diff
Diff configurations specified by filename or stdin between the current online configuration, and the configuration as it would be if applied.
Output is always YAML.
KUBECTL_EXTERNAL_DIFF environment variable can be used to select your own diff command. By default, the “diff” command available in your path will be run with “-u” (unified diff) and “-N” (treat absent files as empty) options.
Exit status
0No differences were found.1Differences were found.>1Kubectl or diff failed with an error.
Command
$ kubectl diff -f FILENAME
Example
Input File
# deployment.yaml - online configuration
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-dev
labels:
app: nginx
spec:
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.14.2
# deployment.yaml - local configuration
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-dev
labels:
app: nginx
spec:
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:latest
Notice that the local configuration refers to the latest nginx container from the registry.
Command
kubectl diff -f deployment.yaml
Output
diff -u -N /tmp/LIVE-435797985/apps.v1.Deployment.default.nginx-dev /tmp/MERGED-822429644/apps.v1.Deployment.default.nginx-dev
--- /tmp/LIVE-435797985/apps.v1.Deployment.default.nginx-dev 2020-09-20 14:50:30.160820677 +0000
+++ /tmp/MERGED-822429644/apps.v1.Deployment.default.nginx-dev 2020-09-20 14:50:30.172820784 +0000
@@ -6,7 +6,7 @@
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":{},"name":"nginx-dev","namespace":"default"},"spec":{"selector":{"matchLabels":{"app":"nginx"}},"template":{"metadata":{"labels":{"app":"nginx"}},"spec":{"containers":[{"image":"nginx:1.14.2","name":"nginx"}]}}}}
creationTimestamp: "2020-09-20T14:48:35Z"
- generation: 1
+ generation: 2
name: nginx-dev
namespace: default
resourceVersion: "2180"
@@ -31,7 +31,7 @@
app: nginx
spec:
containers:
- - image: nginx:1.14.2
+ - image: nginx:latest
imagePullPolicy: IfNotPresent
name: nginx
resources: {}
exit status 1
Generating a Diff
Use the diff program in a user’s path to display a diff of the changes that will be
made by Apply.
kubectl diff -k ./dir/
Setting the Diff Program
The KUBECTL_EXTERNAL_DIFF environment variable can be used to select your own diff command.
By default, the “diff” command available in your path will be run with “-u” (unified) and “-N”
(treat new files as empty) options.
export KUBECTL_EXTERNAL_DIFF=meld; kubectl diff -k ./dir/
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