40 Days Of Kubernetes (40/40)

#kubernetes #40daysofkubernetes

Day 40/40

JSONPath Tutorial - Advanced Kubectl Commands

Video Link
@piyushsachdeva
Git Repository
My Git Repo

In this section we will deep dive into JSONPath from the beginners perspective and see how you can write advanced kubectl commands using JSONPATH

Return result in json format by api-server

kubectl get nodes -o json

Return result in yaml format by api-server

kubectl get nodes -o yaml

Sample of jsonpath:

root@sinaops:~# kubectl get nodes -o=jsonpath='{.items[*].status.nodeInfo.osImage}{"\n"}'
Ubuntu 24.04.1 LTS Ubuntu 22.04.2 LTS Ubuntu 22.04.4 LTS

With custom column:

root@sinaops:~# kubectl get nodes -o='custom-columns=OsType:{.status.nodeInfo.osImage},KubeletVersion:{.status.nodeInfo.kubeletVersion}'
OsType               KubeletVersion
Ubuntu 24.04.1 LTS   v1.30.4
Ubuntu 22.04.2 LTS   v1.30.0
Ubuntu 22.04.4 LTS   v1.30.4

With custom column and statement:

root@sinaops:~# kubectl get nodes -o=custom-columns='Host:{.status.addresses[?(@.type=="Hostname")].address},OsType:{.status.nodeInfo.osImage}'
Host         OsType
cloudy.net   Ubuntu 24.04.1 LTS
jolly-net    Ubuntu 22.04.2 LTS
sinaops      Ubuntu 22.04.4 LTS

Sort by an item:

root@sinaops:~# kubectl get nodes
NAME         STATUS                     ROLES           AGE     VERSION
cloudy.net   Ready                      worker          6d      v1.30.4
jolly-net    Ready,SchedulingDisabled   worker          7d22h   v1.30.0
sinaops      Ready                      control-plane   8d      v1.30.4
root@sinaops:~# kubectl get nodes --sort-by=.status.nodeInfo.kubeletVersion
NAME         STATUS                     ROLES           AGE     VERSION
jolly-net    Ready,SchedulingDisabled   worker          7d22h   v1.30.0
cloudy.net   Ready                      worker          6d      v1.30.4
sinaops      Ready                      control-plane   8d      v1.30.4