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KVM host with bonding and VLAN tagged Virtual Machines setup on Ubuntu 12.04

Published: 15-02-2014 | Author: Remy van Elst | Text only version of this article


Table of Contents


Preface

kvm

I want to set up a KVM host which is only reachable from the management network(VLAN 10). It is going to run VM's in two other VLAN's, VLAN 11 (accept) andVLAN 12 (production). The KVM host itself should not be reachable on the twolatter VLAN's, only on the management network.

The KVM host has 2 NIC's, which are plugged in to two switches who support LACP.The switch ports for the KVM host are trunk ports for the above VLAN's (11, 10and 12). The two NIC's are bonded in balance-xor (bond mode 3) for faulttolerance and load balancing.

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We are going to create three interfaces using the linux vlan config, bond0.11,bond0.10 and bond0.12. We need to do this for the VLAN tagging.

On those interfaces we are going to create bridges for use with KVM: vmbr11,vmbr10 and vmbr12. Only vmbr10 will get an IP address, which we will usefor connecting over ssh for management. The other two bridges only serve asbridges for the virtual machine nic's. Because we do it this way, it will appearto the virtual machines as if they were only in the network they are bridged inand they require no further configuration themselves.

We are using Ubuntu's vmbuilder to build a test VM. Instructions for adding aserial console for troubleshooting are also included.

My management VLAN (10) has the IP range 192.168.10.0/24. The accept VLAN (11)has the IP range 192.168.11.0/24. My production VLAN, as you might haveguessed, has the range 192.168.12.0/24.

This is an example situation to keep the tutorial simple. I actually use aenvironment-dmz, environment-frontend and environment-backend setup withcorresponding VLANs.

Requirements

You can check hardware virtualization support with the following command:

egrep '(vmx|svm)' /proc/cpuinfo

If it results in output like this:

flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl nonstop_tsc extd_apicid aperfmperf pni pclmulqdq monitor ssse3 cx16 sse4_1 sse4_2 popcnt aes xsave avx lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs xop skinit wdt lwp fma4 nodeid_msr topoext perfctr_core arat cpb hw_pstate npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold

Your CPU is able to run KVM virtual machines.

Install required packages

The below command installs all the required packages for KVM virtualization,bridged networking and VLAN support:

apt-get install vlan ifenslave ubuntu-virt-server python-vm-builder kvm-ipxe bridge-utils libguestfs-tools guestfish

Set up NIC bonding

Read this article I wrote for a lot more info on NIC bonding:https://raymii.org/s/tutorials/NIC Bonding on Ubuntu 12.04.html

Set up network bridge for VLAN

We are going to add an interface definition for each VLAN to/etc/network/interfaces. The VLAN interface names must follow one of thenaming conventions supported by vconfig. The one used and recommended here is ofthe form ethx.y, where ethx is the physical interface name and y is the VLANnumber.

As stated above, we are bonding/teaming eth0 and eth1 together in balance-xor mode. This provides load balancing and fault tolerance.

We add an interface for every VLAN on the bond0 interface. This interface isused for the bridge to the KVM VM's. The bridge for the management vlan (VLAN10) will have an IP address and all the other regular network configurationrequired. The other two bridges have the IP stub of 0.0.0.0, if this is notdefined, your VM's will not have network connectivity. The KVM server itselfhowever is not reachable on that network. If you would want that, you would needto change the IP address to something for that VLAN.

vim /etc/network/interfaces

Contents:

# The loopback network interfaceauto loiface lo inet loopback# The primary network interfaceauto eth0iface eth0 inet manual        bond-master bond0auto eth1iface eth1 inet manual        bond-master bond0auto bond0iface bond0 inet manual        bond-miimon 100 # Specifies the MII link monitoring frequency in milliseconds. This determines how often the link state of each slave is inspected for link failures.         bond-downdelay 200 # Specifies the time, in milliseconds, to wait before disabling a slave after a link failure has been detected.        bond-updelay 200 # Specifies the time, in milliseconds, to wait before enabling a slave after a link recovery has been detected.        bond-mode 3 # balance-xor; XOR policy: Transmit based on the selected transmit hash policy.  The default policy is a simple [(source MAC address XOR'd with destination MAC address) modulo slave count].  Alternate transmit policies may be selected via the xmit_hash_policy option, described below.        bond-slaves none # we already defined the interfaces above with bond-master# Management VLANauto bond0.10iface bond0.10 inet manual        vlan-raw-device bond0auto vmbr10iface vmbr10 inet static        address 192.168.10.25        netmask 255.255.255.0        network 192.168.10.0        broadcast 192.168.10.255        gateway 192.168.10.1        dns-nameservers 192.168.9.10        dns-search example.org.eu        bridge_ports bond0.10        bridge_hello 2 # Periodically, a hello packet is sent out by the Root Bridge and the Designated Bridges. Hello packets are used to communicate information about the topology throughout the entire Bridged Local Area Network.        bridge_maxage 12 # If a another bridge in the spanning tree does not send out a hello packet for a long period of time, it is assumed to be dead. This timeout is set with:        bridge_stp off        bridge_fd 9 # Forwarding delay time is the time spent in each of the Listening and Learning states before the Forwarding state is entered. This delay is so that when a new bridge comes onto a busy network it looks at some traffic before participating.        up /sbin/ifconfig $IFACE up || /bin/true# Accept VLANauto bond0.11iface bond0.11 inet manual        vlan-raw-device bond0auto vmbr11iface vmbr11 inet manual        address 0.0.0.0        bridge_ports bond0.11        bridge_hello 2        bridge_maxage 12        bridge_stp off        bridge_fd 9        up /sbin/ifconfig $IFACE up || /bin/true# Production VLANauto bond0.12iface bond0.12 inet manual        vlan-raw-device bond0auto vmbr12iface vmbr12 inet manual        address 0.0.0.0        bridge_ports bond0.12        bridge_hello 2        bridge_maxage 12        bridge_stp off        bridge_fd 9        up /sbin/ifconfig $IFACE up || /bin/true

We want to delete the default libvirt interface which is created by default tobe used for guests (It uses NAT, I never use it).

virsh net-destroy defaultvirsh net-autostart --disable default

Also add the following items to /etc/sysctl.conf:

net.bridge.bridge-nf-call-ip6tables = 0net.bridge.bridge-nf-call-iptables = 0net.bridge.bridge-nf-call-arptables = 0net.bridge.bridge-nf-filter-pppoe-tagged = 0net.bridge.bridge-nf-filter-vlan-tagged = 0

And apply them:

sysctl -p; ebtables -F

We do this to make sure that iptables and ebtables (iptables for arp) do notinterfere with the virtual networking setup.

After all the configuration is set up, restart libvirtd:

/etc/init.d/libvirtd restart/etc/init.d/libvirt-bin restart/etc/init.d/qemu-kvm restart

Add root user to right groups

The root user needs to be in the libvirtd and kvm groups to be able to workwith virsh and related tools. Add it to the groups:

adduser `id -un` libvirtdadduser `id -un` kvm

First VM with VMBuilder

We will use the vmbuilder tool to create VMs. vmbuilder uses a template tocreate virtual machines, this template is located in the /etc/vmbuilder/libvirt/directory. First we create a copy for the new vm, which we will name vm1:

mkdir -p /var/lib/libvirt/images/vm1/mytemplates/libvirtcp /etc/vmbuilder/libvirt/* /var/lib/libvirt/images/vm1/mytemplates/libvirt/

Edit the following file to define the VM disk partitions and size:

vim /var/lib/libvirt/images/vm1/vmbuilder.partition

Contents:

root 10000swap 2000---/var 10000

This defines a 10 GB root partition, a 2 GB swap area and the --- makes thatthe 10 GB /var partition gets its own disk image.

Create a script which will be executed on (and only on) the first boot of theVM. I use this to regenerate the SSH host key, otherwise it will have the SSHhost key from the vmbuilder template:

vim /var/lib/libvirt/images/vm1/boot.sh

Contents:

# This script will run the first time the virtual machine boots as root# Expire the user accountpasswd -e remy# regenerate ssh host keyrm -rf /etc/ssh/ssh_host_*dpkg-reconfigure openssh-server

Now create the VM:

cd /var/lib/libvirt/images/vm1/vmbuilder kvm ubuntu --suite=precise --flavour=virtual --arch=amd64 --mirror=http://nl.archive.ubuntu.com/ubuntu -o --libvirt=qemu:///system --ip=192.168.12.20 --gw=192.168.12.1 --part=vmbuilder.partition --templates=mytemplates --user=remy --name=Remy --pass=example --addpkg=vim-nox --addpkg=unattended-upgrades --addpkg=acpid --addpkg=openssh-server --firstboot=/var/lib/libvirt/images/vm1/boot.sh --mem=512 --hostname=vm1 --bridge=vmbr12

The options explained:

Example output:

2014-02-14 19:13:03,541 INFO    : Calling hook: preflight_check2014-02-14 19:13:03,545 INFO    : Calling hook: set_defaults2014-02-14 19:13:03,546 INFO    : Calling hook: bootstrap2014-02-14 19:20:11,227 INFO    : Calling hook: configure_os2014-02-14 19:21:40,418 INFO    : invoke-rc.d: policy-rc.d denied execution of start.2014-02-14 19:22:02,081 INFO    :2014-02-14 19:22:02,082 INFO    : Current default time zone: 'Etc/UTC'2014-02-14 19:22:02,085 INFO    : Local time is now:      Fri Feb 14 18:22:02 UTC 2014.2014-02-14 19:22:02,085 INFO    : Universal Time is now:  Fri Feb 14 18:22:02 UTC 2014.2014-02-14 19:22:02,086 INFO    :Extracting templates from packages: 100%2014-02-14 19:23:44,503 INFO    : invoke-rc.d: policy-rc.d denied execution of stop.2014-02-14 19:24:36,398 INFO    : invoke-rc.d: policy-rc.d denied execution of start.2014-02-14 19:24:39,584 INFO    : invoke-rc.d: policy-rc.d denied execution of restart.2014-02-14 19:25:13,496 INFO    :2014-02-14 19:25:13,496 INFO    : Current default time zone: 'Etc/UTC'2014-02-14 19:25:13,502 INFO    : Local time is now:      Fri Feb 14 18:25:13 UTC 2014.2014-02-14 19:25:13,502 INFO    : Universal Time is now:  Fri Feb 14 18:25:13 UTC 2014.2014-02-14 19:25:13,502 INFO    : Run 'dpkg-reconfigure tzdata' if you wish to change it.2014-02-14 19:25:13,502 INFO    :2014-02-14 19:25:16,014 INFO    : invoke-rc.d: policy-rc.d denied execution of stop.2014-02-14 19:25:46,843 INFO    : gpg: key 437D05B5: "Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>" not changed2014-02-14 19:25:46,847 INFO    : gpg: key FBB75412: "Ubuntu CD Image Automatic Signing Key <cdimage@ubuntu.com>" not changed2014-02-14 19:25:46,849 INFO    : gpg: key C0B21F32: public key "Ubuntu Archive Automatic Signing Key (2012) <ftpmaster@ubuntu.com>" imported2014-02-14 19:25:46,850 INFO    : gpg: key EFE21092: public key "Ubuntu CD Image Automatic Signing Key (2012) <cdimage@ubuntu.com>" imported2014-02-14 19:25:46,812 INFO    : gpg: Total number processed: 42014-02-14 19:25:46,812 INFO    : gpg:               imported: 2  (RSA: 2)2014-02-14 19:25:46,812 INFO    : gpg:              unchanged: 22014-02-14 19:25:46,852 INFO    : gpg: no ultimately trusted keys found2014-02-14 19:25:58,038 INFO    : gpg: key 437D05B5: "Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>" not changed2014-02-14 19:25:58,042 INFO    : gpg: key FBB75412: "Ubuntu CD Image Automatic Signing Key <cdimage@ubuntu.com>" not changed2014-02-14 19:25:58,044 INFO    : gpg: key C0B21F32: "Ubuntu Archive Automatic Signing Key (2012) <ftpmaster@ubuntu.com>" not changed2014-02-14 19:25:58,045 INFO    : gpg: key EFE21092: "Ubuntu CD Image Automatic Signing Key (2012) <cdimage@ubuntu.com>" not changed2014-02-14 19:25:58,046 INFO    : gpg: Total number processed: 42014-02-14 19:25:58,046 INFO    : gpg:              unchanged: 42014-02-14 19:25:58,094 INFO    : No packages found matching linux-image-[0-9]*.2014-02-14 19:26:44,695 INFO    : invoke-rc.d: policy-rc.d denied execution of stop.2014-02-14 19:27:00,223 INFO    : invoke-rc.d: policy-rc.d denied execution of start.2014-02-14 19:27:08,390 INFO    : invoke-rc.d: policy-rc.d denied execution of start.2014-02-14 19:27:18,082 INFO    : invoke-rc.d: policy-rc.d denied execution of restart.2014-02-14 19:27:24,214 INFO    : invoke-rc.d: policy-rc.d denied execution of start.2014-02-14 19:27:33,555 INFO    : Cleaning up2014-02-14 19:27:33,557 INFO    : Calling hook: preflight_check2014-02-14 19:27:33,868 INFO    : Calling hook: configure_networking2014-02-14 19:27:33,950 INFO    : Calling hook: configure_mounting2014-02-14 19:27:33,979 INFO    : Calling hook: mount_partitions2014-02-14 19:27:33,980 INFO    : Mounting target filesystems2014-02-14 19:27:33,980 INFO    : Creating disk image: "/tmp/tmpd08iAo" of size: 12001MB2014-02-14 19:27:10,070 INFO    : Adding partition table to disk image: /tmp/tmpd08iAo2014-02-14 19:27:10,537 INFO    : Adding type 4 partition to disk image: /tmp/tmpd08iAo2014-02-14 19:27:10,538 INFO    : Partition at beginning of disk - reserving first cylinder2014-02-14 19:27:10,633 INFO    : Adding type 3 partition to disk image: /tmp/tmpd08iAo2014-02-14 19:27:10,642 INFO    : [0] ../../libparted/filesys.c:148 (ped_file_system_type_get): File system alias linux-swap(new) is deprecated2014-02-14 19:27:10,693 INFO    : Creating loop devices corresponding to the created partitions2014-02-14 19:27:10,769 INFO    : Creating file systems2014-02-14 19:27:10,849 INFO    : mke2fs 1.42 (11-Nov-2011)2014-02-14 19:27:37,331 INFO    : mkswap: /dev/mapper/loop0p2: warning: don't erase bootbits sectors2014-02-14 19:27:37,332 INFO    :         on whole disk. Use -f to force.2014-02-14 19:27:44,301 INFO    : Calling hook: install_bootloader2014-02-14 19:28:23,227 INFO    : Removing update-grub hooks from /etc/kernel-img.conf in favour of2014-02-14 19:28:23,227 INFO    : /etc/kernel/ hooks.2014-02-14 19:28:23,312 INFO    : Searching for GRUB installation directory ... found: /boot/grub2014-02-14 19:28:23,422 INFO    : Searching for default file ... Generating /boot/grub/default file and setting the default boot entry to 02014-02-14 19:28:23,424 INFO    : Searching for GRUB installation directory ... found: /boot/grub2014-02-14 19:28:23,431 INFO    : Testing for an existing GRUB menu.lst file ...2014-02-14 19:28:23,432 INFO    :2014-02-14 19:28:23,432 INFO    : Could not find /boot/grub/menu.lst file. Would you like /boot/grub/menu.lst generated for you? (y/N) /usr/sbin/update-grub: line 1094: read: read error: 0: Bad file descriptor2014-02-14 19:28:31,712 INFO    : Searching for GRUB installation directory ... found: /boot/grub2014-02-14 19:28:31,783 INFO    : Searching for default file ... found: /boot/grub/default2014-02-14 19:28:31,789 INFO    : Testing for an existing GRUB menu.lst file ...2014-02-14 19:28:31,789 INFO    :2014-02-14 19:28:31,789 INFO    : Could not find /boot/grub/menu.lst file.2014-02-14 19:28:31,790 INFO    : Generating /boot/grub/menu.lst2014-02-14 19:28:31,902 INFO    : Searching for splash image ... none found, skipping ...2014-02-14 19:28:32,110 INFO    : grep: /boot/config*: No such file or directory2014-02-14 19:28:32,269 INFO    : Updating /boot/grub/menu.lst ... done2014-02-14 19:28:32,270 INFO    :2014-02-14 19:28:32,754 INFO    : Searching for GRUB installation directory ... found: /boot/grub2014-02-14 19:28:32,826 INFO    : Searching for default file ... found: /boot/grub/default2014-02-14 19:28:32,833 INFO    : Testing for an existing GRUB menu.lst file ... found: /boot/grub/menu.lst2014-02-14 19:28:33,025 INFO    : Searching for splash image ... none found, skipping ...2014-02-14 19:28:33,062 INFO    : grep: /boot/config*: No such file or directory2014-02-14 19:28:33,207 INFO    : Updating /boot/grub/menu.lst ... done2014-02-14 19:28:33,207 INFO    :2014-02-14 19:28:33,431 INFO    : Searching for GRUB installation directory ... found: /boot/grub2014-02-14 19:28:33,444 INFO    : Calling hook: install_kernel2014-02-14 19:28:58,376 INFO    : Done.2014-02-14 19:11:19,370 INFO    : Running depmod.2014-02-14 19:11:19,475 INFO    : update-initramfs: deferring update (hook will be called later)2014-02-14 19:11:19,487 INFO    : Examining /etc/kernel/postinst.d.2014-02-14 19:11:19,489 INFO    : run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 3.2.0-58-virtual /boot/vmlinuz-3.2.0-58-virtual2014-02-14 19:11:19,544 INFO    : run-parts: executing /etc/kernel/postinst.d/initramfs-tools 3.2.0-58-virtual /boot/vmlinuz-3.2.0-58-virtual2014-02-14 19:11:19,549 INFO    : update-initramfs: Generating /boot/initrd.img-3.2.0-58-virtual2014-02-14 19:11:23,561 INFO    : run-parts: executing /etc/kernel/postinst.d/zz-update-grub 3.2.0-58-virtual /boot/vmlinuz-3.2.0-58-virtual2014-02-14 19:11:23,686 INFO    : Searching for GRUB installation directory ... found: /boot/grub2014-02-14 19:11:23,757 INFO    : Searching for default file ... found: /boot/grub/default2014-02-14 19:11:23,764 INFO    : Testing for an existing GRUB menu.lst file ... found: /boot/grub/menu.lst2014-02-14 19:11:23,957 INFO    : Searching for splash image ... none found, skipping ...2014-02-14 19:11:24,064 INFO    : Found kernel: /boot/vmlinuz-3.2.0-58-virtual2014-02-14 19:11:24,242 INFO    : Replacing config file /run/grub/menu.lst with new version2014-02-14 19:11:24,283 INFO    : Updating /boot/grub/menu.lst ... done2014-02-14 19:11:24,283 INFO    :2014-02-14 19:11:11,394 INFO    : Calling hook: post_install2014-02-14 19:11:11,474 INFO    : Calling hook: unmount_partitions2014-02-14 19:11:11,475 INFO    : Unmounting target filesystem2014-02-14 19:11:35,991 INFO    : Calling hook: convert2014-02-14 19:11:35,992 INFO    : Converting /tmp/tmpd08iAo to qcow2, format ubuntu-kvm/tmpd08iAo.qcow22014-02-14 19:11:54,187 INFO    : Calling hook: fix_ownership2014-02-14 19:11:54,188 INFO    : Calling hook: deploy

Managing the first VM

We are using virsh to manage the VM. virsh is a hypervisor agnostic way tomanage virtual machines, it work with Xen, KVM and others.

First define it so that virsh knows abot it:

virsh define /etc/libvirt/qemu/vm1.xml

Output:

Domain vm1 defined from /etc/libvirt/qemu/vm1.xml

Then start it:

virsh start vm1

Output:

Domain vm1 started

Check if it is running:

virsh list

Output:

 Id Name                 State----------------------------------  1 vm1                  running

Other commands to manage virtual machines with virsh are listed below:

Shutdown the VM:

virsh shutdown vm1

Pull the power plug from the VM:

virsh destroy vm1

The difference between shutdown and destroy is that the first sends a ACPIsignal to the VM so that it can shut down itself cleanly (like pressing thepower button) and the latter just bluntly pulls the power plug.

Suspend or resume the VM:

virsh suspend vm1virsh resume vm1

Remove the VM from the virsh list:

virsh undefine vm1

You need to manually remove the KVM disk image after this.

Autostart the vm on hypervisor host boot:

virsh autostart vm1

This way, when the machine has a reboot or power loss, the VM will autostartwhen the machine is booted.

You should now be able to SSH in to your virtual machine from another host(which has access to the correct VLAN). The KVM host itself is only managablefrom the management VLAN and the VM's cannot access either the KVM host or themanagement VLAN.

Repeat the above steps to create more virtual machines. Remember to change thename, IP address and VLAN, otherwise they override existing configuration.

Console access to a VM

You might have a network configuration error or any other reason to get consoleaccess to your VM. To access your VM's "serial console" use the followingcommand:

virsh console vm1

If you only get blank output like this:

Connected to domain vm1Escape character is ^]

You might need to set up a serial console. This can be the case on an Ubuntu12.04 guest. Here are instructions to set up a serial console on Ubuntu 12.04.We do a dirty grub hack because we cannot access the VM to do it the clean way.

Use virt-edit on the KVM host machine to edit a few files in the guest:

# first stop the VMvirsh destroy vm1# edit the VM configvirsh edit vm1

Place the following inside the section:

&lt;serial type='pty'&gt;  &lt;target port='0'/&gt;&lt;/serial&gt;&lt;console type='pty'&gt;  &lt;target type='serial' port='0'/&gt;&lt;/console&gt;# then edit the boot menu in the vm:virt-edit vm1 /boot/grub/menu.lst

Add this to the top of the file:

serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1terminal --timeout=15 serial console

Add the following after the kernel line of the boot entry:

console=ttyS0,19200 earlyprint=serial,ttyS0,19200

I also removed the quiet and splash parts.

My entry looks like this:

title           Ubuntu 12.04.4 LTS, kernel 3.2.0-58-virtualuuid            5a17ce36-580b-47ab-95b2-ff9be5d5d6d8kernel          /boot/vmlinuz-3.2.0-58-virtual root=UUID=5a17ce36-580b-47ab-95b2-ff9be5d5d6d8 ro console=ttyS0,19200 earlyprint=serial,ttyS0,19200initrd          /boot/initrd.img-3.2.0-58-virtual

The output from grub will go to the normal console unless input is received fromthe serial port. Whichever receives input first becomes the default console.This gives you the best of both worlds.

We also need to create a file in the VM for the console itself. We'll useguestfish for that because virt-edit does not support creating files in thedisk image:

guestfish --rw -a ubuntu-kvm/tmpIrlKJF.qcow2 -i write /etc/init/ttyS0.conf " "

Change ubuntu-kvm/tmpIrlKJF.qcow2 to the path to your disk image. We can nowuse virt-edit to edit the file again:

virt-edit vm1 /etc/init/ttyS0.conf

Write the following to the file:

# ttyS0 - getty## This service maintains a getty on ttyS0 from the point the system is# started until it is shut down again.start on stopped rc RUNLEVEL=[2105]stop on runlevel [!2105]respawnexec /sbin/getty -L 115200 ttyS0 xterm

This will start a serial console on the VM. If you do not do this you will onlysee the GRUB boot prompt and not the OS output.

Now boot the machine with the console attached:

virsh start vm1 --console

Output:

Domain vm1 startedConnected to domain vm1Escape character is ^]Press any key to continue.Boot from (hd0,0) ext4   5a17ce36-580b-47ab-95b2-ff9be5d5d6d8Starting up ...Waiting for network configuration...Waiting up to 60 more seconds for network configuration...Booting system without full network configuration...Ubuntu 12.04.4 LTS vm1 ttyS0vm1 login:

If the machine is not reachable via ssh you can use the console to do recoveryor maintenance.

Sources

Tags: bonding, failover, kvm, lacp, network, teaming, tutorials, ubuntu, virsh, virtualization, vlan