Thank you for your reply. I am not sure I understand.

I do know Jenkins proxy_pass will work if I do the following:

1 - gitlab-ctl stop
2 - Comment-out the "#include gitlab-http.conf" in the nginx.conf file
3 - gitlab-ctl start
4 - http://localhost/jenkins takes me to http://localhost:8081/jenkins

I assume this means something in gitlab-http.conf is intercpting the http://localhost/jenkins correct?

Is it likely a location directive?


# This file is managed by gitlab-ctl. Manual changes will be
# erased! To change the contents below, edit /etc/gitlab/gitlab.rb
# and run `sudo gitlab-ctl reconfigure`.

## GitLab
## Modified from https://gitlab.com/gitlab-org/gitlab-ce/blob/master/lib/support/nginx/gitlab-ssl & https://gitlab.com/gitlab-org/gitlab-ce/blob/master/lib/support/nginx/gitlab
##
## Lines starting with two hashes (##) are comments with information.
## Lines starting with one hash (#) are configuration parameters that can be uncommented.
##
##################################
## CHUNKED TRANSFER ##
##################################
##
## It is a known issue that Git-over-HTTP requires chunked transfer encoding [0]
## which is not supported by Nginx < 1.3.9 [1]. As a result, pushing a large object
## with Git (i.e. a single large file) can lead to a 411 error. In theory you can get
## around this by tweaking this configuration file and either:
## - installing an old version of Nginx with the chunkin module [2] compiled in, or
## - using a newer version of Nginx.
##
## At the time of writing we do not know if either of these theoretical solutions works.
## As a workaround users can use Git over SSH to push large files.
##
## [0] https://git.kernel.org/cgit/git/git.git/tree/Documentation/technical/http-protocol.txt#n99
## [1] https://github.com/agentzh/chunkin-nginx-module#status
## [2] https://github.com/agentzh/chunkin-nginx-module
##
###################################
## configuration ##
###################################

upstream gitlab {
server unix:/var/opt/gitlab/gitlab-rails/sockets/gitlab.socket fail_timeout=0;
}

upstream gitlab-git-http-server {
server unix:/var/opt/gitlab/gitlab-git-http-server/socket;
}


server {
listen *:80;


server_name gitlab.monserver.fr;
server_tokens off; ## Don't show the nginx version number, a security best practice
root /opt/gitlab/embedded/service/gitlab-rails/public;

## Increase this if you want to upload large attachments
## Or if you want to accept large git objects over http
client_max_body_size 250m;


## Individual nginx logs for this GitLab vhost
access_log /var/log/gitlab/nginx/gitlab_access.log gitlab_access;
error_log /var/log/gitlab/nginx/gitlab_error.log;

location / {
## Serve static files from defined root folder.
## @gitlab is a named location for the upstream fallback, see below.
try_files $uri $uri/index.html $uri.html @gitlab;
}

location /uploads/ {
## If you use HTTPS make sure you disable gzip compression
## to be safe against BREACH attack.


## https://github.com/gitlabhq/gitlabhq/issues/694
## Some requests take more than 30 seconds.
proxy_read_timeout 300;
proxy_connect_timeout 300;
proxy_redirect off;

proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto http;
proxy_set_header X-Frame-Options SAMEORIGIN;

proxy_pass http://gitlab;
}

## If a file, which is not found in the root folder is requested,
## then the proxy passes the request to the upsteam (gitlab unicorn).
location @gitlab {
## If you use HTTPS make sure you disable gzip compression
## to be safe against BREACH attack.


## https://github.com/gitlabhq/gitlabhq/issues/694
## Some requests take more than 30 seconds.
proxy_read_timeout 300;
proxy_connect_timeout 300;
proxy_redirect off;

proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto http;
proxy_set_header X-Frame-Options SAMEORIGIN;

proxy_pass http://gitlab;
}

location ~ [-\/\w\.]+\.git\/ {
## If you use HTTPS make sure you disable gzip compression
## to be safe against BREACH attack.


## https://github.com/gitlabhq/gitlabhq/issues/694
## Some requests take more than 30 seconds.
proxy_read_timeout 300;
proxy_connect_timeout 300;
proxy_redirect off;

proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto http;

proxy_pass http://gitlab-git-http-server;
}

## Enable gzip compression as per rails guide:
## http://guides.rubyonrails.org/asset_pipeline.html#gzip-compression
## WARNING: If you are using relative urls remove the block below
## See config/application.rb under "Relative url support" for the list of
## other files that need to be changed for relative url support
location ~ ^/(assets)/ {
root /opt/gitlab/embedded/service/gitlab-rails/public;
gzip_static on; # to serve pre-gzipped version
expires max;
add_header Cache-Control public;
}


error_page 502 /502.html;


}