Issue with log rate limits in TAS 2.13.20 & 2.13.21

Products

• VMware Tanzu Application Service for VMs

Issue/Introduction

There is a known issue with Apps Manager in TAS 2.13.20 and 2.13.21 where the Apps Manager requires the fields for log rate limiting, but the CAPI is not able to handle that field. Thus, it results in errors as this feature comes from TAS 3.X and it has made its way to TAS 2.13 causing problems. The following screenshot shows the Apps Manager GUI for creating a task and the last field requires us to set the Log Rate Limit (per second) for the task:

When running Apps Manager on TAS 2.13.20 or 2.13.21, the issue presents itself by inability to create a task in Apps Manager (screenshot above) and inability to manually scale an application through Apps Manager. Both of those features are expecting the log rate limit field. It is important to note that autoscaling works fine, but any feature that requires the log rate limiting field is not operational and throws off errors that include the following:

Unknown field(s): 'log_rate_limit_in_bytes_per_second'

Environment

Product Version: 2.13

Resolution

With the release of TAS 3.X there has been a change in how the product handles the app log rate limitations. Operators can configure app log rate quotas for each org and space in a TAS for VMs v3.X deployment, as well as app log rate limits for individual apps so that noisy apps are no longer overwhelming Loggregator with app logs. The global log rate limit that measures app log rates in lines per second is deprecated in favor of per-app log rate limits that measure app log rates in bytes per second. As a result, the option to enable App log rate limit under App containers pane is now showing as “deprecated” in TAS 3.X versions.

However, the change has made its way to TAS 2.13.20 and 2.13.21 where in Apps Manager certain functionalities require to set the log rate limit field. Please note that this feature was not available in versions prior to TAS 2.13.20 and there is no mention of this change in the release notes.
 

Root cause

It was not intended for the newer granular log rate limiting feature to be available in TAS 2.13 and the errors we observed indicate that the log_rate_limit_in_bytes_per_second value is too new for this version and is only meant to be utilised and be visible in TAS 3.X. This is because TAS 2.13 is using CAPI 1.127.x which pre-dates the introduction of the newer log rate limiting feature in CAPI 1.137.0 that is available in TAS 3.X. Since this field is available in Apps Manager in TAS 2.13, but the CAPI is unable to handle it, it results in errors mentioned earlier.
 

Fix

The next release of TAS 2.13 which is expected to be 2.13.22 will contain the fix for this issue and remove this functionality from Apps Manager.