kubectl create configmap

Learn to create a ConfigMap with kubectl create configmap.

kubectl create configmap

The sources for creating a ConfigMap can be combined: literal values, single files, all files in a folder, and env files. A file's key name can be changed with key=file:

kubectl create configmap web-ayar \
  --from-literal=TEMA=koyu \
  --from-file=nginx.conf \
  --from-file=index=site/index.html \
  --from-file=ayarlar/            # each file in the folder is a key

Updating a ConfigMap

kubectl create errors on an existing object. The clean way to update a ConfigMap produced from files: regenerate the YAML and apply it. Then the deployment is restarted for pods reading the change as environment variables:

kubectl create configmap web-ayar --from-file=nginx.conf --dry-run=client -o yaml | kubectl apply -f -
kubectl rollout restart deployment/web

ConfigMaps written with immutable: true can't be changed; in big clusters this reduces the API server's load.

Exercise Generate from files and update

Write two commands: generate the web-ayar ConfigMap with the literal value TEMA=koyu and the nginx.conf file as YAML without creating it, and pipe it straight into kubectl apply -f -; then restart the web deployment.

Show example solution

kubectl create configmap web-ayar --from-literal=TEMA=koyu --from-file=nginx.conf --dry-run=client -o yaml | kubectl apply -f -
kubectl rollout restart deployment/web

Test yourself

Which key does --from-file=index=site/index.html create?
- index.html
- site/index.html
- site
- index
Show answer

index — The key=path form overrides the file name.

Apply the YAML coming from standard input.

... --dry-run=client -o yaml | kubectl apply -f ____

Show answer

... --dry-run=client -o yaml | kubectl apply -f -

Match.

--from-literal

Single value
--from-file=folder/

Each file is a key
| kubectl apply -f -

Update
immutable: true

Can't be changed

Next lesson: Summary - ConfigMap

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies