From: Kefu Chai <kchai@redhat.com>
Date: Thu, 30 Apr 2020 03:34:07 +0000 (+0800)
Subject: mgr: do not load disabled modules
X-Git-Tag: v16.1.0~2453^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=refs%2Fpull%2F34846%2Fhead;p=ceph.git

mgr: do not load disabled modules

an option named "mgr_disabled_modules" is added in this change to
prevent mgr from loading modules listed in this option. because mgr
loads *all* modules found in the configured path, and per
https://tracker.ceph.com/issues/45147, python subinterpreter could hang
when loading numpy, so this behavior practically creates a deadlock
in mgr.

this issue is found when mgr uses python3.8 runtime. in development
environment, it'd be inconvenient to disable the offending mgr module
without changing the source code, even if we can choose to not install
them, for instance, the enduser can workaround this issue by
uninstalling `ceph-mgr-diskprediction-local`.

an option would be useful in this case, so we can add the module to the
list before mgr tries to load it.

as this issue is found with python3.8 + diskprediction_local (numpy), so
this mgr module is disabled by default if mgr is compiled with python3.8
runtime.

Fixes: https://tracker.ceph.com/issues/45147
Signed-off-by: Kefu Chai <kchai@redhat.com>
---

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0f7e86414c2d..fa00d1316bcc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -442,6 +442,11 @@ if(WITH_MGR)
   set(MGR_PYTHON_LIBRARIES ${Python3_LIBRARIES})
   set(MGR_PYTHON_VERSION_MAJOR ${Python3_VERSION_MAJOR})
   set(MGR_PYTHON_VERSION_MINOR ${Python3_VERSION_MINOR})
+  # https://tracker.ceph.com/issues/45147
+  if(Python3_VERSION VERSION_GREATER_EQUAL 3.8)
+    set(MGR_DISABLED_MODULES "diskprediction_local")
+    message(STATUS "mgr module disabled for ${Python3_VERSION}: ${MGR_DISABLED_MODULES}")
+  endif()
   # Boost dependency check deferred to Boost section
 endif(WITH_MGR)
 
diff --git a/src/common/options.cc b/src/common/options.cc
index be1e955ab51e..c78d9b69d759 100644
--- a/src/common/options.cc
+++ b/src/common/options.cc
@@ -5169,6 +5169,20 @@ std::vector<Option> get_global_options() {
     .add_service("mgr")
     .set_description("Filesystem path to manager modules."),
 
+    Option("mgr_disabled_modules", Option::TYPE_STR, Option::LEVEL_ADVANCED)
+#ifdef MGR_DISABLED_MODULES
+    .set_default(MGR_DISABLED_MODULES)
+#endif
+    .set_flag(Option::FLAG_STARTUP)
+    .add_service("mgr")
+    .set_description("List of manager modules never get loaded")
+    .set_long_description("A comma delimited list of module names. This list "
+        "is read by manager when it starts. By default, manager loads all "
+        "modules found in specified 'mgr_module_path', and it starts the "
+        "enabled ones as instructed. The modules in this list will not be "
+        "loaded at all.")
+    .add_see_also("mgr_module_path"),
+
     Option("mgr_initial_modules", Option::TYPE_STR, Option::LEVEL_BASIC)
     .set_default("restful iostat")
     .set_flag(Option::FLAG_NO_MON_UPDATE)
diff --git a/src/include/config-h.in.cmake b/src/include/config-h.in.cmake
index dc213938f5c9..ea550c81e3a0 100644
--- a/src/include/config-h.in.cmake
+++ b/src/include/config-h.in.cmake
@@ -309,6 +309,9 @@
 
 #cmakedefine MGR_PYTHON_EXECUTABLE "@MGR_PYTHON_EXECUTABLE@"
 
+/* the default value of "mgr_disabled_module" option */
+#cmakedefine MGR_DISABLED_MODULES "@MGR_DISABLED_MODULES@"
+
 /* Define to 1 if you have the `getprogname' function. */
 #cmakedefine HAVE_GETPROGNAME 1
 
diff --git a/src/mgr/PyModuleRegistry.cc b/src/mgr/PyModuleRegistry.cc
index 466da5d40496..2e2e080aa76c 100644
--- a/src/mgr/PyModuleRegistry.cc
+++ b/src/mgr/PyModuleRegistry.cc
@@ -25,6 +25,7 @@ namespace fs = std::experimental::filesystem;
 
 #include "include/stringify.h"
 #include "common/errno.h"
+#include "common/split.h"
 
 #include "BaseMgrModule.h"
 #include "PyOSDMap.h"
@@ -267,14 +268,22 @@ void PyModuleRegistry::shutdown()
 
 std::set<std::string> PyModuleRegistry::probe_modules(const std::string &path) const
 {
+  const auto opt = g_conf().get_val<std::string>("mgr_disabled_modules");
+  const auto disabled_modules = ceph::split(opt);
+
   std::set<std::string> modules;
   for (const auto& entry: fs::directory_iterator(path)) {
     if (!fs::is_directory(entry)) {
       continue;
     }
+    const std::string name = entry.path().filename();
+    if (std::count(disabled_modules.begin(), disabled_modules.end(), name)) {
+      dout(10) << "ignoring disabled module " << name << dendl;
+      continue;
+    }
     auto module_path = entry.path() / "module.py";
     if (fs::exists(module_path)) {
-      modules.emplace(entry.path().filename());
+      modules.emplace(name);
     }
   }
   return modules;