Yaml does not permit to share values between documents in the same file. Then this script helps with that problem.

result.yaml

---
apiVersion: extensions/v1beta1
kind: Deployment
env: &env_vars
  val1: "val1"
  val2: "val2" 
---
apiVersion: extensions/v1beta1
kind: Service
env: 
  val1: "val1"
  val2: "val2" 

sample.yaml

documents:
  - apiVersion: extensions/v1beta1
    kind: Deployment
    env: &env_vars
      val1: "val1"
      val2: "val2"      

  - apiVersion: extensions/v1beta1
    kind: Service
    env: *env_vars

yaml_parser.rb

# frozen_string_literal: true
# Generate a new yaml file "tmp_result.yml" for multiple documents sharing blocks/values between them
# Sample: ruby yaml_parser.rb 'pathtoyaml/sample.yaml'

# ARGV[0] = Filename
# ARGV[1] = Command

abort('Must define file name, sample: beta/deployment.yml') unless ARGV[0]
abort('Must define the command to run, sample: kubectl create') unless ARGV[1]

require 'yaml'
require 'json'
dir = __dir__
yaml_file = File.join(dir, ARGV[0])
old_yaml = YAML.load(File.read(yaml_file))
json_data = old_yaml.to_json # fix to skip anchors
data = YAML.load(json_data)

# parse yaml
file_path = File.join(dir, 'tmp_result.yml')
documents = data.delete('documents') || []
File.open(file_path, 'w+') do |f|
  documents.each do |doc|
    f << doc.to_yaml
  end
end

# puts `#{ARGV[1]} -f #{file_path}`