Sometimes, there are HTTP 504 errors in the web app on a Linux server (not always)

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Sometimes, there are HTTP 504 errors in the web app on a Linux server (not always)

Su Myat Hlaing 180

Sometimes, there are HTTP 504 errors in the web app on a Linux server (not always). how to solve, please?

Node.js web app.

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SnehaAgrawal-MSFT 22,706 Reputation points Moderator

2023-11-10T16:49:24.1066667+00:00

@Su Myat Hlaing Just checking if you have chance to see recent response.

Please let us know if further query or issue remains.

Please accept as "Yes" if the answer provided is useful , so that you can help others in the community looking for remediation for similar issues.

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SnehaAgrawal-MSFT 22,706 Reputation points Moderator

2023-11-10T16:49:24.1066667+00:00

@Su Myat Hlaing Just checking if you have chance to see recent response.

Please let us know if further query or issue remains.

Please accept as "Yes" if the answer provided is useful , so that you can help others in the community looking for remediation for similar issues.

Answer 1

@Su Myat Hlaing Thanks for reaching here!

HTTP 504 errors occur when the server is unable to complete a request due to a timeout. This can happen if the server is overloaded or if there is a network issue.

To troubleshoot this issue, you can try the following steps:

Check the server logs: Check the server logs to see if there are any errors or warnings related to the HTTP 504 errors. This can help you identify the root cause of the issue.
The major cause for intermittent connection issues is hitting a limit while making new outbound connections- TCP Connections: There's a limit on the number of outbound connections that can be made. The limit on outbound connections is associated with the size of the worker used.
Go Azure Portal> your web app> click on diagnose and solve problems> click on Availability and performances tile > click on SNAT Failed connection endpoint
SNAT ports- Go Azure Portal> your web app> click on diagnose and solve problems> click on Availability and performances tile > click on SNAT Port Exhaustion
You can modify the application to use connection pooling- By default, connections for NodeJS aren't kept alive. Below are the popular databases and packages for connection pooling which contain examples for how to implement them.
MySQL; MongoDB; PostgreSQL; SQL Server HTTP Keep-alive- agentkeepalive- Node.js v13.9.0 Documentation
Scale your application: If your application is receiving a lot of traffic, you may need to scale it to handle the load.

For Details suggest you refer this document link-

I hope this helps! Let me know if you have any other questions.

Su Myat Hlaing 180 Reputation points

2024-01-04T04:13:29.04+00:00

Hi @SnehaAgrawal-MSFT

Initially, the issue seemed to resolve itself, but I encountered the HTTP 504 error again, and when I check error log, this time the associated error message is as follows:

2024-01-04T01:27:45.291066452Z fail: Middleware[0] 2024-01-04T01:27:45.291436458Z Failed to forward request to http://169...:8080. Encountered a System.Threading.Tasks.TaskCanceledException exception after 300002.058ms with message: The request was canceled due to the configured HttpClient.Timeout of 300 seconds elapsing. Check application logs to verify the application is properly handling HTTP traffic.

I've rechecked the SNAT port section, and there don't seem to be any errors. Already Implemented connection pooling https://node-postgres.com/features/pooling

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Sometimes, there are HTTP 504 errors in the web app on a Linux server (not always)

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