Fix scripts print success when errorining due to unbound variables

Author: triarius

packer/linux/conf/bin/bk-configure-docker.sh

@@ -17,7 +17,7 @@ on_exit() {
   echo "${BASH_SOURCE[0]} completed successfully."
 }
 
-trap on_exit EXIT
+trap '[[ $? = 0 ]] && on_exit' EXIT
 
 ## Configure docker before system starts
 

packer/linux/conf/bin/bk-install-elastic-stack.sh

@@ -35,7 +35,7 @@ on_exit() {
   echo "${BASH_SOURCE[0]} completed successfully."
 }
 
-trap on_exit EXIT
+trap '[[ $? = 0 ]] && on_exit' EXIT
 
 # Write to system console and to our log file
 # See https://alestic.com/2010/12/ec2-user-data-output/

packer/linux/conf/bin/bk-mount-instance-storage.sh

@@ -16,7 +16,7 @@ on_exit() {
   echo "${BASH_SOURCE[0]} completed successfully."
 }
 
-trap on_exit EXIT
+trap '[[ $? = 0 ]] && on_exit' EXIT
 
 # Write to system console and to our log file
 # See https://alestic.com/2010/12/ec2-user-data-output/