The kubectl diff command in Kubernetes is used to compare the current live state of a resource with its prospective state. This helps in visualizing the differences between the configurations that are applied to the cluster and those that are defined in files.
For example, suppose you have a Deployment resource defined in a YAML file and you want to see how it differs from the actual state in your cluster:
kubectl diff -f deployment.yaml
This command will show the differences between the Deployment defined in deployment.yaml and the Deployment currently applied in the Kubernetes cluster.
Another use case involves modifying a resource directly in the cluster and then checking what changes would be applied if the resource were updated:
kubectl diff deployment/myapp
Here, deployment/myapp is the name of the Deployment resource. The command compares the live version with the local version stored in Kubernetes, showing any discrepancies.
You can also use kubectl diff with edits made directly in the cluster. For instance, after editing a service in the cluster:
kubectl diff service/frontend
This command will display the differences between the current live state of the Service named frontend and its prospective state based on the edits.
To verify whether the kubectl diff command has executed correctly, check the output in your terminal or command prompt. If there are no errors and differences are displayed between the current and prospective states, the command has worked as expected.
Also check similar articles.
Listing Kubernetes Events with kubectl events
Troubleshooting Kubernetes with kubectl debug
Managing Kubernetes Authorization with kubectl auth
Copy Files to and from Kubernetes Containers with kubectl cp
Running a Kubernetes API Proxy with kubectl proxy
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