cloudformation.yaml

Description: "Deploy auto-set-fsxn-auto-grow"
#
# This just formats the page that prompts for the parameters when using the AWS Console to deploy your stack.
Metadata: 
  AWS::CloudFormation::Interface: 
    ParameterGroups:
      - Label: 
          default: "Deployment Parameters"
        Parameters: 
          - subNetIds
          - vpcId
          - securityGroupIds
          - dynamoDbSecretsTableName
          - dynamoDbRegion
          - secretsManagerRegion
          - createWatchdogAlarm
          - snsTopicArn
          - createSecretManagerEndpoint
          - createFSxEndpoint
          - createDynamoDbEndpoint
          - routeTableIds
          - endpointSecurityGroupIds
      - Label: 
          default: "Auto Size Parameters"
        Parameters: 
          - autoSizeMode
          - growThresholdPrecentage
          - maxGrowSizePercentage
          - shrinkThresholdPrecentage
          - minShrinkSizePercentage
          - maxWaitTime

Parameters:
  subNetIds:
    Description: "The subnet IDs where you want the Lambda function to run from. These subnets must have access to management end points of all the FSxNs you want it to manage."
    Type: "List<AWS::EC2::Subnet::Id>"

  securityGroupIds:
    Description: "The security group IDs to associate with the Lambda function. Just needs to allow outbound traffic to port 443 to the AWS API endpoints as well as the FSxNs."
    Type: "List<AWS::EC2::SecurityGroup::Id>"

  vpcId:
    Description: "The VPC ID of the subnets where the Lambda function is run from. This is only needed if you are creating an AWS service VPC endpoint."
    Type: String
    Default: ""

  dynamoDbSecretsTableName:
    Description: "The name of the DynamoDB table that contains the list of AWS secrets use to authenicate to the FSxNs with."
    Type: String
    Default: ""

  dynamoDbRegion:
    Description: "The region where the DynamoDB table is located."
    Type: String
    Default: ""

  secretsManagerRegion:
    Description: "The region where the AWS Secrets are located."
    Type: String
    Default: ""

  createWatchdogAlarm:
    Description: "Create a CloudWatch alarm to monitor the this Lambda function."
    Type: String
    Default: "true"
    AllowedValues: ["true", "false"]

  snsTopicArn:
    Description: "The ARN of the SNS topic to send watchdog alerts to. Only needed if createWatchdogAlarm is set to 'true'."
    Type: String
    Default: ""

  createSecretManagerEndpoint:
    Description: "Create a secret manager endpoint."
    Type: String
    Default: "false"
    AllowedValues: ["true", "false"]

  createFSxEndpoint:
    Description: "Create an FSx endpoint."
    Type: String
    Default: "false"
    AllowedValues: ["true", "false"]

  createDynamoDbEndpoint:
    Description: "Create a DynamoDB endpoint."
    Type: String
    Default: "false"
    AllowedValues: ["true", "false"]

  endpointSecurityGroupIds:
    Description: "The security group IDs to associate with the AWS service VPC endpoints. Must allow traffic from from the Lambda function over TCP port 443. This parameter is only needed if you are creating the AWS service VPC endpoints."
    Type: CommaDelimitedList
    Default: ""

  routeTableIds:
    Description: "The route table IDs to update to use the DynamoDB endpoint. Since the DynamoDB endpoint is of type 'Gateway' route tables must be updated to use it. This parameter is only needed if createDynamoDbEndpoint is set to 'true'."
    Type: CommaDelimitedList
    Default: ""

  autoSizeMode:
    Description: "Defines the mode you want auto size run in. Allowed values are grow, grow and shrink, off."
    Type: String
    Default: "grow"
    AllowedValues: ["grow", "grow_and_shrink", "off"]

  growThresholdPrecentage:
    Description: "The percentage of the volume that must be used before the volume will grow."
    Type: Number
    Default: 85
    MinValue: 1
    MaxValue: 100

  shrinkThresholdPrecentage:
    Description: "The percentage of the volume that must be in use before the volume will shrink."
    Type: Number
    Default: 50
    MinValue: 1
    MaxValue: 100

  maxGrowSizePercentage:
    Description: "The maximum size the volume can auto grow to expressed in terms of a percentage of the volume size."
    Type: Number
    Default: 200
    MinValue: 1

  minShrinkSizePercentage:
    Description: "The minimum size the volume can auto shrink to expressed in terms of a percentage of the volume size."
    Type: Number
    Default: 50
    MinValue: 1

  maxWaitTime:
    Description: "The maximum time, in minutes, to wait for a volume to be created before it will give up and exit."
    Type: Number
    Default: 60
    MinValue: 10

Conditions:
  CreateSecretManagerEndpoint: !Equals [!Ref createSecretManagerEndpoint, "true"]
  CreateFSxEndpoint: !Equals [!Ref createFSxEndpoint, "true"]
  CreateDynamoDbEndpoint: !Equals [!Ref createDynamoDbEndpoint, "true"]
  CreateWatchdogAlarm: !Equals [!Ref createWatchdogAlarm, "true"]

Resources:
  SecretManagerEndpoint:
    Type: AWS::EC2::VPCEndpoint
    Condition: CreateSecretManagerEndpoint
    Properties:
      VpcId: !Ref vpcId
      ServiceName: !Sub "com.amazonaws.${AWS::Region}.secretsmanager"
      VpcEndpointType: 'Interface'
      PrivateDnsEnabled: true
      SubnetIds: !Ref subNetIds
      SecurityGroupIds: !Ref endpointSecurityGroupIds

  FSxEndpoint:
    Type: AWS::EC2::VPCEndpoint
    Condition: CreateFSxEndpoint
    Properties:
      VpcId: !Ref vpcId
      ServiceName: !Sub "com.amazonaws.${AWS::Region}.fsx"
      VpcEndpointType: 'Interface'
      PrivateDnsEnabled: true
      SubnetIds: !Ref subNetIds
      SecurityGroupIds: !Ref endpointSecurityGroupIds

  DynamoDbEndpoint:
    Type: AWS::EC2::VPCEndpoint
    Condition: CreateDynamoDbEndpoint
    Properties:
      VpcId: !Ref vpcId
      ServiceName: !Sub "com.amazonaws.${AWS::Region}.dynamodb"
      VpcEndpointType: 'Gateway'
      RouteTableIds: !Ref routeTableIds

  watchDogAlarm:
    Type: "AWS::CloudWatch::Alarm"
    Condition: CreateWatchdogAlarm
    Properties:
      AlarmName: !Sub "auto-set-auto-grow-${AWS::StackName}"
      AlarmDescription: !Sub "Watchdog alarm for the auto-set-auto-grow-${AWS::StackName} Lambda function."
      Namespace: "AWS/Lambda"
      MetricName: "Errors"
      Dimensions:
        - Name: "FunctionName"
          Value: !Sub "auto-set-fsxn-auto-grow-${AWS::StackName}"
      Statistic: "Maximum"
      Period: 300
      EvaluationPeriods: 1
      TreatMissingData: "ignore"
      Threshold: 0.5
      ComparisonOperator: "GreaterThanThreshold"
      AlarmActions:
        - !Ref snsTopicArn

  LambdaRole:
    Type: "AWS::IAM::Role"
    Properties:
      RoleName: !Sub "auto-set-fsxn-auto-grow-${AWS::StackName}"
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: "Allow"
            Principal:
              Service: "lambda.amazonaws.com"
            Action: "sts:AssumeRole"

      ManagedPolicyArns:
        - "arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"

      Policies:
        - PolicyName: "LambdaPolicy"
          PolicyDocument:
            Version: "2012-10-17"
            Statement:
              - Effect: "Allow"
                Action:
                  - "secretsManager:GetSecretValue"
                Resource: 
                  - !Sub "arn:aws:secretsmanager:${secretsManagerRegion}:${AWS::AccountId}:secret:*"
              - Effect: "Allow"
                Action:
                  - "dynamodb:Scan"
                Resource: 
                  - !Sub "arn:aws:dynamodb:${AWS::Region}:${AWS::AccountId}:table/${dynamoDbSecretsTableName}"
              - Effect: "Allow"
                Action:
                  - "fsx:DescribeFileSystems"
                  - "fsx:DescribeVolumes"
                Resource: "*"
              - Effect: "Allow"
                Action:
                  - "ec2:CreateNetworkInterface"
                  - "ec2:DeleteNetworkInterface"
                  - "ec2:DescribeNetworkInterfaces"
                Resource: "*"

  LambdaInvokePermission:
    Type: AWS::Lambda::Permission
    Properties:
      FunctionName: !GetAtt LambdaFunction.Arn
      Action: "lambda:InvokeFunction"
      Principal: "events.amazonaws.com"
      SourceArn: !GetAtt EventBridgeCreateVolumeRule.Arn

  EventBridgeCreateVolumeRule:
    Type: "AWS::Events::Rule"
    Properties:
      Description: "Triggered when a FSx volume is created."
      Name: !Sub "auto-set-fsxn-auto-grow-${AWS::StackName}"
      EventBusName: "default"
      EventPattern:
        detail-type:
          - "AWS API Call via CloudTrail"
        detail:
          eventSource:
            - "fsx.amazonaws.com"
          eventName:
            - "CreateVolume"
      Targets:
        - Arn: !GetAtt LambdaFunction.Arn
          Id: "Target_1"

  LambdaFunction:
    Type: "AWS::Lambda::Function"
    Properties:
      FunctionName: !Sub "auto-set-fsxn-auto-grow-${AWS::StackName}"
      Role: !GetAtt LambdaRole.Arn
      VpcConfig:
        SecurityGroupIds: !Ref securityGroupIds
        SubnetIds: !Ref subNetIds
      PackageType: "Zip"
      Runtime: "python3.12"
      Handler: "index.lambda_handler"
      Timeout: !Ref maxWaitTime
      Environment:
        Variables:
          dynamoDbRegion: !Ref dynamoDbRegion
          dynamoDbSecretsTableName: !Ref dynamoDbSecretsTableName
          secretsManagerRegion: !Ref secretsManagerRegion

          autoSizeMode: !Ref autoSizeMode
          growThresholdPrecentage: !Ref growThresholdPrecentage
          maxGrowSizePercentage: !Ref maxGrowSizePercentage
          shrinkThresholdPrecentage: !Ref shrinkThresholdPrecentage
          minShrinkSizePercentage: !Ref minShrinkSizePercentage
          maxWaitTime: !Ref maxWaitTime

      Code:
        ZipFile: |
          ################################################################################
          # THIS SOFTWARE IS PROVIDED BY NETAPP "AS IS" AND ANY EXPRESS OR IMPLIED
          # WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
          # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
          # EVENT SHALL NETAPP BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
          # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
          # PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
          # OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
          # WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR'
          # OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
          # ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
          ################################################################################
          
          ################################################################################
          # This Lambda function is used to set the auto size feature to 'grow' on a
          # volume that was created in an AWS FSx for NetApp ONTAP file system. It is
          # expected to be triggered by a CloudWatch event that is generated when a
          # volume is created. The function uses the ONTAP API to set the auto size
          # mode to 'grow' on the volume therefore it most run within the VPC where the
          # FSx for ONTAP file system is located.
          #
          # Version: v1.1
          # Date: 2024-12-06-20:30:19
          ################################################################################
          
          import json
          import time
          import urllib3
          from urllib3.util import Retry
          import logging
          import boto3
          import os
          #
          ################################################################################
          # Configuration settings.
          #
          # You can either set the variables in the code below, or set environment variables
          # with the same name as the variables below. Except for the secretsTable, you must
          # set that in the code if you are not going to use DynamoDb to hold your secrets
          # table.
          #
          # NOTE: The environment variables will take precedence over the variables
          # set in the code.
          #
          ################################################################################
          #
          # Create a table of secret names and keys for the username and password for
          # each of the FSxIds. In the example below, it shows using the same
          # secret for four different FSxIds, but you can set it up to use
          # a different secret and/or keys for the username and password for each
          # of the FSxId.
          #secretsTable = [
          #        {"fsxId": "fs-0e8d9172fa5XXXXXX", "secretName": "fsxn-credentials", "usernameKey": "username", "passwordKey": "password"},
          #        {"fsxId": "fs-020de2687bdXXXXXX", "secretName": "fsxn-credentials", "usernameKey": "username", "passwordKey": "password"},
          #        {"fsxId": "fs-07bcb7ad84aXXXXXX", "secretName": "fsxn-credentials", "usernameKey": "username", "passwordKey": "password"},
          #        {"fsxId": "fs-077b5ff4195XXXXXX", "secretName": "fsxn-credentials", "usernameKey": "username", "passwordKey": "password"}
          #    ]
          #
          # If you don't want to define the secretsTable in this script, you can
          # define the following variables to use a DynamoDB table to get the
          # secret information.
          #
          # NOTE: If both the secretsTable, and dynamodbSecretsTableName are defined,
          # then the secretsTable will be used.
          dynamoDbRegion=None
          dynamoDbSecretsTableName=None
          #
          # Set the region where the secrets are stored.
          secretsManagerRegion=None
          #
          # Set the auto size mode. Supported values are "grow", "grow_shrink", and "off".
          autoSizeMode = "grow"
          #
          # Set the grow-threshold-percentage for the volume. This is the percentage of the volume that must be used before it grows.
          growThresholdPercentage = 85
          #
          # Set the maximum grow size for the volume in terms of the percentage of the provisioned size.
          maxGrowSizePercentage = 200
          #
          # Set the shrink-threshold-percentage for the volume. This is the percentage of the volume that must be free before it shrinks.
          shrinkThresholdPercentage = 50
          #
          # Set the minimum shirtk size for the volume in terms of the percentage of the provisioned size.
          minShrinkSizePercentage = 100
          #
          # Set the time to wait for a volume to get created. This Lambda function will
          # loop waiting for the volume to be created on the ONTAP side so it can set
          # the auto size parameters. It will wait up to the number of seconds specified
          # below before giving up. NOTE: You must set the timeout of this function
          # to at least the number of seconds specified here, and probably two times
          # the number to account for the time it takes to do the API calls,
          # otherwise the Lambda timeout feature will kill it before it is able to
          # wait as long you want it to. Also note that the main reason for
          # it to take a while for a volume to get created is when multiple are being
          # created at the same time. So, if you have automation that might create a lot of
          # volumes at the same time, you might need to either adjust this number really
          # high, or come up with another way to get the auto size mode.
          maxWaitTime=60
          
          ################################################################################
          # This function sets the configuration variables from environment variables if
          # they are defined.
          ################################################################################
          def setConfigurationVariables():
              global secretsTable, secretsManagerRegion, autoSizeMode, growThresholdPercentage
              global maxGrowSizePercentage, shrinkThresholdPercentage, minShrinkSizePercentage
              global dynamoDbRegion, dynamoDbSecretsTableName, secretsTable, maxWaitTime, logger
          
              if os.environ.get('dynamoDbRegion') != None:
                  dynamoDbRegion = os.environ['dynamoDbRegion']
              if os.environ.get('dynamoDbSecretsTableName') != None:
                  dynamoDbSecretsTableName = os.environ['dynamoDbSecretsTableName']
              if os.environ.get('secretsManagerRegion') != None:
                  secretsManagerRegion = os.environ['secretsManagerRegion']
              if os.environ.get('autoSizeMode') != None:
                  autoSizeMode = os.environ['autoSizeMode']
              if os.environ.get('growThresholdPercentage') != None:
                  growThresholdPercentage = int(os.environ['growThresholdPercentage'])
              if os.environ.get('maxGrowSizePercentage') != None:
                  maxGrowSizePercentage = int(os.environ['maxGrowSizePercentage'])
              if os.environ.get('shrinkThresholdPercentage') != None:
                  shrinkThresholdPercentage = int(os.environ['shrinkThresholdPercentage'])
              if os.environ.get('minShrinkSizePercentage') != None:
                  minShrinkSizePercentage = int(os.environ['minShrinkSizePercentage'])
              if os.environ.get('maxWaitTime') != None:
                  maxWaitTime = int(os.environ['maxWaitTime'])
              #
              # Check that all the required variables are set.
              message = ""
              if dynamoDbRegion == None and dynamoDbSecretsTableName == None and 'secretsTable' not in globals():
                  message += 'Error, you must either define the secretsTable array at the top of this script, or define dynamodbRegion and dynamoDbSecretsTableName environment variables.\n'
          
              if secretsManagerRegion == None:
                  message += 'Error, you must define the secretsManagerRegion environment variable.\n'
          
              if autoSizeMode == None or autoSizeMode not in ['grow', 'grow_shrink', 'off']:
                  message += 'Error, you must define the autoSizeMode environment variable to either "grow", "grow_shrink", or "off".\n'
          
              if growThresholdPercentage == None or isinstance(growThresholdPercentage, int) == False or growThresholdPercentage < 0 or growThresholdPercentage > 100:
                  message += 'Error, you must define the growThresholdPercentage environment variable between 0 and 100.\n'
          
              if maxGrowSizePercentage == None or isinstance(maxGrowSizePercentage, int) == False or maxGrowSizePercentage < 0 or maxGrowSizePercentage > 1000:
                  message += 'Error, you must define the maxGrowSizePercentage environment variable between 0 and 1000.\n'
          
              if shrinkThresholdPercentage == None or isinstance(shrinkThresholdPercentage, int) == False or shrinkThresholdPercentage < 0 or shrinkThresholdPercentage > 100:
                  message += 'Error, you must define the shrinkThresholdPercentage environment variable between 0 and 100.\n'
          
              if minShrinkSizePercentage == None or isinstance(minShrinkSizePercentage, int) == False or minShrinkSizePercentage < 0 or minShrinkSizePercentage > 100:
                  message += 'Error, you must define the minShrinkSizePercentage environment variable between 0 and 100.\n'
          
              if maxWaitTime == None or isinstance(maxWaitTime, int) == False or maxWaitTime < 0 or maxWaitTime > 600:
                  message += 'Error, you must define the maxWaitTime environment variable between 0 and 600.\n'
          
              if message != "":
                  logger.critical(message)
                  raise Exception(message)
          
          ################################################################################
          # This function is used to obtain the username and password from AWS's Secrets
          # Manager for the fsxnId passed in. It returns empty strings if it can't
          # find the credentials.
          ################################################################################
          def getCredentials(secretsManagerClient, fsxnId):
              global secretsTable
          
              for secretItem in secretsTable:
                  if secretItem['fsxId'] == fsxnId:
                      secretsInfo = secretsManagerClient.get_secret_value(SecretId=secretItem['secretName'])
                      secrets = json.loads(secretsInfo['SecretString'])
                      username = secrets[secretItem['usernameKey']]
                      password = secrets[secretItem['passwordKey']]
                      return (username, password)
              return ("", "")
          
          ################################################################################
          # This function returns the AWS structure for a FSxN volume based on the
          # volumeId passed it. It confirms that the volume has been created on the ONTAP
          # side by checking that the ResourceARN field equals the volumeARN passed in
          # that came from the volume creation event and that the UUID field has been
          # populated. It returns None if it can't find the volume.
          ################################################################################
          def getVolumeData(fsxClient, volumeId, volumeARN):
          
              global logger
          
              cnt = 0
              while cnt < maxWaitTime:
                  awsVolume = fsxClient.describe_volumes(VolumeIds=[volumeId])['Volumes'][0]
                  if awsVolume['ResourceARN'] == volumeARN and awsVolume['OntapConfiguration'].get("UUID") != None:
                      return awsVolume
                  logger.debug(f'Looping, getting the UUID {cnt}')
                  cnt += 1
                  time.sleep(1)
          
              return None
          
          ################################################################################
          ################################################################################
          def lambda_handler(event, context):
          
              global logger, secretsTable
              #
              # Set up "logging" to appropriately display messages. It can be set it up
              # to send messages to a syslog server.
              logging.basicConfig(datefmt='%Y-%m-%d_%H:%M:%S', format='%(asctime)s:%(name)s:%(levelname)s:%(message)s', encoding='utf-8')
              logger = logging.getLogger("set_fsxn_volume_auto_size")
          #    logger.setLevel(logging.DEBUG)
              logger.setLevel(logging.INFO)
              #
              # Set the logging level higher for these noisy modules to mute thier messages.
              logging.getLogger("botocore").setLevel(logging.WARNING)
              logging.getLogger("boto3").setLevel(logging.WARNING)
              logging.getLogger("urllib3").setLevel(logging.WARNING)
              #
              # Set the configuration variables from environment variables if they are defined.
              setConfigurationVariables()
              #
              # If this is an event from a failed call. Report that and return.
              if event['detail'].get('errorCode') != None:
                  logger.warning(f"This is reporting on a error event. Error Code: {event['detail']['errorCode']}. Error Message: {event['detail']['errorMessage']}.")
                  return
              #
              # Create a Secrets Manager client.
              session = boto3.session.Session()
              secretsManagerClient = session.client(service_name='secretsmanager', region_name=secretsManagerRegion)
              #
              # Disable warning about connecting to servers with self-signed SSL certificates.
              urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
              #
              # Set the https retries to 1.
              retries = Retry(total=None, connect=1, read=1, redirect=10, status=0, other=0)
              http = urllib3.PoolManager(cert_reqs='CERT_NONE', retries=retries)
              #
              # Read in the secretTable if it is not already defined.
              # It is safe to assume dynamoDbRegion and dynamoDbSecretsTableName are defined
              # because the setConfigurationVariables function would have errored out if they
              # were not.
              if 'secretsTable' not in globals():
                  dynamodbClient = boto3.resource("dynamodb", region_name=dynamoDbRegion)
                  table = dynamodbClient.Table(dynamoDbSecretsTableName)
                  response = table.scan()
                  secretsTable = response["Items"]
              #
              # Get the FSxN ID, region, volume name, volume ID, and volume ARN from the CloudWatch event.
              fsxId      = event['detail']['responseElements']['volume']['fileSystemId']
              regionName = event['detail']['awsRegion']
              volumeName = event['detail']['requestParameters']['name']
              volumeId   = event['detail']['responseElements']['volume']['volumeId']
              volumeARN  = event['detail']['responseElements']['volume']['resourceARN']
              if fsxId == "" or regionName == "" or volumeId == "" or volumeName == "" or volumeARN == "":
                  message = "Couldn't obtain the fsxId, region, volume name, volume ID or volume ARN from the CloudWatch evevnt."
                  logger.critical(message)
                  return
          
              logger.debug(f'Data from CloudWatch event: FSxID={fsxId}, Region={regionName}, VolumeName={volumeName}, volumeId={volumeId}.')
              #
              # Get the username and password for the FSxN ID.
              (username, password) = getCredentials(secretsManagerClient, fsxId)
              if username == "" or password == "":
                  message = f'No credentials for FSxN ID: {fsxId}.'
                  logger.critical(message)
                  return
              #
              # Build a header that is used for all the ONTAP API requests.
              auth = urllib3.make_headers(basic_auth=f'{username}:{password}')
              headers = { **auth }
              #
              # Get the management IP of the FSxN file system.
              fsxClient = boto3.client('fsx', region_name = regionName)
              fs = fsxClient.describe_file_systems(FileSystemIds = [fsxId])['FileSystems'][0]
              fsxnIp = fs['OntapConfiguration']['Endpoints']['Management']['IpAddresses'][0]
              if fsxnIp == "":
                  message = f"Can't find management IP for FSxN file system with an ID of '{fsxId}'."
                  logger.critical(message)
                  return
              #
              # Get the volume UUID and volume size based on the volume ID.
              volumeData = getVolumeData(fsxClient, volumeId, volumeARN)
              if volumeData == None:
                  message=f'Failed to get volume information for volumeID: {volumeId}.'
                  logger.critical(message)
                  return
              volumeUUID = volumeData["OntapConfiguration"]["UUID"]
              volumeSizeInMegabytes = volumeData["OntapConfiguration"]["SizeInMegabytes"]
              #
              # Set the auto grow feature.
              try:
                  endpoint = f'https://{fsxnIp}/api/storage/volumes/{volumeUUID}'
                  maximum = volumeSizeInMegabytes * maxGrowSizePercentage / 100 * 1024 * 1024
                  minimum = volumeSizeInMegabytes * minShrinkSizePercentage / 100 * 1024 * 1024
                  #
                  # Make sure the minimum is at least 20MB.
                  if minimum < 20 * 1024 * 1024:
                      minimum = 20 * 1024 * 1024
                  data = json.dumps({"autosize": {"mode": autoSizeMode, "grow_threshold": growThresholdPercentage, "maximum": maximum, "minimum": minimum, "shrink_threshold": shrinkThresholdPercentage}})
                  logger.debug(f'Trying {endpoint} with {data}.')
                  response = http.request('PATCH', endpoint, headers=headers, timeout=5.0, body=data)
                  if response.status >= 200 and response.status <= 299:
                      logger.info(f"Updated the auto size parameters for volume name {volumeName}.")
                  else:
                      logger.error(f'API call to {endpoint} failed. HTTP status code: {response.status}. Error message: {response.data}.')
              except Exception as err:
                  logger.critical(f'Failed to issue API against {fsxnIp}. The error messages received: "{err}".')