$ sudo dpkg -i ./ctdb_4.10.0+dfsg-0ubuntu4_amd64.deb
Selecting previously unselected package ctdb.
(Reading database ... 129258 files and directories currently installed.)
Preparing to unpack .../ctdb_4.10.0+dfsg-0ubuntu4_amd64.deb ...
Unpacking ctdb (2:4.10.0+dfsg-0ubuntu4) ...
Setting up ctdb (2:4.10.0+dfsg-0ubuntu4) ...
Created symlink /etc/systemd/system/multi-user.target.wants/ctdb.service → /lib/systemd/system/ctdb.service.
Processing triggers for libc-bin (2.29-0ubuntu2) ...
Processing triggers for systemd (240-6ubuntu9) ...
Processing triggers for man-db (2.8.5-2) ...

(c)inaddy@ctdbdevel:~/work/sources/ubuntu/git$ systemctl enable ctdb
Synchronizing state of ctdb.service with SysV service script with /lib/systemd/systemd-sysv-install.
Executing: /lib/systemd/systemd-sysv-install enable ctdb
(c)inaddy@ctdbdevel:~/work/sources/ubuntu/git$ systemctl start ctdb
(c)inaddy@ctdbdevel:~/work/sources/ubuntu/git$ systemctl status ctdb
● ctdb.service - CTDB
   Loaded: loaded (/lib/systemd/system/ctdb.service; enabled; vendor preset: enabled)
   Active: active (running) since Thu 2019-06-27 12:19:20 UTC; 1s ago
     Docs: man:ctdbd(1)
           man:ctdb(7)
  Process: 26458 ExecStart=/usr/sbin/ctdbd_wrapper start (code=exited, status=0/SUCCESS)
 Main PID: 26460 (ctdbd)
    Tasks: 3 (limit: 4915)
   Memory: 6.1M
   CGroup: /system.slice/ctdb.service
           ├─26460 /usr/sbin/ctdbd
           ├─26462 /usr/lib/x86_64-linux-gnu/ctdb/ctdb-eventd -P 26460 -S 14
           └─26492 /usr/sbin/ctdbd

Jun 27 12:19:19 ctdbdevel systemd[1]: Starting CTDB...
Jun 27 12:19:19 ctdbdevel ctdbd[26459]: CTDB logging to location file:/var/log/ctdb/log.ctdb
Jun 27 12:19:20 ctdbdevel systemd[1]: Started CTDB.

(c)inaddy@ctdbdevel:~/work/sources/ubuntu/git$ dpkg -L ctdb > ctdb.files

(c)inaddy@ctdbdevel:~/work/sources/ubuntu/git$ apt-get remove --purge ctdb
Reading package lists... Done
Building dependency tree
Reading state information... Done
Starting pkgProblemResolver with broken count: 0
Starting 2 pkgProblemResolver with broken count: 0
Done
The following packages were automatically installed and are no longer required:
  ethtool libwbclient0 samba-libs tdb-tools time
Use 'sudo apt autoremove' to remove them.
The following packages will be REMOVED:
  ctdb*
0 upgraded, 0 newly installed, 1 to remove and 1 not upgraded.
After this operation, 7,854 kB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 129371 files and directories currently installed.)
Removing ctdb (2:4.10.0+dfsg-0ubuntu4) ...
Processing triggers for man-db (2.8.5-2) ...
Processing triggers for libc-bin (2.29-0ubuntu2) ...
(Reading database ... 129288 files and directories currently installed.)
Purging configuration files for ctdb (2:4.10.0+dfsg-0ubuntu4) ...
dpkg: warning: while removing ctdb, directory '/var/log/ctdb' not empty so not removed
dpkg: warning: while removing ctdb, directory '/var/lib/ctdb/state' not empty so not removed
dpkg: warning: while removing ctdb, directory '/var/lib/ctdb/persistent' not empty so not removed
Processing triggers for systemd (240-6ubuntu9) ...

(c)inaddy@ctdbdevel:~/work/sources/ubuntu/git$ for entry in $(cat ctdb.files); do [ -f $entry ] && ls -1 $entry; done

(c)inaddy@ctdbdevel:~/work/sources/ubuntu/git$ for entry in $(cat ctdb.files); do [ -d $entry ] && ls -1d $entry; done
/.
/etc
/etc/init.d
/etc/logrotate.d
/etc/sudoers.d
/lib
/lib/systemd
/lib/systemd/system
/usr
/usr/bin
/usr/lib
/usr/lib/tmpfiles.d
/usr/lib/x86_64-linux-gnu
/usr/lib/x86_64-linux-gnu/samba
/usr/sbin
/usr/share
/usr/share/doc
/usr/share/man
/usr/share/man/man1
/usr/share/man/man5
/usr/share/man/man7
/var
/var/lib
/var/lib/ctdb
/var/lib/ctdb/persistent
/var/lib/ctdb/state
/var/log
/var/log/ctdb

Only leftovers are /var/lib/ctdb/{persistent,state} and /var/log/ctdb.

$ ls /var/lib/ctdb/{state,persistent}
/var/lib/ctdb/persistent:
ctdb.tdb.0

/var/lib/ctdb/state:
persistent_health.tdb.0

$ ls /var/log/ctdb/
log.ctdb

I'm not sure if I should delete the CTDB database and persistent data.. I'm checking...