In itopia's Cloud Automation Stack (CAS), Collection Pools allow you to create unique sets of RD Session Host servers and configuration settings for different workloads and users. Each Collection Pool lets you define the following:

When users are created (or imported) in CAS, they are assigned to a Collection Pool. Users can access their Collection Pool resources in several ways; refer to Connection Options for CAS RDS Deployments for more information.

When you create a new deployment in CAS, the CAS Deployment Wizard walks you through configuring your first Collection Pool. To configure additional Collection Pools, log in to the itopia CAS Admin Portal and navigate to Cloud Desktops → Collection Pools.

To create a new Collection Pool, click Create. To view or change the settings of an existing pool, click on the Collection Pool name and then click the Edit button.

The sections below will describe the settings available for Collection Pools. Note that some Collection Pool settings cannot be changed after the Pool is created.

Provide the basic details for your Collection Pool.

If you have enabled Sole-tenant node support in the Deployment Settings, you can deploy the Collection Pool to a sole-tenant node group in your GCP project. If you enable this option, you will also see two additional Collection Pool Types for Windows 10 Session Hosts, as Windows 10 can only be deployed on sole-tenant nodes.

CAS supports multiple Collection Pool types, offering different user experiences based on the requirements for your workload. For more information, refer to Collection Pool Types This setting cannot be edited once the Collection Pool is created.

Each Collection Pool can be deployed across multiple regions. When creating a new Collection Pool, you will have the option to select the GCP regions to include in the Pool. For each region, CAS will create an RD Collection with identical settings, and users will have access to the RD Collection in each region. When users connect through the Cloud VDI Portal, they will be directed to their nearest region; refer to the Nearest Connection Point documentation for more information.

The Host Configuration section contains the parameters for the Session Host VM instances that will be created for your Collection Pool as well as autoscaling parameters.

Collection Scaling refers to the way in which CAS maintains the correct number of Session Hosts to support the users assigned to the Collection Pool. The behavior of this feature depends on the type of Collection Pool.

CAS offers two options for scaling the number of Session Hosts in a Shared Collection Pool or Windows 10 Pooled Collection: Autoscale and Fixed Collection Sizing.

When Autoscale is enabled, CAS will automatically create enough Session Hosts to support all users that are assigned to the Collection Pool based on the number of Users per instance that is configured in the Host Instance Configuration section above. For example, if you have configured 25 Users per instance and assign 100 users to the Collection Pool, CAS will create 4 Session Host servers (in each region).

Fixed Collection Sizing allows administrators to define the number of concurrent users for each region in a Collection Pool. If all users will not be connecting to the Collection Pool simultaneously, you can use Fixed Collection Sizing to set the number of concurrent users that CAS should target for its scaling configuration.

Using our previous example: you configure 25 Users per instance and you assign 100 users to the Collection Pool. However, you expect only 50 users to connect at any given time.

When you enable Fixed Collection Sizing, you can specify these limits in the Collection Pool, and CAS will automatically create the appropriate number of Session Hosts based on the sizing you specify. Therefore in this example, CAS will create only 2 Session Hosts rather than 4.

Fixed Collection Sizing is also useful for multi-region deployments. Continuing our example: let's say the new Collection Pool includes two regions; the first region, us-east4, will host approximately 75 users, and the secondary region, us-central1, will host 25.

You can enable Fixed Collection Sizing and specify the number of users per region, resulting in 3 Session Hosts in us-east4 and 1 Session Host in us-central1. If you don't specify per-region limits, CAS will create enough Session Hosts in each region to serve all 100 users in the deployment.

You can change the Fixed Collection Size at any time or switch to Autoscale, and CAS will create or delete Session Hosts to match the updated number of users automatically.

For Collection Pools configured as Dedicated or Windows 10 Dedicated Desktop, CAS will always maintain a 1:1 ratio of Session Hosts to the number of users assigned. Therefore, Autoscale and Fixed Collection Sizing options do not apply.

However, you can configure the Collection Pool to maintain a number of Unassigned Hosts, which are Session Hosts that are created, configured, and powered down until new users are added to the Collection Pool; this greatly reduces the amount of time required to assign users to the Pool, as their dedicated Session Hosts will only need to be powered on, rather than created from scratch.

For example, you create a Dedicated Collection Pool and configure it to maintain 10 Unassigned Hosts. You then assign 10 users to the Collection Pool. In this scenario, CAS will create and configure 10 Session Hosts and assign them to the 10 users; once the Session Hosts are configured and assigned, CAS will then create 10 additional Session Host VMs and power them down. These additional VMs will remain powered down until new users are added to the Collection Pool.

If you later add 20 users to the Collection Pool, CAS will:

Thus, if you anticipate regularly adding users to Collection Pools, it is useful to enable Unassigned Hosts and specify a quantity larger than the number of users you normally add. This will ensure that Unassigned Hosts are always available for new users and they can begin using their Cloud Desktops very quickly.

Note that Unassigned Hosts incur storage costs in Google Cloud for their OS disk.

Each Collection Pool can be configured with a unique sizing and user density parameters.

Each Collection Pool can use a unique disk image to provide different Session Host experiences for end-users. For example, you can prepare two different disk images-- one for your Accounting team and one for your Design team-- that have different applications and settings defined. You can assign each disk image to a different Collection Pool to ensure each team gets the best user experience on dedicated servers for their needs.

CAS allows you to specify custom GCP metadata labels for all Session Host VMs in a Collection Pool. Metadata labels can be used in a variety of ways in Google Cloud such as for billing reports and crafting custom policies. Add as many custom GCP labels as you wish; these labels will be applied to each Session Host VM in the Collection Pool.

The Dynamic Uptime feature allows CAS to shut down and power on Session Hosts as required based on the number of active users. A detailed explanation of the feature is available in Understanding the Dynamic Uptime Feature.

Collection Pools simplify the installation of Google Cloud's Stackdriver agents on Session Hosts. In each Collection Pool, administrators can choose to separately enable the the Stackdriver Monitoring Agent and Stackdriver Logging Agents on Session Host servers. These agents can then be configured in the Google Cloud Console to provide metrics and alerting based on custom criteria.

To learn more, please review How to Use Stackdriver Logging.

When creating a new Collection Pool, administrators have several options for configuring user profile behavior. This setting cannot be edited once the Collection Pool is created.

Each Collection Pool allows administrators to configure the behavior of user sessions on Cloud Desktops. These settings are enforced using a combination of group policy objects (GPOs), registry keys (for Windows 10 Collections), and Connection Broker settings (for RDS Collections). These settings include:

Additionally, servers for each Collection Pool are created in a dedicated organizational unit (OU) in Active Directory. Administrators can define group policy objects (GPOs) and link them to the OU for specific Collection Pools to further customize the end-user experience for each collection.

If you're creating a new Collection Pool, click Create; if you're updating settings on an existing Collection Pool, click Save. The Collection Pool will appear in the list of Collection pools with an orange status icon. When the status icon is green, you may assign the Collection Pool to users; they will be configured to use the new Collection Pool the next time they download an RDP connection file from the Cloud VDI Portal.

CAS Collection Pools are persistent by default, meaning that Session Hosts are not regularly deleted and re-created. However, administrators can trigger a redeployment of the Session Hosts in one of two ways:

When a redeployment occurs, the Session Host VM instances are deleted and a new VM instance is created using the Boot Image specified for the Collection Pool; all data on the hosts is permanently deleted. However, the server names and IP addresses are reused.

Depending on the size of the Boot Image, this process typically takes between 30-60 minutes per Session Host. When redeploying an entire Collection Pool; CAS will redeploy several Session Hosts concurrently, but this process may still take considerable time for large Collection Pools.

CAS can automatically redeploy all Session Hosts in a Collection Pool. This is useful if you have updated the base OS image for the Collection and wish to standardize the image across all hosts; however, you can also trigger a redeployment without changing the OS image to simply rebuild all servers using the existing OS image. Learn more about Boot Images in Creating OS Images.

To redeploy all Session Hosts in a Collection Pool:

If a specific Session Host has become corrupted or is experiencing issues, you can redeploy it individually. This will remove the Session Host from the Collection Pool, delete and recreate the VM instance using the same configuration and Boot Image specified in its Collection Pool settings, and then rejoin it to the Collection Pool. The new VM will have the same name and IP address, but all data and customization will be erased.

To redeploy a single Session Host:

You can monitor the status of the redeployment in the VM Instances module. the VM status icon will change to orange while it is being redeployed, and will change to green when it has been successfully re-added to the Collection Pool.