CDN 503 Response for Post Calls

[KartikKarnayilDC]

Hi Team,

We see intermittent 503 CDN response for POST Requests.

I have gone through this document 

https://experienceleague.adobe.com/en/docs/experience-cloud-kcs/kbarticles/ka-20878#:~:text=In%20cas....

But it doesn't have many details on the use case we are facing.

We see 

1) Dispatcher has logs at filter / cache level [1], but not in access log.

2) Publish Request Log has request [2] and response [3] log with 200 Response.

3) CDN having 503 [4] in log.

Can this occur due to users network issue? Or some connection issue between CDN <-> Dispatcher ?

Adding details below.

[1] Dispatcher httperror log
Thu Jun 20 00:48:14.439784 2024 [dispatcher:debug] [pid 24527:tid 281473690069680] [cm-p-e-aem-publish-7c44b8dcf8-fqf6w] Filter rule entry /0062 allowed 'POST /adobe/forms/af/submit/L2NvbnRlbnQvZm9ybXMvYWYvZW4vc3RhZmYvZmluYW5jaWFsLXNlcnZpY2VzL3RyYXZlbC1wdXJjaGFzZS1vcmRlci1yZXF1ZXN0 HTTP/1.1', referer: <host>/en/staff/financial-services/travel-purchase-order-request.html
Thu Jun 20 00:48:14.439831 2024 [dispatcher:debug] [pid 24527:tid 281473690069680] [cm-p1-e1-aem-publish-7c44b8dcf8-fqf6w] Reusing connection: localhost:8080, referer: <host>/en/staff/financial-services/travel-purchase-order-request.html
Thu Jun 20 00:48:14.439843 2024 [dispatcher:debug] [pid 24527:tid 281473690069680] [cm-p1-e1-aem-publish-7c44b8dcf8-fqf6w] Connected to backend 0 (localhost:8080), referer: <host>/en/staff/financial-services/travel-purchase-order-request.html

[2] Request Log
Request
20/Jun/2024:00:48:14 +0000 [55354] -> POST /adobe/forms/af/submit/L2NvbnRlbnQvZm9ybXMvYWYvZW4vc3RhZmYvZmluYW5jaWFsLXNlcnZpY2VzL3RyYXZlbC1wdXJjaGFzZS1vcmRlci1yZXF1ZXN0 HTTP/1.1 [cm-p1-e1-aem-publish-7c44b8dcf8-fqf6w]

AEM Debug Log
20.06.2024 00:48:27.485 [cm-p1-e1-aem-publish-7c44b8dcf8-fqf6w] *DEBUG* [qtp2108282425-5598] impl.RestServiceImpl API Response /v2/service-requests : {"id":1054507,"referenceNumber":"2"}
20.06.2024 00:48:31.407 [cm-p1-e1-aem-publish-7c44b8dcf8-fqf6w] *DEBUG* [qtp2108282425-5598] formactions.OracleFormSubmitServiceImpl Form Submission status : true

[3] Request Log Response - 200 
20/Jun/2024:00:48:31 +0000 [55354] <- 200 application/json 16968ms [cm-p1-e1-aem-publish-7c44b8dcf8-fqf6w]

[4] CDN Log - 503
{"timestamp":"2024-06-20T00:48:14+0000","ttfb":20838,"cli_ip":"ip","cli_country":"AU","rid":"","req_ua":"Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/115.0","host":"host","url":"/adobe/forms/af/submit/L2NvbnRlbnQvZm9ybXMvYWYvZW4vc3RhZmYvZmluYW5jaWFsLXNlcnZpY2VzL3RyYXZlbC1wdXJjaGFzZS1vcmRlci1yZXF1ZXN0","method":"POST","res_ctype":"text/html; charset=utf-8","cache":"ERROR","debug":"","res_age":"","status":503,"pop":"","rules":"","alerts":"","sample":""}

After checking with support team said, we got reason for 503 was Service Unavailable

Please note:

I have removed environment/program/ip values from above logs. Also, we have increased timeout configuration at CDN as we have post calls taking time between 0-30 Seconds.

[h_kataria · Accepted solution]

Although its a long shot but if you suspect, request is taking too long, then you might want to check timeout settings in your Apache Felix Jetty Based HTTP Service as well.

[kautuk_sahni]

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