how to move prometheus adapter to another namespace? - kubernetes

Question

For now I have prometheus and prometheus adapter in different namespaces:
I tried to configure adapter YML but I was not successful:
apiVersion: apps/v1
kind: Deployment
metadata:
annotations:
deployment.kubernetes.io/revision: "2"
creationTimestamp: "2020-01-30T08:49:05Z"
generation: 2
labels:
app: prometheus-adapter
chart: prometheus-adapter-2.0.1
heritage: Tiller
release: prometheus-adapter
name: prometheus-adapter
namespace: my-custom-namespace
resourceVersion: "18513075"
selfLink: /apis/apps/v1/namespaces/my-custom-namespace/deployments/prometheus-adapter
...
But I see error:
the namespace of the object (my-custom-namespace) does not match the namespace on the request (default)
How to fix it ?

Answer 1

You can not edit an existing resource to change namespace.You need to delete the existing deployment first and then recreate the deployment in another namespace.
Edit:
With Helm2 you need to delete the release first helm delete --purge release-name and then deploy it to different namespace as helm install stable/prometheus-adapter --namespace namespace-name
With helm 3 since there is no --namespace flag you need to delete the existing deployment and then redeploy it to a different namespace as below example to deploy metrics server.
$ helm install metricserver stable/metrics-server
Error: the namespace from the provided object "kube-system" does not match the namespace "default". You must pass '--namespace=kube-system' to perform this operation.
$ helm install metricserver stable/metrics-server --namespace=kube-system
Error: the namespace from the provided object "kube-system" does not match the namespace "default". You must pass '--namespace=kube-system' to perform this operation.
$ kubectl config set-context kube-system --cluster=kubernetes --user=kubernetes-admin --namespace=kube-system
Context "kube-system" created.
$ kubectl config use-context kube-system
Switched to context "kube-system".
$ kubectl config get-contexts
CURRENT NAME CLUSTER AUTHINFO NAMESPACE
* kube-system kubernetes kubernetes-admin kube-system
kubernetes-admin#kubernetes kubernetes kubernetes-admin
metallb kubernetes kubernetes-admin metallb
nfstorage kubernetes kubernetes-admin nfstorage
$ helm install metricserver stable/metrics-server
NAME: metricserver
LAST DEPLOYED: 2019-05-26 14:37:45.582245559 -0700 PDT m=+2.942929639
NAMESPACE: kube-system
STATUS: deployed

Answer 2

For helm 2 you can install the chart in any namespace you want by using:
helm install stable/prometheus-adapter --name my-release --namespace foo
Keep in mind that you need to remove the previous one.
This can be done using helm delete --purge my-release
Also there is a really nice article regarding changes in Helm3 Breaking Changes in Helm 3 (and How to Fix Them).