Mete Atamel

Motivation When I started working from home in mid-March, I was totally obsessed with COVID-19 news. I was constantly checking number of cases and news from the UK (where I currently live) and from Cyprus (where I’m originally from). It took me a couple of weeks to realize how unproductive this was. I started limiting myself to check for news once a day. This definitely helped me to regain sanity and productivity but it was manual. Read More →

In this post, I want to talk about an event-driven image processing pipeline that I built recently using Knative Eventing. Along the way, I’ll tell you about event sources, custom events and other components provided by Knative that simply development of event-driven architectures. Requirements Let’s first talk about the basic requirements I had for the image processing pipeline: Users upload files to an input bucket and get processed images in an output bucket. Read More →

If you ever used Knative on Google Cloud, you must have heard of Knative-GCP project. As the name suggests, Knative-GCP project provides a number of sources such as CloudPubSubSource, CloudStorageSource, CloudSchedulerSource and more to help reading various Google Cloud sources into your Knative cluster. I recently updated my Knative Tutorial to use the latest Knative Eventing release v0.14.2 and its corresponding Knative-GCP release v0.14.0. I ran into a weird authentication problem that I want to outline here. Read More →

Knative Eventing docs are a little confusing when it comes to different event delivery methods it supports. It talks about event brokers and triggers and it also talks about sources, services, channels, and subscriptions. What to use and when? It’s not clear. Let’s break it down. Delivery methods There are 3 distinct methods in Knative: Simple delivery Complex delivery with optional reply Broker and Trigger delivery Broker and Trigger delivery is what you should care about most of the time. Read More →

In part 3 of the blog series, I talked about how we transformed our Windows-only .NET Framework app to a containerized multi-platform .NET Core app. This removed our dependency on Windows and enabled us to deploy to Linux-based platforms such as App Engine (Flex). On the other hand, the app still ran on VMs, it was billed per second even if nobody used it, deployments were slow and most importantly, it was a single monolith that was deployed and scaled as a single unit. Read More →

In part 1, I talked about the initial app and its challenges. In part 2, I talked about the lift & shift to the cloud with some unexpected benefits. In this part 3 of the series, I’ll talk about how we transformed our Windows-only .NET Framework app to a containerized multi-platform .NET Core app and the huge benefits we got along the way. Why? The initial Windows VM based cloud setup served us well with minimal issues about roughly 2 years (from early 2017 to early 2019). Read More →

In part 1 of app modernization series, I introduced a simple news aggregator and some of the challenges in its initial architecture. In part 2, I’ll talk about the journey to the cloud and some unexpected benefits and learnings along the way. Why Cloud? The initial backend had many issues that I outlined in part 1. After about 1 year, in late 2016, we decided to look into moving it to a more stable home. Read More →

We all have apps running some “legacy code” in some “legacy way”. The term “legacy” means different things in different projects but we know when we see it and we want to get the time to modernize those apps in some way. I recently went through the latest phase of modernization of a legacy app. Even though it’s a relatively small app, it thought me a number of lessons that’s worth sharing. Read More →

It’s hard to keep with Knative releases with a release every 6 weeks. I finally managed to update my Knative Tutorial for the latest Knative v0.12.0. In this blog post, I want to outline some of the differences I’ve observed. Knative Serving Knative Serving has been pretty stable in the recent releases and Knative Serving v0.12.0 is no exception. I didn’t need to update my tutorial specifically for this release. Read More →

The default Knative Installation instructions for Google Kubernete Engine (GKE) is problematic (see bug 2266). In this post, I want to outline what the problem is, tell you what I do, and also provide you the scripts that work for me until a proper solution is implemented either in gcloud or Knative. The problem The default Knative Installation instructions tell you to create a GKE cluster as follows: gcloud beta container clusters create $CLUSTER_NAME \ --addons=HorizontalPodAutoscaling,HttpLoadBalancing,Istio \ --machine-type=n1-standard-4 \ --cluster-version=latest --zone=$CLUSTER_ZONE \ --enable-stackdriver-kubernetes --enable-ip-alias \ --enable-autoscaling --min-nodes=1 --max-nodes=10 \ --enable-autorepair \ --scopes cloud-platform Notice the Istio add-on. Read More →