helm template is a command used in the Helm package manager for Kubernetes to generate Kubernetes manifest files from a Helm chart. A Helm chart is a package containing all the necessary resources and configuration files to deploy an application or service to a Kubernetes cluster.

The helm template command takes a Helm chart as input and processes its templates, which are written in the Go template language. It replaces placeholders in the templates with actual values and generates the resulting Kubernetes manifest files.

$ helm template mychart ./mychart

In this example, mychart is the name of the Helm chart directory, and ./mychart is the path to the chart directory. The command will process the templates in the chart and generate the Kubernetes manifest files without actually deploying the resources to the cluster.

helm template is useful for reviewing and validating the Kubernetes manifests before deploying them to a cluster. It allows you to inspect the resulting manifests, check for any errors, and make any necessary modifications before proceeding with the actual deployment.

example command for “helm template”

$ helm template mychart ./mychart
This command generates Kubernetes manifest files from the mychart Helm chart located in the ./mychart directory.

$ helm template mychart ./mychart --output-dir manifests
It generates the Kubernetes manifest files from the mychart Helm chart and saves them in the manifests directory.

$ helm template mychart ./mychart --namespace mynamespace
This command generates the Kubernetes manifest files and sets the namespace to mynamespace in all the generated manifests.

$ helm template mychart ./mychart --set key1=value1,key2=value2
It generates the Kubernetes manifest files and overrides specific values in the chart's values.yaml file by providing key-value pairs.

$ helm template mychart ./mychart --set-file values.yaml
This command generates the Kubernetes manifest files and overrides the default values in the chart's values.yaml file using a separate YAML file.

$ helm template mychart ./mychart --set-string key1=value1,key2=value2
It generates the Kubernetes manifest files and overrides specific string values in the chart's values.yaml file.

$ helm template mychart ./mychart --set-file secret.yaml --set-file configmap.yaml
This command generates the Kubernetes manifest files and overrides values in the chart's values.yaml file using separate files for secrets and config maps.

$ helm template mychart ./mychart --debug
It generates the Kubernetes manifest files and includes additional debug information in the output.

$ helm template mychart ./mychart --include-crds
This command generates the Kubernetes manifest files and includes any Custom Resource Definitions (CRDs) specified in the chart.

$ helm template mychart ./mychart --dry-run
It generates the Kubernetes manifest files without actually creating any resources, allowing you to validate the chart and its templates.

$ helm template mychart ./mychart -f values.yaml
This command generates the Kubernetes manifest files from the mychart Helm chart, using the values specified in the values.yaml file to override the default values.

$ helm template mychart ./mychart -f values.yaml -f overrides.yaml
It generates the Kubernetes manifest files and combines values from both values.yaml and overrides.yaml files to override the default values in the chart.

$ helm template mychart ./mychart --values values.yaml
This command is an alternative to -f and achieves the same result. It generates the Kubernetes manifest files using the values specified in the values.yaml file.

$ helm template mychart ./mychart --values values.yaml --values overrides.yaml
It generates the Kubernetes manifest files and combines values from both values.yaml and overrides.yaml files to override the default values in the chart.

$ helm template mychart ./mychart -f global.yaml
This command generates the Kubernetes manifest files and uses the values specified in the global.yaml file, which contains global configuration settings that apply to all components in the chart.

$ helm template mychart ./mychart -f values.yaml --set key1=value1
It generates the Kubernetes manifest files and combines values from the values.yaml file with an additional override using the --set option.

$ helm template mychart ./mychart -f values.yaml --set-file secret.yaml
This command generates the Kubernetes manifest files and combines values from the values.yaml file with additional values specified in the secret.yaml file using the --set-file option.

Rajesh Kumar

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