Selector does not match the template labels
selector:
matchLabels: {app: api}
template:
metadata:
labels: {app: backend}The API server rejects the Deployment. YAMLTools shows both sides so you can see which label differs.
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Kubernetes YAML validator
Paste one or many manifests separated by --- and check them before kubectl apply: structure against the Kubernetes API, objects that do not match each other and the settings that put a cluster at risk.
Kubernetes
YAML
Paste a file on the left to validate it.
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What YAMLTools checks in your Kubernetes file
- Each object against the schema of its apiVersion and kind: unknown fields, wrong types and missing required fields.
- Deployments whose selector does not match the labels of their Pod template.
- Services whose selector matches no Pod in the file, and targetPort values that no container exposes.
- Ingress rules pointing to Services or ports that are not defined.
- ConfigMaps and Secrets referenced by a Pod but missing from the manifests.
Risks it flags
- Privileged containers, running as root and allowPrivilegeEscalation left on.
- Passwords and tokens written as plain env values instead of Secrets.
- Images on :latest or without a tag.
- Containers without CPU and memory requests or limits.
- Workloads without readiness or liveness probes.
Common Kubernetes errors
The ones that break a deploy most often, and how YAMLTools reports them.
Service targetPort that no container listens on
targetPort: 8080 # containerPort: 3000
The Service is created but traffic never reaches the Pod. These are the bugs that take an afternoon to find.
Field in the wrong place
spec: containers: [...] # in a Deployment
containers belongs under spec.template.spec. The schema check names the field and where it should go.
Your file stays on your computer
Validation, risk analysis, diagram and conversions run in your browser. Nothing is uploaded unless you decide to save it with an account.
Kubernetes validator FAQ
Manifests, multiple documents and what happens with your file.