Virtual Test Environment for Multihost test

Problem:

For multi-host tests more real computers are required. It is possible to use two virtual guests for most of autotest tests except for virt-tests (kvm, libvirt, ...). It's possible to use Nested Virtualization to serve as first level (L0) guests and run nested guests inside them.

This page explains, how to setup (Fedora/RHEL) and use single computer with nested virtualization for such cases. Be careful that nested virtualization works usually right, but there are cases where it might lead to hidden problems. Do not use nested virtualization production testing.

Nested Virtualization:

1. Emulated:
   • qemu very slow
2. hardware accelerated:

   • Hardware for the accelerated nested virtualization

     AMD Phenom and never            core extension (smv, NPT)
     Intel Nehalem and never         core extension (vmx, EPT)
     

   • Software which supports the accelerated nested virtualization

     kvm, xen, vmware, ....
     almost the same speed like native guest (1.0-0.1 of native quest performance). Performance
     depends on the type of load. IO load could be quite slow. Without vt-d or AMD-Vi and network
     device pass through.
     

Configuration for multi-host virt tests:

Config of host system

• Intel CPU

  options kvm_intel nested=1 to the end of some modules config file /etc/modprobe.d/modules.conf

• AMD CPU

  options kvm_amd nested=1 to the end of some modules config file /etc/modprobe.d/modules.conf

Config of Guest L0

• Intel CPU

  • Virtual manager Procesor config->CPU Features->vmx set to require
  • Native qemu-kvm qemu-kvm -cpu core2duo,+vmx -enable-kvm .....

• AMD CPU

  • Virtual manager Procesor config->CPU Features->svm set to require
  • Native qemu-kvm qemu-kvm -cpu qemu64,+svm -enable-kvm .....

Config of Guest L0 System

Connect to host bridge with guest L0 bridge without DHCP (dhcp collision with host system dhcp).

1. Destroy libvirt bridge which contain dhcp.

2. Enable network service systemctl enable network.service

3. Add new bridge virbr0 manually and insert to them L0 network adapter eth0 which is connected to host bridge

    #interface connected to host system bridge
    vi /etc/sysconfig/network-scripts/ifcfg-eth0
         NM_CONTROLLED="no"
         DEVICE="eth0"
         ONBOOT="yes"
         BRIDGE=virbr0
   
    #Bridge has name virbr0 for compatibility with standard autotest settings.
    vi /etc/sysconfig/network-scripts/ifcfg-virbr0
        DHCP_HOSTNAME="atest-guest"
        NM_CONTROLLED="no"
        BOOTPROTO="dhcp"
        ONBOOT="yes"
        IPV6INIT="no"
        DEVICE=virbr0
        TYPE=Bridge
        DELAY=0
   

and for sure disable NetworkManager systemctl disable NetworkManager.service

Check Guest L0 System

modprobe kvm-intel or modprobe kvm-amd should work

Start for multi-host virt tests:

Manually from host machine

cd autotest/client/tests/virt/qemu/
sudo rm -rf results.*; sudo ../../../../server/autoserv -m guestL0_1,guestL0_2 multi_host.srv

From autotest gui

1. Start autotest frontend RPC or WEB interface https://github.com/autotest/autotest/wiki/SysAdmin
2. Select multi_host test from pull-request https://github.com/autotest/autotest-server-tests/pull/1