亚马逊上的嵌套堆栈中的参数

Question

browsed all google through and did not find an answer... Or just partial with no real example.

Here is my Stack:

{
  "Resources": {
    "NestedStack": {
      "Type": "AWS::CloudFormation::Stack",
      "Properties": {
        "TemplateURL": "https://xyz/json.template",
        "Parameters" : {
          "Sg1" : { "Ref": "Sg1"},
          "Sg2" : { "Ref": "Sg2"}
        },
     "DependsOn": ["Sg1","Sg2"]
   },
   "Sg1": {
     "Type": "AWS_EC2_SecurityGroup",
     .....
   },
   "Sg2": {
     "Type": "AWS_EC2_SecurityGroup",
     .....
   }
}

Here is my nested stack template:

{
  "Resources": {
    "flow1": {
      "Type": "AWS::EC2::SecurityGroupIngress",
      "Properties": {
        "SourceSecurityGroupId": {"Ref": "Sg1"}, 
        "FromPort": "161", 
        "ToPort": "161", 
        "GroupId": {"Ref": "Sg2"}, 
        "IpProtocol": "tcp"
      }
    }
}

When deploying the whole stack via CloudFormation, everything is properly created until it comes to the nested stack and then I simply get this message:

Template format error: Unresolved resource dependencies [Sg1,Sg2] in the Resources block of the template

Please help, with the full example to avoid the similar cases I found on google where the answer was suggesting a solution but so unclear that next 20 people had to ask the same again: where and what?

Thank you soo much, I spent on this the whole afternoon already...

Mike

Answer 1

You might need to add a parameters section to the nested template, eg

{
  "Parameters" : {
    "Sg1" : {
      "Type" : "AWS::EC2::SecurityGroup",
      "Description" : "cool beans"
    },
    "Sg2" : {
      "Type" : "AWS::EC2::SecurityGroup",
      "Description" : "whatever"
    }
  },
  "Resources": {
    "flow1": {
      "Type": "AWS::EC2::SecurityGroupIngress",
      "Properties": {
        "SourceSecurityGroupId": {"Ref": "Sg1"}, 
        "FromPort": "161", 
        "ToPort": "161", 
        "GroupId": {"Ref": "Sg2"}, 
        "IpProtocol": "tcp"
      }
    }
  }
}