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Showing posts from February, 2016

You can't control internal public data

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Everywhere there is some data that is relevant either for all applications or for many applications in different parts of the platform.
The "obvious" solution to this problem is to make such data internally public or world-readable, meaning that the entire platform can read it.
The "obvious" solution to security in this case is actually having no security beyond ensuring the "are you part of us?" question.
Common implementations of this pattern are world-readable NFS shares, S3 buckets readable by all "our" AWS accounts, HTTP APIs that use the client IP as their sole access control mechanism etc.
This is approach is really dangerous and should be used with care. The risks include:
You most likely don't know who actually needs the data and who not. If you ever need to restrict access you will have a very long and tedious job ahead of you.You don't know who accessed the data for which purpose.After a data leak, you probably won't know …

Go Faster - DevOps & Microservices

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At the microXchg 2016 last week Fred George - who takes pride having been called a hand grenade - gave a very inspiring talk about how all the things that we do right now have one primary goal:


Go Faster
Reducing cycle time for deployments, automation everywhere, down-sizing services to "microservices", building resilient and fault-tolerant platforms and more are all facets of a bigger journey: Provide value faster and find out faster what works and what not.
DevOps DevOps is seen by most developers as beeing an Ops movement to catch on with developers before their jobs become obsolete. Attending various DevOps Days in Germany and the USA, the developers who where also there always complained about the lack of developers and the lack of developer topics. They observed that the conference seems to be by and for Ops people. Consequently, DevOps conferences usually have two tracks: Methods and Tools.

Methods teach us how to do "proper" software development also in inf…

Cloud Migration ≈ Microservices Migration

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Day two at the microXchg 2016 conference. After listening to yet another talk detailing the pitfalls and dangers of "doing it wrong" I see more and more similarities between the Cloud migration at ImmobilienScout24 and the microservices journey that most speakers present.
The Cloud migration moves us from a large data center into many smaller AWS accounts. A (legacy) monolithic application is cut into many smaller microservices.
Internal data center communication becomes exposed communication between different AWS accounts and VPCs. Internal function calls are replaced with remote API calls. Both require much more attention to security, necessitate an authentication framework and add significant latency to the platform.
A failed data center takes down the entire platform while a failed AWS account will only take down some function. An uncaught exception will crash the entire monolith while a crashed microservice will leave the others running undisturbed.
Internal service dep…

AWS Account Right-Sizing

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Today I was attending the Microxchg 2016 conference in Berlin. I suddenly realized that going to the cloud allows to ask completely new questions that are impossible to ask in the data center.

One such question is this: What is the optimum size for a data center? Microservices are all about downsizing - and in the cloud we can and should downsize the data center!

In the world of physical data centers the question is usually goverened by two factors:

Ensuring service availability by having at least two physical data centers.Packing as much hardware into as little space as possible to keep the costs in check. As long as we are smaller than the average Internet giant there is no point to ask about the optimum size. The tooling which we build has to be designed for both large data centers and for having more than one. But in the "1, 2, many" series "2" is just the worst place to be. It entails all the disadvantages of "more than 1" without any of the benefits o…