$ cat user-data.yaml
#cloud-config
write_files:
    - content: |
        {"foo": {
              "id": "001100",
              "value": "False"
              }
        }
      path: /root/my.json


root@lxd-xenial-daily:~# ls
my.json
root@lxd-xenial-daily:~# cat my.json 
{"foo": {
      "id": "001100",
      "value": "False"
      }
}