Logstash failing to start or configtest

Elastic Stack Logstash
1

Hi folks. I'm not sure what happened, but yesterday my ELK was logging, and today it isn't. I tried to check the configs on one of the Logstash nodes, and I get an error about loading logstash/runner:

sudo /opt/logstash/bin/logstash --verbose -f /etc/logstash-forwarder.conf
LoadError: no such file to load -- logstash/runner
  require at org/jruby/RubyKernel.java:1040
   (root) at /opt/logstash/lib/bootstrap/environment.rb:57

I get a similar error if I just try to run logstash:

/opt/logstash/bin/logstash
LoadError: no such file to load -- logstash/runner
  require at org/jruby/RubyKernel.java:1040
   (root) at /opt/logstash/lib/bootstrap/environment.rb:57

/var/log/logstash/logstash.err contains the same.

The server is Ubuntu 14.04
Logstash version is Version: 1:2.1.3-1

2

@Cylindric: Hi Mark, I also getting the same issue. Did you get any solution to this??
Please help me in this regard.

thanks in advance.