Other use cases for pre and post scripts

You must create an SSM command document that includes the pre and/or post scripts with the commands you want to run.

You can create an SSM document using the empty SSM document template below and add your pre and post script commands in the appropriate document sections.

###===============================================================================###
# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.

# Permission is hereby granted, free of charge, to any person obtaining a copy of this
# software and associated documentation files (the "Software"), to deal in the Software
# without restriction, including without limitation the rights to use, copy, modify,
# merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
# PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
###===============================================================================###
schemaVersion: '2.2'
description: SSM Document Template for Amazon Data Lifecycle Manager Pre/Post script feature
parameters:
  executionId:
    type: String
    default: None
    description: (Required) Specifies the unique identifier associated with a pre and/or post execution
    allowedPattern: ^(None|[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12})$
  command:
  # Data Lifecycle Manager will trigger the pre-script and post-script actions during policy execution. 
  # 'dry-run' option is intended for validating the document execution without triggering any commands
  # on the instance. The following allowedValues will allow Data Lifecycle Manager to successfully 
  # trigger pre and post script actions.
    type: String
    default: 'dry-run'
    description: (Required) Specifies whether pre-script and/or post-script should be executed.
    allowedValues:
    - pre-script
    - post-script
    - dry-run

mainSteps:
- action: aws:runShellScript
  description: Run Database freeze/thaw commands
  name: run_pre_post_scripts
  precondition:
    StringEquals:
    - platformType
    - Linux
  inputs:
    runCommand:
    - |
      #!/bin/bash

      ###===============================================================================###
      ### Error Codes
      ###===============================================================================###
      # The following Error codes will inform Data Lifecycle Manager of the type of error 
      # and help guide handling of the error. 
      # The Error code will also be emitted via AWS Eventbridge events in the 'cause' field.
      # 1 Pre-script failed during execution - 201
      # 2 Post-script failed during execution - 202
      # 3 Auto thaw occurred before post-script was initiated - 203
      # 4 Pre-script initiated while post-script was expected - 204
      # 5 Post-script initiated while pre-script was expected - 205
      # 6 Application not ready for pre or post-script initiation - 206

      ###===============================================================================###
      ### Global variables
      ###===============================================================================###
      START=$(date +%s)
      # For testing this script locally, replace the below with OPERATION=$1.
      OPERATION={{ command }}

      # Add all pre-script actions to be performed within the function below
      execute_pre_script() {
          echo "INFO: Start execution of pre-script"
      }

      # Add all post-script actions to be performed within the function below
      execute_post_script() {
          echo "INFO: Start execution of post-script"
      }

      # Debug logging for parameters passed to the SSM document
      echo "INFO: ${OPERATION} starting at $(date) with executionId: ${EXECUTION_ID}"

      # Based on the command parameter value execute the function that supports 
      # pre-script/post-script operation
      case ${OPERATION} in
          pre-script)
              execute_pre_script
              ;;
          post-script)
              execute_post_script
              ;;
          dry-run)
              echo "INFO: dry-run option invoked - taking no action"
              ;;
          *)
              echo "ERROR: Invalid command parameter passed. Please use either pre-script, post-script, dry-run."
              exit 1 # return failure
              ;;
      esac

      END=$(date +%s)
      # Debug Log for profiling the script time
      echo "INFO: ${OPERATION} completed at $(date). Total runtime: $((${END} - ${START})) seconds."

You must ensure that that IAM role that you use for the policy grants Amazon Data Lifecycle Manager permission to perform the SSM actions required to run pre and post scripts on instances targeted by the policy.

Amazon Data Lifecycle Manager provides a managed policy (AWSDataLifecycleManagerSSMFullAccess) that includes the required permissions. You can attach this policy to your IAM role for managing snapshots to ensure that it includes the permissions.

Alternatively, you can manually create a custom policy or assign the required permissions directly to the IAM role that you use. You can use the same permissions that are defined in the AWSDataLifecycleManagerSSMFullAccess managed policy, however, the aws:ResourceTag condition key is optional. If you decide to not use that condition key, then you do not need to tag your SSM documents with DLMScriptsAccess:true.

Use one of the following methods to add the AWSDataLifecycleManagerSSMFullAccess policy to your IAM role.