Fix "rendered manifests contain a resource that already exists" during Prometheus agent reinstallation - Application Real-Time Monitoring Service

Symptom

Reinstalling the Prometheus agent after an uninstall fails with the following error:

rendered manifests contain a resource that already exists. Unable to continue with install: existing resource conflict: kind: ClusterRole, namespace: , name: arms-pilot-prom-k8s

Cause

A manual uninstall of the Prometheus agent may leave behind Kubernetes resources such as ClusterRoles. These leftover resources conflict with the reinstallation.

Solution

Step 1: Find leftover ClusterRoles

List the ClusterRoles associated with the Prometheus agent:

kubectl get ClusterRoles --all-namespaces | grep prom

Step 2: Delete the leftover ClusterRoles

Delete each ClusterRole returned in Step 1:

kubectl delete ClusterRole <cluster-role-name> -n arms-prom

Replace <cluster-role-name> with a ClusterRole name from the Step 1 output. Repeat for each listed ClusterRole.

Step 3: Delete other leftover resources if the issue persists

If the error still appears after deleting all ClusterRoles, check the kind field in the error message. This value indicates the conflicting resource type.

Use the same approach to find and delete the remaining resources:

List resources of the conflicting type:

kubectl get <resource-type> --all-namespaces | grep prom

Delete the matching resources:

kubectl delete <resource-type> <resource-name> -n arms-prom

Repeat until no conflicting resources remain.

Step 4: Verify the fix

Reinstall the Prometheus agent. The installation should complete without the "resource that already exists" error.

Applicable scope

Application Real-Time Monitoring Service (ARMS)
Managed Service for Prometheus