How to fix error: "Failed to register flow with Flow Registry due to Error creating snapshot" on NiFi

[#1]

Dears, 

I need help. I trying to version my flows, but is show this error:

(Failed to register flow with Flow Registry due to Error creating snapshot: An unexpected error has occurred. Please check the logs for additional details)

Looking in the logs, I found this error: 

• org.apache.nifi.web.NiFiCoreException: Failed to register flow with Flow Registry due to Error creating snapshot: An unexpected error has occurred. Please check the logs for additional details.
• ERROR o.a.nifi.web.StandardNiFiServiceFacade The flow has been created, but failed to add a snapshot. Returning the created flow information.

Last week it was working perfectly but now this error started. 
Can you help me?

Thanks! 

 

[#2]

@MarcusBrandao Welcome to the Cloudera Community!

To help you get the best possible solution, I have tagged our NiFi experts @cotopaul @MattWho and @SAMSAL  who may be able to assist you further.

Please keep us updated on your post, and we hope you find a satisfactory solution to your query.

[#3]

As much as I would like to help, the provided error does not really help 😞 More than certain there is much more in your logs, either on your NiFi instance (see all the logs) either on your Registry.

You should try and remember everything which has been performed since the last time you know it worked and try to revert those actions.

Otherwise, based on the provided error message, you are out of luck 😞

[#4]

@MarcusBrandao 

As @cotopaul mentioned, providing the full error and any stack trace that may follow might help in your query.  You may also want to to look for any other WARN or ERROR log output generated around the time of attempting the version control your process group.  I'd  look for anything related to Out of Memory (OOM) or too many open files.  Also look at the JVM your NiFi is using. How often and how long are your garbage collection events?

If you found that the provided solution(s) assisted you with your query, please take a moment to login and click Accept as Solution below each response that helped.

Thank you,

Matt

[#5]

@MarcusBrandao Has the reply helped resolve your issue? If so, please mark the appropriate reply as the solution, as it will make it easier for others to find the answer in the future. If you are still experiencing the issue, can you provide the information our experts requested? Thanks.

[#6]

Hi everyone, 
I experienced the same error. After inspecting also the logs of nifi-registry, I found the error 

2023-09-04 16:18:10,346 ERROR [NiFi Registry Web Server-17] o.a.n.r.web.mapper.ThrowableMapper An unexpected error has occurred: org.apache.nifi.registry.flow.FlowPersistenceException: Git directory /data/nifi01/nifi-registry-1.18.0/../nifiregistry_git is not clean or has uncommitted changes, resolve those changes first to save flow contents.. Returning Internal Server Error response.
org.apache.nifi.registry.flow.FlowPersistenceException: Git directory /data/nifi01/nifi-registry-1.18.0/../nifiregistry_git is not clean or has uncommitted changes, resolve those changes first to save flow contents.

I changed to the path noted in the error message, changed to the user, which executes nifi-registry and checked the git repository status: git status

Several files were modified and the git directory clearly was not "clean". I just committed and pushed everything (I had to set the git user name to make a successful commit). 

I don't know, why this all happend. But for now, its fixed.