Xen Project

https://wiki.xenproject.org/wiki/
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### Complete VM Configuration Example

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

An example of a complete VM configuration file, combining UUID, HVM settings, disks (system and CD-ROM), boot order, and network interface definitions.

```config
uuid = 00000000-0000-0000-000000002901
        hvm = true
        acpi = true
        apic = true
        nx = true
        disk = /some/path/disk:vhd:hda:w:disk
        disk = /some/cdrom_image.iso:file:hdd:r:cdrom
        boot = dc
        nic = model=e1000,id=0,bridge=xenbr0,mac=vm
```

--------------------------------

### Start VM and Get Console Information

Source: https://wiki.xenproject.org/wiki/Archive/XCP_Beginners_Guide

Starts the virtual machine and retrieves its domain ID and VNC port for console access. This allows users to connect to the VM's installation interface.

```xe
# xe vm-start uuid=$VMID
# xe vm-param-get uuid=$VMID param-name=dom-id
# xenstore-read /local/domain/<DOMID>/console/vnc-port
```

--------------------------------

### Alternative Xen PV Guest Start

Source: https://wiki.xenproject.org/wiki/Xen_Project_Beginners_Guide

Starts a Xen PV guest and then connects to its console separately. This is an alternative to using the -c flag during creation.

```bash
xl create /etc/xen/tutorial-pv-guest.cfg && xl console tutorial-pv-guest
```

--------------------------------

### Get help for xenvm-cmd

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Displays all available commands and their supported arguments for the xenvm-cmd utility.

```bash
xenvm-cmd <id> help
```

--------------------------------

### Start Xen Guest Instance

Source: https://wiki.xenproject.org/wiki/Debian_Guest_Installation_Using_Debian_Installer

Command to create and start a Xen guest instance using a specified configuration file. This command initiates the booting process for the newly installed Debian guest.

```bash
# xl create -c /etc/xen/debian-installer.cfg

```

--------------------------------

### Example: Create a 100GB logical volume

Source: https://wiki.xenproject.org/wiki/Xen_Project_Beginners_Guide

An example of creating a 100 gigabyte logical volume named 'database-data' within the 'vg0' volume group.

```shell
lvcreate -n database-data -L 100G vg0
```

--------------------------------

### Start VM with xenvm

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Launches a virtual machine using the `xenvm` tool, specifying the path to its configuration file.

```bash
xenvm --config /path/to/my/config
```

--------------------------------

### Start Xen PV Guest Console

Source: https://wiki.xenproject.org/wiki/Xen_Project_Beginners_Guide

Starts a paravirtualized Xen guest and connects to its virtual console. The -c flag is used to initiate the console connection.

```bash
xl create -c /etc/xen/tutorial-pv-guest.cfg
```

--------------------------------

### VM Configuration: Network Interface

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Adds a network interface to the VM. This example configures an `e1000` model, assigns it ID `0`, connects it to the `xenbr0` bridge, and uses a dynamically generated MAC address (`vm`).

```config
nic = model=e1000,id=0,bridge=xenbr0,mac=vm
```

--------------------------------

### Install XenServer Tools (XS-Tools)

Source: https://wiki.xenproject.org/wiki/Archive/XCP_Beginners_Guide

Installs XenServer guest utilities within the VM after the OS installation. It involves ejecting any existing CD, inserting the XS-Tools ISO, mounting it, and running the installer script.

```xe
dom0# xe vm-cd-eject vm=$VMID
dom0# xe vm-cd-insert vm=$VMID cd-name=xs-tools.iso

domU# mount /dev/sr0 /mnt
domU# cd /mnt/Linux/
domU# ./install.sh
```

--------------------------------

### Create and Prepare VM for Installation

Source: https://wiki.xenproject.org/wiki/Archive/XCP_Beginners_Guide

Steps to create a new VM, including specifying its name, storage repository, and disk image. It also details attaching a virtual CD/DVD drive with an ISO for installation.

```xe
# xe vm-install new-name-label=MyNewVM template=CentOS7-minimal
# sr-param-get uuid=$(xe sr-param-get name-label=Local_Storage --minimal) # Example SR UUID
# vdi-create name-label=install-disk sr-uuid=<SR_UUID> type=user virtual-size=20GiB
# vbd-create vdi-uuid=<VDI_UUID> vm-uuid=<VM_UUID> bootable=false type=Disk device=xvda
# vm-cd-add vm=<VM_UUID> device=0 cd-name=CentOS-7-x86_64-Minimal.iso
# vm-param-set uuid=<VM_UUID> other-config:install-behaviour=cdrom
```

--------------------------------

### Create and Start Windows VM

Source: https://wiki.xenproject.org/wiki/Installing_Windows_on_Kronos

Creates a new Windows VM using a specified template, attaches a Windows 7 ISO, and starts the VM. Assumes the ISO is already accessible.

```bash
xe vm-install template=Windows\ 7\ \(32-bit\) new-name-label=windows
xe vm-cd-add vm=windows cd-name=win7.iso device=3
xe vm-start vm=windows

```

--------------------------------

### Start Xen VM

Source: https://wiki.xenproject.org/wiki/RHEL5_CentOS5_Xen_Intel_SR-IOV_NIC_Virtual_Function_VF_PCI_Passthru_Tutorial

This command starts a Xen virtual machine using the specified configuration file. It initiates the VM creation process, and if successful, indicates that the domain has started.

```bash
[root@dom0 ~]# xm create -f /etc/xen/c59x64hvm
Using config file "/etc/xen/c59x64hvm".
Started domain c59x64hvm

```

--------------------------------

### Build and Install Xen

Source: https://wiki.xenproject.org/wiki/COLO_-_Coarse_Grain_Lock_Stepping

Compiles and installs the Xen hypervisor with debugging enabled. It includes steps for generating build scripts, configuring the build, and installing Xen binaries and tools.

```bash
# cd ~/xen 
# ./autogen.sh; ./configure --enable-debug
# make dist-xen; make install-xen
# make dist-tools; make install-tools
```

--------------------------------

### Automate Xen tutorial setup script

Source: https://wiki.xenproject.org/wiki/RHEL6Xen4Tutorial

A script is available to automate the setup process described in this tutorial. The script aims to simplify the deployment and configuration of Xen on RHEL6. The provided link leads to the script's location.

```shell
http://wiki.alteeve.com/index.php/Pxdi
```

--------------------------------

### Xen PV Guest Configuration (Xen Configuration)

Source: https://wiki.xenproject.org/wiki/FreeBSD_Dom0

A sample Xen configuration file for a paravirtualized (PV) guest, specifying memory, VCPUs, network interface, and disk mapping. It includes commented-out sections for installation and standard boot options.

```xen-config
#============================================================================
# TO BOOT INSTALLED SYSTEM
#
# Comment all of the above installation options and uncomment the
# below instead
#============================================================================

bootloader="pygrub"

#============================================================================
# STANDARD OPTIONS
#============================================================================
#
# The following options are common to both installation time and normal booting.
#
# Only a subset of the available options are included below.
# See /usr/share/doc/xen-utils-common/examples for full examples.

#----------------------------------------------------------------------------

# Initial memory allocation (in megabytes) for the new domain.
memory = 512

# A name for your domain. All domains must have different names.
name = "debian"

# Number of Virtual CPUS to use, default is 1
vcpus = 2

#----------------------------------------------------------------------------
# Define network interfaces.

vif = ['bridge=bridge0']

#----------------------------------------------------------------------------
# Define disks

disk = ['phy:/dev/zvol/tank/debian,xvda,w']

```

--------------------------------

### Start Xen PV Guest and Connect to Console

Source: https://wiki.xenproject.org/wiki/Xen_Beginners_Guide

Starts a Xen paravirtualized guest domain and connects to its virtual console. The `-c` flag ensures immediate console access upon creation. This is useful for interactive setup and monitoring of PV guests.

```bash
xl create -c /etc/xen/tutorial-pv-guest.cfg
```

```bash
xl create /etc/xen/tutorial-pv-guest.cfg && xl console tutorial-pv-guest
```

--------------------------------

### Install Xen Dependencies on FreeBSD

Source: https://wiki.xenproject.org/wiki/FreeBSD_Dom0

Installs necessary packages for Xen compilation and operation on FreeBSD. Requires root privileges.

```shell
# pkg install mercurial git bash python bcc glib pkgconf yajl gmake pixman perl5 markdown bison gettext gawk argp-standalone gcc48

```

--------------------------------

### Create VM and Attach ISO for Installation

Source: https://wiki.xenproject.org/wiki/Archive/XCP_Beginners_Guide

This sequence of commands outlines the process of creating a new virtual machine (VM), attaching a virtual disk (VDI) to it, and configuring it to boot from an ISO image for operating system installation. It involves creating a VM with a specified template, a VDI associated with a local SR, and then adding a virtual CD-ROM device pointing to an ISO.

```bash
# VMID=$(xe vm-install new-name-label=TestVM1 template="Other install media")

```

```bash
# LOCALSRID=$(xe sr-list name-label="Local Storage" --minimal)

```

```bash
# VDIID=$(xe vdi-create name-label="VDI for TestVM1" sr-uuid=$LOCALSRID type=user virtual-size=10GiB)

```

```bash
# VBDID=$(xe vbd-create vdi-uuid=$VDIID vm-uuid=$VMID bootable=false type=Disk device=xvda)

```

```bash
# xe vm-cd-add vm=$VMID device=1 cd-name=centos62_x86_64_mini.iso

```

```bash
# xe vm-param-set uuid=$VMID other-config:install-repository=cdrom

```

--------------------------------

### Preseeding Xen Installation with Debian

Source: https://wiki.xenproject.org/wiki/Debian_Guest_Installation_Using_Debian_Installer

Example of how to add command-line directives for preseeding a Xen installation. This is used to automate the installation process by providing necessary parameters and a configuration URL.

```bash
extra = "debian-installer/exit/always_halt=true -- console=hvc0 auto-install/enable=true url=http://example.com/debian/squeeze.cfg"

```

--------------------------------

### VM Configuration: System Disk

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Defines the virtual machine's system disk. This example uses a VHD file (`/some/path/disk`) as the primary hard drive (`hda`) in read-write mode (`w`).

```config
disk = /some/path/disk:vhd:hda:w:disk
```

--------------------------------

### Enable JSON monitor for xenvm

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Starts `xenvm` with the `--monitor-json` option enabled, allowing interaction via a Unix socket that understands JSON queries.

```bash
xenvm --monitor-json true [other args ...]
```

--------------------------------

### VM Configuration: Boot Order

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Sets the boot order for the VM. `dc` specifies booting from the first CD-ROM device.

```config
boot = dc
```

--------------------------------

### Start local graphical DomU install

Source: https://wiki.xenproject.org/wiki/DomU_Install_with_Virt-Install

Initiates a paravirtualized Xen DomU installation using virt-install. It specifies the guest name, RAM, vCPUs, disk image, network bridge, and installation media location.

```bash
virt-install --paravirt --name f16 --ram 768 --vcpus 1 -f /dev/vg_f17/f16 --network bridge=br0 --location http://mirrors.rit.edu/fedora/linux//releases/16/Everything/x86_64/os/"
```

--------------------------------

### Minimal Xen Guest Configuration with Pygrub and ISO Boot

Source: https://wiki.xenproject.org/wiki/Debian_Guest_Installation_Using_Debian_Installer

This example demonstrates a minimal Xen guest configuration for installing Debian using pygrub from an ISO image. It includes the guest name, memory allocation, disk and CDROM configuration, network interface, bootloader settings, and extra kernel arguments for the installer.

```xl
name = "debian-installer"

memory = 256

disk = ['file:/scratch/debian-6.0.4-amd64-i386-netinst.iso,xvdd:cdrom,r', 'phy:/dev/VG/debian-installer,xvda,w']
vif = [' ']

bootloader = "pygrub"
bootloader_args = "--kernel=/install.386/xen/vmlinuz --ramdisk=/install.386/xen/initrd.gz"
extra = "debian-installer/exit/always_halt=true -- console=hvc0"
```

--------------------------------

### Get XCP help and list commands

Source: https://wiki.xenproject.org/wiki/Archive/XCP_Beginners_Guide

Demonstrates how to access help and list available commands for the 'xe' and 'xl' command-line tools in XCP. These commands provide an overview of the system's management capabilities and syntax.

```bash
xe help
```

```bash
xl help
```

--------------------------------

### Start text-based DomU install

Source: https://wiki.xenproject.org/wiki/DomU_Install_with_Virt-Install

Initiates a text-mode installation for a Xen DomU using virt-install. The `--graphics none` option directs the installer output to the current console.

```bash
--graphics none
```

--------------------------------

### VM Configuration: PXE Boot

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Configures the VM to boot over the network using PXE (Preboot Execution Environment). The `n` parameter indicates network boot.

```config
boot = n
```

--------------------------------

### Xen HVM Guest Configuration (Xen Configuration)

Source: https://wiki.xenproject.org/wiki/FreeBSD_Dom0

A sample Xen configuration file for a hardware virtual machine (HVM) guest, specifying it as HVM, memory, VCPUs, network interfaces, disk devices (including a CD-ROM for installation), and VNC settings.

```xen-config
# This configures an HVM rather than PV guest
builder = "hvm"

# Guest name
name = "freebsd"

# Initial memory allocation (MB)
memory = 512

# Number of VCPUS
vcpus = 4

# Network devices
vif = [ 'bridge=bridge0' ]

# Disk Devices
disk =   [
  '/dev/zvol/tank/freebsd,raw,hda,rw',
  '/root/FreeBSD-10.0-RELEASE-amd64-bootonly.iso,raw,hdc:cdrom,r'
  ]

vnc = 1
vnclisten = "0.0.0.0"
serial="pty"

```

--------------------------------

### VM Configuration: Physical CD-ROM/DVD-ROM

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Configures the VM to boot from the host's physical CD-ROM or DVD-ROM drive. `phy` indicates a physical device, `phy` is the target device, `r` for read-only, and `cdrom` is the alias.

```config
disk = /dev/dvd:phy:phy:r:cdrom
```

--------------------------------

### Creating and Starting Xen VM

Source: https://wiki.xenproject.org/wiki/Install_Xen_4.2

This command creates and starts a Xen virtual machine using the specified configuration file (`/etc/xen/rt.cfg`). The `-c` flag attaches a console to the VM, allowing direct interaction during the installation or boot process.

```bash
xm create /etc/xen/rt.cfg -c
# run the install
sudo ln -s /usr/lib/xen-4.1/bin/pygrub /usr/bin/pygrub
```

--------------------------------

### Clone Xen and QEMU Repositories

Source: https://wiki.xenproject.org/wiki/COLO_-_Coarse_Grain_Lock_Stepping

Clones the necessary Xen Project and QEMU repositories from GitHub to prepare for building and installation. This is a prerequisite for setting up the test environment.

```bash
# cd ~
# git clone https://github.com/xen-project/xen.git
# git clone https://github.com/zhangckid/qemu.git
```

--------------------------------

### Start Xen API SSL Daemon

Source: https://wiki.xenproject.org/wiki/Installing_Linux_on_Kronos

This command starts the Xen API SSL daemon (`xapissl`), which is necessary for establishing a console connection to the virtual machine using `xe console`. Ensure this daemon is running before attempting to connect to the VM console.

```bash
/usr/lib/xcp/lib/xapissl start
```

--------------------------------

### Start Xen VM Installation with virt-install

Source: https://wiki.xenproject.org/wiki/How_to_Install_Windows_XP_on_Centos_5

This command initiates the virtual machine installation process using virt-install. It specifies the VM name, memory, disk image, network bridge, and installation ISO.

```shell
virt-install -n _vmname_ -r 384 -f /var/lib/xen/images/_vmname_.img -b xenbr0 --sdl -v -c /var/lib/xen/images/_vmname_-install.iso
```

--------------------------------

### Xen Guest Creation and Destruction (Shell)

Source: https://wiki.xenproject.org/wiki/FreeBSD_Dom0

Demonstrates the Xen commands for creating a guest domain from a configuration file and subsequently destroying it. Assumes a configuration file named 'debian.cfg' exists.

```shell
# xl create -c debian.cfg

# xl destroy debian
```

--------------------------------

### Create Xen HVM Guest Configuration

Source: https://wiki.xenproject.org/wiki/Xen_Project_Beginners_Guide

Defines the configuration for a Hardware Virtualized (HVM) guest, specifying kernel, memory, VCPUs, network interface, disk (including a Windows ISO for installation), and boot parameters. Assumes Xen version 4.0 and Windows ISO at /root/windows.iso.

```xenconfig
kernel = "/usr/lib/xen-4.0/boot/hvmloader"
type='hvm'
memory = 4096
vcpus=4
name = "ovm-1734"
vif = ['bridge=xenbr0']
disk = ['phy:/dev/vg0/windows,hda,w','file:/root/windows.iso,hdc:cdrom,r']
acpi = 1
device_model_version = 'qemu-xen'
boot="d"
sdl=0
serial='pty'
vnc=1
vnclisten=""
vncpasswd=""

```

--------------------------------

### Fetch Debian PV Guest Files

Source: https://wiki.xenproject.org/wiki/FreeBSD_Dom0

Downloads the kernel, initramfs, and configuration file for a Debian PV guest from Debian's netboot archive.

```shell
# fetch http://ftp.nl.debian.org/debian/dists/wheezy/main/installer-amd64/current/images/netboot/xen/initrd.gz
# fetch http://ftp.nl.debian.org/debian/dists/wheezy/main/installer-amd64/current/images/netboot/xen/vmlinuz
# fetch http://ftp.nl.debian.org/debian/dists/wheezy/main/installer-amd64/current/images/netboot/xen/debian.cfg

```

--------------------------------

### Restore a VM from memory snapshot

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Restores a virtual machine from a previously saved memory snapshot file. This allows the VM to resume execution from the state it was in when suspended.

```bash
$ xenvm-cmd <id> restore file=/tmp/my_memory_snapshot
```

--------------------------------

### VM Configuration: Bootable CD-ROM Image

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Configures a CD-ROM drive for booting the VM using an ISO image. The `file` type specifies it's a local file, `hdd` is the target device, `r` indicates read-only, and `cdrom` is the alias.

```config
disk = /some/cdrom_image.iso:file:hdd:r:cdrom
```

--------------------------------

### Starting and Managing Xen VMs

Source: https://wiki.xenproject.org/wiki/Install_Xen_4

This section provides commands for starting a Xen VM, creating a symbolic link for pygrub, modifying the VM configuration to use pygrub, and then starting the VM using `xl`. It also includes commands for listing running VMs and performing live migration.

```bash
xm create /etc/xen/rt.cfg -c
# run the install
sudo ln -s /usr/lib/xen-4.1/bin/pygrub /usr/bin/pygrub
vi  /etc/xen/rt.cfg
# 
bootloader = "pygrub"
# comment out 'kernel' 'ramdisk' and 'extra'
#

# Press Ctrl+] to exit the console view
xl create /etc/xen/rt.cfg -c

# see it running
xl list

# test live migration, if you can't live migrate, then Remus isn't going to work either
xl migrate --live rt right
```

--------------------------------

### Start Xen VM Installation

Source: https://wiki.xenproject.org/wiki/Install_Xen_4.1

Launches the Xen virtual machine using its configuration file, allowing the Ubuntu installation process to begin via the specified kernel and initrd.

```bash
xm create /etc/xen/ubuntu.cfg -c
```

--------------------------------

### Create and Connect to Xen Guest (xl toolstack)

Source: https://wiki.xenproject.org/wiki/Debian_Guest_Installation_Using_Debian_Installer

Starts a Xen guest using the 'xl create' command and connects to its console, assuming the configuration file is at /etc/xen/debian-installer.cfg.

```bash
# xl create -c /etc/xen/debian-installer.cfg
```

--------------------------------

### Fetch and Compile Xen Hypervisor

Source: https://wiki.xenproject.org/wiki/FreeBSD_Dom0

Clones the Xen source code repository and compiles the Xen hypervisor and toolstack using make. Specifies GCC version for compilation.

```shell
# cd xen
# ./configure HOSTCC=gcc48 CC=gcc48 HOSTCXX=g++48 CXX=g++48
# gmake -j8 xen HOSTCC=gcc48 CC=gcc48 HOSTCXX=g++48 CXX=g++48
# cp xen/xen /boot/
# gmake -j8 install-tools HOSTCC=gcc48 CC=gcc48 HOSTCXX=g++48 CXX=g++48

```

--------------------------------

### Chroot Environment Setup Script

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Building_Instructions

A shell script to automate the creation and setup of a Debian Lenny chroot environment. It installs necessary packages, configures locales, downloads and builds external dependencies, and clones the build repository within the chroot.

```bash
#!/bin/sh
DEBOOTSTRAP=/usr/sbin/debootstrap
CHROOT=chroot
PKGS="git-core libdbus-1-3 gcc bcc flex bison bzip2 iasl bin86 autoconf automake1.9 libtool make libncurses5-dev asciidoc cpp g++ libglib2.0-dev texinfo pciutils-dev gawk wget gettext libdbus-glib-1-dev"
if [ $# -lt 1 ]; then
        echo "usage: $0 <destination chroot> [debian mirror]"
        exit 1
fi
DST=$1
MIRROR=$2
if [ $# -lt 2 ]; then
        USE_MIRROR=0
else
        USE_MIRROR=1
fi
if [ -e "${DST}" ]; then
       echo "destination already exists"
       exit 2
fi
mkdir -p ${DST}
if [ "${USE_MIRROR}" -eq 1 ]; then
       ${DEBOOTSTRAP} --arch=i386 lenny ${DST} ${MIRROR}
else
       ${DEBOOTSTRAP} --arch=i386 lenny ${DST} ${MIRROR}
fi
linux32 ${CHROOT} ${DST} apt-get update
linux32 ${CHROOT} ${DST} apt-get install -y --force-yes ${PKGS}
linux32 ${CHROOT} ${DST} bash -c "cd /usr/src; \
        wget http://www.kernel.org/pub/linux/kernel/people/jsipek/guilt/guilt-0.32.1.tar.gz; \
        tar zxvf guilt-0.32.1.tar.gz; \
        cd /usr/src/guilt-0.32.1; \
        make && make install"
linux32 ${CHROOT} ${DST} bash -c "echo \"en_US.UTF-8 UTF-8\" > /etc/locale.gen; locale-gen"
linux32 ${CHROOT} ${DST} bash -c "cd /usr/src; git clone http://xenbits.xen.org/git-http/xenclient/build.git"
```

--------------------------------

### Check libvirtd service status

Source: https://wiki.xenproject.org/wiki/RHEL6Xen4Tutorial

Displays the current run levels for the libvirtd service to ensure it is configured to start on boot.

```bash
[root@el6 ~]# chkconfig --list libvirtd
libvirtd        0:off   1:off   2:off   3:on    4:on    5:on    6:off
```

--------------------------------

### Start Xen VM using Configuration File

Source: https://wiki.xenproject.org/wiki/RHEL5_CentOS5_Xen_Intel_SR-IOV_NIC_Virtual_Function_VF_PCI_Passthru_Tutorial

Command to start a Xen virtual machine using its configuration file. This command is executed from the Xen host (dom0).

```bash
[root@dom0 ~]# xm create -f /etc/xen/c59x64hvm
Using config file "/etc/xen/c59x64hvm".
Started domain c59x64hvm
```

--------------------------------

### Set a VM configuration field

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Dynamically sets a specified field in the xenvm configuration for a virtual machine. Requires 'field' and 'value' parameters. Changes may only take effect on the next VM start.

```bash
$ xenvm-cmd <id> set field="hvm" value="true"
```

--------------------------------

### Starting Xen VM with Console

Source: https://wiki.xenproject.org/wiki/Install_Xen_4.2

This command creates and starts a Xen virtual machine using the updated configuration file (`/etc/xen/rt.cfg`). The `-c` flag attaches a console to the VM for interactive access.

```bash
xl create /etc/xen/rt.cfg -c
```

--------------------------------

### FreeBSD Zvol Creation and ISO Fetch (Shell)

Source: https://wiki.xenproject.org/wiki/FreeBSD_Dom0

Commands to download a FreeBSD ISO image and create a ZFS volume (zvol) to be used as a disk for a virtual machine. This is a prerequisite for setting up an HVM guest.

```shell
# fetch ftp://ftp.freebsd.org/pub/FreeBSD/ISO-IMAGES-amd64/10.0/FreeBSD-10.0-RELEASE-amd64-bootonly.iso
# zfs create -V 10g tank/freebsd
```

--------------------------------

### VM Configuration: HVM and CPU Flags

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Specifies hardware virtual machine (HVM) settings and CPU-related flags for the VM. These include enabling ACPI, APIC, and No-Execute (NX) protection.

```config
hvm = true
        acpi = true
        apic = true
        nx = true
```

--------------------------------

### Interact with xenvm using xenvm-cmd

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Uses the `xenvm-cmd` tool to send commands to a running `xenvm` instance. By default, it uses the D-Bus monitor. The `--use-socket` flag directs commands to the Unix socket monitor. Commands are specified with the VM's ID (UUID) and arguments in key=value format.

```bash
xenvm-cmd [--use-socket] <id> <cmd> [args]
```

--------------------------------

### Enable D-Bus monitor for xenvm

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Starts `xenvm` with the `--monitor-dbus` option enabled, allowing interaction via D-Bus, typically listening on the `org.xen.vm.%uuid` hierarchy. The `--monitor-dbus-session` flag can be used to listen on the session bus instead of the system bus.

```bash
xenvm --monitor-dbus true [other args ...]
```

--------------------------------

### Get Xen Information with xm info

Source: https://wiki.xenproject.org/wiki/RHEL5_CentOS5_Xen_Intel_SR-IOV_NIC_Virtual_Function_VF_PCI_Passthru_Tutorial

Provides detailed information about the Xen host environment, including CPU details, memory statistics, Xen version, and compiler information. This is essential for understanding the Xen setup.

```bash
[root@dom0 ~]# xm info
host                   : dom0.localdomain
release                : 2.6.18-348.el5xen
version                : #1 SMP Tue Jan 8 18:35:04 EST 2013
machine                : x86_64
nr_cpus                : 12
nr_nodes               : 1
sockets_per_node       : 1
cores_per_socket       : 6
threads_per_core       : 2
cpu_mhz                : 2266
hw_caps                : bfebfbff:2c100800:00000000:00000940:029ee3ff:00000000:00000001
total_memory           : 49139
free_memory            : 46145
node_to_cpu            : node0:0-11
xen_major              : 3
xen_minor              : 1
xen_extra              : .2-348.el5
xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
xen_pagesize           : 4096
platform_params        : virt_start=0xffff800000000000
xen_changeset          : unavailable
cc_compiler            : gcc version 4.1.2 20080704 (Red Hat 4.1.2-54)
cc_compile_by          : mockbuild
cc_compile_domain      : (none)
cc_compile_date        : Tue Jan  8 17:45:10 EST 2013
xend_config_format     : 2


```

--------------------------------

### DRBD Configuration and Setup

Source: https://wiki.xenproject.org/wiki/Install_Xen_4

This section covers the initial setup of DRBD, including copying configuration files, creating logical volumes, defining DRBD resources, creating metadata, and bringing the DRBD resource online. It also includes commands for promoting a secondary to primary and monitoring DRBD status.

```bash
cp /home/user/drbd-8.3.11/scripts/global_common.conf.protoD /etc/drbd.d/global_common.conf
cp /home/user/drbd-8.3.11/scripts/testvms_protoD.res /etc/drbd.d/SystemHA_protoD.res
uname -a # right
lvcreate -n test -L 10G right
vi /etc/drbd.d/SystemHA_protoD.res
#
resource drbd-vm {
        device /dev/drbd1;
        disk /dev/right/test;
        meta-disk internal;
        on left {
                address 10.0.1.50:7791;
        }
        on right{
                address 10.0.1.51:7791;
        }
}
#

#Create the meta-data for the SystemHA-disk and then bring up the resource. Do this on both machines
drbdadm create-md drbd-vm
###answer y or yes for all questions, in the above command
drbdadm up drbd-vm

###Sanity check. You should see something like this in the output
root@null:~$ cat /proc/drbd 
version: 8.3.9 (api:88/proto:86-95)
GIT-hash: 3ba4fc581d6215744597b3d4c525db276ce000ee build by root@null, 2011-05-14 19:33:56

 1: cs:Connected ro:Secondary/Secondary ds:Inconsistent/Inconsistent D r-----
```

```bash
drbdadm -- --overwrite-data-of-peer primary drbd-vm
```

```bash
cat /proc/drbd
```

--------------------------------

### Xen HVM Guest Launch and VNC Attachment (Shell)

Source: https://wiki.xenproject.org/wiki/FreeBSD_Dom0

Commands to load the necessary kernel module for tap devices, launch an HVM guest using its configuration file, and then connect to the guest's console via VNC. Requires the 'if_tap' module to be loaded first.

```shell
# kldload if_tap
# xl create freebsd.cfg
# vncviewer <addr>
```

--------------------------------

### Start Virt-Manager

Source: https://wiki.xenproject.org/wiki/DomU_Install_with_Virt-Manager

Launches the virt-manager graphical interface, which is used to create, configure, and manage Xen virtual machines. The '&' symbol runs the command in the background.

```bash
[root@f13 ~]# virt-manager &
[1] 2126

```

--------------------------------

### Display All CPU Information

Source: https://wiki.xenproject.org/wiki/Xen_Project_Beginners_Guide

Displays the entire content of the '/proc/cpuinfo' file. This is useful for manually reviewing all CPU flags and details if the 'egrep' command does not return expected virtualization extensions.

```bash
cat /proc/cpuinfo
```

--------------------------------

### arch_init() Initialization Steps

Source: https://wiki.xenproject.org/wiki/Mini-OS-DevNotes

Details the actions performed by the arch_init() function, including copying the start_info structure, storing physical-to-machine mappings, and mapping the shared_info page.

```APIDOC
## GET /arch_init

### Description
Initializes architecture-specific settings for Mini-OS, including memory mapping and setup for Xen hypervisor interaction.

### Method
GET

### Endpoint
/arch_init

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```
GET /arch_init
```

### Response
#### Success Response (200)
- **status** (string) - Indicates successful initialization.
- **message** (string) - Provides details about the initialization process.

#### Response Example
```json
{
  "status": "success",
  "message": "Architecture initialization complete. Shared info page mapped."
}
```
```

--------------------------------

### Finalize Xen Installation and GRUB Configuration

Source: https://wiki.xenproject.org/wiki/Install_Xen_4.1

Completes the Xen installation by running the install script, updating the GRUB bootloader configuration to include Xen, and setting up Xen services to start on boot.

```bash
cd /home/user/xen-4.1.4/dist
./install.sh

update-grub

ls -al /boot/xen*
-rw-r--r-- 1 root root   737577 Feb 18 10:53 /boot/xen-4.1.4.gz
lrwxrwxrwx 1 root root       12 Feb 18 10:53 /boot/xen-4.1.gz -> xen-4.1.4.gz
lrwxrwxrwx 1 root root       12 Feb 18 10:53 /boot/xen-4.gz -> xen-4.1.4.gz
lrwxrwxrwx 1 root root       12 Feb 18 10:53 /boot/xen.gz -> xen-4.1.4.gz
-rw-r--r-- 1 root root 14003510 Feb 18 10:53 /boot/xen-syms-4.1.4

update-rc.d xencommons defaults 19 18
update-rc.d xend defaults 20 21
update-rc.d xendomains defaults 21 20
update-rc.d xen-watchdog defaults 22 23

grep Xen /boot/grub/grub.cfg
# You should see "Ubuntu GNU\/Linux, with Xen hypervisor" in there, that's where I got the below from
sed -i 's/GRUB_DEFAULT=.*\+/GRUB_DEFAULT="Ubuntu GNU\/Linux, with Xen hypervisor"/' /etc/default/grub
update-grub
reboot
```

--------------------------------

### Create a VM disk image with vhd-util

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Creates an empty virtual hard disk (VHD) file for a VM. The `-s` flag specifies the size in megabytes, and `-n` specifies the disk name and path. Other storage types like LVs or disk partitions are also supported.

```bash
vhd-util create -s 10000 -n /some/path/disk
```

--------------------------------

### PVHVM Configuration Example

Source: https://wiki.xenproject.org/wiki/Understanding_the_Virtualization_Spectrum

Example of a kernel configuration option related to PVHVM, indicating its use in a hybrid virtualization setup.

```config
CONFIG_XEN_PVHVM
```

--------------------------------

### List Available Xen Templates

Source: https://wiki.xenproject.org/wiki/Installing_Linux_on_Kronos

This command lists all available virtual machine templates that can be used for installation. It's a prerequisite to identify the correct template name for VM creation.

```bash
xe template-list
```

--------------------------------

### Install Xen on Fedora

Source: https://wiki.xenproject.org/wiki/Fedora_13_Xen_4_Tutorial

This demonstrates how to install Xen on Fedora systems. For Fedora 14 and later, 'yum install xen' is sufficient. For Fedora 13, local installation of RPMs is suggested, and for manual compilation, a separate guide is referenced.

```shell
# yum install xen
# yum localinstall *.rpm
```

--------------------------------

### Start Xen HVM Guest

Source: https://wiki.xenproject.org/wiki/RHEL5_CentOS5_Xen_Intel_SR-IOV_NIC_Virtual_Function_VF_PCI_Passthru_Tutorial

Starts a Xen HVM guest using the specified configuration file. This command is executed on the Xen host (dom0).

```shell
[root@dom0 ~]# xm create -f /etc/xen/c63x64hvm
Using config file "/etc/xen/c63x64hvm".
Started domain c63x64hvm
```

--------------------------------

### Get a VM configuration field

Source: https://wiki.xenproject.org/wiki/Archived/XCI_Getting_Started

Retrieves the value of a specified field from the xenvm configuration for a given virtual machine. Requires the 'field' parameter.

```bash
$ xenvm-cmd <id> get field="hvm"
true
```

--------------------------------

### Example Xen Domain Configuration File

Source: https://wiki.xenproject.org/wiki/Introduction_to_Xen_3

A sample configuration file for creating a Xen domain, specifying kernel, memory, network interfaces, IP address, and disk image details. This example uses ttylinux.

```ini
kernel = "/boot/vmlinuz-2.6.12-xenU"
memory = 64
name = "ttylinux"
মাদেরcs = 1
ip = "10.0.0.3"
disk = ['file:/home/work/downloads/tmp/ttylinux-xen,hda3,w']
root = "/dev/hda3 ro"
```

--------------------------------

### Starting the Xend Daemon

Source: https://wiki.xenproject.org/wiki/Introduction_to_Xen_3

This command starts the Xend daemon on the Xen system, which is responsible for handling requests related to domain management like creation, listing, and destruction. It also initiates helper daemons and a Python server instance.

```bash
xend start
```

--------------------------------

### Setting Up Xen Development Environment

Source: https://wiki.xenproject.org/wiki/Archived/2018-Summer-Internships

Instructions on how to set up the Xen development environment, which is a prerequisite for starting with hypervisor projects. This typically involves fixing issues, building, and testing Xen.

```bash
Ask on xen-devel@ for a set of suitable Coverity issues.
Note that this does not require any access to the Coverity scan results.
Open bugs to fix under the Small Code Contribution Requirement can also be found on bugs.xenproject.org.
Also note that to do Hypervisor development, you will need to have the correct hardware. You can find more information on how to check whether you have the right hardware at Outreachy/Hypervisor.
```

--------------------------------

### Example of Setting Xen Default GRUB Entry

Source: https://wiki.xenproject.org/wiki/Fedora_Host_Installation

An example demonstrating how to set the 'Fedora, with Xen hypervisor' entry as the default in GRUB2 after listing available menu entries.

```shell
# grep ^menuentry /boot/grub2/grub.cfg | cut -d "'" -f2
 Fedora, with Linux 3.11.3-201.fc19.x86_64
 Fedora, with Xen hypervisor
# sudo grub2-set-default "Fedora, with Xen hypervisor"
```

--------------------------------

### Package and Transfer DRBD Source

Source: https://wiki.xenproject.org/wiki/Install_Xen_4

Creates a tarball of the DRBD source directory and securely copies it to another server for installation. This is part of the DRBD setup process.

```bash
tar zcvf drbd.tgz ./remus-drbd
scp ./drbd.tgz user@10.0.1.51:.
```

--------------------------------

### GRUB Configuration Example

Source: https://wiki.xenproject.org/wiki/Xen4CentOS

An example snippet showing how the GRUB configuration file (`/boot/grub/grub.conf`) might look after running the `grub-bootxen.sh` script. It specifies the Xen kernel and its parameters for the Control Domain (Dom0).

```text
title CentOS (3.10.34-11.el6.centos.alt.x86_64)
 root (hd0,0)
 kernel /xen.gz dom0_mem=1024M,max:1024M loglvl=all guest_loglvl=all
 module /vmlinuz-3.10.34-11.el6.centos.alt.x86_64 ro 
   root=/dev/mapper/vg_xen01-lv_root rd_LVM_LV=vg_xen01/lv_swap 
   rd_NO_LUKS KEYBOARDTYPE=pc KEYTABLE=uk rd_NO_MD LANG=en_GB 
   rd_LVM_LV=vg_xen01/lv_root SYSFONT=latarcyrheb-sun16
   crashkernel=auto rd_NO_DM rhgb quiet
 module /initramfs-3.10.34-11.el6.centos.alt.x86_64.img

```

--------------------------------

### Install htop package on Debian

Source: https://wiki.xenproject.org/wiki/Xen_Beginners_Guide

Demonstrates the command to install the 'htop' application using Debian's Apt package management system.

```bash
apt-get install htop
```

--------------------------------

### Creating a Basic MirageOS Kernel

Source: https://wiki.xenproject.org/wiki/Xen_Development_Projects

This snippet outlines the process of creating a simple kernel using a MirageOS example, specifically 'basic_block'. The goal is to integrate previously generated I/O logs into the kernel to simulate load.

```ocaml
// Based on http://github.com/mirage/mirage-skeleton
// The 'basic_block' example shows how reads and writes are done.
// The previously-generated log could be statically compiled into the kernel and executed to generate load.
```

--------------------------------

### Setup ARM64 Chroot Environment

Source: https://wiki.xenproject.org/wiki/Xen_ARM_with_Virtualization_Extensions

Copies the QEMU static binary into the chroot environment and then enters the chroot to establish a full ARM64 environment on an x86 machine.

```bash
cp /usr/bin/qemu-aarch64-static /chroot/distro_arm64/usr/bin/qemu-aarch64-static
chroot /chroot/distro_arm64
```

--------------------------------

### blktap Sample Usage Commands

Source: https://wiki.xenproject.org/wiki/Blktap

Provides a sequence of commands for interacting with blktap, demonstrating how to allocate a minor number, spawn a tapdisk process, attach the devices, and open a VHD or raw file.

```bash
# tap-ctl allocate
/dev/xen/blktap-2/tapdev4

# tap-ctl spawn
tapdisk spawned with pid 28453

# tap-ctl attach -m 4 -p 28453

# tap-ctl open -m 4 -p 28453 -a vhd:/path/to/vhd
```

--------------------------------

### Create Kernel Packages

Source: https://wiki.xenproject.org/wiki/Mainline_Linux_Kernel_Configs

Demonstrates how to create installable kernel packages using makefile targets. The example shows creating a Debian package (`deb-pkg`) which can then be installed using `dpkg`.

```bash
make deb-pkg
```

```bash
sudo dpkg -i ../linux-image-<version>_<version>_<arch>.deb
```

--------------------------------

### Recreate Xen VM for Initial Windows Setup

Source: https://wiki.xenproject.org/wiki/How_to_Install_Windows_XP_on_Centos_5

This command restarts the Xen virtual machine after initial configuration changes, allowing the Windows XP installation to proceed.

```shell
xm create _vmname_
```

--------------------------------

### Xen start_info Structure Definition

Source: https://wiki.xenproject.org/wiki/Mini-OS-DevNotes

Defines the `start_info` structure, which contains essential information passed from the Xen hypervisor (or domain loader) to the guest domain (domU) kernel during its initial boot or resume. It includes details about shared memory, console configuration, and bootstrap parameters.

```c
struct start_info {
    /* THE FOLLOWING ARE FILLED IN BOTH ON INITIAL BOOT AND ON RESUME.    */
    char magic[32];             /* "xen--".            */
    unsigned long nr_pages;     /* Total pages allocated to this domain.  */
    unsigned long shared_info;  /* MACHINE address of shared info struct. */
    uint32_t flags;             /* SIF_xxx flags.                         */
    xen_pfn_t store_mfn;        /* MACHINE page number of shared page.    */
    uint32_t store_evtchn;      /* Event channel for store communication. */
    union {
        struct {
            xen_pfn_t mfn;      /* MACHINE page number of console page.   */
            uint32_t  evtchn;   /* Event channel for console page.        */
        } domU;
        struct {
            uint32_t info_off;
            uint32_t info_size;
        } dom0;
    } console;
    /* THE FOLLOWING ARE ONLY FILLED IN ON INITIAL BOOT (NOT RESUME).     */
    unsigned long pt_base;      /* VIRTUAL address of page directory.     */
    unsigned long nr_pt_frames; /* Number of bootstrap p.t. frames.       */
    unsigned long mfn_list;     /* VIRTUAL address of page-frame list.    */
    unsigned long mod_start;    /* VIRTUAL address of pre-loaded module.  */
    unsigned long mod_len;      /* Size (bytes) of pre-loaded module.     */
    int8_t cmd_line[MAX_GUEST_CMDLINE];
};
```

--------------------------------

### Starting Xen Guest with pygrub for Kernel Selection

Source: https://wiki.xenproject.org/wiki/Xen_Common_Problems

Command to start a Xen PV guest and attach to its console, allowing interactive kernel selection via pygrub if multiple options are available.

```shell
xl create -c /etc/xen/guest

```

--------------------------------

### Start Xencommons Service

Source: https://wiki.xenproject.org/wiki/COLO_-_Coarse_Grain_Lock_Stepping

This command starts the xencommons service, which is a prerequisite for managing Xen virtual machines and enabling features like COLO. This service needs to be running on both the primary and secondary hosts.

```shell
# service xencommons start
```

--------------------------------

### List all scheduler parameters including VMs

Source: https://wiki.xenproject.org/wiki/Cpupools_Howto

Displays scheduling parameters for all cpupools and individual virtual machines, showing their current settings like weight and capacity.

```bash
# xl sched-credit
```

--------------------------------

### Reboot System (Bash)

Source: https://wiki.xenproject.org/wiki/RHEL6Xen4Tutorial

This command initiates a system reboot. It's the final step after configuring Xen to allow the system to start with the newly installed Xen kernel. Users are advised to select the Xen entry from the GRUB menu upon reboot.

```bash
[root@el6 ~]# reboot
```

--------------------------------

### Compiling, Deploying, and Running Xen for Testing

Source: https://wiki.xenproject.org/wiki/Outreachy/Hypervisor

This section details the process of compiling a Xen tarball, potentially with added debug information, deploying it, running it, and collecting serial logs. This serves as a basic test to ensure a developer can handle core hypervisor tasks.

```makefile
# Example commands for compiling Xen (specific commands may vary based on Xen version and configuration)
make dist
# make install
# xm create <config_file.cfg>
```

```bash
# Example commands for obtaining serial logs
# Assuming Xen is configured to output logs to a serial console or file
cat /var/log/xen/console/guest-name.log
```
Tokens:
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