Kubernetes is a container orchestration system that originated at Google, and is now being maintained by the Cloud Native Computing Foundation. In this post, I am going to dissect some Kubernetes internals—especially, Deployments and how gradual rollouts of new containers are handled.

What Is a Deployment?

This is how the Kubernetes documentation describes Deployments:

A Deployment controller provides declarative updates for Pods and ReplicaSets.

A Pod is a group of one or more containers which can be started inside a cluster. A pod started manually is not going to be very useful though, as it won't automatically be restarted if it crashes. A ReplicaSet ensures that a Pod...


The following is the story of how Randall Degges created a simple API to solve the common problem of external IP address lookup and how he scaled it from zero to over 10 thousand requests per second (30B/month!) using Node.js and Go on Heroku.

Several years ago I created a free web service, ipify. It is a highly scalable IP address lookup service. When you make a GET request against it, it returns your public-facing IP address. Try it out yourself!


I created ipify because, at the time, I was building complex infrastructure...


Designing scalable, fault tolerant, and maintainable stream processing systems is not trivial. The Kafka Streams Java library paired with an Apache Kafka cluster simplifies the amount and complexity of the code you have to write for your stream processing system.

Unlike other stream processing systems, Kafka Streams frees you from having to worry about building and maintaining separate infrastructural dependencies alongside your Kafka clusters. However, you still need to worry about provisioning, orchestrating, and monitoring infrastructure for your Kafka Streams applications.

Heroku makes it easy for you to deploy, run, and scale your Kafka Streams applications by using supported...


Jekyll, the static website generator written in Ruby and popularized by GitHub, is a great candidate for being run on Heroku. Originally built to run on GitHub Pages, running Jekyll on Heroku allows you to take advantage of Jekyll’s powerful plugin system to do more than convert Markdown to HTML. On my blog, I have plugins to download my Goodreads current and recently read books and to generate Open Graph images for posts. That said, it’s not straightforward to get up and running on Heroku without using jekyll serve to do the heavy lifting. jekyll serve uses Ruby’s built-in, single threaded web server WEBrick, but a public site should be using a web server more suited for production, like...


Pushing an app to the cloud can feel like launching a probe into space. Once your project is thousands of miles away you can't bang on it with a hammer or replace broken parts when there's a problem. Your debugging efforts must rely on the instrumentation, telemetry, and remote controls included with the app when it was deployed. On Heroku, we've gladly done some of that prep work for you.

Two new Heroku features, Heroku Exec and Language Runtime Metrics, improve your production monitoring, inspecting, and debugging experience on the platform. With Heroku Exec, you can create secure TCP and SSH tunnels into a dyno, which facilitate SSH sessions, port forwarding, remote...


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