Appsmanager not loading the metrics in UI

Products

• VMware Tanzu Application Service

Issue/Introduction

The Appsmanager will not show any metrics for the spaces in the UI like the below image

For the same spaces when accessed from the cf cli, we can see the metrics for the apps running.

Cause

This is due to the request header data which is too long. Currently, that's set at around 8KB of data and our internal web server is rejecting the request.

You can collect the HAR file using the steps mentioned in this KB https://knowledge.broadcom.com/external/article/293696/how-to-capture-and-preserve-network-requ.html and check the header size to confirm the same.

The reason that we have this issue is due to the increased setting of  "per UI page" or "per_page" value in apps manager in recent versions to 500.

In the newer versions we discovered that we can scale that value back down to 50 where headers will no longer be overloaded.

Resolution

To fix in the current version you are running you can follow the below steps.

Set the `per_page` value of the apps manager to a lower value

1. 1. Obtain the list of environment variables for apps_manager
   2. `cf env apps-manager-js-green`
   3. Update the `API_PER_PAGE` value to something lower, like 100. The default is 50 in later versions of apps manager
   4. `cf set-env apps-manager-js-green API_PER_PAGE 100`
   5. Restage the apps-manager-js-green  -- this will restart all the instances 

 

 The performance improvement for apps man was introduced in v6.0.11 which defaults this value down to 50.