Monitor Your Mesos Cluster with StackState

This post is part 2 in a 4-part series about Container Monitoring. Post 1 dives into some of the new challenges containers and microservices create and the information you should focus on. This article describes how to monitor your Mesos cluster.

Apache Mesos is a distributed systems kernel at the heart of the Mesosphere DC/OS and is designed for operations at very large scale. It abstracts the entire data center into a single pool of computing resources, simplifying running distributed systems at scale. Mesos supports different types of workloads to build a truly modern application. These distributed workloads include container orchestration (like Mesos containers, Docker and Kubernetes), analytics (Spark), big data technologies (Kafka and Cassandra) and much more.

Read more →

Docker container secrets on AWS ECS

Almost every application needs some kind of a secret or secrets to do it's work. There are all kind of ways to provide this to the containers but it all comes down to the following five:

  1. Save the secrets inside the image
  2. Provide the secrets trough ENV variables
  3. Provide the secrets trough volume mounts
  4. Use a secrets encryption file
  5. Use a secrets store

Read more →

TDD is not about unit tests

-- Dave Farley & Arjan Molenaar

On many occasions when we come at a customer, we're told the development team is doing TDD. Often, though, a team is writing unit tests, but it's not doing TDD.

This is an important distinction. Unit tests are useful things. Unit testing though says nothing about how to create useful tests that can live alongside your code. On the other hand TDD is an essential practice for improving the design of your code. These are very different things.

Read more →

The Container Monitoring Problem

This post is part 1 in a 4-part series about Docker, Kubernetes and Mesos monitoring. This article dives into some of the new challenges containers and microservices create and the metrics you should focus on.

Containers are a solution to the problem of how to get software to run reliably when moved from one environment to another. It’s a lightweight virtual machine with a purpose to provide software isolation.

So why are containers such a big deal?

Containers simply make it easier for developers and operators to know that their software will run, no matter where it is deployed. We see companies moving from physical machines, to virtual machines and now to containers. This shift in architecture looks very promising, but in reality you might introduce problems you didn’t see coming.

Read the full article on http://blog.stackstate.com/the-container-monitoring-problem

Caveats and pitfalls of cookie domains

Not too long ago, we ran into an apparent security issue at my current assignment - people could sign in with a regular account, but get the authentication and permissions of an administrator user (a privilege escalation bug). As it turned out, the impact  of the security issue was low, as the user would need to be logged in as an admin user already, but it was a very confusing issue. In this post I’ll try and explain the situation, how browsers handle wildcard subdomain cookies, and what to keep in mind when building an authentication back-end when it comes to cookies storing session information.

Read more →

The secret to making people buy your product

There is no greater waste than building something extremely efficient, well architectured (is that a word?), with high quality that nobody wants.

Yet we see it all the time. We have the Agile manifesto and Scrum probably to thank for that (the seeing bit.) “Our highest priority is to satisfy the customer through early and continuous delivery of valuable software”. It’s the valuable bit that is embodied by the Product Owner in Scrum, or “the value maximiser”.

Lean Startup has taught us that we suffer from cognitive bias and simply assume we know what customers want, and therefor should treat our requirements as assumptions. Get out of the building and ask our customers! We all know that Henry Ford would disagree. But could both be right.

Read more →

Deep dive into Windows Server Containers and Docker – Part 2 – Underlying implementation of Windows Server Containers

With the introduction of Windows Server 2016 Technical Preview 3 in August 2015, Microsoft enabled the container technology on the Windows platform. While Linux had its container technology since August 2008 such functionality was not supported on Microsoft operating systems before. Thanks to the success of Docker on Linux, Microsoft decided almost 3 years ago to start working on a container implementation for Windows. Since September 2016 we are able to work with a public released version of this new container technology in Windows Server 2016 and Windows 10. But what is the difference between containers and VMs? And how are Windows containers implemented internally within the Windows architecture? In this blogpost we’ll dive into the underlying implementation of containers on Windows.

Read more →

Automate incident investigation to save money and become proactive

How many hours did your best engineers spent investigating incidents and problems last month? Do those engineers get a big applause when they solved the issue? Most likely the answers are “a lot” and “yes”…

The reason that problem and incident investigation is hard, is because usually you have to search through multiple tools, correlate data from all those tools and interpret this data.

Click here to read the full post.

Fixing “HNS failed with error : Unspecified error” on docker-compose for Windows

The past few days I worked quite a lot with docker-compose on my windows machine and after something strange happened to my machine that crashed it, I was not able to start any containers anymore that had connectivity over the network with each other.

Every time I used the command-line docker-compose up, I would get a message telling me it failed to start the container. the full message I got was:

“ERROR: for web  Cannot start service web: failed to create endpoint aspnetblogapplication_web_1 on network nat: HNS failed with error : Unspecified error”

Read more →

Share This