Mappings

The Mappings section defines static key-value lookup tables in a template. Use Fn::FindInMap in the Resources or Outputs section to retrieve a value from a two-level map declared here.

Syntax

The Mappings section contains key-value pairs. Keys must be strings. Values can be of the String, Number, Boolean, List, or Dictionary type. When declaring multiple mappings in JSON, separate them with commas (,). Each mapping name must be unique within the section.

Mappings:
  ValidMap:
    '1234567890':
      TestValu3: value3
    TestKey1:
      TestValu1: value1
    TestKey2:
      TestValu2: value2
    TestKey4:
      TestValu4: 1234

Each field in the Mappings section has a specific role:

• ValidMap — the mapping logical name, unique within the template.

• TestKey1, TestKey2, TestKey4, '1234567890' — top-level keys (strings).

• TestValu1: value1 — second-level key-value pairs. Fn::FindInMap looks up values at this level.

  Example

  The following template uses Fn::FindInMap to select an image ID based on a region parameter. The RegionMap mapping stores image IDs for two regions (hangzhou and beijing), each with '32' and '64' keys.

  ROSTemplateFormatVersion: '2015-09-01'
  Parameters:
    regionParam:
      Description: the region where you want to create the Elastic Compute Service (ECS) instance
      Type: String
      AllowedValues:
        - hangzhou
        - beijing
  Mappings:
    RegionMap:
      hangzhou:
        '32': m-25l0rcfjo
        '64': m-25l0rcfj1
      beijing:
        '32': m-25l0rcfj2
        '64': m-25l0rcfj3
  Resources:
    WebServer:
      Type: ALIYUN::ECS::Instance
      Properties:
        ImageId:
          Fn::FindInMap:
            - RegionMap
            - Ref: regionParam
            - '32'
        InstanceType: ecs.t1.small
        SecurityGroupId: sg-25zwc****
        ZoneId: cn-beijing-b
        Tags:
          - Key: Department1
            Value: HumanResource
          - Key: Department2
            Value: Finance
                      

  Fn::FindInMap takes three arguments: the mapping name (RegionMap), the top-level key (resolved at deploy time from regionParam), and the second-level key ('32').

FAQ

You cannot query a value from a single-level map defined in the Mappings section. For more information, see How to query a value from a map in a template?