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+---
+products:
+  - Alauda Container Platform
+kind:
+  - Solution
+ProductsVersion:
+  - 4.3.3
+weight: 10
+queries:
+  - "How do I remove a stale region AppRelease after upgrading ACP from 4.0 to 4.3?"
+  - "ACP 4.3.3 region AppRelease cleanup"
+  - "helm.sh/resource-policy keep region AppRelease"
+---
+
+# Remove the Residual region AppRelease After Upgrading ACP from 4.0 to 4.3
+
+## Issue
+
+After upgrading Alauda Container Platform (ACP) from 4.0 to 4.3, the upgrade workflow can leave the historical `cpaas-system/region` AppRelease in the cluster. The AppRelease contains both resources that the upgraded platform still needs and resources that are no longer required. Deleting the AppRelease without protecting the required resources can therefore remove platform resources that must remain available.
+
+This issue applies through ACP 4.3.3. ACP 4.3.4 and later include the fix and do not require this cleanup procedure.
+
+## Environment
+
+- Upgrade path: ACP 4.0 to ACP 4.3.
+- Affected target versions: ACP 4.3.0 through 4.3.3.
+- Fixed target version: ACP 4.3.4 and later.
+- The upgrade has completed and the `cpaas-system/base` AppRelease is healthy.
+- The residual AppRelease is named `region` in the `cpaas-system` namespace.
+
+## Resolution
+
+The resolution has four phases:
+
+1. Use the helper script to inspect the resource inventory.
+2. Add `helm.sh/resource-policy=keep` to the 11 resources that must remain.
+3. Manually delete the `region` AppRelease and confirm that it is gone.
+4. Remove the temporary `keep` annotation from the retained resources.
+
+The helper script manages annotations and performs read-only checks. It does not delete the AppRelease. The AppRelease deletion must remain an explicit, manually reviewed operation.
+
+:::danger
+Deleting `cpaas-system/region` is an irreversible cluster operation. Do not continue if the `base` AppRelease is not healthy, if a protected resource is missing, or if the `region` AppRelease is already being deleted.
+:::
+
+### Prerequisites
+
+Prepare the following items before starting:
+
+- A kubeconfig that can connect to the target `global` cluster.
+- `kubectl` and Bash on the execution host.
+- Cluster-administrator permissions to read and annotate the listed resources and to delete an AppRelease.
+- The helper script saved as `region-apprelease-keep-helper.sh` in the current directory.
+
+Run the helper script from the directory where you saved it. Set `KUBECTL` if the cluster uses a non-default `kubectl` command.
+
+### Resources to Retain
+
+The following 11 resources must remain after the `region` AppRelease is deleted:
+
+| Kind | Namespace | Name |
+| --- | --- | --- |
+| `Namespace` | - | `argocd` |
+| `Namespace` | - | `data-services-system` |
+| `Namespace` | - | `kubevirt` |
+| `Namespace` | - | `metallb-system` |
+| `Namespace` | - | `minio-system` |
+| `Namespace` | - | `nativestor-system` |
+| `Namespace` | - | `rook-ceph` |
+| `ConfigMap` | `cpaas-system` | `etcd-backup` |
+| `ConfigMap` | `kube-public` | `global-info` |
+| `AdvancedCronJob` | `cpaas-system` | `etcd-backup-default` |
+| `ClusterAlaudaFeatureGate` | - | `loadbalancer-service` |
+
+The `frontend`, `zeus`, Ingress, ServiceAccount, and RBAC resources are not in the retention set. The `alauda-cluster-base-jobs` ServiceAccount, ClusterRole, and ClusterRoleBinding are used by the upgrade hook Job and are not runtime dependencies of `etcd-backup-default`. Retaining them leaves unnecessary high-privilege RBAC in the cluster.
+
+### Helper Script
+
+Save the following script as `region-apprelease-keep-helper.sh` and make it executable. The inventory is derived from the `region` AppRelease in `alauda-cluster-base v4.0.23`; do not reuse it for another upgrade path or version.
+
+```bash
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+KUBECTL=${KUBECTL:-kubectl}
+KEEP_KEY=helm.sh/resource-policy
+
+log() {
+  printf '[%s] %s\n' "$(date '+%Y-%m-%d %H:%M:%S')" "$*" >&2
+}
+
+die() {
+  log "ERROR: $*"
+  return 1
+}
+
+require_kubectl() {
+  command -v "$KUBECTL" >/dev/null 2>&1 ||
+    die "required command not found: $KUBECTL"
+}
+
+# Resource list captured from the region AppRelease (alauda-cluster-base v4.0.23).
+# Fields: action|kind|namespace|name. A dash means cluster-scoped.
+region_resources() {
+  cat <<'EOF'
+protect|Namespace|-|argocd
+protect|Namespace|-|data-services-system
+protect|Namespace|-|kubevirt
+protect|Namespace|-|metallb-system
+protect|Namespace|-|minio-system
+protect|Namespace|-|nativestor-system
+protect|Namespace|-|rook-ceph
+delete|ServiceAccount|cpaas-system|zeus
+delete|ServiceAccount|cpaas-system|frontend
+delete|ServiceAccount|cpaas-system|operator-migration
+delete|ConfigMap|cpaas-system|global-values
+protect|ConfigMap|cpaas-system|etcd-backup
+protect|ConfigMap|kube-public|global-info
+delete|ConfigMap|cpaas-system|image-loader
+delete|ConfigMap|cpaas-system|update-containerd-config
+delete|ConfigMap|cpaas-system|upgrade-sysctl
+delete|ClusterRole|-|zeus
+delete|ClusterRole|-|cpaas:frontend
+delete|ClusterRole|-|operator-migration
+delete|ClusterRoleBinding|-|cpass:zeus
+delete|ClusterRoleBinding|-|cpaas:frontend
+delete|ClusterRoleBinding|-|operator-migration
+delete|Role|cpaas-system|cpaas:frontend
+delete|RoleBinding|cpaas-system|cpaas:frontend
+delete|Service|cpaas-system|zeus
+delete|Service|cpaas-system|frontend
+delete|DaemonSet|cpaas-system|zeus
+delete|Deployment|cpaas-system|frontend
+delete|Ingress|cpaas-system|console-plugins-ingress
+delete|Ingress|cpaas-system|machine-provider-ingress
+protect|AdvancedCronJob|cpaas-system|etcd-backup-default
+delete|Certificate|cpaas-system|cpaas-system
+protect|ClusterAlaudaFeatureGate|-|loadbalancer-service
+delete|ServiceAccount|cpaas-system|alauda-cluster-base-jobs
+delete|ClusterRole|-|cpaas:alauda-cluster-base-jobs
+delete|ClusterRoleBinding|-|cpaas:alauda-cluster-base-jobs
+delete|Job|cpaas-system|remove-psp
+delete|Job|cpaas-system|patch-etcd-backup-annotation
+delete|Job|cpaas-system|update-etcd-backup
+delete|Job|cpaas-system|update-storage-ns
+delete|BroadcastJob|cpaas-system|update-containerd-config
+delete|BroadcastJob|cpaas-system|upgrade-sysctl
+EOF
+}
+
+ordered_resources() {
+  region_resources | awk -F'|' '
+    $1 == "protect" { protected[++protect_count] = $0; next }
+    { removable[++remove_count] = $0 }
+    END {
+      for (i = 1; i <= protect_count; i++) print protected[i]
+      for (i = 1; i <= remove_count; i++) print removable[i]
+    }
+  '
+}
+
+format_table() {
+  awk -F'\t' '
+    {
+      rows[NR] = $0
+      columns = NF
+      for (i = 1; i <= NF; i++)
+        if (length($i) > width[i]) width[i] = length($i)
+    }
+    END {
+      for (row = 1; row <= NR; row++) {
+        split(rows[row], values, FS)
+        for (column = 1; column < columns; column++)
+          printf "%-*s  ", width[column], values[column]
+        print values[columns]
+      }
+    }
+  '
+}
+
+kubectl_get() {
+  local kind=$1 namespace=$2 name=$3 output=$4
+  if [[ "$namespace" == "-" ]]; then
+    "$KUBECTL" get "$kind" "$name" --ignore-not-found -o "$output"
+  else
+    "$KUBECTL" -n "$namespace" get "$kind" "$name" --ignore-not-found -o "$output"
+  fi
+}
+
+object_state() {
+  local output
+  output=$(kubectl_get "$1" "$2" "$3" \
+    'jsonpath={.metadata.name}{"|"}{.metadata.annotations.helm\.sh/resource-policy}')
+  if [[ -z "$output" ]]; then
+    printf 'no|\n'
+  else
+    printf 'yes|%s\n' "${output#*|}"
+  fi
+}
+
+annotate_resource() {
+  local kind=$1 namespace=$2 name=$3 operation=$4 annotation
+  if [[ "$operation" == "keep" ]]; then
+    annotation="$KEEP_KEY=keep"
+  else
+    annotation="$KEEP_KEY-"
+  fi
+
+  if [[ "$namespace" == "-" ]]; then
+    "$KUBECTL" annotate "$kind" "$name" "$annotation" --overwrite >/dev/null
+  else
+    "$KUBECTL" -n "$namespace" annotate "$kind" "$name" \
+      "$annotation" --overwrite >/dev/null
+  fi
+}
+
+apply_inventory() {
+  local mode=$1 action kind namespace name state exists value changed=0 operation
+  local total
+  total=$(region_resources | wc -l)
+  log "$mode: checking $total region resources"
+  while IFS='|' read -r action kind namespace name; do
+    state=$(object_state "$kind" "$namespace" "$name")
+    exists=${state%%|*}
+    value=${state#*|}
+    [[ "$exists" == "yes" ]] || continue
+
+    if [[ "$mode" == "keep" ]]; then
+      if [[ "$action" == "protect" && "$value" != "keep" ]]; then
+        operation=keep
+      elif [[ "$action" == "delete" && "$value" == "keep" ]]; then
+        operation=remove
+      else
+        continue
+      fi
+    elif [[ "$action" == "protect" && "$value" == "keep" ]]; then
+      operation=remove
+    else
+      continue
+    fi
+    log "$mode: $operation $kind/$namespace/$name"
+    annotate_resource "$kind" "$namespace" "$name" "$operation"
+    changed=$((changed + 1))
+  done < <(ordered_resources)
+  log "$mode updated $changed resources"
+}
+
+keep_phase() {
+  require_kubectl
+  apply_inventory keep
+}
+
+check_phase() {
+  require_kubectl
+  {
+    printf 'ACTION\tKIND\tNAMESPACE\tNAME\tEXISTS\tKEEP\n'
+    local action kind namespace name state exists value keep
+    while IFS='|' read -r action kind namespace name; do
+      state=$(object_state "$kind" "$namespace" "$name")
+      exists=${state%%|*}
+      value=${state#*|}
+      if [[ "$exists" == "no" ]]; then
+        keep=-
+      elif [[ "$value" == "keep" ]]; then
+        keep=yes
+      else
+        keep=no
+      fi
+      printf '%s\t%s\t%s\t%s\t%s\t%s\n' \
+        "$action" "$kind" "$namespace" "$name" "$exists" "$keep"
+    done < <(ordered_resources)
+  } | format_table
+}
+
+unkeep_phase() {
+  require_kubectl
+  apply_inventory unkeep
+}
+
+usage() {
+  cat >&2 <<EOF
+Usage:
+  $0 keep
+  $0 check
+  $0 unkeep
+EOF
+}
+
+main() {
+  [[ $# -eq 1 ]] || { usage; return 2; }
+  case "$1" in
+    keep) keep_phase ;;
+    check) check_phase ;;
+    unkeep) unkeep_phase ;;
+    *) usage; return 2 ;;
+  esac
+}
+
+if [[ "${BASH_SOURCE[0]}" == "$0" ]]; then
+  main "$@"
+fi
+```
+
+### 1. Prepare the Script and Confirm the Inventory
+
+Make the script executable and confirm that the `base` and `region` AppReleases exist:
+
+```bash
+chmod +x ./region-apprelease-keep-helper.sh
+kubectl -n cpaas-system get apprelease base region
+./region-apprelease-keep-helper.sh check
+```
+
+The `check` command lists all 42 resources. Protected resources appear first and each row reports whether the object exists and whether its `helm.sh/resource-policy` annotation is `keep`.
+
+Confirm that `base` is healthy and `region` exists. Stop if any protected resource is missing.
+
+### 2. Add Protection and Recheck
+
+Add the temporary annotation and inspect the result:
+
+```bash
+./region-apprelease-keep-helper.sh keep
+./region-apprelease-keep-helper.sh check
+```
+
+For every existing protected resource, confirm `EXISTS=yes` and `KEEP=yes`. Existing resources marked for deletion must show `KEEP=no`; the script removes an unexpected `keep` annotation from those resources.
+
+### 3. Delete the `region` AppRelease Manually
+
+After the protected-resource check passes, delete the AppRelease explicitly:
+
+```bash
+kubectl -n cpaas-system delete apprelease region
+kubectl -n cpaas-system get apprelease region
+```
+
+The second command must return `NotFound`. Do not run `unkeep` while deletion is still in progress or if any protected resource is not healthy.
+
+### 4. Remove the Temporary Protection and Recheck
+
+Confirm that the retained resources survived the deletion, then remove the temporary annotations:
+
+```bash
+./region-apprelease-keep-helper.sh check
+./region-apprelease-keep-helper.sh unkeep
+./region-apprelease-keep-helper.sh check
+```
+
+Before `unkeep`, the 11 protected resources must still show `EXISTS=yes` and `KEEP=yes`. After `unkeep`, they must still exist and show `KEEP=no`.
+
+## Exception Handling
+
+- If AppRelease deletion fails or remains in progress, keep the annotations and investigate the deletion before continuing.
+- If any protected resource is missing or abnormal, stop and determine why before deleting the AppRelease or removing annotations.
+- The `keep`, `check`, and `unkeep` operations are repeatable. The script changes only resources in its inventory.
+- The inventory is specific to the `region` AppRelease from `alauda-cluster-base v4.0.23`. Do not use it for another upgrade path or version.
+
+## Acceptance Criteria
+
+The cleanup is complete when all of the following conditions hold:
+
+- `cpaas-system/region` no longer exists.
+- All 11 protected resources still exist and no longer have `helm.sh/resource-policy=keep`.
+- The `frontend`, `zeus`, Ingress, and region hook ServiceAccount/RBAC resources have been removed with the `region` AppRelease.
+- `cpaas-system/etcd-backup-default` and `cpaas-system/etcd-backup` still exist.