(MODAClouds) AWS Elastic Beanstalk

Overview

In order to ease the deployment of applications over its IaaS solution, Amazon provides a simple wrapper service, namely AWS Elastic Beanstalk, which given a deployable software artifact --- either in compiled form, or source code, depending on the target platform --- automates the following aspects of the application's life-cycle: [Beanstalk-1]

• provisioning the required VM's from EC2, with the right image needed for the targeted run-time;
• configuring both the VM related aspects, like security groups, but also the complementary required services, like AWS Elastic Load Balancer, or AWS CloudWatch;
• deploying the software artifact inside the run-time environment;
• managing complementary services like the Elastic Load Balancer solution;

The following are the core concepts that Elastic Beanstalk operates with: [Beanstalk-2] [Beanstalk-3]

application

An umbrella concept for all the entities that belong to the same logical "application".

version

A deployable software artifact, suitable for deployment. Each application can have at any time multiple versions, each prepared for immediate execution, thus enabling the operator to rollback to previous versions if a particular deployment manifests issues. [Beanstalk-4]

environment

The run-time instance of a particular version, again there can be multiple concurrent environments, possibly of the same version. The environment also specifies the characteristics of the VM to be deployed on. [Beanstalk-4]

resources

Any external database, middleware, etc., that the application needs, and which is completely out of the control of the platform. (Although the various web-based wizards, do allow the operator to create an Elastic Load Balancer or an RDS instance).

Characteristics

Notes and limitations

Right from the start, the AWS Elastic Beanstalk documentation, [Beanstalk-1], clearly states that this is a solution meant for getting developers or operators to quickly adopt cloud-based deployments. Furthermore it states that once the user has a deeper understanding of the principles governing AWS, it should migrate towards using AWS CloudFormation.

However for the simple case of 1-tier web-applications, or 2-tier ones, where the second tier is the database, it proves a perfect match by providing a simple API to manage the application's life cycle.

From a technical perspective it can be seen as a parallel to Windows Azure's cloud services solution, in that although it exposes a PaaS-like functionality, each component is deployed on an individual VM, granting the code full access to the underlying OS --- most of which are unique to Elastic Beanstalk --- such as:

• each application version, can have dependencies on native packages; [Beanstalk-5]
• moreover the user can choose a customized VM image for each environment; [Beanstalk-5]
• the operator is granted full SSH access on the underlaying VM;
• there is the option to attach AWS EBS volumes or take snapshots;

On the downside it doesn't automatically handle any other services or resources, like AWS S3, DynamoDB, etc., but are left to the user to provision and properly configure; this being one of the reasons why AWS CloudFormation is a better choice in this respect.

ModaClouds integration

As stated AWS Elastic Beanstalk could be used in order to deploy simple web applications on-top of AWS EC2, without handling ourselves the VM provisioning and container deployment.

Although, in terms in functionality, it doesn't offer more than a hosted PaaS, like Heroku, or a deployable one, like CloudFoundry, it does prove useful in the case where the application requires more resources than the PaaS offers; for example in case of demanding Java-based web applications, which require VM's from the top of the EC2 offering. Moreover it provides an API as simple as the other PaaS's for managing the application instance.

References