I have been using RHEL Linux for a long time. However, I seldom have a chance to use a Debian Linux. These days I am working on an application deployed in Debian Linux. To make this application applicable by outside,… Read More
an introduction to wine
Recently I have changed my working city from one to another. At the same time, my working laptop also has changed. It now has stricter rules on installing software. My favorite pdf reader, foxit pdf reader, is not in the… Read More
the EDITOR and VISUAL environment variables
I installed a Debian Linux OS today, but found that the default text editor is nano, which I am not familiar with. After searching how to set text editor using google, I got the solution. Two environment variables can be… Read More
a few words about prometheus
A few days ago I implemented the horizontal pod auto scaling for our application based on customer metrics in the Kubernetes. During the implementation, I setup a Prometheus server to gather metrics from the application and setup a Prometheus-Adapter to… Read More
crd-install for apiextensions.k8s.io/v1 does not work in helm v2 command
A few days ago, when I tried to install the below application with the latest helm chart using helm v2 command, I got an error message complaining that the helm chart is a helm v3 chart. https://github.com/prometheus-community/helm-charts/tree/main/charts/kube-prometheus-stack After struggling for… Read More
boilerplate code for Linux getopt
Linux getopt command is often used to parse script options. I find a piece of boilerplate code for this command and mark it in this post for further reference. set -eu set +e options=$(getopt –name “demo.sh” -o “f:d” -l “file:,debug”… Read More
a few kubectl command examples
In this post, I will list a few examples for kubectl comman, which can be referenced in daily work. 1. create tls secret kubectl create secret tls secret-name –cert=/path/to/cert –key=/path/to/key 2. get information from pod get the ready status of… Read More
disk block size vs filesystem block size
In this post, I will briefly describe the differences between disk block size and filesystem block size. In the computer architecture, every byte in the main memory has a unique address. In x86 arch, the CPU can read 4 bytes… Read More
pitfalls and tips when using self-signed certificate
A few days ago, I encountered an issue when using a self-signed certificate. The use case of the self-signed certificate is simple. I created a self-signed certificate with openssl and configure it in the application. There is no issue on… Read More
avoid large size of helm chart
These days I am trying to integrate one helm chart as a sub chart into another helm chart. However, I encountered a installation problem after the integration. When I run the below command to install a release, I got the… Read More