주의할 점은 저 같은 경우 브릿지 네트워크를 설정할 때, ifcfg-eth0에 static IP를 설정하려고 하는 실수를 하게되더군요. 아래의 네트워크 브릿징 설명대로 eth0에는 아이피를 세팅하지 않고 br0에 호스트 메인 IP를 세팅하여야 합니다. (/etc/sysconfig/network-scripts/ifcfg-br0)
CentOS7에서는 재부팅 후 ifcfg-eth0(eno?, enp?)과 같은 환경파일이 사라지는
If you choose the “Minimal” option during CentOS 6 then this step is
necessary. To get the full set of tools there are 4 software groups to
install…
Virtualization
Virtualization Client
Virtualization Platform
Virtualization Tools
To install run
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yum groupinstall "Virtualization*"
dejavu-lgc-sans-fonts is necessary or all the fonts in virt-manager will show as squares
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yum install dejavu-lgc-sans-fonts
Once the install is finished verify that the KVM kernel module is loaded.
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lsmod | grep kvm
You should see either kvm_intel or kvm_amd depending on your host’s CPU manufacturer.
At this point I chose to reboot the server. This allows services to
be started and udev rules for KVM to be applied. This will also allow
dbus to create the machine-id file, otherwise you would see something
like the below when running virt-manager
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# virt-manager
Xlib: extension "RANDR" missing on display "localhost:10.0".
process 1869: D-Bus library appears to be incorrectly set up; failed to
read machine uuid: Failed to open "/var/lib/dbus/machine-id": No such
file or directory
See the manual page for dbus-uuidgen to correct this issue.
D-Bus not built with -rdynamic so unable to print a backtrace
Aborted
If you receive that D-Bus error and would prefer not to restart then run this command to generate the necessary machine-id file
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dbus-uuidgen > /var/lib/dbus/machine-id
Final configuration steps
The server I run KVM on is headless, but I still like using
virt-manager. So we must install the necessary tools to do X11
forwarding through SSH.
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yum install xorg-x11-xauth
# If you plan to use VNC to connect to the virtual machine's console locally
yum install tigervnc
Now when you connect through SSH be sure to pass the -X flag to enable X11 forwarding.
Optional: Using an alternate location for VM images with SELinux
With SELinux enabled, special steps must be taken to change the default VM store from /var/lib/libvirt/images. My particular server I choose to keep all images and ISOs for VMs under /vmstore. The steps below give your new store the correct security context for SELinux.
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# this package is necessary to run semanage
yum install policycoreutils-python
semanage fcontext -a -t virt_image_t "/vmstore(/.*)?"
restorecon -R /vmstore
To activate this store you must open virt-manager, select your host, then do Edit-> Host Details. Under the Storage tab you can add your new storage volume.
Optional : Network Bridging for Virtual Machines
If you wish for your virtual machines to be accessible remotely then
you must use network bridging to share your host’s network interface
with the virtual machines. The setup requires linking one of your
host’s physical interfaces with a bridge device. First copy your
physical interface’s ifcfg file to create the new bridge device, named br0.
Modify ifcfg-br0 to have the IP information in ifcfg-eth0 and remove,
or comment out, that information in ifcfg-eth0. Below are examples of
ifcfg-eth0 and ifcfg-br0. The highlighted lines are important.
Once those two files are configured restart the network service
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service network restart
Optional: Managing libvirt with standard user account
Beginning in CentOS 6 access to managing libvirt is handled by PolicyKit.
It’s always a good practice to do your daily administration tasks as
some user besides root, and using PolicyKit you can give access to
libvirt functions to a standard account.
First we create the necessary config file to define the access
controls. The file must begin with a numeric value and have the .pkla
extension.
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vim /etc/polkit-1/localauthority/50-local.d/50-libvirt-remote-access.pkla
Here’s an example of the file I used to give access to a single user. Be sure to put your desired username in place of username on the highlighted line.
You can optionally replace Identity=unix-user:username with Identity=unix-group:groupname to allow access to a group of users.
Finally restart the libvirtd daemon to apply your changes.
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/etc/init.d/libvirtd restart
Creating the first virtual machine
You are now ready to create your virtual machines.
Create the virtual disk
With the version of virt-manager shipped with CentOS 6 you cannot create qcow2
images from within the GUI. If you wish to create your new VM with a
qcow2 format virtual disk you must do so from the command line, or see
the next section for RPMs to upgrade virt-manager.
Update: Through some testing I’ve found that
performance can be greatly improved if the preallocation is set when
creating a qcow2 image. See my recent post at Improve disk I/O performance in KVM for more information on improving performance in KVM.
# Without preallocation
qemu-img create -f qcow2 CentOS-6.0-x86_64-Template.qcow2 20G
NOTE: Replace the filename
“CentOS-6.0-x86_64-Template” with your desired name, and also replace
“20G” with the desired max size of the virtual disk.
Now when creating your virtual machine select to use an existing virtual disk.
virt-manager-0.8.7
See my blog post virt-manager 0.8.7 for CentOS 6 Updated
to get RPMs to upgrade the version of virt-manager that comes with
CentOS 6. With this version you can change / specify the virtual disk
format from within the GUI.
2) Halt the vmware VM . Check the format of the vmware vmdk file
# qemu-img info mtdhost-xp.vmdk image: mtdhost-xp.vmdk file format: raw virtual size: 15G disk size: 15G
3) If the file format is “raw”, we need not convert the image file using qemu-img convert, just rename to .img file. If it is not “raw”, use “qemu-img” to convert the image to raw format. Otherwise skip step 4.
4) How to convert using qemu-img.
# qemu-img convert mtdhost-xp.vmdk -O raw /VM/mtdhost-xp.img
4-2) Hyper-V이미지를 qemu-img로 변경하는 법 # qemu-img convert -f vpc ./ww-dlp.vhd -O raw ./ww-dlp.img
5) Create xen config file in /etc/xen/mtdhost-xp (or use the virt-manager utility and choose the newly converted file as the harddrive image), with the renamed/converted image file as disk.
disk = [ 'file:/VM/mtdhost-xp.img,hda,w' ]
6) Boot up the xen domU guest. It should boot up fine.
Re
네트워크 설정 후, network restart할 때 에러가 난다면....
Admin
* 브릿지 설정 후 재부팅하면 최초부팅 시에만 되고 네트웤을 재시작하면 Failed to start LSB 또는 master connection not found와 같은 에러가 발생되어 IP가 올라오지 않는 현상이 특정 서버에서 발견되었다.
* 심지어는 ifcfg-eno0(eth0)와 같은 환경파일마저 삭제되어버리고 없어지는 경우도 있는데, 이때는 직접 수작업으로 다시 생성해주고 아래와 같이 처리하자
NetworkManager 데몬이 너무 친절해서 간섭하여 발생되는 에러이므로 내리고 재시작하자.
service NetworkManager stop service network restart
chkconfig로 아예 부팅시 실행이 안되게 설정해두는 것도 좋다.
br0와 eno0(eth0)에 모두 IP가 보이면 잘못된 것임. 차라리 NetworkManager를 삭제하는 것도 좋음
4. 네트워크 인터페이스는 브릿지 장치(vnet0(br0))가 보이면 선택하고 장치모델은 hypervisor기본값으로 선택하지만, 만약 보이지 않는다면 아래처럼 세팅하자. 원본장치: 공유장치 이름을 지정 브릿지 이름: br0 장치모델: hypervisor기본값 --혹시 안된다면 virtio로 해보도록.
5. 이미지 스토리지에 권한이 없어서 생성이 불가능하다면 아래처럼 처리하자. chmod go+rx /var/lib/libvirt/images
chmod o-rwx /var/lib/libvirt/images/*
*. 콘솔명령으로 제어하려면 아래와 같이 접속하면 되지만, 어차피 GUI로 봐야하므로 원격접속하여 편하게 virt-manager로 해결하자.
KVM: A full virtualization solution for Linux on x86 hardware containing virtualization extensions (Intel VT or AMD-V). Virt-Manager: A desktop user interface for managing virtual machines through libvirt. Libvirt: A toolkit to interact with the virtualization capabilities of recent versions of Linux. Virt-Install: A command line tool for creating new KVM container guests using the "libvirt"hypervisor management library. Qemu-kvm: A Linux kernel module that allows a user space program to utilize the hardware virtualization features of various processors. Dejavu-lgc-sans-fonts: A font family based on the Vera Fonts. virt-viewer: A minimal tool for displaying the graphical console of a virtual machine.
-- NAT기능 사용(필요한 경우만): 하나의 IP를 공유하려면 아래와 같이 포워딩 설정하자
echo "net.ipv4.ip_forward = 1"|sudo tee /etc/sysctl.d/99-ipforward.conf
sudo sysctl -p/etc/sysctl.d/99-ipforward.conf
-- 가상OS에 각각 공인 IP를 부여할 수 있는 브릿지 기능을 사용하기
vi /etc/sysconfig/network-scripts/ifcfg-eth0(장치에 따라 다름)
