Linux System Learning 12th Day-<< Engineer Technology >>

Overview of Virtualization
? Virtualization Resource Management
–x a physical resource--y logical resource
– Degree of implementation: full, partial, hardware-assisted (CPU)

To create a new virtual machine manually:
Virtual machine Name: Example
Network type selection: private1

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? Using the Virt-manager Client tool

To operate on a real machine:

? View KVM Node (server) Information
–virsh NodeInfo
? List virtual machines
–virsh list [--all]
? View information for a specified virtual machine
–virsh Dominfo Virtual machine name
? Set the specified virtual machine to run automatically
–virsh autostart [--disable] Virtual machine name

? Run | restart | Close the specified virtual machine
–virsh Start|reboot|shutdown Virtual machine name
? Force shutdown of the specified virtual machine
–virsh Destroy virtual machine name

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Setting up local yum in virtual machine example

1. Mount the disc
[Root@a ~]# Mount/dev/cdrom/dvd

2. Client Files
[Root@a ~]# Cat/etc/yum.repos.d/dvd.repo
[DVD]
Name=dvd
Baseurl=file:///dvd
Enabled=1
Gpgcheck=0

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? Using preset groupings for the RHEL7 software warehouse

–yum Groups list [hidden] [group name] ...
–yum groups Info [group name] ...
–yum groups install [group name] ...
–yum groups Remove [group name] ...

[Root@a ~]# yum Groups install
virtualization\ Client
virtualization\ Hypervisor
virtualization\ Platform
virtualization\ Tools

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Desktop icons

/usr/share/applications/

Right-click-----icon---------> Copy to---------->home-------> Desktop

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Start the LIBVIRTD service side
? LIBVIRTD providing a service interface for managing virtual machines

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In Linux, the KVM virtual machine consists of:

– An XML configuration file (virtual machine Profile): Defines the name of the virtual machine, UUID, CPU, internal
Various parameter settings such as storage, virtual disk, network card, etc.
/etc/libvirt/qemu/*.xml

– Disk image file: Saves the virtual machine's operating system and document data,
The mirror path depends on the definition in the XML configuration file
/var/lib/libvirt/images/

[[Email protected] Desktop]# ls/etc/libvirt/qemu/
[[Email protected] Desktop]# ls/var/lib/libvirt/images/

[[Email protected] Desktop]# du-sh/var/lib/libvirt/images/

Details: template Virtual Machine example, note delete Channel device

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Create a new virtual machine by example a virtual machine

1. Turn off the example virtual machine
[Email protected] Desktop]# Virsh Destroy example
2. Copying a copy of the disk file via example virtual machine
[[Email protected] Desktop]# cd/var/lib/libvirt/images/
[Email protected] images]# qemu-img info example.qcow2
[email protected] images]# CP example.qcow2 Test01.qcow2
3. Copy the virtual machine description file via example virtual machine
[Email protected] images]# cd/etc/libvirt/qemu/
[[email protected] qemu]# ls
[email protected] qemu]# CP example.xml Test01.xml
[Email protected] qemu]# vim Test01.xml
Virtual machine name, UUID, virtual machine disk file, Nic Mac

[Email protected] qemu]# Uuidgen

4. Import new virtual machine information
# Virsh Define/etc/libvirt/qemu/test01.xml #导入虚拟机信息
# Virsh List--all

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Exporting an XML configuration file
– View: Virsh dumpxml Virtual machine name
– Backup: Virsh dumpxml virtual machine name > virtual machine name. xml

Adjusting the configuration of a virtual machine
– Edit: Virsh Edit Virtual machine name

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Cow copy on write, quickly rebuild virtual machine

1. Virtual machine disk files, fast generation

? Copy on write, copying on write
– Direct mapping of the data contents of the original disk
– When the old data of the original disk has been modified, the old data is automatically stored
Into the front-end disk
– Modifications to the front-end disk are not written back to the original disk

2.qemu-img specifying the original disk via the-B option multiplexing

–qemu-img create-f qcow2-b Original disk front end disk

1. Turn off the virtual machine
[Email protected]/]# Virsh Destroy example

2. Creating a front-end disk
# qemu-img Create-f qcow2-b/var/lib/libvirt/images/example.qcow2/var/lib/libvirt/images/test02.qcow2

3. Generate a new virtual machine profile
[Email protected]/]# cd/etc/libvirt/qemu/
[email protected] qemu]# CP example.xml Test02.xml
[Email protected] qemu]# vim Test02.xml

Virtual machine name, UUID, virtual machine disk file, Nic Mac

[Email protected] qemu]# Uuidgen

4. Import new virtual machine information
# Virsh Define/etc/libvirt/qemu/test02.xml #导入虚拟机信息
# Virsh List--all

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Offline access to virtual machines
? Using the Guestmount tool
– Supports offline mounting of raw, QCOW2 format virtual machine disks
– You can modify the document on disk directly in the case of a virtual machine
– Easy to customize, repair, and script maintenance for virtual machines

# guestmount-a/var/lib/libvirt/images/example.qcow2-i/mnt/

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1) Production environment can be labeled/.unconfigured, convenient for new virtual machines
Configuration (equivalent to factory settings, prompting user initialization)

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Building a new teaching environment

1. Generate two virtual machines in the real machine
[[Email protected] Desktop]# CLONE-VM7
Enter VM Number:8
[[Email protected] Desktop]# CLONE-VM7
Enter VM Number:9

2. Modify the virtual machine name, a another B

Virtual Machine A:
Host Name: svr7.tedu.cn
IP Address: 192.168.4.7/24

Virtual Machine B:
Host Name: pc207.tedu.cn
IP Address: 192.168.4.207/24

Construction of 3.Yum Warehouse

Real-machine Yum server, Web shared disc all content
[[Email protected] Desktop]# MKDIR/VAR/WWW/HTML/RHEL7
[[Email protected] Desktop]# LS/VAR/WWW/HTML/RHEL7
[[Email protected] Desktop]# MOUNT/ISO/RHEL-SERVER-7.2-X86_64-DVD.ISO/VAR/WWW/HTML/RHEL7

[[Email protected] Desktop]# LS/VAR/WWW/HTML/RHEL7
[[Email protected] Desktop]# Firefox 127.0.0.1/rhel7
[[Email protected] Desktop]# Vim/etc/fstab

/iso/rhel-server-7.2-x86_64-dvd.iso/var/www/html/rhel7 iso9660 Defaults 0 0

[[Email protected] Desktop]# umount/var/www/html/rhel7/
[[Email protected] Desktop]# ls/var/www/html/rhel7/
[[Email protected] Desktop]# mount-a
[[Email protected] Desktop]# ls/var/www/html/rhel7/

Client: Virtual machine a vs. virtual machine B

Virtual Machine A
[Email protected] ~]# Vim/etc/yum.repos.d/dvd.repo
[DVD]
Name=dvd
Baseurl=http://192.168.4.254/rhel7
Enabled=1
Gpgcheck=0

[email protected] ~]# Yum repolist

With remote copy data, between different hosts of the network

SCP Local Path User name @ each other's IP address: The path of the other party

Scp/etc/yum.repos.d/dvd.repo [Email PROTECTED]:/ETC/YUM.REPOS.D

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Virtual Machine A
Virtual Machine B

Linux System Learning 12th Day-<< Engineer Technology >>