NiFi UI is not loading template after login.

[#1]

If I create a new template, it is creating a flow.xml.gz and working fine. However If I replace the flow.xml.gz with old flow.xml.gz (one backup taken earlier in same cluster node HDF2.X) nifi UI is not coming after login and giving error as "com.sun.jersey.api.client.ClientHandlerException: java.net.SocketTimeoutException: Read timed out".

Have tried with all parameter tuning as described by "Matt Clarke" in some other post but no results.

Again If I move old file and replace with new flow.xml.gz then nifi is working fine.

Please let me know if anyone faces such issues and probable reason and working around.

Thanks,

SP

[#2]

@Matt Clarke

Have tried with all parameter tuning as described by "Matt Clarke" in some other post but no results.

[#3]

@SP

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I am confused by your statement:
"If I create a new template, it is creating a flow.xml.gz and working fine"

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A template is not the same thing as a flow.xml.gz file.

Are you generating a template, downloading it, and then trying to use that template as a new flow.xml.gz file? If so, that will not work.

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Thank you,

Matt

[#4]

@SP

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A couple of things that can be done to troubleshoot this.

1. Did you inspect both the nifi-app.log and nifi-bootstrap.log for any ERROR or WARN messages during NiFi start?

2. After Staring NiFi and waiting at least 5 minutes, take a series of 3 thread dumps (3-5 minutes apart) that can be inspected for any threads that may not be progressing (same thread ID in same state in every thread dump). NiFi will validate the components as it loads the flow from the flow.xml.gz. If you are using any type of mounted NAS and that mount is in a bad state and your new flow is trying to access that mount it may cause the validation thread to hang waiting on response from that NAS.

3. Perform a diff between working flow.xml.gz and non working flow.xml.gz to see what kind of components are i use in new flow and how they have been configured.

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Thank you,

Matt

[#5]

Hi Matt,

Sorry for the delayed response.

Actually NiFi UI was not loading so that users are unable to login to NiFi.

What I have done is removed the current flow.xml.gz and replaced with the latest backup of flow.xml and certainly NiFi UI was up and working.

Not sure how to fix if the current flow.xml got corrupted for some reason and there were no error log which I can track for the above issue.

Thanks & regards,

SP

[#6]

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[#7]

Yes I have already checked the logs as you have mentioned and nothing specific I can point out to this behavior. Have not taken thread dump but checked with diff and there seems to be some deployment of nar file but can't say specifically if that causes this. Anyway I have not faced it after that and incase if I face the same issue again I will follow your recommendations.

Thanks for your help and support Matt.