AWS Solution Architect Associate (SAA-C02) Review Material – DevOps and Other Services

CloudFormation

• Components
  1. Resources – declare the AWS resources to deploy (Mandatory)
  2. Parameters – input values
  3. Mappings – static variables
  4. Outputs – a reference to what was created
  5. Conditional
  6. Transform – include code snippets outside your template
  7. Meta Data

• Template Helpers
  • Functions
  • References

• Stacks
  • Stack Set – For multi-account and cross-region deployments.
  • Nested Stacks – make the process of updating stacks easier.
• cfn-init
  • Helper script must be installed
  • Needs to be called from within the EC2 instance
  • The call will query the Meta-Data ‘AWS::CloudFormation::Init’ block which defines the script that will be executed.
• cfn-signal:
  • Signals CloudFormation to indicate whether Amazon EC2 instances have been successfully created or updated. 
  • Helper script must be installed
  • Run after cfn-init
  • Sends a signal to a WaitCondition whether an action is a success or fail.
  • Requires a WaitCondition (Defines success or failure) with CreationPolicy
  • EC2 requires internet access.
• CreationPolicy:
  • Prevent a resource status from reaching create complete until AWS CloudFormation receives a specified number of success signals or the timeout period is exceeded. 
  • Requires cfn-signal to signal a resource
• UpdatePolicy
  • Specify how AWS CloudFormation handles updates on some resources:
  • 3 Update Policies:
    1.  AutoScalingReplacingUpdate
    2. AutoScalingRollingUpdate
    3. AutoScalingScheduledAction
• DeletionPolicy
  1. Retain
  2. Backup – Only apply to DBs (Default for DB)
  3. Delete (Default for all except DB)
• StackPolicies:
  • After you set a stack policy, all of the resources in the stack are protected by default. To allow updates on specific resources, you specify an explicit Allow statement for those resources in your stack policy.
  • A stack policy applies only during stack updates. 
• TerminationProtection:
  • Prevent a stack from being deleted.
  • If enabled, must be disabled if stack is needed to be deleted.

Code Commit

OpsWorks

• Managed Chef and Puppet

AppSync

• Manage service for developing GraphQL APIs
• GraphQL APIs built with AWS AppSync give front-end developers the ability to query multiple databases, microservices, and APIs from a single GraphQL endpoint. 
• Use cases:
  • Automatically synchronize data between mobile/web applications and the cloud 
  • IoT Dashboard
  • Real-time Chat

Step Function & SWF (Simple Work Flow)

• Both are used for workflow
• Step Function is new and prefered than SWF except if the workflow requires human intervention/
• Step Function
  • has a visual tool to design the flow. And the flow is represented as a JSON state machine.
  • common use cases are to orchestrate: (1) micro-services (lambda), (2) ETL, & (3) machine learning.
• The maximum execution time is 1 year.

AWS Backup

• Fully managed backup service
• Works across the region and across the account
• Backup consists of a
  • a Backup Plan with
  • one more Backup Rule
  • backing up one or more Resources (e.g. EFS, EBS)
  • Resources can include: 1) all in the account, 2) specific resources or 3) based on a tag.