Some basic k8s commands and tricks.
16 June 2023
declarative
- manifest file based.
- manifest files: all objects are difined in the manifest file.
- kubectl apply command is usually used.
imperative
- command based.
- No manifest files: objects are created using cli commands.
Some useful things of kubectl
Generate a manifest file using imperative commands :
Example :-
kubectl create deployment nginx-deployment --image=nginx --dry-run -o yaml
or
kubectl create deploy nginx --image=nginx --dry-run=client -o yaml
Record the commands to the deployment annotations
kubectl scale deployment nginx-deployment --replicas=5 --record
The --record flag records the command in the annotations.
(How is this useful ? , This habit helps in tracking what actually caused changes to the deployment.)
Example :-
kubectl describe deployment nginx-deployment
using --record
kubectl scale deployment nginx-deployment --replicas=5 --record
not using --record
kubectl scale deployment nginx-deployment --replicas=2
You can see that when we used no record flag we got the last command executed on the Annotations: to be of the last scale to 5.