Error running samples when testing FME installation behind an AWS load balancer

  • 21 May 2024
  • 2 replies

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We cannot get FME to work behind an AWS loadbalancer.


Deploying FME behind an AWS Application load balancer with a HTTPs listener, works for signing in and browsing https://.../fmeserver/. However, when testing the installation using the following instructions, this error is returned “400 - Bad Request The plain HTTP request was sent to HTTPS port”

The FME server has a security group that only allows HTTP and SSH connections and so connections to port 443 are not possible.


The Browser issues two requests

-> 200

-> 400


The AWS Application Loadbalancer terminates the HTTPs connection and forwards to FME on HTTP port 80.


Nginx receives these requests on HTTP

Nginx - - [21/May/2024:09:00:19 +0000] "POST /fmeapiv4/workspaces/Samples/austinApartments.fmw/encodeparametervalues HTTP/1.1" 200 44 "https://.../fmeserver/workspaces/run/Samples/austinApartments.fmw/fmedatadownload" "Mozilla/5.0 (...) Gecko/20100101 Firefox/115.0" - - [21/May/2024:09:00:19 +0000] "POST /fmeserver/run/form/fmedatadownload/Samples/austinApartments.fmw HTTP/1.1" 400 220 "https://.../fmeserver/workspaces/run/Samples/austinApartments.fmw/fmedatadownload" "Mozilla/5.0 (...) Gecko/20100101 Firefox/115.0"


Tomcat receives these requests on HTTP

POST - - [21/May/2024:09:00:19 +0000] "POST /fmeapiv4/workspaces/Samples/austinApartments.fmw/encodeparametervalues HTTP/1.0" 200 28 11 10
POST - - [21/May/2024:09:00:19 +0000] "POST /fmeserver/run/form/fmedatadownload/Samples/austinApartments.fmw HTTP/1.0" 400 220 54 54


Running this command on the FME VM shows the connections are on port 80

tcpdump port 80 and '(tcp-syn|tcp-ack)!=0'

10:10:x.y IP ip-10-xxx-25-0.ap-southeast-2.compute.internal.46854 > ip-10-xxx-135-206.ap-southeast-2.compute.internal.http: Flags [P.], seq 1638914259:1638915245, ack 366946563, win 122, options [nop,nop,TS val 4181154778 ecr 331460248], length 986: HTTP: POST /fmeapiv4/workspaces/Samples/austinApartments.fmw/encodeparametervalues HTTP/1.1

10:10:x.1y IP ip-10-xxx-25-0.ap-southeast-2.compute.internal.46854 > ip-10-xxx-135-206.ap-southeast-2.compute.internal.http: Flags [P.], seq 986:2101, ack 354, win 126, options [nop,nop,TS val 4181154827 ecr 331485525], length 1115: HTTP: POST /fmeserver/run/form/fmedatadownload/Samples/austinApartments.fmw HTTP/1.1


Best answer by chrisb 22 May 2024, 02:46

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2 replies

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Today we re-created the FME installation and this time we accepted the defaults. The errors above happened when we entered 443 when asked this question 'Specify the port that users will use to connect to the Web UI of this installation of FME Flow...'. The default is 80.

Now when we run the sample we get:

-> 200

-> 200

However the second request contains the following body and the web page displays “There was an error submitting the job.”

<head><title>301 Moved Permanently</title></head>
<center><h1>301 Moved Permanently</h1></center>

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We have it working now, we just needed to also carry out these instructions “Are the Service URLs correct?”


So changing the scheme to ‘https’ for all URLs at ‘ADMIN / System Configuration / Network & Email / Services’