Update doc for install legacy chart

Signed-off-by: zzxwill <[email protected]>

Makefile

@@ -32,7 +32,7 @@ LEGACY_HELM_CHART = oam-kubernetes-runtime-legacy
 HELM_CHARTS = $(HELM_CHART) $(LEGACY_HELM_CHART)
 LEGACY_HELM_CHART_DIR=$(ROOT_DIR)/legacy/charts
 HELM_CHART_LINT_ARGS_oam-kubernetes-runtime = --set serviceAccount.name=''
-HELM_CHART_LINT_ARGS_oam-kubernetes-runtime-legacy = --set serviceAccount.name='' --set image.tag='master'
+HELM_CHART_LINT_ARGS_oam-kubernetes-runtime-legacy = --set serviceAccount.name=''
 
 -include build/makelib/helm.mk
 

legacy/README.md

@@ -7,11 +7,33 @@ Currently, the main block is OAM runtime use CRD v1, while these old K8s version
 So we generate v1beta1 CRD here for convenience. But we have no guarantee that oam-runtime will support the
 legacy k8s versions. 
 
-`IMAGE-TAG` marks the image tag of OAM Kubernetes Runtime, like `v0.3.0`. If omitted, the latest image will
- be used in the chart.
+Follow the instructions in [README](../README.md) to create a namespace like `oam-system` and add the OAM Kubernetes
+Runtime helm repo.
 
 ```
 $ kubectl create namespace oam-system
 $ helm repo add crossplane-master https://charts.crossplane.io/master/
-$ helm install oam --namespace oam-system crossplane-master/oam-kubernetes-runtime-legacy --set image.tag=$IMAGE-TAG --devel
+```
+
+Run the following command to install an OAM Kubernetes Runtime legacy chart.
+
+```
+$ helm install oam --namespace oam-system crossplane-master/oam-kubernetes-runtime-legacy --devel
+```
+
+If you'd like to install an older version of the legacy chart, use `helm search` to choose a proper chart version.
+```
+$ helm search repo oam-kubernetes-runtime-legacy --devel -l
+  NAME                                           	CHART VERSION   	APP VERSION     	DESCRIPTION
+  crossplane-master/oam-kubernetes-runtime-legacy	0.3......       	0.3......           A Helm chart for OAM Kubernetes Resources Contr
+  crossplane-master/oam-kubernetes-runtime-legacy	0.3.1-5.g11e1894	0.3.1-5.g11e1894	A Helm chart for OAM Kubernetes Resources Contr
+  crossplane-master/oam-kubernetes-runtime-legacy	0.3......       	0.3......	        A Helm chart for OAM Kubernetes Resources Contr
+
+$ helm install oam --namespace oam-system crossplane-master/oam-kubernetes-runtime-legacy --version 0.3.1-5.g11e1894 --devel
+```
+
+Install the legacy chart as below if you want a nightly version.
+
+```
+$ helm install oam --namespace oam-system crossplane-master/oam-kubernetes-runtime-legacy --set image.tag=master --devel
 ```