ManageIQ: New VM disk configuration

In ManageIQ, virtual machine deployment is started using the standard configuration dialog. The standard dialog allows you to set basic VM parameters, but it has its limitations, for example, on adding disks. Let’s consider the advanced configuration of the VM disk subsystem (deployment on the VMware vSphere virtualization platform).

Statement of the problem: When cloning a VM from a template, it is necessary to:

• ensure the ability to add the required number of additional disks;
• all disks, including additional ones, must be thin format;
• to connect additional disks, it is necessary to create a separate SCSI controller of the ‘VMware Paravirtual’ type.

All files, paths to files and scripts described in the article have been tested and are relevant for the current version of MIQ at the time of writing – Quinteros-2.

Thin disks

To create a new deployment, we use the create_provision_request request, all the parameters of the server being created are defined in the passed array of arguments:

# Launching a request to create a new deployment
request = $evm.execute('create_provision_request', *args)

Many deployment parameters coincide with the attributes of REST API calls: provision_requests, the list of supported parameters: provision_attributes. However, “many” does not mean “all”, and the REST API guide is not suitable as a universal source of information. The most complete and up-to-date documentation on working with ManageIQ is its open source code, I recommend that you study it when solving your problems.

The gem manageiq-providers-vmware is responsible for interaction with VMware vSphere in MIQ; on the MIQ server, gems are located in /opt/manageiq/. The gem code handles the disk_format attribute (see the disk.rb file) in the build_disk_relocate_spec function:

...
def build_disk_relocate_spec(datastore)
...
  case get_option(:disk_format)
  when 'thin'
    bck.thinProvisioned = "true"
  when 'thick'
    bck.thinProvisioned = "false"
    bck.eagerlyScrub = "false"
  when 'thick_eager'
    bck.eagerlyScrub = "true"
    bck.thinProvisioned = "false"
  end
...

According to this code, to get thin disks when creating a VM deployment request, you need to pass an additional attribute disk_format with the value “thin” (this attribute is also in the REST API description). Passing the disk_format attribute will only affect the “primary” disks of the VM cloned from the template.

Creating additional disks in ManageIQ

To create additional disks, you must pass an array of disk parameters in the disk_scsi attribute. Configurations of future disks (disk.rb) are formed from the parameters in the add_disk method. Configurations for additional controllers are created using the add_scsi_controller method. Controller settings are passed via the ctrl_scsi attribute.

Setting up the new VM deployment parameters in automation scripts is done in / ManageIQ / Infrastructure / VM / Provisioning / StateMachines / Methods / vmware_PreProvision. We have modified this method to configure disks according to our technical requirements:

• The required number of disks is added to the new VM (line 35 of the code fragment);
• If there are additional disks, a dedicated SCSI controller is created for them (line 34);
• All disks are created in thin format (line 20);
• The method is universal, the number of disks in the code is unlimited (line 30).

...
def initialize(handle = $env)
  ...
  @set_disks = true
end

...

def input_fields_data(prefix)
  inputs = prov.options.merge(prov.get_option(:ws_values) || {})
  inputs.filter { |key, _value| key.start_with?(prefix) }
        .map { |key, value| [key.to_s.scan(/\d+/).first.to_i, value] }
        .sort.to_h.values
end

def disk_config(size, index)
  { bus: 1,
    pos: index + ((index >= 7 && 1) || 0),
    sizeInMB: size * 1024,
    backing: { thinprovisioned: true } }
end

def scsi_config
  { busnumber: 1,
    devicetype: 'ParaVirtualSCSIController' }
end

def set_disks
  log(:info, 'Processing set_disks...', true)
  disks = input_fields_data('add_disk')
          .map(&:to_i).select(&:positive?)
          .map.with_index { |size, index| disk_config(size, index) }
  if disks.any?
    prov.set_option(:ctrl_scsi, scsi_config)
    prov.set_option(:disk_scsi, disks)
    log(:info, "Provisioning object <:disk_scsi> updated with <#{disks}>")
  end
  log(:info, 'Processing set_disks...Complete', true)
end

...

def process_customization
  ...
  set_disks if @set_disks
end
...

All that remains is to transfer the required parameters… Add fields to the vm order form, the names of which correspond to the format ‘add_diskN’, where N is the disk number, an integer. When entering a positive number in any such field, a disk of the specified size (in GiB) will be added to the VM configuration. The order of connecting disks to the controller corresponds to the order of the form field numbers.

Files to the article

vmware_PreProvision – full code of the modified VM setup script