Windows Diego Cells in Isolation Segments

This topic describes how to run Windows Diego Cells in isolation segments, which are compartmentalized resource pools for Diego Cells.

Diego Cells in one isolation segment share routing, computing, and logging resources with other Diego Cells in the same segment, and do not use resources from other isolation segments.

Overview

To run Windows Diego Cells in multiple isolation segments, you must create and install multiple VMware Tanzu Application Service for VMs [Windows] tiles and configure each to run in a different isolation segment.

To create multiple copies of the TAS for VMs [Windows] tile, see Replicate a Tile.

To associate a TAS for VMs [Windows] tile with an isolation segment, so that its Diego Cells run in that segment, see Assign a Tile to an Isolation Segment.

Prerequisites

To run a Windows Diego Cell in a particular isolation segment, the isolation segment must first already exist in the Cloud Controller database (CCDB) before the Windows Diego Cell can be assigned to it.

To create an isolation segment in the CCDB, see Create an Isolation Segment in Managing Isolation Segments.

Replicate a Tile

To make multiple copies of the TAS for VMs [Windows] tile that you can assign to different isolation segments, you must use the Replicator tool.

To use the Replicator tool:

Download the Replicator tool from the VMware Tanzu Application Service for VMs [Windows] page on VMware Tanzu Network.
Navigate to the directory where you downloaded the Replicator tool.
Replicate the tile by running:
```
replicator-windows -name "TILE-NAME" -path PATH-TO-ORIGINAL -output PATH-TO-COPY
```
Where:
- TILE-NAME is a unique name for the new TAS for VMs [Windows] tile. The name must be ten or fewer characters in length and contain only alphanumeric characters, dashes, underscores, and spaces.
- PATH-TO-ORIGINAL is the absolute path to the original .pivotal TAS for VMs [Windows] tile you downloaded from VMware Tanzu Network.
- PATH-TO-COPY is the absolute path for the copy of the .pivotal TAS for VMs [Windows] tile that the Replicator tool produces.
For example:
```
C:\Users\admin\> replicator-windows -name "Shiny Tile" ^
-path c:\downloads\TileOriginal.pivotal ^
-output c:\temp\TileCopy.pivotal
```
Install and configure the Windows isolation segment, using the new .pivotal file and, following the procedures in Installing and Configuring TAS for VMs [Windows], starting with the Import a Product step of Install the Tile.

Assign a Tile to an Isolation Segment

To assign a TAS for VMs [Windows] tile to an isolation segment:

Select App Containers.
Under Segment name, enter the name for the isolation segment to associate the tile with. If you are creating a new isolation segment, ensure that this name is unique across your deployment.
(Optional) To limit the number of log lines each app instance in your isolation segment can generate per second, select Enable under App log rate limit (beta) and enter an integer for Maximum app log lines per second. At minimum, VMware recommends using the default limit of 100. This feature is disabled by default. Enabling this feature prevents app instances from overloading the Loggregator Agent with logs, so the Loggregator Agent does not drop logs for other app instances. Enabling this feature also prevents apps from reporting inaccurate app metrics in the cf CLI or increasing the CPU usage on the Diego Cell VM. You can use this value to monitor the AppInstanceExceededLogRateLimitCount metric for the number of app instances that exceed the log rate limit.
Click Save.