[Kimchi-devel] [PATCH v2 3/3] Github bug #327: NFS pool workaround: model changes

[Daniel Barboza]

From: Daniel Henrique Barboza <danielhb at linux.vnet.ibm.com>

Implementing a workaround in '_get_storagepool_vols_num',
'lookup', 'activate' and 'deactivate' methods to avoid
libvirt calls in NFS pools when the corresponding NFS server
is unreachable.

In the 'lookup' method the state of the pool returned in
such scenario is 'inaccessible' to warn the UI that the pool
isn't available for normal operation.

Signed-off-by: Daniel Henrique Barboza <danielhb at linux.vnet.ibm.com>
---
 src/kimchi/model/storagepools.py | 52 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 51 insertions(+), 1 deletion(-)

diff --git a/src/kimchi/model/storagepools.py b/src/kimchi/model/storagepools.py
index 011feb0..d0708e8 100644
--- a/src/kimchi/model/storagepools.py
+++ b/src/kimchi/model/storagepools.py
@@ -194,15 +194,45 @@ class StoragePoolModel(object):
 
         return source
 
+    def _nfs_status_online(self, pool, poolArgs=None):
+        if not poolArgs:
+            xml = pool.XMLDesc(0)
+            pool_type = xmlutils.xpath_get_text(xml, "/pool/@type")[0]
+            source = self._get_storage_source(pool_type, xml)
+            poolArgs = {}
+            poolArgs['name'] = pool.name()
+            poolArgs['type'] = pool_type
+            poolArgs['source'] = {'path': source['path'],
+                                  'host': source['addr']}
+        conn = self.conn.get()
+        poolDef = StoragePoolDef.create(poolArgs)
+        try:
+            poolDef.prepare(conn)
+            return True
+        except Exception as e:
+            return False
+
     def lookup(self, name):
         pool = self.get_storagepool(name, self.conn)
         info = pool.info()
-        nr_volumes = self._get_storagepool_vols_num(pool)
         autostart = True if pool.autostart() else False
         xml = pool.XMLDesc(0)
         path = xmlutils.xpath_get_text(xml, "/pool/target/path")[0]
         pool_type = xmlutils.xpath_get_text(xml, "/pool/@type")[0]
         source = self._get_storage_source(pool_type, xml)
+        #FIXME: nfs workaround - prevent any libvirt operation
+        # for a nfs if the corresponding NFS server is down.
+        if pool_type == 'netfs' and not self._nfs_status_online(pool):
+            kimchi_log.debug("NFS pool %s is offline, reason: NFS "
+                             "server %s is unreachable.", name,
+                             source['addr'])
+            # Mark state as '4' => inaccessible.
+            info[0] = 4
+            # skip calculating volumes
+            nr_volumes = 0
+        else:
+            nr_volumes = self._get_storagepool_vols_num(pool)
+
         res = {'state': POOL_STATE_MAP[info[0]],
                'path': path,
                'source': source,
@@ -267,6 +297,16 @@ class StoragePoolModel(object):
 
     def activate(self, name):
         pool = self.get_storagepool(name, self.conn)
+        #FIXME: nfs workaround - do not activate a NFS pool
+        # if the NFS server is not reachable.
+        xml = pool.XMLDesc(0)
+        pool_type = xmlutils.xpath_get_text(xml, "/pool/@type")[0]
+        if pool_type == 'netfs' and not self._nfs_status_online(pool):
+            # block the user from activating the pool.
+            source = self._get_storage_source(pool_type, xml)
+            raise OperationFailed("KCHPOOL0032E",
+                                  {'name': name, 'server': source['addr']})
+            return
         try:
             pool.create(0)
         except libvirt.libvirtError as e:
@@ -275,6 +315,16 @@ class StoragePoolModel(object):
 
     def deactivate(self, name):
         pool = self.get_storagepool(name, self.conn)
+        #FIXME: nfs workaround - do not try to deactivate a NFS pool
+        # if the NFS server is not reachable.
+        xml = pool.XMLDesc(0)
+        pool_type = xmlutils.xpath_get_text(xml, "/pool/@type")[0]
+        if pool_type == 'netfs' and not self._nfs_status_online(pool):
+            # block the user from dactivating the pool.
+            source = self._get_storage_source(pool_type, xml)
+            raise OperationFailed("KCHPOOL0033E",
+                                  {'name': name, 'server': source['addr']})
+            return
         try:
             pool.destroy()
         except libvirt.libvirtError as e:
-- 
1.8.3.1