ec_shutdown

[nepi.git] / src / nepi / resources / linux / node.py

diff --git a/src/nepi/resources/linux/node.py b/src/nepi/resources/linux/node.py
index 9188022..9cab4ca 100644 (file)
--- a/src/nepi/resources/linux/node.py
+++ b/src/nepi/resources/linux/node.py
@@ -142,6 +142,9 @@ class LinuxNode(ResourceManager):
 
     """
     _rtype = "LinuxNode"
+    _help = "Controls Linux host machines ( either localhost or a host " \
+            "that can be accessed using a SSH key)"
+    _backend_type = "linux"
 
     @classmethod
     def _register_attributes(cls):
@@ -196,8 +199,14 @@ class LinuxNode(ResourceManager):
         # home directory at Linux host
         self._home_dir = ""
         
-        # lock to avoid concurrency issues on methods used by applications 
-        self._lock = threading.Lock()
+        # lock to prevent concurrent applications on the same node,
+        # to execute commands at the same time. There are potential
+        # concurrency issues when using SSH to a same host from 
+        # multiple threads. There are also possible operational 
+        # issues, e.g. an application querying the existence 
+        # of a file or folder prior to its creation, and another 
+        # application creating the same file or folder in between.
+        self._node_lock = threading.Lock()
     
     def log_message(self, msg):
         return " guid %d - host %s - %s " % (self.guid, 
@@ -317,7 +326,6 @@ class LinuxNode(ResourceManager):
     def provision(self):
         # check if host is alive
         if not self.is_alive():
-            self.fail()
             
             msg = "Deploy failed. Unresponsive node %s" % self.get("hostname")
             self.error(msg)
@@ -351,8 +359,8 @@ class LinuxNode(ResourceManager):
                 self.discover()
                 self.provision()
             except:
-                self._state = ResourceState.FAILED
-                raise
+                self.fail()
+                return
 
         # Node needs to wait until all associated interfaces are 
         # ready before it can finalize deployment
@@ -456,7 +464,7 @@ class LinuxNode(ResourceManager):
                     env = env)
         else:
             if with_lock:
-                with self._lock:
+                with self._node_lock:
                     (out, err), proc = sshfuncs.rexec(
                         command, 
                         host = self.get("hostname"),
@@ -524,7 +532,7 @@ class LinuxNode(ResourceManager):
                     sudo = sudo,
                     user = user) 
         else:
-            with self._lock:
+            with self._node_lock:
                 (out, err), proc = sshfuncs.rspawn(
                     command,
                     pidfile = pidfile,
@@ -549,7 +557,7 @@ class LinuxNode(ResourceManager):
         if self.localhost:
             pidtuple =  execfuncs.lgetpid(os.path.join(home, pidfile))
         else:
-            with self._lock:
+            with self._node_lock:
                 pidtuple = sshfuncs.rgetpid(
                     os.path.join(home, pidfile),
                     host = self.get("hostname"),
@@ -566,7 +574,7 @@ class LinuxNode(ResourceManager):
         if self.localhost:
             status = execfuncs.lstatus(pid, ppid)
         else:
-            with self._lock:
+            with self._node_lock:
                 status = sshfuncs.rstatus(
                         pid, ppid,
                         host = self.get("hostname"),
@@ -588,7 +596,7 @@ class LinuxNode(ResourceManager):
             if self.localhost:
                 (out, err), proc = execfuncs.lkill(pid, ppid, sudo)
             else:
-                with self._lock:
+                with self._node_lock:
                     (out, err), proc = sshfuncs.rkill(
                         pid, ppid,
                         host = self.get("hostname"),
@@ -608,7 +616,7 @@ class LinuxNode(ResourceManager):
                     recursive = True,
                     strict_host_checking = False)
         else:
-            with self._lock:
+            with self._node_lock:
                 (out, err), proc = sshfuncs.rcopy(
                     src, dst, 
                     port = self.get("port"),