# cat write.yaml 
#cloud-config
write_files:
  - path: /tmp/myfile
    content: |
      # my content here
      content: {"chef_org":"foo_eu","chef_run_list":"role[\"eu-base\"],role[\"bastion-host\"]","chef_server":"chef.eu-infra.local","dns_domain":"eu-infra.local","service":"bastion"}
root@z1:~# cloud-init --file write.yaml single --frequency=always --name=cc_write_files 
Cloud-init v. 0.7.9 running 'single' at Tue, 20 Jun 2017 16:05:57 +0000. Up 80620.0 seconds.
root@z1:~# cat /tmp/myfile 
# my content here
content: {"chef_org":"foo_eu","chef_run_list":"role[\"eu-base\"],role[\"bastion-host\"]","chef_server":"chef.eu-infra.local","dns_domain":"eu-infra.local","service":"bastion"}