Microservices and cloud resource limitations

2
votes

I am at the beginning of a large migration from a single monolithic web service to a collection of microservices using Spring Cloud/Spring Cloud Netflix. Through my research of microservices I understand that the lines of demarcation between services should mirror the separations of concerns between them. An additional factor affecting separation is which services are required to scale individually.

As a concrete example, depending on the level of granularity desired, a microservice environment could end up like this:

  • Accounts (containing Signup, Login, Profiles, etc.)
  • Store (containing Products, Payments, Reporting, Inventories, etc.)
  • Chat/Social (containing chat rooms, user statuses, etc.)
  • ...

Or it could end up with each of the areas of concern in brackets represented by their own microservice, e.g:

  • Accounts
  • Signup
  • Login
  • ...

I believe there is a preference in the microservices community for the second approach, and I tend to agree. However, the issue I have is one of hosting and resource limitations.

In the migration I would like to streamline the provisioning of resources and the installation of updated services. Since we use the AWS stack, Elastic Beanstalk seemed like the perfect choice. While researching Elastic Beanstalk though I was rather disheartened to discover that there was a limit of 25 applications per account. Not only that, but EC2 has a limit of 20 instances per region per account. It seems like a microservice architecture will hit that limit very quickly, especially when you add multiple environments (staging and production) for each service into the mix, let alone websites and internal tooling.

With all of the amazing content that I've seen around the web regarding microservices, I'm surprised and somewhat disappointed at the lack of information regarding the actual hosting of microservices beyond the development of them. Have I missed something? Is there any information about deploying more than a couple of microservices on AWS?

It is my understanding that Netflix use AWS for their own microservice hosting, beyond requesting additional resources from Amazon and throwing money at it, are there other solutions? Would their Asgard tool help with this issue (possibly by handling the sharing of instances between services) or would it result in the same outcome?

1
amazon-web-servicesamazon-ec2spring-cloudmicroservicesamazon-elastic-beanstalk
AWS will raise those limits quite readily. You might also want to look at ECS - Frederick Cheung
You can contact AWS to raise the limits. I have done this a number of times and the process is relatively quick. They just want to know your use case. - John Wheal

1 Answers

3
votes

As mentioned in the above comments, AWS will raise your limits if you have a legit use case - why wouldn't they? they are in the business of selling you services.

But since you have asked for suggestion other than increasing those limits, and since you are in the early stages of designing your solution, you should consider basing part of your micro-services architecture on Docker or another container/container like service (my own preference would be for the AWS's container service). Depending on the nature of you solution, even within the limits of 20 EC2 instances (per region), if you had large enough instances running you could fit dozens (or even hundreds of lightweight) docker images running on each of those allocated 20 instances - so potentially hundres or thousands of walled off micro-services running on those 20 EC2 instances.

Using an entire EC2 image for each of many micro-services you may have may end up being a lot more expensive than it needs to be.

You should also consider the use of AWS Lamba for at least portions of your micro-service architecture - its the 'ultra-micro service' tool also offered by AWS.