{     "ZStackTemplateFormatVersion" : "YYYY-MM-DD",     "Description" : "The description of the stack template, which is used to provide information such as application scenarios and the structure of the stack template.",     "Parameters" : {       // The parameters you can specify when creating a resource stack.     },     "Mappings" : {       // The mapping tables. Mapping tables are nested tables.     },     "Resources" : {       // The detailed information of resources, including configurations and dependencies.     },     "Outputs" : {       // The outputs that are used to provide useful information such as resource properties. You can use API to obtain this information.   }

• ZStackTemplateFormatVersion (Required)
  The version of the stack template.

  • Format: YYYY-MM-DD
• Description (Optional)
  The description of the stack template, which is used to provide information such as application scenarios and the structure of the stack template.

  • A detailed description can help users better understand the content of the stack template.
• Parameters (Optional)
  The parameters you can specify when creating a resource stack.

  • For example, an instance offering is often defined as a parameter.
  • Parameters have default values.
  • Parameters can improve the flexibility and reusability of the stack template.
  • For more information about Parameters, see the Parameters topic.
• Mappings (Optional)
  The mapping tables. Mapping tables are nested tables.

  • You can use Fn::FindInMap to select values through corresponding keys.
  • You can use parameter values as keys.
  • For example, you can search the region-image mapping table for desired images by region.
  • For more information about Mappings, see the Mappings topic.
• Resources (Optional)
  The detailed information of resources, including configurations and dependencies.

  • For more information about Resources, see the Resources topic.
• Outputs (Optional)
  The outputs that are used to provide useful information such as resource properties. You can use API to obtain this information.

  • For more information about Outputs, see the Outputs topic.

• The parameter name can only contain letters and digits and must be unique in the template.
• You can use the Label field to define user-friendly parameter names.

• Pseudo parameters are parameters that are predefined by CloudFormation. They can be referenced directly. You do not need to declare them in Parameters. (You are actually not allowed to declare them.)
• The values of the pseudo parameters are determined when CloudFormation is running.

"Parameters" : {   "username" : {     "Label": "Login name",     "Description" : "Login name",     "DefaultValue": "root",     "Type" : "String"   },   "password" : {     "Label": "Password",     "NoEcho" : "true",     "Description" : "Login password",     "Type" : "String",   } }

• username
  • A string type parameter with a default value of root.
  • The username must contain 2 to 12 characters.
  Note: The default value of username must also meet the length and valid values requirements.
• password
  • A string type parameter with no default value.
  • If you set NoEcho to true, CloudFormation returns the parameter value masked as asterisks (*****).
    Note: The NoEcho property cannot be configured currently.
  • The password must contain 6 to 41 characters.
  • The password can contain uppercase/lowercase letters and digits.

• All resource descriptions are enclosed in braces { }.
• Multiple resources are separated with commas ,.

"Resources" : {     "UUID-1" : {         "Description" : "The resource description",         "Type" : "The resource type",         "Properties" : {             The resource properties         }     },     "UUID-2" : {         "Description" : "The resource description"         "Type" : "The resource type",         "Properties" : {             The resource properties         }，         "DependsOn":"The dependent resource. Take UUID-1 for example. Note that this dependent resource should be contained in the context.",         "DeletionPolicy":"The deletion policy"     } }

• Resource UUID
  • UUID-1 and UUID-2 are the resource UUIDs. Both of them are variables.
  • You can use the resource UUID to reference the resource in other parts of the template.
  • The resource UUID is unique in a template.
• Type
  • The type of the resource that is being declared, including the Resource type and Action type.
  • For example, "Type": "ZStack::Resource::VmInstance" indicates that the resource is a VM instance. "Type": "ZStack::Action::AddIpRange" indicates the IP range to be added.
  • For more information about the resource types supported by CloudFormation, see the Resource Index topic.
• Properties
  • The resource properties that specify parameters for resource creation.
  • The following example shows the Properties syntax.

    "Resources" : {         "InstanceOffering" : {         "Type" : "ZStack::InstanceOffering",         "Properties" : {             "cpuNum" : "1",             "cpuSpeed" : "1",             "memorySize" : "1073741824",             "name" : "instance-offering",             "type" : "UserVm",             "sortKey": 0,             "allocatorStrategy": "LeastVmPreferredHostAllocatorStrategy"                }     } }

  • The rules of defining resource property values are as follows:
    • Property values can be text strings, string lists, boolean values, references, or return values of functions.
    • Text strings are enclosed with double quotation marks "".
    • String lists are enclosed with brackets [].
    • Return values of intrinsic functions and references are enclosed with braces {}.
    • The preceding rules also apply when property values are the combinations of text strings, string lists, references, and return values of functions.
    • The following example shows how to declare different types of properties.

      "Properties" : {     "String" : "string",     "LiteralList" : [ "value1", "value2" ],     "Boolean" : "true"     "ReferenceForOneValue" :  { "Ref" : "ResourceID" } ,     "FunctionResultWithFunctionParams" : {         "Fn::Join" : [ "%", [ "Key=", { "Ref" : "SomeParameter" } ] ] } }

  • If the resource does not require you to declare a property, this part can be skipped.
• DependsOn
  • With the DependsOn attribute, you can specify that the creation of a specific resource follows another.
  • When you add a DependsOn attribute to a resource, the resource is created only after the creation of the resource specified in the DependsOn attribute.
  • The following example shows the DependsOn syntax.

    {     "ZStackTemplateFormatVersion" : "2018-06-18",     "Resources" : {         "WebServer": {             "Type": "ZStack::Resource::VmInstance",             "DependsOn": "DatabseServer"         },         "DatabseServer": {             "Type": "ZStack::Resource::VmInstance",             "Properties": {                 "name": {"Fn::Join":["-",[{"Ref":"ZStack::StackName"},"VM"]]},                           "instanceOfferingUuid": {"Ref":"InstanceOfferingUuid"},                           "imageUuid":{"Ref":"ImageUuid"},                 "l3NetworkUuids":[{"Ref":"PrivateNetworkUuid"}],                 "dataDiskOfferingUuids":[{"Ref":"DiskOfferingUuid"}], 	         "hostUuid":{"Ref":"HostUuid"}             }         }     } }

    This example indicates that WebServer is created only after DatabaseServer is created.

• DeletionPolicy
  • DeletionPolicy specifies whether to retain a resource after its stack is deleted.
  • DeletionPolicy has two options: Retain and Delete.
    • Delete: The default value, which indicates that after a resource stack is deleted, all resources in the stack will be deleted.
    • Retain: If the DeletionPolicy attribute is set to Retain, the specific resource will be retained after its stack is deleted. Furthermore, the dependent resource of the resource will also be retained. (The system automatically retains the dependent resource.)
      The following example shows that the VM instance is retained after the template-based resource stack is deleted.

      "Resources" : {     "VMInstance" : {         "Type" : "ZStack::Resource::VmInstance",         "Properties": {             "name": {"Fn::Join":["-",[{"Ref":"ZStack::StackName"},"VM"]]},                       "instanceOfferingUuid": {"Ref":"InstanceOfferingUuid"},                       "imageUuid":{"Ref":"ImageUuid"},             "l3NetworkUuids":[{"Ref":"PrivateNetworkUuid"}],             "dataDiskOfferingUuids":[{"Ref":"DiskOfferingUuid"}], 	     "hostUuid":{"Ref":"HostUuid"}     },     "DeletionPolicy" : "Retain"   } }