RDS Modify Iops

Describe the bug An RDS policy to modify the Iops of a database fails with error "An error occurred (InvalidParameterCombination) when calling the ModifyDBInstance operation: You must specify both the storage size and iops when modifying the storage size or iops on a DB instance that has iops."

To Reproduce

"actions": [
  {
    "type": "modify-db",
    "update": [
      {
        "property": "Iops",
        "value": 4000
      }
    ],
    "immediate": true
  }

Expected behavior Modify the Iops of an RDS database.

Background

• Custodian Version: c7n:0.9.6
• Cloud Provider: AWS
• Policy:

policies:
  - name: rds_iops_higher
    resource: rds
    mode:
      type: periodic
      role: cloud-custodian-rds-iops-modify
      schedule: "cron(1 * * * ? *)"
      dead_letter_config:
        TargetArn: arn:aws:sqs:us-east-1:{account_id}:CustodianLambdasDLQ
    filters:
      - type: onhour
        weekends: false
        default_tz: ct
        tag: xray_iops_modify
        opt-out: false
        onhour: 5
    actions:
       - type: modify-db
         update:
           - property: 'Iops'
             value: 12000
         immediate: true

Additional context When adding an additional property for AllocatedStorage, the same error happened. It does not look like, when looking at CloudTrail, Custodian is passing the property though? Is that because it matches the current value?

This might not be a custodian thing if it’s simply passing every property specified along verbatim to the eventual API call…

[kapilt]

yes we’re pass through on parameters here, its worth reading the rds docs. ie. you can’t set iops on an instance thats not using provisioned iops storage. ie you should be filtering on storage type io1 else provisioned iops isn’t valid.

https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_Storage.html#USER_PIOPS

[rneu31]

https://github.com/cloud-custodian/cloud-custodian/blob/master/c7n/resources/rds.py#L1785-L1790

This code here seems to be filtering any parameter that matches the current value, right?