Creating ansible inventory for multiple target hosts

Question

I am using terraform to create resources then using templatefile approach to create ansible inventory in yaml language. I am creating multiple Virtual Machines in terraform and configure them using ansible in single pipeline.

Issue I am having is yaml file uses - for lists which is giving error in ansible playbook

Outputs.tf

resource "local_file" "AnsibleInventory" {
content = templatefile("inventory.tmpl",
{
ansible_port = "5986"
ansible_connection = "winrm"
ansible_winrm_server_cert_validation = "ignore"
ansible_winrm_transport = "ntlm"
vm-ip = data.azurerm_public_ip.main.*.ip_address,
username = "testadmin",
ansible_password = "abc"
}
)
filename = "inventory.json"
}

inventory.tmpl

${jsonencode({
  "all": {
    "hosts": {
      "server": [
        for ip in vm-ip : { 
        "ansible_host": "${ip}",
        "ansible_port": 5986,
        "ansible_user": "testadmin",
        "ansible_winrm_transport": "ntlm",
        "ansible_connection": "winrm",
        "ansible_winrm_server_cert_validation": "ignore",
        "ansible_password": "abc"
        }
      ]
    }
  }
})}

inventory.json

{"all":{"hosts":{"server":{"ansible_connection":"winrm","ansible_host":"343434","ansible_password":"abc","ansible_port":5986,"ansible_user":"testadmin","ansible_winrm_server_cert_validation":"ignore","ansible_winrm_transport":"ntlm"}}}}

inventory.yaml

all:
  hosts:
    server:
    - ansible_connection: winrm
      ansible_host: 40.88.14.205
      ansible_password: abc
      ansible_port: 5986
      ansible_user: testadmin
      ansible_winrm_server_cert_validation: ignore
      ansible_winrm_transport: ntlm

Is my approach right then how to remove "-" from code or am I doing something wrong.

Edited:

I am converting json file to yaml file using bash in pipeline.

python -c 'import sys, yaml, json; yaml.safe_dump(json.load(sys.stdin), sys.stdout, default_flow_style=False)' < inventory.json > inventory.yaml

Answer 1

As pointed out by @ydaetskcoR's comment, your inventory is wrong because you need the list of hosts to be an immediate child of the hosts attribute.

---

Note that the list you end up with is produced by the use of the brackets [], producing tuples, around for in your Terraform template as opposed to the use of the bracket {}, producing objects.

The type of brackets around the for expression decide what type of result it produces. The above example uses [ and ], which produces a tuple. If { and } are used instead, the result is an object, and two result expressions must be provided separated by the => symbol.

^{https://www.terraform.io/docs/configuration/expressions.html#for-expressions}

---

If your structure, should look like all > server1, server2, server3

Then your inventory should be

all:
  hosts:
    server1:
      ansible_host: 10.0.0.2
      ansible_port: 5986
    server2:
      ansible_host: 10.0.0.3
      ansible_port: 5986
    server3:
      ansible_host: 10.0.0.4
      ansible_port: 5986

This is an approach for a Terraform template producing this:

${yamlencode({
  "all": {
    "hosts": {
      for i, ip in vm-ip:
        "server${i+1}" => {
          "ansible_host": "${ip}",
          "ansible_port": 5986
        }
    }
  }
})}

Which gives this valid inventory.yaml:

"all":
  "hosts":
    "server1":
      "ansible_host": "10.0.0.2"
      "ansible_port": 5986
    "server2":
      "ansible_host": "10.0.0.3"
      "ansible_port": 5986
    "server3":
      "ansible_host": "10.0.0.4"
      "ansible_port": 5986

---

On the other hand, if you want a structure like all > server > server1, server2, server3

Then you should make server a child of all and use the children entry in your inventory:

all:
  children:
    server:
      hosts:
        server1:
          ansible_host: 10.0.0.2
          ansible_port: 5986
        server2:
          ansible_host: 10.0.0.3
          ansible_port: 5986
        server3:
          ansible_host: 10.0.0.4
          ansible_port: 5986

For this one, the corresponding Terraform template would be

${yamlencode({
  "all": {
    "children": {
      "server": {
        "hosts": {
          for i, ip in vm-ip:
            "server${i+1}" => {
              "ansible_host": "${ip}",
              "ansible_port": 5986
            }
        }
      }
    }
  }
})}

Which produce this inventory.yaml:

"all":
  "children":
    "server":
      "hosts":
        "server1":
          "ansible_host": "10.0.0.2"
          "ansible_port": 5986
        "server2":
          "ansible_host": "10.0.0.3"
          "ansible_port": 5986
        "server3":
          "ansible_host": "10.0.0.4"
          "ansible_port": 5986

---

Note: for all the examples above, I am using the terraform file test.tf below:

resource "local_file" "AnsibleInventory" {
  content = templatefile("inventory.tpl", {
    vm-ip = ["10.0.0.2","10.0.0.3","10.0.0.4"],
  })
  filename = "inventory.yaml"
}