feat(linstor): simplify get_controller_uri using ss command (#121)

A significant improvement to avoid relying on DRBD commands or XAPI plugins.
This change uses `ss` to obtain the destination IP address of the LINSTOR satellite source port.

Signed-off-by: Ronan Abhamon <ronan.abhamon@vates.tech>

Author: Wescoeur

drivers/linstor-manager

@@ -29,7 +29,12 @@ import XenAPIPlugin
 from json import JSONEncoder
 from linstorjournaler import LinstorJournaler
 from linstorvhdutil import LinstorVhdUtil, check_ex
-from linstorvolumemanager import get_controller_uri, get_local_volume_openers, LinstorVolumeManager
+from linstorvolumemanager import (
+    get_controller_uri,
+    get_local_volume_openers,
+    LinstorVolumeManager,
+    LINSTOR_SATELLITE_PORT,
+)
 from lock import Lock
 import json
 import LinstorSR
@@ -42,7 +47,7 @@ LVM_PLUGIN = 'lvm.py'
 THIN_POOL = 'thin_pool'
 
 FIREWALL_PORT_SCRIPT = '/etc/xapi.d/plugins/firewall-port'
-LINSTOR_PORTS = [3366, 3370, 3376, 3377, 8076, 8077]
+LINSTOR_PORTS = (LINSTOR_SATELLITE_PORT, 3370, 3376, 3377, 8076, 8077)
 DRBD_PORTS = '7000:8000'
 
 DRBD_REACTOR_CONF = '/etc/drbd-reactor.d/sm-linstor.toml'

drivers/linstorvolumemanager.py

@@ -15,9 +15,13 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #
 
-from sm_typing import Any, Dict, override
+from sm_typing import (
+    Any,
+    Dict,
+    List,
+    override,
+)
 
-import errno
 import json
 import linstor
 import os.path
@@ -38,6 +42,8 @@
 DATABASE_PATH = '/var/lib/linstor'
 DATABASE_MKFS = 'mkfs.ext4'
 
+LINSTOR_SATELLITE_PORT = 3366
+
 REG_DRBDADM_PRIMARY = re.compile("([^\\s]+)\\s+role:Primary")
 REG_DRBDSETUP_IP = re.compile('[^\\s]+\\s+(.*):.*$')
 
@@ -128,73 +134,25 @@ def round_down(value, divisor):
 
 # ==============================================================================
 
-def get_remote_host_ip(node_name):
-    (ret, stdout, stderr) = util.doexec([
-        'drbdsetup', 'show', DATABASE_VOLUME_NAME, '--json'
-    ])
-    if ret != 0:
-        return
-
+def _get_controller_addresses() -> List[str]:
     try:
-        conf = json.loads(stdout)
-        if not conf:
-            return
-
-        for connection in conf[0]['connections']:
-            if connection['net']['_name'] == node_name:
-                value = connection['path']['_remote_host']
-                res = REG_DRBDSETUP_IP.match(value)
-                if res:
-                    return res.groups()[0]
-                break
-    except Exception:
-        pass
-
-
-def _get_controller_uri():
-    PLUGIN_CMD = 'hasControllerRunning'
-
-    # Try to find controller using drbdadm.
-    (ret, stdout, stderr) = util.doexec([
-        'drbdadm', 'status', DATABASE_VOLUME_NAME
-    ])
-    if ret == 0:
-        # If we are here, the database device exists locally.
-
-        if stdout.startswith('{} role:Primary'.format(DATABASE_VOLUME_NAME)):
-            # Nice case, we have the controller running on this local host.
-            return 'linstor://localhost'
-
-        # Try to find the host using DRBD connections.
-        res = REG_DRBDADM_PRIMARY.search(stdout)
-        if res:
-            node_name = res.groups()[0]
-            ip = get_remote_host_ip(node_name)
-            if ip:
-                return 'linstor://' + ip
-
-    # Worst case: we use many hosts in the pool (>= 4), so we can't find the
-    # primary using drbdadm because we don't have all connections to the
-    # replicated volume. `drbdadm status xcp-persistent-database` returns
-    # 3 connections by default.
-    try:
-        session = util.timeout_call(10, util.get_localAPI_session)
+        (ret, stdout, stderr) = util.doexec([
+            "/usr/sbin/ss", "-tnpH", "state", "established", f"( sport = :{LINSTOR_SATELLITE_PORT} )"
+        ])
+        if ret == 0:
+            return [
+                line.split()[3].rsplit(":", 1)[0]
+                for line in stdout.splitlines()
+            ]
+        util.SMlog(f"Unexpected code {ret}: {stderr}")
+    except Exception as e:
+        util.SMlog(f"Unable to get controller addresses: {e}")
+    return []
 
-        for host_ref, host_record in session.xenapi.host.get_all_records().items():
-            node_name = host_record['hostname']
-            try:
-                if util.strtobool(
-                    session.xenapi.host.call_plugin(host_ref, PLUGIN, PLUGIN_CMD, {})
-                ):
-                    return 'linstor://' + host_record['address']
-            except Exception as e:
-                # Can throw and exception if a host is offline. So catch it.
-                util.SMlog('Unable to search controller on `{}`: {}'.format(
-                    node_name, e
-                ))
-    except:
-        # Not found, maybe we are trying to create the SR...
-        pass
+def _get_controller_uri() -> str:
+    # TODO: Check that an IP address from the current pool is returned.
+    addresses = _get_controller_addresses()
+    return "linstor://" + addresses[0] if addresses else ""
 
 def get_controller_uri():
     retries = 0
@@ -204,7 +162,7 @@ def get_controller_uri():
             return uri
 
         retries += 1
-        if retries >= 10:
+        if retries >= 30:
             break
         time.sleep(1)