From 74f18b9c3ed5391d1300795816041e0d5a43d3a9 Mon Sep 17 00:00:00 2001 From: Sergio Rubio Date: Sun, 16 Dec 2012 00:18:24 +0100 Subject: [PATCH] [xenserver|docs] added creating_servers.md tutorial --- .../xenserver/examples/creating_servers.md | 168 ++++++++++++++++++ 1 file changed, 168 insertions(+) create mode 100644 lib/fog/xenserver/examples/creating_servers.md diff --git a/lib/fog/xenserver/examples/creating_servers.md b/lib/fog/xenserver/examples/creating_servers.md new file mode 100644 index 000000000..a01c4ffe3 --- /dev/null +++ b/lib/fog/xenserver/examples/creating_servers.md @@ -0,0 +1,168 @@ +# Creating servers (VMs) and templates + +The basic server creation steps are detailed in the getting started tutorial. + +Now let's do something a little bit more complex and probably more useful in +day-to-day operations. That is: + +1. Uploading a VHD image. +2. Create a new template with it. +3. Spin a new server using the recently added template. + +## Part I: Upload the VHD + +Assuming we have an image file 'ubuntu.vhd' ready to be uploaded, let's create +the connection to the XenServer host and upload the image to the storage repository, +using SSH. The code also assumes that you have a file storage repository mounted +somewhere in /var/run/sr-mount/#{sr-UUID} (the standard XenServer base directory +for mounted storage repositories). + + require 'fog' + require 'net/scp' + require 'uuidtools' + + # + # Create the connection to the XenServer host + # + xenserver = Fog::Compute.new({ + :provider => 'XenServer', + :xenserver_url => 'xenserver-test', + :xenserver_username => 'root', + :xenserver_password => 'secret', + }) + + +We'll be uploading the image to the "Local File SR" storage repository, so +we need the reference to this SR (Storage Repository): + + sr = xenserver.storage_repositories.find { |sr| sr.name == "Local File SR" } + +XenServer uses UUIDs to store images in the storage repositories, so we will +emulate that behavior, creating a new UUID for our image and uploading it. + + # + # Use the excelent uuidtools gem to create the new UUID + # for the image + # + image_uuid = UUIDTools::UUID.random_create.to_s + + +To upload the new image using SCP, we need the destination directory, where the +SR is mounted. In our case, the storage repository mount point is +/var/run/sr-mount/#{sr.uuid} (where sr.uuid is the UUID of the storage +repository). We will upload the new image there: + + sr_mount_point = "/var/run/sr-mount/#{sr.uuid}" + # Target image file path. We will upload the local image to the destination + # using SCP + destination = File.join(sr_mount_point, "#{image_uuid}.vhd") + # source image, located in the current directory + source = 'ubuntu.vhd' + # Use the XenServer root credentials to upload + Net::SSH.start('xenserver-test', 'root', :password => 'secret') do |ssh| + ssh.scp.upload!(source, destination) do |ch, name, sent, total| + # print progress + p = (sent.to_f * 100 / total.to_f).to_i.to_s + print "\rProgress: #{p}% completed" + end + end + +We need to let the XenServer know, that there's a new image: + + sr.scan + +Now that XenServer is aware of the new image, get its reference +and set the image name attribute to 'ubuntu-template' + + ubuntu_vdi = xenserver.vdis.find { |vdi| vdi.uuid == image_uuid } + ubuntu_vdi.set_attribute 'name_label', 'ubuntu-template' + +Good! the image is ready to be used. + +## Part II: create the server template + +We have the image ready to be used by our new template. + +Templates are regular servers, so let's create one with 512 MB of RAM, 1 CPU +and a network card. The main difference with a regular server from an API +point of view is that we will not start it. + +We will also create the template as PV (paravirtual): + + server_mem = (512 * 1024 * 1024).to_s + server = xenserver.servers.new :name => "ubuntu-template", + # Required when using Server.new + :affinity => xenserver.hosts.first, + :other_config => {}, + :pv_bootloader => 'pygrub', # PV related + :hvm_boot_policy => '', # PV related + :pv_args => '-- console=hvc0', # PV related + :memory_static_max => mem, + :memory_static_min => mem, + :memory_dynamic_max => mem, + :memory_dynamic_min => mem + server.save + +We need to attach the disk image to a VBD and to the server + + xenserver.vbds.create :server => server, :vdi => ubuntu_vdi + +Note that we're using Server.new here, instead of Server.create. +Server.create would start the server, and that's not what we want here. + +Let's add the NIC (VIF or virtual interface) to the server. + +I have a network in my XenServer named "Pool-wide network associated with eth0" +bridged to the physical eth0 NIC and I will attach the new NIC to that network. + +Don't be scared by the VIF creation code. There are easier ways to create a +VIF, and we'll be dealing with that and some other cases in the networking +tutorial (TODO). + +First, let's find the network since we'll need the reference. + + net = xenserver.networks.find { |n| n.name == 'Pool-wide network associated with eth0' } + +To create the VM VIF, we need to set some attributes and use the +create_vif_custom request: + + vif_attr = { + 'MAC_autogenerated' => 'True', + 'VM' => server.reference, # we need the VM reference here + 'network' => net.reference, # we need the Network reference here + 'MAC' => '', # ignored, since we use autogeneration + 'device' => '0', + 'MTU' => '0', + 'other_config' => {}, + 'qos_algorithm_type' => 'ratelimit', + 'qos_algorithm_params' => {} + } + xenserver.create_vif_custom vif_attr + + +The template is now ready to be used and we can list it! + + xenserver.servers.custom_templates.find { |t| puts t.name } + +## Party III: spin a new server using the brand new template + +Now that we have the template in place, it's easy to create as many servers +as you want. All of them will share hardware specs with the template. That is, +512 MB of RAM, 1 CPU, 1 NIC attached to the 'Pool-wide network...': + + xenserver.servers.create :name => 'my-brand-new-server', + :template_name => 'ubuntu-template' + + +# The End + +Pretty similar code is used by knife-xenserver (http://github.com/bvox/knife-xenserver) +to upload new templates. Have a look at it if you're interested, it's full of +examples and fog/xenserver tricks to manage XenServer/XCP hosts. + +The full source code used in this tutorial is available at: + +https://github.com/bvox/fog-xenserver-examples/blob/master/upload_template_and_create.rb + +Enjoy! +