In an ideal world you wouldn't have to perform multiple steps for the rendering, but unfortunately we don't live in an ideal world...
Kustomize
Nowadays, most applications that are meant to be deployed in Kubernetes provide a Helm chart to ease deployment. Unfortunately, sometimes the Helm chart is not flexible enough to do what you want to do, so you have to fork and contribute and hope that your contribution is quickly merged upstream so that you don't have to maintain your fork.
Instead of pointing to your fork, you could use Kustomize to apply some post-rendering to your templatized Helm release. This is possible natively since Helm 3.1 using the --post-process
flag.
Integration in ArgoCD
At Camptocamp, we use ArgoCD to manage the deployment of our objects into Kubernetes. Let's see how we can use Kustomize to do post-rendering of Helm charts in ArgoCD:
At first, declare a new config management plugin into your argocd-cm
configMap (the way to do it depends on the way you deployed ArgoCD):
apiVersion: v1
kind: ConfigMap
metadata:
name: argocd-cm
namespace: argocd
data:
configManagementPlugins: |
- name: kustomized-helm
init:
command: ["/bin/sh", "-c"]
args: ["helm dependency build || true"]
generate:
command: ["/bin/sh", "-c"]
args: ["helm template . --name-template $ARGOCD_APP_NAME --namespace $ARGOCD_APP_NAMESPACE --include-crds > all.yaml && kustomize build"]
Then add a kustomization.yaml
file next to your application's Chart.yaml
file:
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
- all.yaml
patchesJson6902:
- target:
group: apps
version: v1
kind: Deployment
name: myapplication
patch: |-
- op: remove
path: /spec/template/spec/securityContext
Now configure your Applications
object to use this plugin:
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
name: myapplication
namespace: argocd
spec:
project: myproject
source:
path: myapplication
repoURL: {{ .Values.spec.source.repoURL }}
targetRevision: {{ .Values.spec.source.targetRevision }}
plugin:
name: kustomized-helm
destination:
namespace: myproject
server: {{ .Values.spec.destination.server }}
And... voilà!
Integration in App of Apps
One thing that I often do is to use spec.source.helm
in my Application
object to pass some values that comes from my app of apps. This is not possible using a configuration plugin as the keys helm
and plugin
are mutually exclusive.
The workaround I found is to use plugin's envs. You have to change your config management plugin configuration to (note the $HELM_ARGS
):
apiVersion: v1
kind: ConfigMap
metadata:
name: argocd-cm
namespace: argocd
data:
configManagementPlugins: |
- name: kustomized-helm
init:
command: ["/bin/sh", "-c"]
args: ["helm dependency build || true"]
generate:
command: ["/bin/sh", "-c"]
args: ["echo \"$HELM_VALUES\" | helm template . --name-template $ARGOCD_APP_NAME --namespace $ARGOCD_APP_NAMESPACE $HELM_ARGS -f - --include-crds > all.yaml && kustomize build"]
You'll then be able to use this in your Application
:
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
name: myapplication
namespace: argocd
spec:
project: myproject
source:
path: myapplication
repoURL: {{ .Values.spec.source.repoURL }}
targetRevision: {{ .Values.spec.source.targetRevision }}
plugin:
name: kustomized-helm
env:
- name: HELM_ARGS
value: "--set targetRevision={{ .Values.spec.source.targetRevision }}"
destination:
namespace: myproject
server: {{ .Values.spec.destination.server }}
Or
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
name: myapplication
namespace: argocd
spec:
project: myproject
source:
path: myapplication
repoURL: {{ .Values.spec.source.repoURL }}
targetRevision: {{ .Values.spec.source.targetRevision }}
plugin:
name: kustomized-helm
env:
- name: HELM_VALUES
value: |
targetRevision: {{ .Values.spec.source.targetRevision }}
destination:
namespace: myproject
server: {{ .Values.spec.destination.server }}