k8s
Posts about kubernetes, kind, helm, etc.
April 28, 2025
Kubernetes CoreDNS Notes
Some notes to help me remember some Kubernetes items: Core DNS handles all of the DNS internally. If it's not in CoreDNS then it checks the external network. ClusterIP means it's only accessible...
ReadApril 23, 2025
Writing to stdout/stderr in Docker / Kubernetes
Recently I was testing some log aggregation, and I needed to write data to stdout/stderr so that the logging agent could send them to the aggregator. Here's a snippet of code to run that for awhile...
ReadApril 23, 2025
Check Whether an AWS VPC is Being Used
If you need to check whether a VPC is being used -- you do not want to delete a VPC if it is being used, you can double-check it with this command:
ReadDecember 29, 2024
Kubernetes ConfigMap Values
Extract a Specific Key from a ConfigMap: You can use jq or yq to parse JSON or YAML output to get specific values. For example, to get the value of a specific key in a...
December 3, 2024
Kubernetes Control Plane
Control Plane is a group of components to run the cluster; Data Plane is everything that is actually the app and things supporting the app. It's like the Control Plane is the OS and the Data Plane is...
ReadNovember 23, 2024
Add a Kubernetes Cluster Context
This is for my own understanding. Please don't assume it is 100% correct.
Each cluster provider will have some sort of kubeconfig command so you can add a context locally, for whatever...
November 23, 2024
View Your Current a Kubernetes `kubectl` Cluster Context on the CLI
When I first started using git many years ago, you would be working pretty blind on the command line (and I don't know of any GUI tools at the beginning). So, to make sure you didn't...
November 23, 2024
Install a Kubernetes Ingress
This is for my own understanding. It might be wrong but reflects my current understanding.
(using kind)
This setup maps ports 80 and 443 from localhost to the ingress. It's like...
November 23, 2024
Difference Between Kubernetes yaml and Helm Chart
This is for my own understanding. Please don't assume it is 100% correct. A helm chart is an abstraction that allows you to group multiple k8s configuration files into one package and deploy...
ReadNovember 23, 2024
Kubernetes Helm Releases
This is for my own understanding. Please don't assume it is 100% correct. When releasing with helm, the release name typically stays the same when you then upgrade a Helm chart. The release name...
ReadNovember 14, 2024
Kubernetes `Rollout`
In k8s, you don't "deploy", you "rollout". But, you don't "rollout" either. You either apply a deployment (or do it through helm, preferably), or kubectl create deployment <name>....
November 13, 2024
Kubernetes Scaling
CA - Cluster Autoscaling. VPA - Vertical Pod Autoscaling. HPA - Horizontal Pod Autoscaling. To me, using VPA/HPA alone can’t be much cost savings. At best, it can rearrange the resources you are...
ReadNovember 13, 2024
Kubernetes Helm Basics
This is for my own understanding. It might be wrong but reflects my current understanding. Helm is a package manager and templater. It stores whatever info it has about the configuration in the...
ReadNovember 13, 2024
Kubernetes Cluster Management
This reflects how I currently understand this, and may be incorrect: kops: create k8s clusters that you manage yourself, on whatever provider (AWS, Azure, etc) eksctl: create k8s clusters managed...
ReadNovember 6, 2024
How to Find What Resource to List for `kind:`
When creating an application in kubernetes, there are a lot of values for the kind: field. This is how to find those, and explain them so you know what values should be there.
Example:...
October 25, 2024
Kubernetes Namespace v Context
This SO answer really helped.
Essentially, a context is just a way to set the namespace on the client side when running kubectl so that you don't have to type out the namespace part of...
October 25, 2024
Why You Need an HPA for Every Container
HPA = Horizontal Pod Autoscaler. POD You need to configure resource request values for all of your containers in Kubernetes because HPA makes scaling decisions based on those values. It makes those...
ReadOctober 7, 2024
Kubernetes Hierarchy
Hierarchy: Cluster (parent) --- Nodes Group (collection of machines) ----- Node (machines) ------- Pods (workload units on nodes) --------- Containers (running applications) Think of the Node as...
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