Increased latency observed after Tanzu Application Service upgrade

Products

• VMware Tanzu Application Service

Issue/Introduction

Increased response time occurs after upgrading Tanzu Application Service (TAS) from version 6.0.7 to 10.2.6. Latency remains higher than observed on TAS 6 even after deploying a version containing the Go 1.26.x package fix.

Environment

• Tanzu Application Service 10.2.x
• Gorouter

Cause

Tanzu Application Service introduces changes to the communication protocol between Gorouter and backend applications across versions:

• Version 6.0: Uses TLS exclusively.
• Version 10.0: Introduces the ability to use mTLS, though TLS remains the default.
• Version 10.2: Changes the default protocol to mTLS, which introduces additional overhead. The option to revert to TLS remains available.
• Version 10.3: Uses mTLS exclusively.

The observed latency in version 10.2 stems from this default shift to Mutual TLS (mTLS) for Gorouter communication.

Resolution

The latency decreases after reverting the Gorouter configuration from mTLS to standard TLS. For that go to TAS/ERT -> App Containers -> Gorouter and TCP Router app identity verification and move from"Gorouter and TCP Router use mutual TLS with apps to verify each other's identity" to "Gorouter and TCP Router use TLS to verify app identity".