you require.
How to Use a private libvirt network ?
1. Boot a guest virtual machine using libvirt with PXE booting enabled. You can use the virt-install command to create/install a new virtual machine using PXE:
virt-install --pxe --network network=default --prompt
2. Alternatively, ensure that the guest network is configured to use your private libvirt network, and that the XML guest configuration file has a <boot dev='network'/> element inside the <os> element, as shown in the following example:
<os>
<type arch='x86_64' machine='pc-i440fx-rhel7.0.0'>hvm</type>
<boot dev='network'/>
<boot dev='hd'/>
</os>
3. Also ensure that the guest virtual machine is connected to the private network:
<interface type='network'>
<mac address='52:54:00:66:79:14'/>
<source network='default'/>
<target dev='vnet0'/>
<alias name='net0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
</interface>
Create CentOS Fedora RHEL VM Template on KVM - How to do it
This article covers how to create CentOS/Fedora/RHEL VM Templates on KVM. VM Templates are more useful when deploying high numbers of similar VMs that require consistency across deployments. If something goes wrong in an instance created from the Template, you can clone a fresh VM from the template with minimal effort.
To install KVM in your Linux system:
The KVM service (libvirtd) should be running and enabled to start at boot.
$ sudo systemctl start libvirtd
$ sudo systemctl enable libvirtd
Enable vhost-net kernel module on Ubuntu/Debian.
$ sudo modprobe vhost_net
# echo vhost_net | sudo tee -a /etc/modules
How to Prepare CentOS / Fedora / RHEL VM template ?
1. Update system
After you finish VM installation, login to the instance and update all system packages to the latest versions.
$ sudo yum -y update
2. Install standard basic packages missing:
$ sudo yum install -y epel-release vim bash-completion wget curl telnet net-tools unzip lvm2
3. Install acpid and cloud-init packages.
$ sudo yum -y install acpid cloud-init cloud-utils-growpart
$ sudo sudo systemctl enable --now acpid
4. Disable the zeroconf route
$ echo "NOZEROCONF=yes" | sudo tee -a /etc/sysconfig/network
5. Configure GRUB_CMDLINE_LINUX – For Openstack usage.
If you plan on exporting template to Openstack Glance image service, edit the /etc/default/grub file and configure the GRUB_CMDLINE_LINUX option. Your line should look like below – remove rhgb quiet and add console=tty0 console=ttyS0,115200n8.
GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=cl/root rd.lvm.lv=cl/swap console=tty0 console=ttyS0,115200n8"
Generate grub configuration.
$ sudo grub2-mkconfig -o /boot/grub2/grub.cfg
6. Install other packages you need on your baseline template.
7. When done, power off the virtual machine.
How to Clean VM template ?
You need virt-sysprep tool for cleaning the instance.
$ sudo virt-sysprep -d centos7
Redirect FreeBSD Console To A Serial Port for KVM Virsh - How to do it
This article covers how to redirect FreeBSD in KVM to the serial port.
FreeBSD does support a dumb terminal on a serial port as a console.
This is useful for quick login or debug guest system problem without using ssh.
1. First, login as root using ssh to your guest operating systems:
$ ssh ibmimedia@freebsd.ibmimedia.com
su -
2. Edit /boot/loader.conf, enter:
# vi /boot/loader.conf
3. Append the following entry:
console="comconsole"
4. Save and close the file. Edit /etc/ttys, enter:
# vi /etc/ttys
5. Find the line that read as follows:
ttyd0 "/usr/libexec/getty std.9600" dialup off secure
6. Update it as follows:
ttyd0 "/usr/libexec/getty std.9600" vt100 on secure
7. Save and close the file. Reboot the guest, enter:
# reboot
8. After reboot, you can connect to FreeBSD guest as follows from host (first guest the list of running guest operating systems):
# virsh list
Sample outputs:
Id Name State
----------------------------------
3 ographics running
4 freebsd running
9. Now, connect to Freebsd guest, enter:
virsh console 4
OR
virsh console freebsd
PXE Boot or DHCP Failure on Guest - Fix it now
This article covers how to fix PXE Boot (or DHCP) Failure on Guest.
Nature of this error:
A guest virtual machine starts successfully, but is then either unable to acquire an IP address from DHCP or boot using the PXE protocol, or both. There are two common causes of this error: having a long forward delay time set for the bridge, and when the iptables package and kernel do not support checksum mangling rules.
Cause of PXE BOOT (OR DHCP) ON GUEST FAILED:
Long forward delay time on bridge.
This is the most common cause of this error. If the guest network interface is connecting to a bridge device that has STP (Spanning Tree Protocol) enabled, as well as a long forward delay set, the bridge will not forward network packets from the guest virtual machine onto the bridge until at least that number of forward delay seconds have elapsed since the guest connected to the bridge. This delay allows the bridge time to watch traffic from the interface and determine the MAC addresses behind it, and prevent forwarding loops in the network topology. If the forward delay is longer than the timeout of the guest's PXE or DHCP client, then the client's operation will fail, and the guest will either fail to boot (in the case of PXE) or fail to acquire an IP address (in the case of DHCP).
Fix to PXE BOOT (OR DHCP) ON GUEST FAILED:
If this is the case, change the forward delay on the bridge to 0, or disable STP on the bridge.
This solution applies only if the bridge is not used to connect multiple networks, but just to connect multiple endpoints to a single network (the most common use case for bridges used by libvirt).
If the guest has interfaces connecting to a libvirt-managed virtual network, edit the definition for the network, and restart it.
For example, edit the default network with the following command:
# virsh net-edit default
Add the following attributes to the <bridge> element:
<name_of_bridge='virbr0' delay='0' stp='on'/>
XML
If this problem is still not resolved, the issue may be due to a conflict between firewalld and the default libvirt network.
To fix this, stop firewalld with the service firewalld stop command, then restart libvirt with the service libvirtd restart command.
Unable to allow access for disk path in libvirtd - Fix it Now
This article covers tips to fix the error Unable to allow access for disk path in libvirtd. By default, migration only transfers the in-memory state of a running guest (such as memory or CPU state). Although disk images are not transferred during migration, they need to remain accessible at the same path by both hosts.
To fix Unable to allow access for disk path in libvirtd error:
Set up and mount shared storage at the same location on both hosts. The simplest way to do this is to use NFS:
1. Set up an NFS server on a host serving as shared storage. The NFS server can be one of the hosts involved in the migration, as long as all hosts involved are accessing the shared storage through NFS.
# mkdir -p /exports/images
# cat >>/etc/exports <<EOF
/exports/images 192.168.122.0/24(rw,no_root_squash)
EOF2. Mount the exported directory at a common location on all hosts running libvirt. For example, if the IP address of the NFS server is 192.168.122.1, mount the directory with the following commands:
# cat >>/etc/fstab <<EOF
192.168.122.1:/exports/images /var/lib/libvirt/images nfs auto 0 0
EOF
# mount /var/lib/libvirt/images
No guest machines present libvirtd - Fix it now
This article covers how to troubleshoot and fix No guest machines present libvirtd for our customers.
The virsh program is the main interface for managing virsh guest domains. The program can be used to create, pause, and shutdown domains.
It can also be used to list current domains. Libvirt is a C toolkit to interact with the virtualization capabilities of recent versions of Linux (and other OSes).
The libvirt daemon is successfully started, but no guest virtual machines appear to be present.
There are various possible causes of this problem.
Performing these tests will help to determine the cause of this situation:
1. Verify KVM kernel modules
Verify that KVM kernel modules are inserted in the kernel:
$ lsmod | grep kvm
If you are using an AMD machine, verify the kvm_amd kernel modules are inserted in the kernel instead, using the similar command lsmod | grep kvm_amd in the root shell.
If the modules are not present, insert them using the modprobe <modulename> command.
Note: Although it is uncommon, KVM virtualization support may be compiled into the kernel. In this case, modules are not needed.
2. Verify virtualization extensions
Verify that virtualization extensions are supported and enabled on the host:
# egrep "(vmx|svm)" /proc/cpuinfo
Enable virtualization extensions in your hardware's firmware configuration within the BIOS setup.
3. Verify client URI configuration
Verify that the URI of the client is configured as desired:
# virsh uri
How to fix No guest machines present #libvirtd #error:
After performing these tests, use the following command to view a list of guest virtual machines:
# virsh list --all
Install OpenBSD As Guest Operating System using KVM virt-install
This article covers how to install OpenBSD as guest operating while using KVM. OpenBSD is well know for focus on security features such as Memory protection, cryptography, randomization and much more in default base installation.
virt-install provides the option of supporting graphics for the guest operating system installation. This is achieved through use of QEMU.
virt-install is a command line tool for creating new KVM, Xen, or Linux container guests using the libvirt hypervisor management library
The virt-install tool provides a number of options that can be passed on the command line.
To see a complete list of options run the following command:
# virt-install --help
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.
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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