Provision Tools

1. AWS ELASTIC BEANSTALK

Platform as Service Developer Centric Fully Manged Cloud service to deploy code.

• Free Service but need to pay for underlying hardware.
• Internally use Cloudformation
• We can jump start using pre configured loader.
• Application code + configuration to auto deploy infrastructure in dev environment
• Support creating multiple Environments: Dev, Prod etc along with Cloning to create similar environment
• Built in Health & Monitoring
• Logs & Events for tracing

BeanStalk CLI (eb cli)

help speed up deployment to beanstalk using cli

• Basic command:

  eb create, status, health, events, logs, open, deploy, config, terminate
  

Beanstalk LifeCycle Policy

• EB can store at most 1000 app versions
• Old versions must phase out using time or space constrains
• Current live version cant be deleted

EB Extensions

Set UI parameters using code

• JSON/YAML file reside in .ebextensions/ directory of root of source code zip.
• Must have extension .config (eg. logging.config)
• Modify default settings & Environment variables in EB Console using code
• Can add resources eg RDS, ElastiCache, DynamoDB
• Added resources gets auto deleted when eb env goes away

Adding SSL Support Can be done in 2 ways

1. Directly from Console in ALB config
2. Using Extension .ebextension/securelistener-alb.config

Using Worker Schedule tasks to run periodically and asynchronously away from EB. These tasks typically take more than 1 hour to complete.

• Use Worker environment & cron.yaml

Creating Custom EB Platform

Define custom platform : OS + Software + Scripts of EB

• Define AMI using Platform.yaml & build the platform AMI using Packer

• Used to create a whole new platform or tweak programming languages
• Use Case: Run Incompatible language on eb & does not support docker.

Deployment Modes

1. All at Once:

Deploy all instance at the same time

• Result in downtime
• Fastest

2. Rolling

Roll update on a fix number of host called Bucket Size

• No Additional Cost=> Number of EC2 stays the same
• App Run new & old version at some time of update
• App run below Capacity during deployment
• Can take a long time to deploy

3. Rolling with additional Batch

Roll update with additional EC2 Batch

• Small Additional Cost
• App Run new & old version at some time of update
• App always run at Capacity even during deployment
• Good for production

4. Immutable Deployment

Duplicate deployment on new ASG with new version

• Costly because of duplication of resources
• Quick Rollback in case of Failure
• Zero Downtime

5. Blue Green Deployment

Route a part of traffic to new deployment to test A/B environment

• URL need to swap once testing is done
• USe Route 53 to route traffic

6. Traffic Splitting

used for Canary Testing.

• New Version deployed to temporary ASG
• A small part of traffic is routed to new ASG using ALB
• Deployment health is monitored
• In case of failure quick rollback can be initiated
• No Application downtime

2. AWS CLOUDFORMATION

Declarative way of defining AWS Infrastructure as Code

• CloudFormation Template Use JSON or YAML template to define process
• Template is uploaded to S3 & version maintained on S3

Advantages:

• Save cost by deleting Infrastructure in night.
• Estimate cost using resource used in Template.
• Increase productivity : Automate provision of resources automatically based on Template
• Version controlled: Change in infrastructure is reviewed through code.
• Separation of Concern : Create Stack for different apps/layer
• Don't reinvent the wheel: use existing template & documentation for best practices

Cloudformation Drift

Detect manual changes to infrastructure created by Cloudformation

• Used to detect changes made stack resources outside CloudFormation

StackSet

Create Delete or update stack across multiple Account & Regions

• One account to edit, delete, create stack in multiple region
• Create Stack for different apps/layer
• Deleting a Stack also delete all resources created from Stack

Cross Stack

!Output of a Stack is !Import to multiple Stacks

Nested Stack

Used when Stack is reused & recreated

ChangeSet

Set of changes to update Cloudformation stack

Rollback

• If Stack creation failed everything roll back(deleted)
• Rollback Can be disabled for troubleshooting
• If Update failed everything rollback to previous known state

Template Component

Resources:(Mendatory)

Actual AWS Resources (MANDATORY) eg EC2, ALB etc

• AWS:: aws-product-name::data-type-name
• Resources can reference each other
• Dynamic resources are not supported
• Over 224 resources in AWS: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-template-resource-type-ref.html

Parameter: (Optional)

dynamic variables act as input to reuse template

• fn::!Ref, !fn(YAML) function is used to reference parameters and resources

Pseudo parameter

• AWS internal parameter
• Example:
  • AWS::AccountId
  • AWS::StackId
  • AWS::StackName

Mapping:(Optional)

static hardcoded variables

• Used to assign different value for different environments dev, prod, qa
• !FinInMap[MapName, FirstLevelKey, SecondLevelKey] : find value in Map for a Key

Output: (Optional)

Output Reference to what has been created to use in other cloudformation template

• value contain reference to AWS resource
• fn::ImportValue/!ImportValue used by other template to use Output
• You cant delete resource if Output is referenced

Conditions:

conditions to create resource or output

• !And, !Or, !Not, !Equal, !If

Intrinsic Functions:

• !Ref: Return value of Parameter or Physical ID of resource
• GetAtt: List of attributes attached to a resource
• !FinInMap[MapName, FirstLevelKey, SecondLevelKey] : find value in Map for a Key
• !ImportValue Import resources create from Output
• !join[delimiter [comm separated values]]
• !Sub substitute variable from text
• !And, !Or, !Not, !Equal, !If: Conditions

Cloud Development Kit(CDK)

Use Programming Language code to convert into Cloudformation template