Using condition keys - Amazon ElastiCache
Specifying Conditions: Using Condition KeysExample Policies: Using Conditions for Fine-Grained Parameter Control
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Using condition keys

You can specify conditions that determine how an IAM policy takes effect. In ElastiCache, you can use the Condition element of a JSON policy to compare keys in the request context with key values that you specify in your policy. For more information, see IAM JSON policy elements: Condition.

To see a list of ElastiCache condition keys, see Condition Keys for Amazon ElastiCache in the Service Authorization Reference.

For a list of global condition keys, see Amazon global condition context keys.

Specifying Conditions: Using Condition Keys

To implement fine-grained control, you write an IAM permissions policy that specifies conditions to control a set of individual parameters on certain requests. You then apply the policy to IAM users, groups, or roles that you create using the IAM console.

To apply a condition, you add the condition information to the IAM policy statement. In the following example, you specify the condition that any self-designed cache cluster created will be of node type cache.r5.large. 

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateCacheCluster"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:parametergroup:*",
                "arn:aws:elasticache:*:*:subnetgroup:*"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateCacheCluster"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:cluster:*"
            ],
            "Condition": {
                "StringEquals": {
                    "elasticache:CacheNodeType": [
                        "cache.r5.large"
                    ]
                }
            }
        }
    ]
}

For more information, see Tag-Based access control policy examples.

For more information on using policy condition operators, see ElastiCache API permissions: Actions, resources, and conditions reference.

Example Policies: Using Conditions for Fine-Grained Parameter Control

This section shows example policies for implementing fine-grained access control on the previously listed ElastiCache parameters.

  1. elasticache:MaximumDataStorage:   Specify the maximum data storage of a serverless cache. Using the provided conditions, the customer can not create caches that can store more than a specific amount of data.

    {
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AllowDependentResources",
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateServerlessCache"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:serverlesscachesnapshot:*",
                "arn:aws:elasticache:*:*:snapshot:*",
                "arn:aws:elasticache:*:*:usergroup:*"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateServerlessCache"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:serverlesscache:*"
            ],
            "Condition": {
                "NumericLessThanEquals": {
                    "elasticache:MaximumDataStorage": "30"
                },
                "StringEquals": {
                    "elasticache:DataStorageUnit": "GB"
                }
            }
        }
    ]
}

  2. elasticache:MaximumECPUPerSecond:   Specify the maximum ECPU per second value of a serverless cache. Using the provided conditions, the customer can not create caches that can execute more than a specific number of ECPUs per second.

    {
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AllowDependentResources",
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateServerlessCache"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:serverlesscachesnapshot:*",
                "arn:aws:elasticache:*:*:snapshot:*",
                "arn:aws:elasticache:*:*:usergroup:*"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateServerlessCache"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:serverlesscache:*"
            ],
            "Condition": {
                "NumericLessThanEquals": {
                    "elasticache:MaximumECPUPerSecond": "100000"
                }
            }
        }
    ]
}

  3. elasticache:CacheNodeType:   Specify which NodeType(s) a user can create. Using the provided conditions, the customer can specify a single or a range value for a node type.

    {
    "Version": "2012-10-17",
    "Statement": [
         {
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateCacheCluster"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:parametergroup:*",
                "arn:aws:elasticache:*:*:subnetgroup:*"
            ]
        },

        {
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateCacheCluster"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:cluster:*"
            ],
            "Condition": {
                "StringEquals": {
                    "elasticache:CacheNodeType": [
                        "cache.t2.micro",
                        "cache.t2.medium"
                    ]
                }
            }
        }
    ]
}

  4. elasticache:EngineVersion:   Specify usage of engine version 1.6.6

    {
    "Version": "2012-10-17",
    "Statement": [
     {
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateCacheCluster"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:parametergroup:*",
                "arn:aws:elasticache:*:*:subnetgroup:*"
            ]
        },

        {
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateCacheCluster"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:cluster:*"
            ],
            "Condition": {
                "StringEquals": {
                    "elasticache:EngineVersion": "1.6.6"
                }
            }
        }
    ]
}

  5. elasticache:KmsKeyId:   Specify usage of customer managed Amazon KMS keys.

    {
  "Version": "2012-10-17",
  "Statement": [
    {
        "Sid": "AllowDependentResources",
        "Effect": "Allow",
        "Action": [
            "elasticache:CreateServerlessCache"
        ],
        "Resource": [
            "arn:aws:elasticache:*:*:serverlesscachesnapshot:*",
            "arn:aws:elasticache:*:*:snapshot:*",
            "arn:aws:elasticache:*:*:usergroup:*"
        ]
    },
    {
        "Effect": "Allow",
        "Action": [
            "elasticache:CreateServerlessCache"
        ],
        "Resource": [
            "arn:aws:elasticache:*:*:serverlesscache:*"
        ],
        "Condition": {
            "StringEquals": {
                "elasticache:KmsKeyId": "my-key"
            }
        }
    }
  ]
}

  6. elasticache:CacheParameterGroupName:   Specify a non default parameter group with specific parameters from an organization on your clusters. You could also specify a naming pattern for your parameter groups or block delete on a specific parameter group name. Following is an example constraining usage of only "my-org-param-group".

    {
    "Version": "2012-10-17",
    "Statement": [

         {
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateCacheCluster"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:parametergroup:*",
                "arn:aws:elasticache:*:*:subnetgroup:*"
            ]
        },

        {
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateCacheCluster"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:cluster:*"
            ],
            "Condition": {
                "StringEquals": {
                    "elasticache:CacheParameterGroupName": "my-org-param-group"
                }
            }
        }
    ]
}

  7. elasticache:CreateCacheCluster: Denying CreateCacheCluster action if the request tag Project is missing or is not equal to Dev, QA or Prod.

    {
    "Version": "2012-10-17",
    "Statement": [
          {
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateCacheCluster"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:parametergroup:*",
                "arn:aws:elasticache:*:*:subnetgroup:*",
                "arn:aws:elasticache:*:*:securitygroup:*",
                "arn:aws:elasticache:*:*:replicationgroup:*"
            ]
        },
        {
            "Effect": "Deny",
            "Action": [
                "elasticache:CreateCacheCluster"
            ],
            "Resource": [
                "arn:aws:elasticache:*:*:cluster:*"
            ],
            "Condition": {
                "Null": {
                    "aws:RequestTag/Project": "true"
                }
            }
        },
        {
            "Effect": "Allow",
            "Action": [
                "elasticache:CreateCacheCluster",
                "elasticache:AddTagsToResource"
            ],
            "Resource": "arn:aws:elasticache:*:*:cluster:*",
            "Condition": {
                "StringEquals": {
                    "aws:RequestTag/Project": [
                        "Dev",
                        "Prod",
                        "QA"
                    ]
                }
            }
        }
    ]
}

  8. elasticache:CacheNodeType:   Allowing CreateCacheCluster with cacheNodeType cache.r5.large or cache.r6g.4xlarge and tag Project=XYZ. 

    {
  "Version": "2012-10-17",
  "Statement": [
      {
      "Effect": "Allow",
      "Action": [
        "elasticache:CreateCacheCluster"
      ],
      "Resource": [
        "arn:aws:elasticache:*:*:parametergroup:*",
        "arn:aws:elasticache:*:*:subnetgroup:*"
      ]
    },
    {
      "Effect": "Allow",
      "Action": [
        "elasticache:CreateCacheCluster"
      ],
      "Resource": [
        "arn:aws:elasticache:*:*:cluster:*"
      ],
      "Condition": {
        "StringEqualsIfExists": {
          "elasticache:CacheNodeType": [
            "cache.r5.large",
            "cache.r6g.4xlarge"
          ]
        },
        "StringEquals": {
          "aws:RequestTag/Project": "XYZ"
        }
      }
    }
  ]
}
Note

When creating polices to enforce tags and other condition keys together, the conditional IfExists may be required on condition key elements due to the extra elasticache:AddTagsToResource policy requirements for creation requests with the --tags parameter.