Everyone is used to Web and desktop dashboards. Kubernetes users are divided between those who prefer performing operations through UIs or through a terminal. How about combining the two modes of operations? K9s is giving us just that. It provides a terminal-based Vim-like UI for operating and observing k8s clusters.
Argo CD is a declarative GitOps deployment tool for Kubernetes.
It is one of the best, if not the best tool we have today to deploy applications inside Kubernetes clusters. It is based on GitOps principles, and it is a perfect fit to be a part of continuous delivery pipelines. It provides all the building blocks we might need if we would like to adopt GitOps principles for deployments and inject them inside the process of application lifecycle management.
Argo CD is a tool that helps us forget the existence of kubectl apply, helm install, and similar commands. It is a mechanism that allows us to focus on defining the desired state of our environments and pushing definitions to Git. It is up to Argo CD to figure out how to converge our desires into reality.
Before we dive into the actual usage of Knative, let's see which components we got and how they interact with each other. We'll approach the subject by trying to figure out the flow of a request. It starts with a user.
Should we use managed Containers as a Service (CaaS)? That must be the most crucial question we should try to answer. Unfortunately, it is hard to provide a universal answer since the solutions differ significantly from one provider to another. Currently (July 2020), CaaS can be described as wild west with solutions ranging from amazing to useless.
Azure Container Instances are a way to deploy containers in the Cloud. Based on that, you might think that ACI is not much different from other Containers as a Service solutions. But it is. It does not have horizontal scaling, nor any other features often associated with schedulers like Kubernetes. It is limited to the ability to run a single container in isolation. It is very similar to using Docker, except that it is in Azure, and that it saves us from worrying about the infrastructure needed to run containers.
So, if Azure Container Instances are very similar to Docker, why not use docker instead of az CLI? Fortunately, folks at Docker asked themselves the same question and released Docker Desktop that supports ACI. It is available since version 2.3.3+.
Personally, I do not think that managed Functions as a Service are a good idea. Functions are too small for my taste. The execution model in which each request is served by a fresh instance is deeply flawed. The pricing is too high for my budget.
All that being said, I can see use cases where managed FaaS is a perfect fit, but only if that would be the only flavor of serverless deployments. But it's not, even though many are putting the equation between FaaS and serverless computing.
We should ask two significant questions when contemplating whether we should use managed Functions as a Service (FaaS) flavor of serverless computing. Should we use them? If we should, shall it be AWS Lambda, Azure Functions, Google Cloud Functions, or something completely different?
So, should we use managed FaaS? We probably should. But that's not the right question. We can almost certainly find at least one good example. A more important question is whether managed FaaS can be the solution for a significant percentage of our workload. That's the question that is much more difficult to tackle. To answer it, we might need first to establish good use cases for deploying and running functions.
Linux Shell is essential and I will not go into great length to explain the reasons given that I am assuming that you already know that. So, we'll jump straight into Windows Subsystem for Linux (WSL). It lets us run Linux environment directly on Windows, and without the overhead of a virtual machine. It is part of Windows (not a replacement), so you can keep doing "Windows stuff", while still benefiting from Linux Shells and quite a few other things. It is a much better solution than using Shell emulators like Cygwin or GitBash, and it saves you from wasting resources on a virtual machine. WSL might be the best thing that happened to Windows, at least during the last couple of years.