packer validate -var 'source_ami=ami-02fe94dee086c0c37' ami.json
packer build \
-var 'aws_access_key=' \
-var 'aws_secret_key=' \
-var 'aws_region=us-east-1' \
-var 'subnet_id=subnet-0fa5ba21' \
-var 'source_ami=ami-02fe94dee086c0c37' \
ami.json