Unexpected response from MQ based virtual service.

Products

• Service Virtualization

Issue/Introduction

A VS has started providing the following response as of last week:

0000: 54 68 65 20  72 65 71 75  65 73 74 20  66 61 69 6C  | The request fail |
0010: 65 64 20 74  6F 20 70 72  6F 64 75 63  65 20 61 20  | ed to produce a  |
0020: 72 65 73 70  6F 6E 73 65  20 66 6F 72  20 74 68 65  | response for the |
0030: 20 76 69 72  74 75 61 6C  20 73 65 72  76 69 63 65  |  virtual service |
0040: 20 74 6F 20  72 65 70 6C  79 20 77 69  74 68 2E     |  to reply with.  |

The request failed to produce a response for the virtual service to reply with.

No changes have been made to the VS or to the consuming application.

Cause

Investigation steps:

- Tried to update the default service image response and deployed the VS still got the same error.

- Updated the response headers for the impacted transaction but got the same response.

- Tested the VS in ITR mode but couldn't see the impacted transaction coming into the VS. 

- At the MQ side, could see that every time the transaction was getting picked and put into response queue and consumed by the client application.

- Found that there was one another listener on the same queue from another environment.

- Tried to find the VS that may be using the same queue in that DevTest environment portal but couldn't find one.

- Finally stopped the VSEs(around 10) on that environment and could see that the extra listener was removed from the queue.

With this test, concluded that the issue was not with Virtual Service(SV) as such but because another virtual service started to listen on the same queue that was used by impacted Virtual Service and hence an unexpected response was sent.

Resolution

The VSEs on the other environment were stopped, and then impacted Virtual Service could pick and process the messages correctly.