Application Source Types

ArgoCD supports several different ways in which kubernetes manifests can be defined:

ksonnet applications
helm charts
Simple directory of YAML/json manifests

Some additional considerations should be made when deploying apps of a particular type:

Ksonnet

Environments

Ksonnet has a first class concept of an "environment." To create an application from a ksonnet app directory, an environment must be specified. For example, the following command creates the "guestbook-default" app, which points to the default environment:

argocd app create --name guestbook-default --repo https://github.com/argoproj/argocd-example-apps.git --path guestbook --env default

Parameters

Ksonnet parameters all belong to a component. For example, the following are the parameters available in the guestbook app, all of which belong to the guestbook-ui component:

$ ks param list
COMPONENT    PARAM         VALUE
=========    =====         =====
guestbook-ui containerPort 80
guestbook-ui image         "gcr.io/heptio-images/ks-guestbook-demo:0.1"
guestbook-ui name          "guestbook-ui"
guestbook-ui replicas      1
guestbook-ui servicePort   80
guestbook-ui type          "LoadBalancer"

When overriding ksonnet parameters in ArgoCD, the component name should also be specified in the argocd app set command, in the form of -p COMPONENT=PARAM=VALUE. For example:

argocd app set guestbook-default -p guestbook-ui=image=gcr.io/heptio-images/ks-guestbook-demo:0.1

Helm

Values Files

Helm has the ability to use a different, or even multiple "values.yaml" files to derive its parameters from. Alternate or multiple values file(s), can be specified using the --values flag. The flag can be repeated to support multiple values files:

argocd app set helm-guestbook --values values-production.yaml

Helm Parameters

Helm has the ability to set parameter values, which override any values in a values.yaml. For example, service.type is a common parameter which is exposed in a Helm chart:

helm template . --set service.type=LoadBalancer

Similarly ArgoCD can override values in the values.yaml parameters using argo app set command, in the form of -p PARAM=VALUE. For example:

argocd app set helm-guestbook -p service.type=LoadBalancer

Helm Hooks

Helm hooks are equivalent in concept to ArgoCD resource hooks. In helm, a hook is any normal kubernetes resource annotated with the helm.sh/hook annotation. When ArgoCD deploys helm application which contains helm hooks, all helm hook resources are currently ignored during the kubectl apply of the manifests. There is an open issue to map Helm hooks to ArgoCD's concept of Pre/Post/Sync hooks.

Random Data

Helm templating has the ability to generate random data during chart rendering via the randAlphaNum function. Many helm charts from the charts repository make use of this feature. For example, the following is the secret for the redis helm chart:

data:
  {{- if .Values.password }}
  redis-password: {{ .Values.password | b64enc | quote }}
  {{- else }}
  redis-password: {{ randAlphaNum 10 | b64enc | quote }}
  {{- end }}

The ArgoCD application controller periodically compares git state against the live state, running the helm template <CHART> command to generate the helm manifests. Because the random value is regenerated every time the comparison is made, any application which makes use of the randAlphaNum function will always be in an OutOfSync state. This can be mitigated by explicitly setting a value, in the values.yaml such that the value is stable between each comparison. For example:

argocd app set redis -p password=abc123

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