We were running ELOG for many many years in our experiments and the instance was operated on a Debian XEN server as a container. I am now trying to migrate it into our Docker Swarm cluster and I am using the https://hub.docker.com/r/de1lz/elog-docker Docker image, which works very well with our logbooks when I run it as a single container. However, when I put the container behind my load balancer (HAProxy) using the simple HTTP mode (which works very well for all the other HTTP-based services) with this simple configuration:

backend be_elog.km3net.de
    mode http
    server-template km3net-elog- 1 km3net-elog_elog:8080 check resolvers docker init-addr libc,none

I get a "too many redirects" error when I try to access one of the logbooks. The starting page works fine, but every other link leads to a pile-up of redirects.

Here is the current instance running, where you can see the behaviour: https://elog.test.km3net.de (all log entries deleted and only two logbooks activated)

My question is: what kind of redirect could go wrong here? I don't know how the internal HTTP server of ELOG works, but maybe someone faced similar issues.

My ELOG configuration is also pretty basic, and as I wrote above, everything works when I run it without the load balancer (single instance at the moment). Here is the top part of the configuration, it contains a few dozens of logbooks but they are configured the very same way. 

;User Settings
;=============
Password file = login.xml
Admin user = km3net_admin
Self register = 0
Allow password change = 0
Allow config = km3net_admin

;Group Settings:
;====
Group ELOGKM3NET = Operations IT, Operations FR

[Operations IT]
Subdir = Operations_IT
Theme = default
Default encoding = 0
Comment = KM3NeT IT Detector Operations
Attributes = Author, Type, Subject
Options Author = A, B, C
Options Type = PPM-DOM, PPM-DU, Comment, Power cut, New run
Extendable Options = Type
Required Attributes = Author, Type, Subject
Page Title = ELOG - $subject
;Sort Attributes = Author, Type
Quick filter = Date, Type, Author
Resubmit default = 2
Reverse sort = 1
Menu commands = List, New, Edit, Reply, Duplicate, Find, Config, Help, Logout
Preset on first reply Subject = Re: $Subject
Preset on reply author =

Probably you need a setting

URL = https://elog.test.km3net.de

or so in your elogd.cfg file.

Stefan

I also tried the default configuration (example config) and it that works behind the load balancer. So I guess it's related to the password-page, which causes this redirect loop? Our logbooks are all password protected, so when a logbook URL is clicked, it should first present the login-form, and that's where it chokes.

Yeah, after you enter a password, elog redirects to what it finds in "URL". You can trace that by opening "development tools" in Google Chrome, go to "network" and watch packets going back and forth. I never worked with the load balancer, but maybe you need a different "URL" containing a '/' at the end?

Yes I see the redirects. You say with the example logbook it works, right? Is it the password protection which triggers the problem or anything else? Does it work if you take out the password protection? The key is to identify which setting in your config file triggers the problem, so you can bracket the problem down between the example logbook and your logbook definition.