Invoke disk check periodically (#7374)

Helps with periodic scan of disk for RO state.
If found, this script makes transient fix and raise error message.

files/image_config/monit/conf.d/sonic-host

@@ -31,6 +31,13 @@ check program routeCheck with path "/usr/bin/route_check.py"
  every 5 cycles
  if status != 0 for 3 cycle then alert repeat every 1 cycles
 
+# Check if /etc & /home are writable. If not, make them writable.
+# Raise syslog error message, in case of underlying issues
+#
+check program diskCheck with path "/usr/bin/disk_check.py"
+ every 5 cycles
+ if status != 0 for 3 cycle then alert repeat every 1 cycles
+
 # vnet_route_check.py: tool that verifies VNET routes consistancy between SONiC and vendor SDK DBs.
 check program vnetRouteCheck with path "/usr/bin/vnet_route_check.py"
  every 5 cycles