Imperative Commands

In this guide, you’ll learn how to imperatively update your kustomization.yaml using the kustomize edit subcommands. Anything you normally declare in YAML—adding or removing labels, prefixes, namespaces, modifying images or replica counts—can also be done directly via the CLI.

Before you start, check the help output for available subcommands:

kustomize edit --help

You’ll see usage examples and commands such as:

# Adds a ConfigMap to the kustomization file
kustomize edit add configmap NAME --from-literal=k=v

# Sets the nameprefix field
kustomize edit set nameprefix <prefix-value>

# Sets the namesuffix field
kustomize edit set namesuffix <suffix-value>

Key Subcommands

edit set

Use kustomize edit set to change fields in your kustomization.yaml without editing it by hand.

Change an image tag

kustomize edit set image nginx=nginx:1.2.2

Resulting entry:

images:
- name: nginx
  newTag: 1.2.2

Set or update a namespace

kustomize edit set namespace staging

Produces:

namespace: staging

Add common labels

kustomize edit set label org=KodeKloud env=staging

Yields:

commonLabels:
  org: KodeKloud
  env: staging

Set replica count for a Deployment

kustomize edit set replicas nginx-deployment=5

Adds:

replicas:
- name: nginx-deployment
  count: 5

edit add

The add subcommands let you generate ConfigMaps, Secrets, and include additional resources.

Add a ConfigMap generator

kustomize edit add configmap db-creds \
  --from-literal=password=password1 \
  --from-literal=username=root

Generates:

configMapGenerator:
- name: db-creds
  literals:
  - password=password1
  - username=root

Add a Secret generator

kustomize edit add secret my-secret \
  --from-literal=login=user1 \
  --from-literal=password=mypassword

Produces:

secretGenerator:
- name: my-secret
  type: Opaque
  literals:
  - login=user1
  - password=mypassword

Add a resource

Include external YAML manifests in your kustomization:

kustomize edit add resource db/db-depl.yaml

Results in:

resources:
- db/db-depl.yaml

Which kustomization.yaml Gets Updated?

If your project uses multiple overlays or bases, the file modified depends on where you run the command:

cd k8/base
kustomize edit set label org=KodeKloud
cd ../overlays/prod
kustomize edit set namespace prod
# Updates k8/overlays/prod/kustomization.yaml

If there’s no kustomization.yaml in your current directory, you’ll see an error.

Links and References

• Kustomize Documentation
• Kubernetes Configuration
• GitHub: kustomize