Cloud / HELM Interview Questions
How do you create conditionals and loops in Helm templates? Provide practical examples.
Helm templates support powerful control structures for dynamic manifest generation.
If/Else Conditionals: {{- if .Values.ingress.enabled }}...{{- else }}...{{- end }} Conditional operators: eq, ne, lt, gt, and, or, not.
Range Loops (Iteration): Loop over arrays: {{- range .Values.nodeSelector }}- {{ . }}{{- end }}. With index: {{- range $index, $service := .Values.services }}. Loop over maps: {{- range $key, $value := .Values.annotations }}.
Practical patterns:
- Conditional resource creation: Entire file omitted if condition false using
{{- if .Values.serviceAccount.create }} - Loop with conditional filter:
{{- range .Values.containers }}{{- if not .disabled }}- name: {{ .name }}{{- end }}{{- end }} - Nested loops for multi-dimensional data
Performance note: Complex loops with hundreds of iterations may slow helm template rendering. For large datasets, consider pre-processing.
What syntax iterates over a list in Helm templates?
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