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Introduction

Currently CloudStack has following 3 deployment planners available out-of-the-box:

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• Expose deployment planner as part of a ServiceOffering API. By default, the value can be set to the default CS FirstFitPlanner, but admin can override it and set some other strategy as per needs.
• Add a resource reservation mechanism to let deployment planners co-exist

Resource reservation between planners

When the Deployment planner gets exposed per ServiceOffering, then in a CS deployment multiple planners will have to co-exist.

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e.g Refer to the Implicit Dedication Planner being added as part of this 4.2 release.

Design

1. Planner Choice in ServiceOffering:
   1. Admin can set a deployment_planner to be used while creating a service offering. Changes are needed to createServiceOffering API to add a deployment_planner.
   2. During VM deployment, each planner can check if it is supposed to execute based on the ServiceOffering of the VM being deployed. DeploymentPlanner :: canHandle() can be modified to do this check.
2. Reservation Mechanism:
   1. As part of the Affinity feature, a new manager on top of deployment planners is added, called as the DeploymentPlanningManager. This manager can handle the resource reservation as well.
   2. Currently, the DPM invokes the planners to find suitable host and storage pools for the VM being deployed.
   3. After a planner finds a host to use, DPM can make a check if that host is reserved by any planner explicitly or if it can be shared across planners.

   4. Wiki Markup
      When a planner like the \[Implicit Dedication Planner\] chooses a host for deployment, DPM can store it as a 'dedicated' host. No other planner will be able to pick it up for any other VM deployment.

   5. VMs deployed through FirstFitPlanner, UserDispersingPlanner and UserConcentratedPodPlanner can share hosts - so DPM can mark those hosts as 'shared'.
   6. DPM will store this reservation info in a separate table 'op_host_planner_reservation'
   7. Also in order to free up the reservations, DPM can listen to VM state transitions. When a VM is stopped, DPM can check if the host has no other VMs. If yes, it can free up the reservation so that it can be picked up by other planner.

API Changes

1. listDeploymentPlanners Admin API - This will be a new API that will let Admin list the available set of deployment planners.
2. createServiceOffering API changes - Following new field will be added to this API
   1. deploymentplanner - String value (default: 'FirstFitPlanner' )

DB Changes

1. Additional column to service_offering:
   ALTER TABLE `cloud`.`service_offering` ADD COLUMN `deployment_planner` varchar(255) NOT NULL DEFAULT 'FirstFitPlanner'  COMMENT 'Planner heuristics used to deploy a VM of this offering';
2. A new table to store planner reservations. Following are some columns needed:
   CREATE TABLE `cloud`.`op_host_planner_reservation` (
     `id` bigint unsigned NOT NULL auto_increment,
     `data_center_id` bigint unsigned NOT NULL,
     `pod_id` bigint unsigned,
     `cluster_id` bigint unsigned,
     `host_id` bigint unsigned,
     `account_id` bigint unsigned,
     `domain_id` bigint unsigned,
     `deployment_planner` int(1) unsigned NOT NULL COMMENT 'Name of the Planner',
     `resource_type` datetime COMMENT 'shared(0) Vs dedicated(1)',
     PRIMARY KEY  (`id`),
     INDEX `i_op_host_capacity__host_type`(`host_id`, `resource_type`)
   ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

UI Changes

Following UI changes are needed:

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