Vagrant Libvirt Provider
Note: Actual version (0.0.15) is still a development one. Feedback is welcome and can help a lot :-)
- Control local Libvirt hypervisors.
- Upload box image (qcow2 format) to Libvirt storage pool.
- Create volume as COW diff image for domains.
- Create private networks.
- Create and boot Libvirt domains.
- SSH into domains.
- Setup hostname and network interfaces.
- Provision domains with any built-in Vagrant provisioner.
- Synced folder support via
- Snapshots via sahara.
- Package caching via vagrant-cachier.
- Use boxes from other Vagrant providers via vagrant-mutate.
- More boxes should be available.
- Take a look at open issues.
Install using standard Vagrant 1.4.3+ plugin installation methods. After
vagrant up and specify the
libvirt provider. An example is shown below.
$ vagrant plugin install vagrant-libvirt
Possible problems with plugin installation on Linux
In case of problems with building nokogiri and ruby-libvirt gem, install missing development libraries for libxslt, libxml2 and libvirt.
In Ubuntu, Debian, ...
$ sudo apt-get install libxslt-dev libxml2-dev libvirt-dev
In RedHat, Centos, Fedora, ...
# yum install libxslt-devel libxml2-devel libvirt-devel
Vagrant Project Preparation
After installing the plugin (instructions above), the quickest way to get
started is to add Libvirt box and specify all the details manually within
config.vm.provider block. So first, add Libvirt box using any name you
want. This is just an example of Libvirt CentOS 6.4 box available:
$ vagrant box add centos64 http://kwok.cz/centos64.box
And then make a Vagrantfile that looks like the following, filling in your information where necessary. In example below, VM named test_vm is created from centos64 box and setup with 10.20.30.40 IP address.
Vagrant.configure("2") do |config| # If you are still using old centos box, you have to setup root username for # ssh access. Read more in section 'SSH Access To VM'. config.ssh.username = "root" config.vm.define :test_vm do |test_vm| test_vm.vm.box = "centos64" test_vm.vm.network :private_network, :ip => '10.20.30.40' end config.vm.provider :libvirt do |libvirt| libvirt.driver = "kvm" libvirt.host = "localhost" libvirt.connect_via_ssh = true libvirt.username = "root" libvirt.storage_pool_name = "default" # include as many of these addition disks as you want to libvirt.storage :file, #:path => '', # automatically chosen if unspecified! #:device => 'vdb', # automatically chosen if unspecified! #:size => '10G', # defaults to 10G if unspecified! :type => 'qcow2' # defaults to 'qcow2' if unspecified! end end
Libvirt Configuration Options
This provider exposes quite a few provider-specific configuration options:
driver- A hypervisor name to access. For now only kvm and qemu are supported.
host- The name of the server, where libvirtd is running.
connect_via_ssh- If use ssh tunnel to connect to Libvirt.
username- Username and password to access Libvirt.
password- Password to access Libvirt.
id_ssh_key_file- The id ssh key file name to access Libvirt (eg: id_dsa or id_rsa or ... in the user .ssh directory)
socket- Path to the libvirt unix socket (eg: /var/run/libvirt/libvirt-sock)
storage_pool_name- Libvirt storage pool name, where box image and instance snapshots will be stored.
Domain Specific Options
disk_bus- The type of disk device to emulate. Defaults to virtio if not set. Possible values are documented in libvirt's description for target.
memory- Amount of memory in MBytes. Defaults to 512 if not set.
cpus- Number of virtual cpus. Defaults to 1 if not set.
nested- Enable nested virtualization. Default is false.
cpu_mode- What cpu mode to use for nested virtualization. Defaults to 'host-model' if not set.
volume_cache- Controls the cache mechanism. Possible values are "default", "none", "writethrough", "writeback", "directsync" and "unsafe". See driver->cache in libvirt documentation.
kernel- To launch the guest with a kernel residing on host filesystems. Equivalent to qemu
initrd- To specify the initramfs/initrd to use for the guest. Equivalent to qemu
cmd_line- Arguments passed on to the guest kernel initramfs or initrd to use. Equivalent to qemu
Specific domain settings can be set for each domain separately in multi-VM environment. Example below shows a part of Vagrantfile, where specific options are set for dbserver domain.
Vagrant.configure("2") do |config| config.vm.define :dbserver do |dbserver| dbserver.vm.box = "centos64" dbserver.vm.provider :libvirt do |domain| domain.memory = 2048 domain.cpus = 2 domain.nested = true domain.volume_cache = 'none' end end # ...
Create Project - Vagrant up
In prepared project directory, run following command:
$ vagrant up --provider=libvirt
Vagrant needs to know that we want to use Libvirt and not default VirtualBox.
That's why there is
--provider=libvirt option specified. Other way to tell
Vagrant to use Libvirt provider is to setup environment variable
How Project Is Created
Vagrant goes through steps below when creating new project:
- Connect to Libvirt localy or remotely via SSH.
- Check if box image is available in Libvirt storage pool. If not, upload it to remote Libvirt storage pool as new volume.
- Create COW diff image of base box image for new Libvirt domain.
- Create and start new domain on Libvirt host.
- Check for DHCP lease from dnsmasq server.
- Wait till SSH is available.
- Sync folders and run Vagrant provisioner on new domain if setup in Vagrantfile.
Networking features in the form of
config.vm.network support private networks
Public Network interfaces are currently implemented using the macvtap driver. The macvtap driver is only available with the Linux Kernel version >= 2.6.24. See the following libvirt documentation for the details of the macvtap usage.
An examples of network interface definitions:
# Private network config.vm.define :test_vm1 do |test_vm1| test_vm1.vm.network :private_network, :ip => "10.20.30.40" end # Public Network config.vm.define :test_vm1 do |test_vm1| test_vm1.vm.network :public_network, :dev => "eth0", :mode => 'bridge' end
In example below, one network interface is configured for VM test_vm1. After
vagrant up, VM will be accessible on IP address 10.20.30.40. So if
you install a web server via provisioner, you will be able to access your
testing server on http://10.20.30.40 URL. But beware that this address is
private to libvirt host only. It's not visible outside of the hypervisor box.
If network 10.20.30.0/24 doesn't exist, provider will create it. By default created networks are NATed to outside world, so your VM will be able to connect to the internet (if hypervisor can). And by default, DHCP is offering addresses on newly created networks.
The second interface is created and bridged into the physical device 'eth0'. This mechanism uses the macvtap Kernel driver and therefore does not require an existing bridge device. This configuration assumes that DHCP and DNS services are being provided by the public network. This public interface should be reachable by anyone with access to the public network.
Private Network Options
Note: These options are not applicable to public network interfaces.
There is a way to pass specific options for libvirt provider when using
config.vm.network to configure new network interface. Each parameter name
starts with 'libvirt__' string. Here is a list of those options:
:libvirt__network_name- Name of libvirt network to connect to. By default, network 'default' is used.
:libvirt__netmask- Used only together with
:ipoption. Default is '255.255.255.0'.
:libvirt__dhcp_enabled- If DHCP will offer addresses, or not. Used only when creating new network. Default is true.
:libvirt__adapter- Number specifiyng sequence number of interface.
:libvirt__forward_mode- Specify one of
routeoptions. This option is used only when creating new network. Mode
nonewill create isolated network without NATing or routing outside. You will want to use NATed forwarding typically to reach networks outside of hypervisor. Routed forwarding is typically useful to reach other networks within hypervisor. By default, option
:libvirt__forward_device- Name of interface/device, where network should be forwarded (NATed or routed). Used only when creating new network. By default, all physical interfaces are used.
:mac- MAC address for the interface.
Public Network Options
:dev- Physical device that the public interface should use. Default is 'eth0'.
:mode- The mode in which the public interface should operate in. Supported modes are available from the libvirt documentation. Default mode is 'bridge'.
:mac- MAC address for the interface.
Vagrant-libvirt uses a private network to perform some management operations on VMs. All VMs will have an interface connected to this network and an IP address dynamically assigned by libvirt. This is in addition to any networks you configure. The name and address used by this network are configurable at the provider level.
management_network_name- Name of libvirt network to which all VMs will be connected. If not specified the default is 'vagrant-libvirt'.
management_network_address- Address of network to which all VMs will be connected. Must include the address and subnet mask. If not specified the default is '192.168.121.0/24'.
You may wonder how vagrant-libvirt knows the IP address a VM received.
Libvirt doesn't provide a standard way to find out the IP address of a running
domain. But we do know the MAC address of the virtual machine's interface on
the management network. Libvirt is closely connected with dnsmasq, which acts as
a DHCP server. dnsmasq writes lease information in the
directory. Vagrant-libvirt looks for the MAC address in this file and extracts
the corresponding IP address.
SSH Access To VM
There are some configuration options for ssh access to VM via
Vagrantfile. Untill provider version 0.0.5, root user was hardcoded and used to
access VMs ssh. Now, vagrant user is used by default, but it's configurable via
config.ssh.username option in Vagrantfile now.
If you are still using CentOS 6.4 box from example in this README, please set ssh username back to root, because user vagrant is not usable (I forgot to add necessary ssh key to his authorized_keys).
Configurable ssh parameters in Vagrantfile after provider version 0.0.5 are:
config.ssh.username- Default is username vagrant.
config.ssh.guest_port- Default port is set to 22.
config.ssh.forward_agent- Default is false.
config.ssh.forward_x11- Default is false.
vagrant-libvirt supports Forwarded Ports via ssh port forwarding. For each
forwarded_port directive you specify in your Vagrantfile, vagrant-libvirt
will maintain an active ssh process for the lifetime of the VM.
vagrant-libvirt supports bidirectional synced folders via nfs or 9p and unidirectional via rsync. The default is nfs. Vagrant automatically syncs the project folder on the host to /vagrant in the guest. You can also configure additional synced folders.
You can change the synced folder type for /vagrant by explicity configuring it an setting the type, e.g.
config.vm.synced_folder './', '/vagrant', type: 'rsync'
You can view an example box in the example_box/directory. That directory also contains instructions on how to build a box.
The box is a tarball containing:
- qcow2 image file named
metadata.jsonfile describing box image (provider, virtual_size, format).
Vagrantfilethat does default settings for the provider-specific configuration for this provider.
To work on the
vagrant-libvirt plugin, clone this repository out, and use
Bundler to get the dependencies:
$ git clone https://github.com/pradels/vagrant-libvirt.git $ cd vagrant-libvirt $ bundle install
Once you have the dependencies, verify the unit tests pass with
$ bundle exec rake
If those pass, you're ready to start developing the plugin. You can test
the plugin without installing it into your Vagrant environment by just
Vagrantfile in the top level of this directory (it is gitignored)
that uses it. Don't forget to add following line at the beginning of your
Vagrantfile while in development mode:
Now you can use bundler to execute Vagrant:
$ bundle exec vagrant up --provider=libvirt
IMPORTANT NOTE: bundle is crucial. You need to use bundled vagrant.
- Fork it.
- Create your feature branch (
git checkout -b my-new-feature).
- Commit your changes (
git commit -am 'Add some feature').
- Push to the branch (
git push origin my-new-feature).
- Create new Pull Request.