[OSGeoLive] #2250: Installing tomcat breaks iso live session

[OSGeoLive]

#2250: Installing tomcat breaks iso live session
-----------------------+---------------------------
 Reporter:  kalxas     |      Owner:  kalxas
     Type:  defect     |     Status:  assigned
 Priority:  blocker    |  Milestone:  OSGeoLive14.0
Component:  OSGeoLive  |   Keywords:  tomcat9
-----------------------+---------------------------
 While reviewing the tomcat installer for OSGeoLive 14, I have noticed that
 by enabling the tomcat installer, the live iso boot process breaks so I
 had to disable tomcat until a solution can be found.

 https://github.com/OSGeo/OSGeoLive/commit/25fbe20f5d07978e77eba4887de1386dab29122a

 https://github.com/OSGeo/OSGeoLive/commit/5665abb2818f8801936486454092ec0f0840a956

 In order to figure out what the problem is, I managed to get a snapshot
 during the iso booting process (tomcat-boot-failure.png). The error is:

 {{{
 adduser: The UID 999 is already in use
 usermod: user 'user' does not exist
 install: invalid user 'user'
 }}}

 The system (casper) fails to create the 'user' account as the live system
 user, leaving the system hanging.

 Digging a bit deeper, I see the following:
 On build 37 (without tomcat) right after the startup this is how the
 /etc/passwd file looks like (live_system_users.png):

 {{{
 ...
 postgres:x:122:131:PostgreSQL
 administrator,,,:/var/lib/postgresql:/bin/bash
 user:x:999:999:Live session user,,,:/home/user:/bin/bash
 systemd-coredump:x:998:998:systemd Core Dumper:/:/usr/sbin/nologin
 }}}

 By manually creating the build chroot environment, right after tomcat
 installation, this is how the /etc/passwd file looks like
 (tomcat_user_chroot.png):

 {{{
 ...
 user:x:1000:1000:user,,,:/home/user:/bin/bash
 systemd-coredump:x:999:999:systemd Core Dumper:/:/usr/sbin/nologin
 tomcat:x:998:998:Apache Tomcat:/:/usr/sbin/nologin
 }}}

 My understanding of the problem is that tomcat user occupies UID 998 and
 this makes systemd-coredump user to pick up UID 999, leaving no UID
 available for the live session user (has to be < 1000). Casper then fails
 to create the user 'user' leaving the iso hanging on boot.

 I see some possible solutions:
 1. delete tomcat user in setdown script (as we currently do with user
 https://github.com/OSGeo/OSGeoLive/blob/master/bin/inchroot.sh#L252 ) and
 find a way to create the tomcat user during boot time.
 2. patch tomcat debian package to create the tomcat user with another UID.

 Any proposals for other solutions?

-- 
Ticket URL: <https://trac.osgeo.org/osgeolive/ticket/2250>
OSGeoLive <https://live.osgeo.org/>
self-contained bootable DVD, USB thumb drive or Virtual Machine based on Lubuntu, that allows you to try a wide variety of open source geospatial software without installing anything.