====== Setting up kvm network ======
{{tag>kvm}}

===== kvm packages =====

   yum install bridge-utils tunctl libvirt qemu-kvm virt-manager
   yum install spice-server.x86_64 spice-gtk3.x86_64 spice-client.x86_64 qemu-kvm-tools
   
   
===== ip routing etc =====
   net.ipv4.tcp_window_scaling=0
   
====== VM Network Types ======
  * http://wiki.libvirt.org/page/Networking#Host_configuration
  * http://www.virtualbox.org/manual/ch06.html#network_hostonly
  * THIS IS IT: http://www.linux-kvm.org/page/Networking
  * other links:
    * http://wiki.qemu.org/Documentation/Networking
    * https://help.ubuntu.com/community/KVM/Networking
    * 

===== NAT forwarding (aka "virtual networks") : =====
  * virtual bridge with IP Masq
  * connects Host virbr and Guests and NATing Guests
  * Accessing Guests from outside require additional IP rules
==== Create Host bridge, tap, iptables masqerading ====
Make sure everything is up and run:
    sudo qemu-kvm -hda instances/controller.qcow2 -m 1024 -vnc :3 -cdrom cloud-init/default/default-cidata.iso -device e1000,netdev=br_ql_mgmt -netdev tap,id=br_ql_mgmt,ifname=controller-eth0,script=no,downscript=no
    
Use scripts to setup network when vm start:
    sudo qemu-kvm -hda $DIR/images/Fedora-x86_64-20-300G-20150130-sda-network.qcow2 \
    -m 1500 -vnc :2 \
    -device e1000,netdev=snet0,mac=DE:AD:BE:EF:12:07 -netdev tap,id=snet0,script=$DIR/scripts/qemu-ifup-stackbr0.sh &

==== Generate MAC ====

If you are managing your guests via command line, the following script might be helpful to generate a randomized MAC using QEMU's registered OUI (52:54:00):

    MACADDR="52:54:00:$(dd if=/dev/urandom bs=512 count=1 2>/dev/null | md5sum | sed 's/^\(..\)\(..\)\(..\).*$/\1:\2:\3/')"; echo $MACADDR
===== Bridged networking (aka "shared physical device") =====

  * Bridge connecting with physical iface (eth0)
  * Host, VM and outside network

Bridge and NAT (red dot): http://blogs.virtualizationadmin.com/lowe/wp-content/blogs/60/files/2011/11/image_thumb2.png

PCI Passthrough of host network devices 

====== DNSMASQ ======
  * https://fedoraproject.org/wiki/Changes/Default_Local_DNS_Resolver
  * journalctl -b show all log from boot