mykvm

• mykvm is a small python script to create multiple kvm instances from the yaml configuration file.
• mykvm is using some nice tools like virt-install, vmbuilder, qemu-img and ansible.

Installation

• Install kvm, virt-install, vmbuilder and some packages for ansible. Ansible will be used to initialize kvm instances.

    $ sudo apt-get update
    $ sudo apt-get install kvm libvirt-bin virtinst	python-vm-builder python-dev python-pip
  

• If you don't have any ssh key, generate a new ssh key. This key will be used to ssh into the kvm instances.

    $ ssh-keygen -t rsa
  

• Install mykvm with pip

    $ sudo pip install mykvm
  

• Now, mykvm is ready

    $ mykvm 
    Usage: mykvm command [<args>]
  
    Available subcommands:
        init
        up [<vm>]
        halt
        destroy
        status
  

Usage

• Create a new directory

    $ mkdir grizzly
    $ cd grizzly
  

• Run init command. If there's no base image, vmbuilder will create a precise64.qcow2 base image.

    $ mykvm init
    initialize mykvm
    
    * create mykvm.yml
    * copy vmbuilder script
    * copy ansible files
    * build base image /home/cirros/.mykvm/base/precise64.qcow2
    + rm -rf ubuntu-kvm
    + SUDOERS_TMPL=/etc/vmbuilder/ubuntu/sudoers.tmpl
    + grep -q -e ubuntu /etc/vmbuilder/ubuntu/sudoers.tmpl
    + sudo sed -i '$a ubuntu ALL=(ALL) NOPASSWD:ALL\n#includedir /etc/sudoers.d' /etc/vmbuilder/ubuntu/sudoers.tmpl
    + sudo vmbuilder kvm ubuntu --suite precise --arch amd64 --flavour virtual --ssh-user-key /home/cirros/.ssh/id_rsa.pub ...
    ...
  

• Up command will start networks and kvm instances with configurations in mykvm.yml.

    $ mykvm up
  

• Check the status of kvm instances.

    $ mykvm status
    status
    
     Id Name                 State
    ----------------------------------
      1 controller           running
      2 netnode              running
      3 compute1             running
      4 compute2             running
  

• You can use virsh to control kvm instances.

    $ sudo virsh list
     Id Name                 State
    ----------------------------------
      1 controller           running
      2 netnode              running
      3 compute1             running
      4 compute2             running
  

• You can ssh into the kvm instances with hostname. /etc/resolv.conf is updated to use the dnsmasq of first network in mykvm.yml as a nameserver.

    $ ssh ubuntu@controller
  

• Destroy command will stop networks and destroy kvm instances.

    $ mykvm destroy 
  

Configuration

• mykvm.yml configuration file look like this.

• You can define multiple networks and vm instances with multiple network interfaces.

• You can create nested kvm instances with 'kvm_nested' option.

    $ cat mykvm.yml 
    ---
    - networks:
      - name: mgmt
        external: true
        autostart: true
        ip: 10.0.10.1
    
      - name: int
        ip: 10.0.20.1
    
      - name: ext
        external: true
        ip: 192.168.101.1
    
    - vms:
      - name: controller 
        vcpus: 1
        ram: 2048 
        template: precise64.qcow2
        netdevs:
        - network: mgmt
          ip: 10.0.10.10
        - network: ext
          ip: 192.168.101.10
    
      - name: netnode 
        vcpus: 2
        ram: 1024 
        template: precise64.qcow2
        netdevs:
        - network: mgmt
          ip: 10.0.10.11
        - network: int
          ip: 10.0.20.11
        - network: ext
          ip: 192.168.101.11 
          
      - name: compute1 
        vcpus: 2
        kvm_nested: True
        ram: 2048 
        template: precise64.qcow2
        netdevs:
        - network: mgmt
          ip: 10.0.10.12
        - network: int
          ip: 10.0.20.12
  

• Nested KVM Hypervisor Support

    $ echo "options kvm-intel nested=1" | sudo tee /etc/modprobe.d/kvm-intel.conf
    $ sudo reboot
    $ cat /sys/module/kvm_intel/parameters/nested 
    Y
  

Issues

• Only tested on Ubuntu 12.04 boxes with intel cpu.
• Sometimes the base image generated by vmbuilder is not bootable. In that case, delete ubuntu-kvm directory and the base image under ~/.mykvm/base and run again init command to recreate a base image.