Multiple conditions in cloud formation resource creation

问题

I'm using a platform condition to control the type of environment that gets spun up on AWS. There are plenty of shared resources, but I need certain EC2 instances with pre-baked AMIs depending on a number conditions.

"Parameters": {
"Platform": {
  "Description": "Select platform type - linux or windows",
  "Default": "linux",
  "Type": "String",
  "AllowedValues": [ "linux", "windows", "both" ],
  "ConstraintDescription": "Must enter either linux, windows, or both"
},

Then I set the conditions.

"Conditions" : {
  "LinuxPlatform" : {"Fn::Equals" : [{"Ref" : "Platform"}, "linux"]},
  "WindowsPlatform" : {"Fn::Equals" : [{"Ref" : "Platform"}, "windows"]},
  "BothPlatform" : {"Fn::Equals" : [{"Ref" : "Platform"}, "both"]}
},

In a resource I'd like to use either linux or windows to trigger a Windows or Linux Ec2 creation, or use both to deploy every ec2 resource declared.

I've tried the following using fn:or in a few ways.

"Fn::Or": [{"Condition": "LinuxPlatform"}, {"Condition": "BothPlatform" }],

and...

"Condition" : {
   "Fn::Or" : [
      {"Condition" : "LinuxPlatform"},
      {"Condition" : "BothPlatform"}
   ]
}

I keep getting the following error when trying to deploying and validating using the aws cli.

aws cloudformation validate-template --template-body       file://./cloudformation/deploy.json

A client error (ValidationError) occurred when calling the ValidateTemplate operation: Template format error: Every Condition member must be a string.

Is it possible to evaluate multiple conditions to control resource creation? If not are there any alternatives I could try?

回答1:

Try adding

"MyCondition": {"Fn::Or": [{"Condition": "LinuxPlatform"}, {"Condition": "BothPlatform" }]}

to the bottom of your Conditions like that:

    "Conditions" : {
        "LinuxPlatform" : {"Fn::Equals" : [{"Ref" : "Platform"}, "linux"]},
        "WindowsPlatform" : {"Fn::Equals" : [{"Ref" : "Platform"}, "windows"]},
        "BothPlatform" : {"Fn::Equals" : [{"Ref" : "Platform"}, "both"]},
        "MyCondition": {"Fn::Or": [{"Condition": "LinuxPlatform"}, {"Condition": "BothPlatform" }]}
    },

回答2:

I was looking for the same thing with different scenarios in the YAML format. Below is the YAML format for the reference.

CreateResources: !Or [!Equals [!Ref "Environment", prod], !Equals [!Ref "Environment", dev], !Equals [!Ref "Environment", preprod], !Equals [!Ref "Environment", test]]

来源：https://stackoverflow.com/questions/39086361/multiple-conditions-in-cloud-formation-resource-creation