Given i have this example template:
{ "AWSTemplateFormatVersion" : "2010-09-09", "Mappings" : { "RegionMap" : { "us-west-1" : { "AMI" : "ami-655a0a20" }, ... } }, "Resources" : { "Ec2Instance" : { "Type" : "AWS::EC2::Instance", "Properties" : { ... }, "DependsOn" : "myDB" }, "myDB" : { "Type" : "AWS::RDS::DBInstance", "Properties" : { ... } }, "myDB2" : { "Type" : "AWS::RDS::DBInstance", "Properties" : { ... } } } }
Is it possible to specify multiple DependsOn in any way? Would be great to have somethink like:
"DependsOn" : ["myDB", "myDB2"]
Whats the normal way?
Yes,
The DependsOn attribute can take a single string or list of strings.
http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-attribute-dependson.html
Syntax:
"DependsOn" : [ String, ... ]
Yes, "DependsOn" can take multiple strings. I have listed an example below:
"DependsOn": [ "S3BucketAppElbLogs", "ElbLogAppBucketPolicy" ]
{ "Description": "Create a variable number of EC2 instance resources.", "Parameters": { "InstanceCount": { "Description": "Number of EC2 instances (must be between 1 and 5).", "Type": "Number", "Default": 1, "MinValue": 1, "MaxValue": 5, "ConstraintDescription": "Must be a number between 1 and 5." }, "ImageId": { "Description": "Image ID to launch EC2 instances.", "Type": "AWS::EC2::Image::Id", "Default": "ami-31c9924e" }, "InstanceType": { "Description": "Instance type to launch EC2 instances.", "Type": "String", "Default": "m3.medium", "AllowedValues": [ "m3.medium", "m3.large", "m3.xlarge", "m3.2xlarge" ] } }, "Conditions": { "Launch1" : {"Fn::Equals" : [{"Ref" : "InstanceCount"}, "1"]}, "Launch2" : {"Fn::Equals" : [{"Ref" : "InstanceCount"}, "2"]} }, "Resources": { "Instance2": { "Condition": "Launch2", "Type": "AWS::EC2::Instance", "Properties": { "ImageId": { "Ref": "ImageId" }, "InstanceType": { "Ref": "InstanceType" } }, "DependsOn": "Instance1" }, "Instance1": { "Condition": "Launch1", "Type": "AWS::EC2::Instance", "Properties": { "ImageId": { "Ref": "ImageId" }, "InstanceType": { "Ref": "InstanceType" } } } } }
