VMOMI - VMware vSphere API Perl Bindings


    use VMOMI;

    stub = new VMOMI::SoapStub(host => $host) || die "Failed to initialize VMOMI::SoapStub";
    $instance = new VMOMI::ServiceInstance(
        new VMOMI::ManagedObjectReference(
            type  => 'ServiceInstance',
            value => 'ServiceInstance',

    # Login
    $content = $instance->RetrieveServiceContent;
    $session = $content->sessionManager->Login(userName => $user, password => $pass);

    @vms = VMOMI::find_entities($content, 'VirtualMachine');
    foreach (@vms) {
        print $_->name . ", " . $_->config->guestFullName . "\n";

    # Logout


    apk add openssl-dev libxml2-dev
    cpanm install VMOMI


VMOMI provides an alternative to the VMware Perl SDK for vSphere and was created to address some limitations with the offical VMware Perl SDK.

  • Preserve main:: namespace by avoid globals and the import of all API classes

  • Reduce memory footprint through Class::Autouse

  • Enable installation through CPAN

Finding ManagedEntities

Managed entities in the VMware vSphere Web Service inventory, e.g. VirtualMachine or HostSystem, can be fetched with the utilty function VMOMI::find_entities():

    @vms = VMOMI::find_entities($content, 'VirtualMachine', { 'config.guestFullName' => qr/Linux/ });
    @hosts = VMOMI::find_entities($content, 'HostSystem');

$content should be an authenticated instance of VMOMI::ServiceContent:

    $stub = new VMOMI::SoapStub(host => $host);
    $instance = new VMOMI::ServiceInstance(
        new VMOMI::ManagedObjectReference(
            type  => 'ServiceInstance',
            value => 'ServiceInstance',
    $content = $instance->RetrieveServiceContent;
    $session = $content->sessionManager->Login(userName => $user, password => $pass);

Working with ManagedObjectReferences

The VMware vSphere Web Service API primarily works through ManagedObjectReferences (moref). Most SDKs therefore generate "view classes" of the common objects managed through the API, e.g. VirtualMachine, HostSystem, Folder, Datacenter, ClusterComputeResource, etc.

VMOMI provides similar, manually generated classes for these managed objects. During deserialization of the vSphere Web Service API, ManagedObjectReferences are automatically instantiated to corresponding "view classes". The underlying ManagedObjectReference can be accessed through the moref property. ManagedObjectReference consists of two properties type and value:

    $vm = VMOMI::find_entities($content, 'VirtualMachine', { name => qr/TestVM2/ })->shift;
    $moref = $vm->moref;
    print $moref->type . ":" . $moref->value . "\n"; # 'VirtualMachine:vm-12'

"View" classes can instantiated using known, valid ManagedObjectReference type and value properties along with a current, authenticated connection stub:

    $vm = new VMOMI::VirtualMachine(
        new VMOMI::ManagedObjectReference
            type => 'VirtualMachine', 
            value => 'vm-12'),
    print $vm->name . "\n"; # TestVM2


Support for JSON::XS object serialization is available through the TO_JSON method on the SDK classes, which may be of benefit for storing objects or integration with NoSQL databases.

    $coder = JSON::XS->new->convert_blessed->pretty;
    $encoded_json = $coder->encode($session);
    print $encoded_json;
       "lastActiveTime" : "2017-05-03T13:17:03.152908Z",
       "extensionSession" : 0,
       "key" : "52956fcc-bab5-ad78-9ca8-8a773192c2d1",
       "locale" : "en",
       "ipAddress" : "",
       "fullName" : "Administrator vlab.local",
       "userName" : "VLAB.LOCAL\\Administrator",
       "loginTime" : "2017-05-03T13:17:03.152908Z",
       "messageLocale" : "en",
       "userAgent" : "Perl/VMOMI",
       "_ancestors" : [
       "callCount" : "0",
       "_class" : "UserSession"

Two additional properties are added to the JSON encoded string, _class and _ancestors. _class is the object's class name and _ancestors provides the class inheritance in descending order.

Performance Considerations

Properties are only retrieved from the vSphere Web Services API on access through AUTOLOAD, and as such, can impact performance in iterations. The following logic will invoke three API calls to vSphere for each virtual machine:

    @vms = VMOMI::find_entities($content, 'VirtualMachine');
    foreach (@vms) {
        print $_->name . ": " . $_->runtime->powerState . "\n"; # three API invocations

As future enhancement, preserving values previously fetched from the API to avoid reptitive calls would improve performance. As a work around, pulling requested properties in bulk through PropertyCollector.RetrievePropertiesEx or PropertyCollector.WaitForUpdatesEx and parsing them into a data structure will provide the best performance.


Reuben M. Stump


VMware vSphere Web Services SDK Documentation

vSphere SDK for Perl Documentation


This code is distributed under the Apache 2 License. The full text of the license can be found in the LICENSE file included with this module.


Copyright (c) 2015 by Reuben M. Stump