Install elastiflow on ubuntu18.04

[kase]

Hi there,
I followed this tutorial to study elastiflow(https://www.catapultsystems.com/blogs/install-elastiflow-on-ubuntu-18-04-part-3/), but faced some problem with using this command: sudo /usr/share/logstash/bin/system-install
the output is

OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.
2020-06-03T06:12:04.406Z [main] WARN FilenoUtil : Native subprocess control requires open access to sun.nio.ch
Pass '--add-opens java.base/sun.nio.ch=org.jruby.dist' or '=org.jruby.core' to enable.
Errno::EBADF: Bad file descriptor - systemctl
            spawn at org/jruby/RubyProcess.java:1635
            spawn at org/jruby/RubyKernel.java:1658
        popen_run at /usr/share/logstash/vendor/jruby/lib/ruby/stdlib/open3.rb:202
           popen3 at /usr/share/logstash/vendor/jruby/lib/ruby/stdlib/open3.rb:98
          execute at /usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/pleaserun-0.0.31/lib/pleaserun/detector.rb:74
   detect_systemd at /usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/pleaserun-0.0.31/lib/pleaserun/detector.rb:29
  detect_platform at /usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/pleaserun-0.0.31/lib/pleaserun/detector.rb:24
           detect at /usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/pleaserun-0.0.31/lib/pleaserun/detector.rb:18
   setup_defaults at /usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/pleaserun-0.0.31/lib/pleaserun/cli.rb:153
          execute at /usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/pleaserun-0.0.31/lib/pleaserun/cli.rb:119
              run at /usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/clamp-0.6.5/lib/clamp/command.rb:67
              run at /usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/pleaserun-0.0.31/lib/pleaserun/cli.rb:114
              run at /usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/clamp-0.6.5/lib/clamp/command.rb:132
           <main> at /usr/share/logstash/lib/systeminstall/pleasewrap.rb:28
Unable to install system startup script for Logstash.

I tried sudo nano /etc/logstash/jvm.options, change GC configuration to G1GC

GC configuration

#-XX:+UseConcMarkSweepGC
#-XX:CMSInitiatingOccupancyFraction=75
#-XX:+UseCMSInitiatingOccupancyOnly
#add G1GC
-XX:+UseG1GC
-XX:MaxGCPauseMillis=50

but still don't work...

(My elasticsearch version is 7.7.0, java version is openjdk version "11.0.7")
Can anyone help into this?
Thanks