# One-off: copy ClickHouse data from the old NFS PVC to serber:/srv/monitoring-db.
# NOT applied by `kubectl apply -f k8s/` (subdirectory). Run it while the
# StatefulSet is scaled to 0 so the copy is consistent:
#
#   kubectl scale sts clickhouse -n monitoring --replicas=0
#   kubectl apply -f k8s/migrate/clickhouse-nfs-to-local.yaml
#   kubectl wait --for=condition=complete job/clickhouse-nfs-to-local -n monitoring --timeout=30m
#   kubectl delete sts clickhouse -n monitoring          # PVC is retained (rollback copy)
#   kubectl apply -f k8s/clickhouse.yaml                 # new hostPath StatefulSet
#   kubectl delete job clickhouse-nfs-to-local -n monitoring
#
# The old PVC (data-clickhouse-0) is left untouched until you delete it.
apiVersion: batch/v1
kind: Job
metadata:
  name: clickhouse-nfs-to-local
  namespace: monitoring
spec:
  backoffLimit: 0
  template:
    spec:
      restartPolicy: Never
      nodeSelector:
        kubernetes.io/hostname: serber
      containers:
      - name: copy
        image: busybox:1.36
        securityContext:
          runAsUser: 0
        command:
        - sh
        - -c
        - |
          set -eu
          if [ -n "$(ls -A /new 2>/dev/null)" ]; then
            echo "refusing to copy: /new (serber:/srv/monitoring-db) is not empty"; exit 1
          fi
          du -sh /old
          cp -a /old/. /new/
          chown -R 101:101 /new
          echo "old: $(find /old -type f | wc -l) files, new: $(find /new -type f | wc -l) files"
          [ "$(find /old -type f | wc -l)" = "$(find /new -type f | wc -l)" ]
        volumeMounts:
        - name: old
          mountPath: /old
          readOnly: true
        - name: new
          mountPath: /new
      volumes:
      - name: old
        persistentVolumeClaim:
          claimName: data-clickhouse-0
          readOnly: true
      - name: new
        hostPath:
          path: /srv/monitoring-db
          type: DirectoryOrCreate