1. Preface (the journey of playing this)
recent period of time want to play some clusters and things like that, learning to engage in K8s, clusters and so on, but I do not have multiple servers, if the cost of purchasing cloud servers is too high, and then thought of buying a desktop to get some virtual machines to play, so I am in a fish on the second-hand desktop (24-core +32G +512G +4G graphics), the price of 1,280. and then thought of installing a virtual machine, I I thought of the cloud platform that is often used now, so I looked for some open source cloud platforms on the Internet, so I looked for some open source cloud platforms
2. Reasons for the final choice of KVM
The beginning of the choice is FreeVM, purely domesticated security virtualization platform, directly all-in-one package installation is simple, pure Chinese interface, for the Chinese relatively friendly, in addition to reading the introduction of the operation is relatively simple and open source (enterprise version of the function basically can not be used), so I used this official website all-in-one package, directly download the ISO image, like the installation of the operating system, according to the official website process is very simple to install. It's very easy to install according to the process on the official website. Ultimately abandoned the reason is, not stable, just a week I cloud platform reinstalled twice (may be my hardware is too much garbage, or build a good after I can always hit the system bugs, in short, my feeling is not stable), decisively abandoned.
I gave up FreeVM and checked the most stable and long history to belong to OpenStack, an open source cloud computing management platform project.OpenStack provides scalable and elastic cloud computing services for private and public clouds. The goal of the project is to provide a simple to implement, massively scalable, rich, standardized cloud computing management platform. At that time, the pursuit of stability, did not take into account the complexity of the installation and configuration issues, directly start looking for a variety of tutorials to start dry, while the weekend from the morning to the evening to get it done, and ultimately found that it does not apply to me in this case, OpenStack is relatively heavy, a variety of components inside the more than a dozen, the entire service start-up, directly to the end of the memory to eat me. So I gave up.
Later figured out that if you want to build a stable and practical cloud platform rely on the resources of this machine is difficult to achieve, so I took into account the most stupid way to use a virtual machine (similar to VMware). Because my original system positioning is Centos, after querying found KVM (an open source system virtualization module). Virtualization requires hardware support (such as Intel VT technology or AMD V technology). It is a full hardware-based virtualization
3. Say yes and start installing (Centos system)
I was directly installed with yum, now because Centos has stopped maintenance, yum source can be used Ali source or Tencent source, Ali source has a problem, use in the virtual machine for a long time is easy to be blocked off the IP, resulting in your IP can not be used again (at that time, because of this let me troubleshooting for a long time). If you encounter problems with the yum source, you can just change the source to solve the problem. After all, we are not philanthropists, free things we can not say anything.
The installation command steps are directly below:
# Command line tools for building virtual machines
yum -y install virt-install
# Network support tools, installed by default
yum -y install bridge-utils
# Install virtual machine management tools
yum -y install libvirt libvirt-devel libvirt-daemon-kvm libvirt-client
yum -y install virt-manager
# Start the libvirtd KVM service to enable support:
systemctl start libvirtd
systemctl enable libvirtd --now
# Install additional toolkits:
yum install libvirt-python python-virtinst virt-install virt-viewer -y
yum install libguestfs-tools -y
As of the last step above, KVM has been installed
These are some of the relevant commands, and there are only two or three that I actually use (since I've only used two or three so far). virsh, virt-install, virt-manager
4. Using kvm to create a virtual machine, the virt-install command
The above has been installed KVM, the next step is to start using KVM to create a virtual machine, virtual machine need to have a mirror, here with or with Centos to do examples, I am in the AliCloud download:/centos/7/isos/x86_64
# Download Mirror
wget /centos/7/isos/x86_64/CentOS-7-x86_64
# Put the mirror in your customized location
mv CentOS-7-x86_64 /data/iso/
# Create a file with the namemaster random access memory (RAM)8196M 8classifier for individual things or people, general, catch-all classifierC virtual machine The storage volume is in the/var/lib/libvirt/images/master.qcow2
virt-install --name=master --memory=8196 --vcpus=8 --os-type=linux --location=/data/iso/CentOS-7-x86_64 --disk /data/vmdisk/images/master.qcow2,device=disk,bus=virtio,size=80 --network network=default --network bridge=virbr0 --nographics --extra-args='console=tty0 console=ttyS0,115200n8 serial'
The virt-install command is related to
# Default path to VM image files: /var/lib/libvirt/images/
Disk image files with qcow2, img, raw, etc. suffixes
Disk image file format.
Virtual machine disk files have raw, qcow2 format and qed (this kind is no longer used). qcow2 format is the standard format supported by kvm, raw format is the common format for virtual disk files. raw format has the best performance and the fastest speed, the disadvantage is that it doesn't support some new features, such as mirroring, Zlib disk compression, AES encryption, snapshots, etc., and in addition, raw format files are In addition, raw format files are much larger than qcow2 format files, nearly 15 times. And qcow2 format is to support snapshot mode, do snapshot to convert it to qcow2 format.
Example of # command to create a virtual machine
virt-install \ # create command
-n kvm1 \ #Virtual machine display name (not VM host name)
-r 4096 \ #Virtual machine memory size
--vcpus 2 \ #Number of VM cpu's.
--disk path=/var/lib/libvirt/images/kvm1.qcow2,size=50,format=qcow2,bus=virtio \ #Specify the hard disk path, size, format=qcow2,bus type as virtio
--location /root/iso/CentOS-7-x86_64 \ #System install iso path
--nographics \ # Do not invoke the GUI.
--network network=default \ # Specify bridge for NIC 1.
--network bridge=br0 \ #Specify the bridge for NIC 2.
--console pty,target_type=serial \ #console control channel
--extra-args 'console=ttyS0,115200n8 serial' #text output
Or vnc way to connect to the installation
virt-install \
--name=kvm001 --ram 1024 --vcpus=1 \
--disk path=/home/raw/,size=10,format=raw,bus=virtio \
--cdrom=/mnt/CentOS-7-x86_64 --network bridge=br0,model=virtio \
--graphics vnc,listen=0.0.0.0 --noautoconsole
Parameter Description:
--name #Virtual machine name
--ram #Memory allocated to the VM, in MB
--vcpus #Number of cpu's assigned to the VM
--cdrom #Specify the path to the CentOS image ISO file.
--disk #Specify the path to the virtual machine raw file.
size #Virtual machine file size in gigabytes.
bus #The type of bus used by the VM disk, for good performance of the VM, virtio is used here.
cache #The type of cache for the VM disk.
--network bridge #Specify the bridge network card.
model #The model of the network card, here we also use virtio for better performance.
--graphics #Graphics parameters
5. Virtual machine management virsh
Virtual Machine State Maintenance
virsh list --all #View all virtual machines
virsh dominfo virtual machine name or virtual machine ID #View an overview of virtual machine information
virsh console VM name or VM ID #Enter the virtual machine
Shortcut: ctrl+] #Exit the virtual machine
virsh shutdown virtual machine name or virtual machine ID #Shut down the virtual machine
virsh destroy virtual machine name or virtual machine ID #Forcibly shut down the virtual machine
virsh start virtual machine name or virtual machine ID #Power on the virtual machine
virsh suspend virtual machine name or virtual machine ID #Suspend the virtual machine
virsh resume virtual machine name or virtual machine ID #Resume the virtual machine
virsh reset virtual machine name or virtual machine ID #reset the virtual machine
virsh undefine virtual machine name or virtual machine ID #delete the virtual machine
virsh autostart virtual machine name or virtual machine ID #Set the virtual machine to start automatically
virsh autostart --disable virtual machine name #disable virtual machine autostart
virsh dumpxml virtual machine name or virtual machine ID #View virtual machine configuration files
virsh edit VM name or VM ID #Modify VM configuration, must be powered off
virsh snapshot-create-as virtual machine name snapshot name #Create a snapshot of the virtual machine
virsh snapshot-list virtual machine name #View the list of virtual machine snapshots
virsh snapshot-revert virtual-machine-name virtual-machine-snapshot-name #Restore virtual-machine snapshots
virt-clone -o source VM name -n new VM name -f file path where new VM will be stored #clone a VM
KVM Storage Pool Management
virsh pool-list --all #View the current list of storage pools
virsh pool-info storage-pool-name #View storage-pool information
virsh pool-dumpxml storage-pool-name #View storage-pool information Note: The configuration information of the storage pool is also in xml format and is stored in /etc/libvirt/storage.
virsh pool-destroy vmdisk #Deactivate the storage pool
virsh pool-undefine vmdisk #Undefine the storage pool
virsh pool-delete vmdisk #Delete the storage pool defined directory
#Create the local pool, the directory where the pool is located
mkdir -p /data/vmfs # Directory where pool is located
virsh pool-define-as vmdisk --type dir --target /data/vmfs/ # Define the storage pool
virsh pool-build vmdisk #Create a defined pool
virsh pool-start vmdisk #Activate and start the defined pool, the pool cannot be used without activation.
virsh pool-autostart vmdisk #Activate and autostart the defined pool, the pool cannot be used without activation
Storage Volume Management
#Create a storage volume, in the vmdisk storage pool, create a VM storage volume with a capacity of 80G and a format of qcow2 with the name master.qcow2
virsh vol-create-as vmdisk master.qcow2 80G --format qcow2
# Delete the storage volume
virsh vol-delete --pool vmdisk kvm2_2.qcow2