A Jenkins,Artifactory/Nginx reverse proxy setup (is work, no touchy)

0_tomcat.conf

# /etc/nginx/sites-available/tomcat.conf

server {
  include snippets/listen_both_le.conf;
  include snippets/cert_l1t.conf;

  server_name ci.l1t.li;

  location / {
    include snippets/proxy-header.conf;
    proxy_pass http://127.0.0.1:8080$request_uri;
    proxy_redirect http://127.0.0.1:8080 $scheme://$host;
  }
}

server {
  include snippets/listen_both_le.conf;
  include snippets/cert_l1t.conf;
  
  server_name repo.l1t.li;

  location /repo {
    rewrite "^/repo(.*)$" "https://repo.l1t.li/$1";
  }

  location /robots.txt {
    return 200 "User-agent: *\nDisallow: /";
  }

  location / {
    include snippets/proxy-header.conf;
    proxy_pass http://127.0.0.2:8080$request_uri;
    proxy_redirect http://127.0.0.2:8080 $scheme://$host;
  }
}

1_proxy-header.conf

# /etc/nginx/snippets/proxy-header.conf

proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-Server $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Real-IP $remote_addr;

client_max_body_size 20M; # Increase here if uploading big files 
client_body_buffer_size 128k;
proxy_connect_timeout 90;
proxy_read_timeout 90;
proxy_buffer_size 4k;
proxy_buffers 4 32k;
proxy_busy_buffers_size 64k;
proxy_temp_file_write_size 64k;

proxy_hide_header X-Content-Type-Options;
proxy_hide_header X-Frame-Options;
proxy_hide_header X-XSS-Protection;

2_catalina.properties

# /etc/tomcat8/catalina.properties
... defaults ...
# add at the end:

# Jenkins javadoc iframes (is this still necessary? it remains a mystery)
hudson.model.DirectoryBrowserSupport.CSP=default-src 'none'; img-src 'self'; style-src 'self'; child-src 'self'; frame-src 'self';

3_server.xml

<?xml version='1.0' encoding='utf-8'?>
<!-- /etc/tomcat8/server.xml -->
<!--
  Licensed to the Apache Software Foundation (ASF) under one or more
  contributor license agreements.  See the NOTICE file distributed with
  this work for additional information regarding copyright ownership.
  The ASF licenses this file to You under the Apache License, Version 2.0
  (the "License"); you may not use this file except in compliance with
  the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
-->
<!-- Note:  A "Server" is not itself a "Container", so you may not
     define subcomponents such as "Valves" at this level.
     Documentation at /docs/config/server.html
 -->
<Server port="8005" shutdown="SHUTDOWN" maxPostSize="-1">
  <Listener className="org.apache.catalina.startup.VersionLoggerListener" />
  <!-- Security listener. Documentation at /docs/config/listeners.html
  <Listener className="org.apache.catalina.security.SecurityListener" />
  -->
  <!--APR library loader. Documentation at /docs/apr.html -->
  <!--
  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
  -->
  <!-- Prevent memory leaks due to use of particular java/javax APIs-->
  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
  <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

  <!-- Global JNDI resources
       Documentation at /docs/jndi-resources-howto.html
  -->
  <GlobalNamingResources>
    <!-- Editable user database that can also be used by
         UserDatabaseRealm to authenticate users
    -->
    <Resource name="UserDatabase" auth="Container"
              type="org.apache.catalina.UserDatabase"
              description="User database that can be updated and saved"
              factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
              pathname="conf/tomcat-users.xml" />
  </GlobalNamingResources>

  <!-- A "Service" is a collection of one or more "Connectors" that share
       a single "Container" Note:  A "Service" is not itself a "Container",
       so you may not define subcomponents such as "Valves" at this level.
       Documentation at /docs/config/service.html
   -->
  <Service name="Catalina">

    <!--The connectors can use a shared executor, you can define one or more named thread pools-->
    <!--
    <Executor name="tomcatThreadPool" namePrefix="catalina-exec-"
        maxThreads="150" minSpareThreads="4"/>
    -->


    <!-- A "Connector" represents an endpoint by which requests are received
         and responses are returned. Documentation at :
         Java HTTP Connector: /docs/config/http.html (blocking & non-blocking)
         Java AJP  Connector: /docs/config/ajp.html
         APR (HTTP/AJP) Connector: /docs/apr.html
         Define a non-SSL HTTP/1.1 Connector on port 8080
    -->
    <Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               URIEncoding="UTF-8"
               redirectPort="8443" />
    <!-- A "Connector" using the shared thread pool-->
    <!--
    <Connector executor="tomcatThreadPool"
               port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443" />
    -->
    <!-- Define a SSL HTTP/1.1 Connector on port 8443
         This connector uses the NIO implementation that requires the JSSE
         style configuration. When using the APR/native implementation, the
         OpenSSL style configuration is required as described in the APR/native
         documentation -->
    <!--
    <Connector port="8443" protocol="org.apache.coyote.http11.Http11NioProtocol"
               maxThreads="150" SSLEnabled="true" scheme="https" secure="true"
               clientAuth="false" sslProtocol="TLS" />
    -->

    <!-- Define an AJP 1.3 Connector on port 8009 -->
    <!--
    <Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />
    -->


    <!-- An Engine represents the entry point (within Catalina) that processes
         every request.  The Engine implementation for Tomcat stand alone
         analyzes the HTTP headers included with the request, and passes them
         on to the appropriate Host (virtual host).
         Documentation at /docs/config/engine.html -->

    <!-- You should set jvmRoute to support load-balancing via AJP ie :
    <Engine name="Catalina" defaultHost="localhost" jvmRoute="jvm1">
    -->
    <Engine name="Catalina" defaultHost="127.0.0.1">

      <!--For clustering, please take a look at documentation at:
          /docs/cluster-howto.html  (simple how to)
          /docs/config/cluster.html (reference documentation) -->
      <!--
      <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>
      -->

      <!-- Use the LockOutRealm to prevent attempts to guess user passwords
           via a brute-force attack -->
      <Realm className="org.apache.catalina.realm.LockOutRealm">
        <!-- This Realm uses the UserDatabase configured in the global JNDI
             resources under the key "UserDatabase".  Any edits
             that are performed against this UserDatabase are immediately
             available for use by the Realm.  -->
        <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
               resourceName="UserDatabase"/>
      </Realm>

      <Host name="127.0.0.1" appBase="webapps"
            unpackWARs="true" autoDeploy="true">

        <!-- SingleSignOn valve, share authentication between web applications
             Documentation at: /docs/config/valve.html -->
        <!--
        <Valve className="org.apache.catalina.authenticator.SingleSignOn" />
        -->

        <!-- Access log processes all example.
             Documentation at: /docs/config/valve.html
             Note: The pattern used is equivalent to using pattern="common" -->
        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log" suffix=".txt"
               pattern="%h %l %u %t &quot;%r&quot; %s %b" />

      </Host>
      <Host name="127.0.0.2" appBase="webapps/artifactory" unpackWARs="true" autoDeploy="true">
        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="artifactory_access" suffix=".log"
               pattern="%h %l %u %t &quot;%r&quot; %s %b" />
      </Host>
    </Engine>
  </Service>
</Server>

4_README.md

I have /var/lib/tomcat8/webapps symlinked to /var/www/webapps.

That folder looks something like:

xxyy$ ls -hla
total 452M
drwxrwxr-x  4 www-data www-data 4.0K 27.10.2017 23:39 ./
drwxrwxr-x 17 www-data www-data 4.0K 10.12.2017 15:13 ../
drwxrwxr-x  3 www-data www-data 4.0K 20.03.2016 02:59 artifactory/
drwxr-x--- 10 www-data www-data 4.0K 27.10.2017 23:39 ROOT/
-rw-r--r--  1 www-data www-data  68M 28.05.2017 23:04 jenkins.war.2.63
-rw-r--r--  1 www-data www-data  70M 28.08.2017 03:01 jenkins.war.2.76
-rw-r--r--  1 www-data www-data  71M 23.10.2017 03:00 jenkins.war.2.86
lrwxrwxrwx  1 root     root       16 27.10.2017 23:39 ROOT.war -> jenkins.war.2.86
xxyy$ ls -hla artifactory
total 80M
drwxrwxr-x 3 www-data www-data 4.0K 20.03.2016 02:59 ./
drwxrwxr-x 4 www-data www-data 4.0K 27.10.2017 23:39 ../
drwxr-xr-x 5 www-data www-data 4.0K 20.03.2016 02:59 ROOT/
-rw-r--r-- 1 www-data www-data  36M 20.03.2016 02:59 ROOT.war
-rw-rw-r-- 1 www-data www-data  44M 03.09.2015 21:47 ROOT.war.old