---
title: KVM虚拟机常用操作记录
abbrlink: 4926dc90
categories:
  - 基础运维
tags:
  - VirtualMachine
  - 配置记录
date: 2021-07-21 14:20:55
---

## 添加和删除网卡（虚拟硬件）

### 查看网卡列表

```bash
sudo virsh domiflist vm-yaohai
```

### 添加网卡(模式桥接到br0)

```bash
sudo virsh attach-interface vm-yaohai --type bridge --source br0 --model virtio --config
```

### 删除网卡(指定mac地址删除)

```bash
sudo virsh detach-interface vm-yaohai --type bridge --mac 52:54:00:61:4c:f3 --config
```

~~添加网卡或删除网卡后需要重新定义,不然重启会失效~~

~~virsh dumpxml vm-yaohai > /etc/libvirt/qemu/vm-yaohai.xml~~
~~virsh define /etc/libvirt/qemu/vm-yaohai.xml~~

## kvm默认网桥

> libvirt默认使用了一个名为default的nat网络，这个网络默认使用virbr0作为桥接接口，使用dnsmasq来为使用nat网络的虚拟机提供dns及dhcp服务，dnsmasq生效后的配置文件：`/var/lib/libvirt/network/default.xml`
> 当libvirtd服务启动的时候，它会将它管理的被标记为autostart的network一并启动起来，而启动network的时候就会自动调用dnsmasq并赋予其适宜的配置文件来运行服务。

### KVM网桥启动

```bash
# default网卡自动启动（virbr0）
virsh net-autostart default

# default网卡启动（virbr0）
virsh net-start default

# 查看网卡列表
virsh net-list --all
```

### 修改网段

编辑配置文件

```bash
sudo virsh net-edit default
```

~~重新定义~~

~~```bash~~
~~sudo virsh net-define /etc/libvirt/qemu/networks/default.xml~~
~~```~~

重新启动网卡

```bash
sudo virsh net-destroy default
sudo virsh net-start default
```

## kickstart自动装机

### virt-install命令

```bash
virt-install \
    --hvm --virt-type kvm \
    --accelerate \
    --name vm-1 \
    --os-type linux \
    --os-variant centos-stream8 \
    --vcpus 2 \
    --ram 4096 \
    --disk path=/dev/mapper/lv_name \
    --network "bridge:br0,model=virtio" \
    --nographics \
    --location https://mirrors.aliyun.com/centos/8-stream/BaseOS/x86_64/os/ \
    --initrd-inject=./ks.cfg \
    --cpu host \
    --extra-args "ks=file:/ks.cfg console=tty0 console=ttyS0,115200n8 net.ifnames=0 biosdevname=0"
```

> 后面的`net.ifnames=0 biosdevname=0` 是内核参数,将网卡设备名固定为eth0..eth1等  
> --os-type 可以通过命令 `osinfo-query os` 获取

### kickstart 内容

> 在系统安装后桌面上会生成一份`anaconda-ks.cfg`这个就是安装这个系统使用的kickstart配置

安装 `centos8 stream` 的 `ks.cfg`

```bash
# Kickstart file automatically generated by anaconda.

#version=DEVEL
install
url --url="https://mirrors.aliyun.com/centos/8-stream/BaseOS/x86_64/os/"
repo --name="CentOS"  --baseurl="https://mirrors.aliyun.com/centos/8-stream/BaseOS/x86_64/os/" --cost=100

lang en_US.UTF-8
keyboard us
network --onboot yes --device eth0 --bootproto static --ip 10.0.0.120 --netmask 255.255.0.0 --gateway 10.0.0.8 --noipv6 --nameserver 10.0.0.35,10.0.0.30
network  --hostname=vm-name

#default pwd is R/)ydu.?egUdT'Xl
rootpw  --iscrypted $6$7ljjIEi8rX8ydAOv$N4qtXrPQZIp5n5pbLf/BQ/1BgE0ODHoXGJzCiWCYl006hOhZeITXl.yz0kpRvolScvAMOZ..XzPIX7iiRtV5v/
firewall --service=ssh
authconfig --enableshadow --passalgo=sha512
selinux --enforcing
timezone --utc Asia/Shanghai
text
bootloader --location=mbr --driveorder=vda --append=" crashkernel=auto console=ttyS0,115200n8 net.ifnames=0 biosdevname=0"

# The following is the partition information you requested
# Note that any partitions you deleted are not expressed
# here so unless you clear all partitions first, this is
# not guaranteed to work

clearpart --all --drives=vda
part /boot --fstype=xfs --size=500
part pv.01 --grow
volgroup vg_os pv.01
logvol / --fstype=xfs --name=lv_root --vgname=vg_os --percent 90

# any invalid partition tables found on disks are initialized

zerombr

%packages
@core
curl

# install puppet agent. But it could be very slow, so you have to install it manually

#%post
#(
#    echo 'Install Puppet'
#    curl -OL https://yum.puppetlabs.com/puppet6-release-el-7.noarch.rpm
#    rpm -i puppet6-release-el-7.noarch.rpm
#    yum update -y
#    yum install -y puppet-agent
#) 1>> /root/post_install.log 2>&1

%end
```

## kvm透传主机usb设备

```bash
sudo usermod -aG kvm $USER
```

## kvm修改配置

### 修改内存大小

```bash
sudo virsh setmaxmem <vm-name> 16G --config
sudo virsh setmem <vm-name> 16G --config
```