You got your Flapjack in my Sensu! You got your Sensu in my Flapjack! How to install Flapjack into Sensu's omnibus ruby path under CentOS 6.

sensjack.sh

#!/bin/sh

### This seemed to install Flapjack under CentOS6, using the embedded Ruby that comes with Sensu
### This does not install init scripts or anything else important
### Very likely this is a horrible thing I've done and should be repeated by no one, ever

# install gcc because we are going to build some things, and libtcmalloc for redis 2.8
yum -q -y install gcc gcc-c++ gperftools-libs

export OLD_GEM_PATH=${GEM_PATH}
export OLD_PATH=${PATH}
export GEM_PATH=/opt/sensu/embedded/lib/ruby/gems/2.0.0:${GEM_PATH}
export PATH=/opt/sensu/embedded/bin/:/opt/sensu/embedded/lib/ruby/gems/2.0.0/gems/flapjack-0.9.0/bin/:$PATH
# Install via gem
/opt/sensu/embedded/bin/gem install flapjack
# Install default config
cp /opt/sensu/embedded/lib/ruby/gems/2.0.0/gems/flapjack-0.9.0/etc/flapjack_config.yaml.example /opt/sensu/embedded/lib/ruby/gems/2.0.0/gems/flapjack-0.9.0/etc/flapjack_config.yaml
# go edit /opt/sensu/embedded/lib/ruby/gems/2.0.0/gems/flapjack-0.9.0/etc/flapjack_config.yaml

#  Install redis 2.8 for CentOS here, for testing
rpm -i http://mirrors.mediatemple.net/remi/enterprise/6/remi/x86_64/redis-2.8.9-1.el6.remi.x86_64.rpm
# start flapper -- or don't. whatever.
flapper start
# start flapjack, you crazy person you
/opt/sensu/embedded/bin/flapjack -c /opt/sensu/embedded/lib/ruby/gems/2.0.0/gems/flapjack-0.9.0/etc/flapjack_config.yaml -n development

### return env vars back to prior state.. or.. not
#export GEM_PATH=${OLD_GEM_PATH}
#export PATH=${OLD_PATH}