AWS OpsWorks

OpsWorks provides 3 different services:
- OpsWorks Stacks
- OpsWorks for Chef Automate
- OpsWorks for Puppet Enterprise

OpsWorks Stacks

OpsWorks Stacks is a configuration management service which helps deploy applications using Chef Cookbooks
With OpsWorks we are managing infrastructure, configurations and the application in the same service
A stack is a set of layers, instances and related AWS resources whose configuration we would want to manage together
A layer is a blueprint for a set of EC2 instances. It specifies the instance’s settings, associated resources, installed packages, profiles and security groups. We can add also recipes to lifecycle events such as set up, deploy, configure, discover resources
Auto healing: if a stack is unhealthy, OpsWorks will re-provision that stack automatically
Instance types:
- 24/7 instances: Instances which are running all the time
- Time-based instances: OpsWorks will automatically start and stop time-based instances based on a specified schedule
- Load-based instances: OpsWorks will automatically start and stop instances based on response to CPU, memory and application load changes across all the instances in a layer
OpsWorks autoscaling is not as flexible as ASG. Instances has to be pre-created and they will be started based on time schedule or load
Apps represent code stored in a repository that we want to install on application server instances
Deployments:
- OpsWork will run a deploy or undeploy command on a given number of instances
- Run Command: we can run a command on all the instances (execute recipes)

Each layer has a set of 5 lifecycle events
Each event has an associated set of recipes
When an event occurs on a layer’s instance, OpsWorks automatically runs the appropriate set of recipes
Lifecycle events:
- Setup: this event occurs after a started instance finished booting
- Configure: this event occurs on all of the stack instances when:
  - An instance enters or leaves the online state
  - Associate/disassociate an Elastic IP from an instance
  - We attach/detach an ELB load balancer to a layer
- Deploy: occurs when we run a deploy command, typically to deploy an application to a set of application server instances. Setup event includes the deploy event
- Undeploy: occurs when we delete an app or run undeploy command to remove an app from a set of application server instances
- Shutdown: occurs when we shut down an instance, but before the associated EC2 instance is actually terminated
AWS OpsWorks stack configuration: https://docs.aws.amazon.com/opsworks/latest/userguide/workingcookbook-json.html

Auto Healing:
- For Amazon EBS-backed instance: 1. OpsWorks stops the EC2 instance and verifies that is sopped 2. Starts the EC2 instance
CloudWatch Events: we can create rules for reacting to OpsWork instance changes