rbd: improve Windows remap failure handling

At the moment, if an image can't be remapped when the centralized
RBD service starts, the service will stop and already started
daemons will continue running.

This change adds a new option: "--remap-failure-fatal". If set,
when an image can't be remmaped, the service stops AND cleans up
the running daemons. By default, an error will be logged and the
service will continue running.

Signed-off-by: Lucian Petrut <lpetrut@cloudbasesolutions.com>

2 files changed, 21 insertions, 5 deletions

diff --git a/src/tools/rbd_wnbd/rbd_wnbd.cc b/src/tools/rbd_wnbd/rbd_wnbd.cc
index ce85ae94c01..5d45fa75fa6 100644
--- a/src/tools/rbd_wnbd/rbd_wnbd.cc
+++ b/src/tools/rbd_wnbd/rbd_wnbd.cc
@@ -687,7 +687,7 @@ int disconnect_all_mappings(
 
         dout(5) << "Removing mapping: " << cfg.devpath
                 << ". Timeout: " << cfg.soft_disconnect_timeout
-                << "ms. Hard disconnect: " << cfg.hard_disconnect
+                << "s. Hard disconnect: " << cfg.hard_disconnect
                 << dendl;
 
         r = do_unmap(&cfg, unregister);
@@ -718,19 +718,22 @@ class RBDService : public ServiceBase {
     int thread_count;
     int service_start_timeout;
     int image_map_timeout;
+    bool remap_failure_fatal;
 
   public:
     RBDService(bool _hard_disconnect,
                int _soft_disconnect_timeout,
                int _thread_count,
                int _service_start_timeout,
-               int _image_map_timeout)
+               int _image_map_timeout,
+               bool _remap_failure_fatal)
       : ServiceBase(g_ceph_context)
       , hard_disconnect(_hard_disconnect)
       , soft_disconnect_timeout(_soft_disconnect_timeout)
       , thread_count(_thread_count)
       , service_start_timeout(_service_start_timeout)
       , image_map_timeout(_image_map_timeout)
+      , remap_failure_fatal(_remap_failure_fatal)
     {
     }
 
@@ -877,8 +880,14 @@ exit:
       // Restart registered mappings before accepting new ones.
       int r = restart_registered_mappings(
         thread_count, service_start_timeout, image_map_timeout);
-      if (r)
-        return r;
+      if (r) {
+        if (remap_failure_fatal) {
+          derr << "Couldn't remap all images. Cleaning up." << dendl;
+          return r;
+        } else {
+          dout(0) << "Ignoring image remap failure." << dendl;
+        }
+      }
 
       return create_pipe_server();
     }
@@ -937,6 +946,9 @@ Service options:
                               unmapping images. Default: 8
   --start-timeout             The service start timeout in seconds. Default: 120
   --map-timeout               Individual image map timeout in seconds. Default: 20
+  --remap-failure-fatal       If set, the service will stop when failing to remap
+                              an image at start time, unmapping images that have
+                              been mapped so far.
 
 Show|List options:
   --format plain|json|xml Output format (default: plain)
@@ -1424,6 +1436,8 @@ static int parse_args(std::vector<const char*>& args,
       cfg->persistent = false;
     } else if (ceph_argparse_flag(args, i, "--pretty-format", (char *)NULL)) {
       cfg->pretty_format = true;
+    } else if (ceph_argparse_flag(args, i, "--remap-failure-fatal", (char *)NULL)) {
+      cfg->remap_failure_fatal = true;
     } else if (ceph_argparse_witharg(args, i, &cfg->parent_pipe, err,
                                      "--pipe-name", (char *)NULL)) {
       if (!err.str().empty()) {
@@ -1638,7 +1652,8 @@ static int rbd_wnbd(int argc, const char *argv[])
       RBDService service(cfg.hard_disconnect, cfg.soft_disconnect_timeout,
                          cfg.service_thread_count,
                          cfg.service_start_timeout,
-                         cfg.image_map_timeout);
+                         cfg.image_map_timeout,
+                         cfg.remap_failure_fatal);
       // This call will block until the service stops.
       r = RBDService::initialize(&service);
       if (r < 0)
diff --git a/src/tools/rbd_wnbd/rbd_wnbd.h b/src/tools/rbd_wnbd/rbd_wnbd.h
index 62cb1dd6a38..d17eb792b0a 100644
--- a/src/tools/rbd_wnbd/rbd_wnbd.h
+++ b/src/tools/rbd_wnbd/rbd_wnbd.h
@@ -66,6 +66,7 @@ struct Config {
 
   int service_start_timeout = DEFAULT_SERVICE_START_TIMEOUT;
   int image_map_timeout = DEFAULT_IMAGE_MAP_TIMEOUT;
+  bool remap_failure_fatal = false;
 
   // TODO: consider moving those fields to a separate structure. Those
   // provide connection information without actually being configurable.