Helm: How to avoid recreating secrets on upgrade? - kubernetes

Question

I have something in a secret template like this:
apiVersion: v1
kind: Secret
metadata:
# not relevant
type: Opaque
data:
password: {{ randAlphaNum 32 | b64enc | quote }}
Now, when doing helm upgrade, the secret is recreated, but the pods using this aren't (they also shouldn't, this is OK).
This causes the pods to fail when they are restarted or upgraded as the new password now doesn't match the old one.
Is it possible to skip re-creation of the secret when it exists, like, a {{- if not(exists theSecret) }} and how to do it?

Answer 1

You can use the look up function in HELM to check the if secret exist or not
https://helm.sh/docs/chart_template_guide/functions_and_pipelines/#using-the-lookup-function
Function in helm chart goes like : https://github.com/sankalp-r/helm-charts-examples/blob/1081ab5a5af3a1c7924c826c5a2bed4c19889daf/sample_chart/templates/_helpers.tpl#L67
{{/*
Example for function
*/}}
{{- define "gen.secret" -}}
{{- $secret := lookup "v1" "Secret" .Release.Namespace "test-secret" -}}
{{- if $secret -}}
{{/*
Reusing value of secret if exist
*/}}
password: {{ $secret.data.password }}
{{- else -}}
{{/*
add new data
*/}}
password: {{ randAlphaNum 32 | b64enc | quote }}
{{- end -}}
{{- end -}}
secret creation will be something like
example file : https://github.com/sankalp-r/helm-charts-examples/blob/main/sample_chart/templates/secret.yaml
apiVersion: v1
kind: Secret
metadata:
name: "test-secret"
type: Opaque
data:
{{- ( include "gen.secret" . ) | indent 2 -}}
chart example : https://github.com/sankalp-r/helm-charts-examples
{{- $secret := (lookup "v1" "Secret" .Release.Namespace "test-secret" -}}
apiVersion: v1
kind: Secret
metadata:
name: test-secret
type: Opaque
# 2. If the secret exists, write it back
{{ if $secret -}}
data:
password: {{ $secret.data.password }}
# 3. If it doesn't exist ... create new
{{ else -}}
stringData:
password: {{ randAlphaNum 32 | b64enc | quote }}
{{ end }}