Put restic cache on ephemeral disk

backups/backup.nomad

@@ -44,6 +44,11 @@ job "backup%{ if batch_node != null }-oneoff-${batch_node}%{ endif }" {
       source = "all-volumes"
     }
 
+    ephemeral_disk {
+      # Try to keep restic cache intact
+      sticky = true
+    }
+
     service {
       name = "backup"
       provider = "nomad"
@@ -84,6 +89,7 @@ job "backup%{ if batch_node != null }-oneoff-${batch_node}%{ endif }" {
         "RCLONE_CHECKERS" = "2"
         "RCLONE_TRANSFERS" = "2"
         "RCLONE_FTP_CONCURRENCY" = "5"
+        "RESTIC_CACHE_DIR" = "$${NOMAD_ALLOC_DIR}/data"
       }
 
       template {
@@ -113,7 +119,6 @@ RCLONE_FTP_NO_CHECK_CERTIFICATE=true
         env = true
       }
 
-
       template {
         # Build jobs based on node
         data = <<EOF