Is it possible to have a required .Value without using it in the template.
For example in my case I want to require to write a password for a subchart of mongodb but I won't use it on my templates so can I have something like bellow in a template:
{{- required 'You must set a mongodb password' .Values.mongodb.mongodbPassword | noPrint -}}
apiVersion: apps/v1
kind: Deployment
metadata:
name: {{ include "cloud.fullname" . }}
labels:
{{- include "cloud.labels" . | nindent 4 }}
app.kubernetes.io/component: cloud
spec:
replicas: {{ .Values.cloud.minReplicaCount }}
selector:
....
And the result would be something like:
apiVersion: apps/v1
kind: Deployment
metadata:
name: blablablabla
...
Possibly the most direct way is to use sprig's fail function.
{{- if not .Values.mongodb.mongodbPassword -}}
{{- fail "You must set a mongodb password" -}}
{{- end -}}
Assigning the required expression to a variable (that you never use) will probably also have the desired effect.
{{- $unused := required "You must set a mongodb password" .Values.mongodb.mongodbPassword -}}
Yes, it is possible. Let's consider the below Values.yaml file:
Values.yaml:
mongodb:
mongodbPassword: "AbDEX***"
So, you want to generate the deployment file only if the password is set. You can do by using if-block of go-templating. If the length of the password field is greater than zero, the deployment yaml will be generated otherwise not.
{{- if .Values.mongodb.mongodbPassword}}
apiVersion: apps/v1
kind: Deployment
metadata:
name: {{ include "cloud.fullname" . }}
labels:
{{- include "cloud.labels" . | nindent 4 }}
app.kubernetes.io/component: cloud
spec:
replicas: {{ .Values.cloud.minReplicaCount }}
selector:
....
{{- end }}
Reference:
{{if pipeline}} T1 {{end}}
If the value of the pipeline is empty, no output is generated;
otherwise, T1 is executed. The empty values are false, 0, any nil pointer or
interface value, and any array, slice, map, or string of length zero.
Dot is unaffected.
Related
I have an ArgoCD App which is generating symbols
apiVersion: v1
kind: Secret
metadata:
labels:
{{- include "myapp.labels" . | nindent 4 }}
annotations:
helm.sh/hook: pre-install,post-delete
name: {{ include "myapp.fullname" . }}
type: Opaque
data:
{{- if .Values.password }}
password: {{ .Values.password | b64enc | quote }}
{{- else }}
password: {{ randAlphaNum 10 | b64enc | quote }}
{{- end }}
A second service is adding additional values to the secrets later. I don't want this secrets in my chart
Now when something is changed on the app, the secrets are recreated.
How can i change this behaviour in ArgoCD?
Add annotation to that particular object and it should work
apiVersion: v1
kind: Secret
metadata:
labels:
{{- include "myapp.labels" . | nindent 4 }}
annotations:
helm.sh/hook: pre-install,post-delete
argocd.argoproj.io/sync-options: Prune=false
Some Sync Options can defined as annotations in a specific resource. Most of the Sync Options are configured in the Application resource spec.syncPolicy.syncOptions attribute. Multiple Sync Options which are configured with the argocd.argoproj.io/sync-options annotation can be concatenated with a , in the annotation value; white spaces will be trimmed.
no-prune-resources
Or if you don’t want to apply auto sync on this object then you can try ApplyOutOfSyncOnly=false
selective-sync
Kubectl provides a nice way to convert environment variable files into secrets using:
$ kubectl create secret generic my-env-list --from-env-file=envfile
Is there any way to achieve this in Helm? I tried the below snippet but the result was quite different:
kind: Secret
metadata:
name: my-env-list
data:
{{ .Files.Get "envfile" | b64enc }}
It appears kubectl just does the simple thing and only splits on a single = character so the Helm way would be to replicate that behavior (helm has regexSplit which will suffice for our purposes):
apiVersion: v1
kind: Secret
data:
{{ range .Files.Lines "envfile" }}
{{ if . }}
{{ $parts := regexSplit "=" . 2 }}
{{ index $parts 0 }}: {{ index $parts 1 | b64enc }}
{{ end }}
{{ end }}
that {{ if . }} is because .Files.Lines returned an empty string which of course doesn't comply with the pattern
Be aware that kubectl's version accepts barewords looked up from the environment which helm has no support for doing, so if your envfile is formatted like that, this specific implementation will fail
I would like to use env files but it seems to be helm doesn't support that yet.
Instead of using an env file you could use a yaml file.
I mean to convert from this env file
#envfile
MYENV1=VALUE1
MYENV2=VALUE2
to this yaml file (verify the yaml format, always it should be an empty space after the colon)
#envfile.yaml
MYENV1: VALUE1
MYENV2: VALUE2
After this, you should move the envfile.yaml generated in the root folder of your helm chart (same level of values yaml files)
You have to set up your secret.yaml in this way:
apiVersion: v1
kind: Secret
metadata:
name: my-secret
annotations:
checksum/config: {{ (tpl (.Files.Glob "envfile.yaml").AsSecrets . ) | sha256sum }}
type: Opaque
data:
{{- $v := $.Files.Get "envfile.yaml" | fromYaml }}
{{- range $key, $val := $v }}
{{ $key | indent 2 }}: {{ $val | b64enc }}
{{- end}}
We are iterating in the data property the envfile.yaml generated and encoding the value to base64. The result secret will be the next:
kubectl get secret my-secret -o yaml
apiVersion: v1
data:
MYENV1: VkFMVUUx
MYENV2: VkFMVUUy
kind: Secret
metadata:
annotations:
checksum/config: 8365925e9f9cf07b2a2b7f2ad8525ff79837d67eb0d41bb64c410a382bc3fcbc
creationTimestamp: "2022-07-09T10:25:16Z"
labels:
app.kubernetes.io/managed-by: Helm
name: my-secret
resourceVersion: "645673"
uid: fc2b3722-e5ef-435e-85e0-57c63725bd8b
type: Opaque
Also, I'm using checksum/config annotation to update the secret object every time a value is updated.
I'm trying to install a chart to my cluster but I'm getting a error
Error: template: go-api/templates/deployment.yaml:18:24: executing "go-api/templates/deployment.yaml"
at <.Values.deployment.container.name>: nil pointer evaluating interface {}.name
However I executed the same commands for another 2 charts and it worked fine.
The template file I'm using is this:
apiVersion: apps/v1
kind: Deployment
metadata:
namespace: {{ .Values.namespace}}
labels: {{- include "chart.labels" . | nindent 4 }}
name: {{ .Values.deployment.name}}
spec:
replicas: {{ .Values.deployment.replicas}}
selector:
matchLabels: {{ include "chart.matchLabels" . | nindent 6 }}
template:
metadata:
labels:
app.kubernetes.io/name: {{ template "chart.name" . }}
app.kubernetes.io/instance: {{ .Release.Name }}
spec:
containers:
- name: {{ .Values.deployment.container.name }}
image: {{ .Values.deployment.container.image }}
imagePullPolicy: Never
ports:
- containerPort: {{ .Values.deployment.container.port }}
This can happen if the Helm values you're using to install don't have that particular block:
namespace: default
deployment:
name: a-name
replicas: 1
# but no container:
To avoid this specific error in the template code, it's useful to pick out the parent dictionary into a variable; then if the parent is totally absent, you can decide what to do about it. This technique is a little more useful if there are optional fields or sensible defaults:
{{- $deployment := .Values.deployment | default dict }}
metadata:
name: {{ $deployment.name | default (include "chart.fullname" .) }}
spec:
{{- if $deployment.replicas }}
replicas: {{ $deployment.replicas }}
{{- end }}
If you really can't work without the value, Helm has an undocumented required function that can print a more specific error message.
{{- $deployment := .Values.deployment | required "deployment configuration is required" }}
(My experience has been that required values are somewhat frustrating as an end user, particularly if you're trying to run someone else's chart, and I would try to avoid this if possible.)
Given what you show, it's also possible you're making the chart too configurable. The container name, for example, is mostly a detail that only appears if you have a multi-container pod (or are using Istio); the container port is a fixed attribute of the image you're running. You can safely fix these values in the Helm template file, and then it's reasonable to provide defaults for things like the replica count or image name (consider setting the repository name, image name, and tag as separate variables).
{{- $deployment := .Values.deployment | default dict }}
{{- $registry := $deployment.registry | default "docker.io" }}
{{- $image := $deployment.image | default "my/image" }}
{{- $tag := $deployment.tag | default "latest" }}
containers:
- name: app # fixed
image: {{ printf "%s/%s:%s" $registry $image $tag }}
{{- with .Values.imagePullPolicy }}
imagePullPolicy: {{ . }}
{{- end }}
ports:
- name: http
containerPort: 3000 # fixed
If the value is defined in your values file, and you're still getting the error then the issue could be due to accessing that value inside range or similar function which changes the context.
For example, to use a named template mySuffix that has been defined with .Values and using that inside range with template function, we need to provide $ to the template function instead of the usual .:
{{- define "mySuffix" -}}
{{- .Values.suffix }}
{{- end }}
...
{{- range .Values.listOfValues }}
echo {{ template "mySuffix" $ }}
{{- end }}
I have close to 25 deployments and services. Each Helm template has the following:
apiVersion: v1
kind: Deployment
metadata:
name: aa1
spec:
replicas: 1
strategy: {}
template:
metadata:
labels:
app: aa1
spec:
containers:
- env:
- name: {{ .Values.env1 }}
value: "yes"
volumeMounts:
- name: {{ .Values.v1 }}
mountPath: {{ .Values.v1monthPath}}
subPath: {{ .Values.v1subpath }}
Similarly I have same env and volumeMount defined for all 25 templates.
Is there any way I can use template inheritance in Helm?
A single Helm .tpl file can contain multiple YAML documents, separated with the --- start-of-document separator. Also, you can use all of the standard Go text/template capabilities, including its looping constructs.
That means that you could write a template like this:
{{- $top := . -}}
{{- range .Values.names -}}
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: {{ . }}
spec:
...
template:
spec:
containers:
- env:
- name: {{ $top.Values.env1 }}
value: "yes"
---
apiVersion: v1
kind: Service
metadata:
name: {{ . }}
spec: { ... }
{{ end -}}
What this does is first to save away the current context; since range resets the current template default context . to the iterator value, we need to remember what its current value is. We then iterate through every value in a list from the values file. (The Sprig list function could create the list in the template.) For each item, we create a Deployment and a Service, each starting with a --- on its own line. When we need the current name, it is .; when we need something from the Helm values, we need to explicitly look it up in $top.Values.
Another possible approach is to write separate templates for the deployment and service, and then have files invoke each of them. Technically a template only takes one parameter, but you can use list and index to have that one parameter be a list.
{{/* _deployment.tpl */}}
{{- define "deployment" -}}
{{- $name := index 0 . -}}
{{- $top := index 1 . -}}
---
apiVersion: apps/v1
kind: Deployment
...
name: {{ $name }}
...
name: {{ $top.Values.env1 }}
...
{{ end -}}
{{/* aa1.yaml */}}
{{- template "deployment" (list "aa1" .) -}}
{{- template "service" (list "aa1" .) -}}
This can get almost arbitrarily complex (you can have conditionals based on the current object name; you can use the template index function to look up values in the values object; and so on). helm template will do some validation and write the rendered template to stdout without invoking Kubernetes, which is helpful for eyeballing it and can be a basis for automated tests.
The text/template "inheritance" capabilities (using e.g. block) aren't a good match here. The documentation for (*text/template.Template).Parse notes that, if Parse is called multiple times, the last define found wins, which gives you a room to Parse a base template with a placeholder block and then Parse a refined template that redefines that. Helm doesn't really use this functionality; while it loads all of the YAML and supporting template files into the same template instance, it renders all of the top-level files separately instead of rendering some root template that allows for overrides.
I'm trying to define n StatefulSets where n is the number of nodes required, set in values.yaml as nodeCount. I get an error that looks to be scope related, but I can't seem to get the scope sorted out. Am I missing something here?
The relevant content in my StatefulSet .yaml file:
{{ range $k, $v := until ( .Values.nodeCount | int) }}
---
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
name: {{ $.Release.Name }}
labels:
app: {{ $.Release.Name }}
chart: {{ template "myapp-on-kube.chart" . }} #here's my call to _helpers
release: {{ $.Release.Name }}
heritage: {{ $.Release.Service }}
The relevant content in _helpers.tpl:
{{/*
Create chart name and version as used by the chart label.
*/}}
{{- define "myapp-on-kube.chart" -}}
{{- printf "%s-%s" .Chart.Name .Chart.Version | replace "+" "_" | trunc 63 | trimSuffix "-" -}}
{{- end -}}
The error I get:
Error: render error in "myapp-on-kube/templates/statefulset.yaml": template: myapp-on-kube/templates/_helpers.tpl:31:25: executing "myapp-on-kube.chart" at <.Chart.Name>: can't evaluate field Chart in type int
Several of the Go templating constructs change the meaning of . to be the thing that's being looped over, and you need to use $ to refer to the initial value. Most of your template correctly refers to e.g. $.Release.Name, but when you invoke the helper template, it's using the current context rather than the root value. Change:
chart: {{ template "myapp-on-kube.chart" $ }}
(Note that the template as you have it will declare several StatefulSets all with the same name, which won't go well. I might create just one StatefulSet with replicas: {{ .Values.nodeCount }}.)