From 424f32f04d9c6c97f684782b35e1c25fbf83ce05 Mon Sep 17 00:00:00 2001
From: Armando Migliaccio <armando.migliaccio@eu.citrix.com>
Date: Wed, 1 Feb 2012 15:01:26 +0000
Subject: blueprint host-aggregates: xenapi implementation

This commit introduces some clean-up/improvements on the current model
and api for host aggregates. It also introduces a first version of the
xenapi implementation. More precisely:

- it lays out the structure of the virt driver,
- it introduces compute and xenapi unit tests coverage,
- it deals with join/eject of pool master and slaves,
- it fixes xenapi_conn, when used in resource pool configurations

More commits to follow (to ensure that VM placement, networking setup,
performance metrics work just as well in cases where resource pools
are present). However, these may be outside the scope of this blueprint
and considered as ad-hoc bug fixes.

Change-Id: Ib3cff71160264c5547e1c060d3fd566ad87337cb
---
 .../xenserver/xenapi/etc/xapi.d/plugins/xenhost    | 54 ++++++++++++++++++++++
 1 file changed, 54 insertions(+)

(limited to 'plugins')

diff --git a/plugins/xenserver/xenapi/etc/xapi.d/plugins/xenhost b/plugins/xenserver/xenapi/etc/xapi.d/plugins/xenhost
index 64938641f..9a7ad84af 100644
--- a/plugins/xenserver/xenapi/etc/xapi.d/plugins/xenhost
+++ b/plugins/xenserver/xenapi/etc/xapi.d/plugins/xenhost
@@ -33,6 +33,7 @@ import subprocess
 import tempfile
 import time
 
+import XenAPI
 import XenAPIPlugin
 import pluginlib_nova as pluginlib
 
@@ -41,6 +42,8 @@ pluginlib.configure_logging("xenhost")
 
 host_data_pattern = re.compile(r"\s*(\S+) \([^\)]+\) *: ?(.*)")
 config_file_path = "/usr/etc/xenhost.conf"
+DEFAULT_TRIES = 23
+DEFAULT_SLEEP = 10
 
 
 def jsonify(fnc):
@@ -97,6 +100,28 @@ def _run_command_with_input(cmd, process_input):
     return output
 
 
+def _resume_compute(session, compute_ref, compute_uuid):
+    """Resume compute node on slave host after pool join. This has to
+    happen regardless of the success or failure of the join operation."""
+    try:
+        # session is valid if the join operation has failed
+        session.xenapi.VM.start(compute_ref, False, True)
+    except XenAPI.Failure, e:
+        # if session is invalid, e.g. xapi has restarted, then the pool
+        # join has been successful, wait for xapi to become alive again
+        for c in xrange(0, DEFAULT_TRIES):
+            try:
+                _run_command("xe vm-start uuid=%s" % compute_uuid)
+                return
+            except pluginlib.PluginError, e:
+                logging.exception('Waited %d seconds for the slave to '
+                                  'become available.' % (c * DEFAULT_SLEEP))
+                time.sleep(DEFAULT_SLEEP)
+    raise pluginlib.PluginError('Unrecoverable error: the host has '
+                                'not come back for more than %d seconds'
+                                % (DEFAULT_SLEEP * (DEFAULT_TRIES + 1)))
+
+
 def _get_host_uuid():
     cmd = "xe host-list | grep uuid"
     resp = _run_command(cmd)
@@ -257,6 +282,34 @@ def host_start(self, arg_dict):
     return _power_action("startup")
 
 
+@jsonify
+def host_join(self, arg_dict):
+    """Join a remote host into a pool whose master is the host
+    where the plugin is called from. The following constraints apply:
+
+    - The host must have no VMs running, except nova-compute, which will be
+      shut down (and restarted upon pool-join) automatically,
+    - The host must have no shared storage currently set up,
+    - The host must have the same license of the master,
+    - The host must have the same supplemental packs as the master."""
+    session = XenAPI.Session(arg_dict.get("url"))
+    session.login_with_password(arg_dict.get("user"),
+                                arg_dict.get("password"))
+    compute_ref = session.xenapi.VM.get_by_uuid(arg_dict.get('compute_uuid'))
+    session.xenapi.VM.clean_shutdown(compute_ref)
+    try:
+        if arg_dict.get("force"):
+            session.xenapi.pool.join(arg_dict.get("master_addr"),
+                                     arg_dict.get("master_user"),
+                                     arg_dict.get("master_pass"))
+        else:
+            session.xenapi.pool.join_force(arg_dict.get("master_addr"),
+                                           arg_dict.get("master_user"),
+                                           arg_dict.get("master_pass"))
+    finally:
+        _resume_compute(session, compute_ref, arg_dict.get("compute_uuid"))
+
+
 @jsonify
 def host_data(self, arg_dict):
     """Runs the commands on the xenstore host to return the current status
@@ -380,6 +433,7 @@ if __name__ == "__main__":
             "host_shutdown": host_shutdown,
             "host_reboot": host_reboot,
             "host_start": host_start,
+            "host_join": host_join,
             "get_config": get_config,
             "set_config": set_config,
             "iptables_config": iptables_config})
-- 
cgit