[backups] Add throttlling of remote etcd backups

This PS adds a possibility to limit (to throttle) the number of
simultaneously uploaded backups while keeping the logic on the client
side using flag files on remote side.

Change-Id: I753faab8f3d934346d54e38bfc94cec3a8f79385

charts/etcd/Chart.yaml

@@ -15,4 +15,4 @@
 apiVersion: v1
 description: A chart for a DaemonSet-based etcd deployment.
 name: etcd
-version: 0.1.3
+version: 0.1.4

charts/etcd/templates/cron-job-etcd-backup.yaml

@@ -134,6 +134,16 @@ spec:
                   value: {{ .Values.backup.remote_backup.delay_range.min | quote }}
                 - name: MAX_DELAY_SEND_BACKUP_TO_REMOTE
                   value: {{ .Values.backup.remote_backup.delay_range.max | quote }}
+                - name: THROTTLE_BACKUPS_ENABLED
+                  value: {{ .Values.conf.backup.remote_backup.throttle_backups.enabled }}
+                - name: THROTTLE_LIMIT
+                  value: {{ .Values.conf.backup.remote_backup.throttle_backups.sessions_limit | quote }}
+                - name: THROTTLE_LOCK_EXPIRE_AFTER
+                  value: {{ .Values.conf.backup.remote_backup.throttle_backups.lock_expire_after | quote }}
+                - name: THROTTLE_RETRY_AFTER
+                  value: {{ .Values.conf.backup.remote_backup.throttle_backups.retry_after | quote }}
+                - name: THROTTLE_CONTAINER_NAME
+                  value: {{ .Values.conf.backup.remote_backup.throttle_backups.container_name | quote }}
 {{- with $env := dict "ksUserSecret" $envAll.Values.secrets.identity.kubernetes }}
 {{- include "helm-toolkit.snippets.keystone_openrc_env_vars" $env | indent 16 }}
 {{- end }}

charts/etcd/values.yaml

@@ -74,6 +74,12 @@ backup:
     delay_range:
       min: 30
       max: 60
+      throttle_backups:
+        enabled: false
+        sessions_limit: 200
+        lock_expire_after: 3600
+        retry_after:  1800
+        container_name: throttle-backups-manager
 
 endpoints:
   identity: