Saturday, August 21, 2021

Kubectl Plugin for Oracle Database


We often need to provision new oracle databases for developers
This is the kubectl plugin to automate the creation of oracle database statefulset in the Kubernetes cluster


Full details and source codes are on the GitHub repository


Friday, August 20, 2021

Tip: what are the GVK GVR CRD CR Scheme in Kuberentes Core API

  • GVK stands for Group Version Kind 
  • Each Kind in K8S has Group and Version. i.e. Kind "Pod" is in Group "core" , Version "v1". Refer to official API doc
  • GVK  is defined to associate Group, Version and Kind
  • Each GVK map to a given root Go type in the package
  • Source code definition is  here 
  • GVR stands for Group Version Resource
  • GVR is a "use" or "instance" of GVK in the K8S API
  • The command "kubectl api-resources"  gives us a list of GVR in the K8S cluster
  • CRD stands for Custom Resource Definition
  • Each CRD is like Kind in K8S, so it also has Group, Version
  • CRD is the extension of the K8S API. Refer to official doc
  • Once it is defined, it acts like GVK in K8S API.
  • CR stands for Custom Resource
  • CR is a "use" or "instance" of CRD in the K8S API
  • Once it is instantiated, it acts like GVR in K8S API.
  • The command "kubectl api-resources"  gives us a list including both GVR and CR in the cluster.
  • The scheme is defined to keep track of a given GO type mapping to a given GVK. 
    • For example, we define{}
    • The scheme is going to map it to the API group we defined in CRD:
    • {
          kind:  mykind
  • Source code definition is here.

Wednesday, August 11, 2021

Tip: Git Squash and Force Push Tips

  • Try to avoid changing files on the local branch while updating contents on the web for the remote branch simultaneously. We may forget or lose track of what we did on the web and cause conflict with the local branch.
  • Always use "git rm" to remove files, so git has the index to track them. 
  • git rebase interactive mode is a wonderful tool to squash commits. Refer link
  • git force push is an alternative way to overwrite or squash commits for the remote branch. 
    • git push -f -u origin <branch name>