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
extract files from rpm packages
These days I am developing a feature involving rpm packages. Sometimes I need to extract the files from the rpm package instead of installing it. I mark the command here for further reference. rpm2cpio demo.rpm | cpio -idmv
database transaction acid
A few days ago, I encountered the term ‘ACID’ when reading one article about database. I summarized the term in this post after searching it using google, so that it can be referenced later. Atomicity Transactions are often composed of… Read More
use openssl to retrieve certificate
These days I am working on a certificate issue. During the debug session, I got a trick about how to retrieve the certificate from a server without using a browser. This is convenient in non-GUI environment, for example, shell environment.… Read More
Kubernetes pod termination events
A few days ago I was assigned a user story to investigate the upgrade of our application in Kubernetes environment without breaking the application servicing customers. One key point in this story is to find out how the Kubernetes pods terminates.… Read More