DTK-1536: use host instead of dig
dig doesn't come preinstalled on CentOS official AMI
Merge branch 'master' of github.com:rich-reactor8/dtk-node-agent

* 'master' of github.com:rich-reactor8/dtk-node-agent:
  DTK-1536: use host instead of dig dig doesn't come preinstalled on CentOS offifical AMI