swift/test/probe/test_empty_device_handoff.py
Darrell Bishop df134df901 Allow 1+ object-servers-per-disk deployment
Enabled by a new > 0 integer config value, "servers_per_port" in the
[DEFAULT] config section for object-server and/or replication server
configs.  The setting's integer value determines how many different
object-server workers handle requests for any single unique local port
in the ring.  In this mode, the parent swift-object-server process
continues to run as the original user (i.e. root if low-port binding
is required), binds to all ports as defined in the ring, and forks off
the specified number of workers per listen socket.  The child, per-port
servers drop privileges and behave pretty much how object-server workers
always have, except that because the ring has unique ports per disk, the
object-servers will only be handling requests for a single disk.  The
parent process detects dead servers and restarts them (with the correct
listen socket), starts missing servers when an updated ring file is
found with a device on the server with a new port, and kills extraneous
servers when their port is found to no longer be in the ring.  The ring
files are stat'ed at most every "ring_check_interval" seconds, as
configured in the object-server config (same default of 15s).

Immediately stopping all swift-object-worker processes still works by
sending the parent a SIGTERM.  Likewise, a SIGHUP to the parent process
still causes the parent process to close all listen sockets and exit,
allowing existing children to finish serving their existing requests.
The drop_privileges helper function now has an optional param to
suppress the setsid() call, which otherwise screws up the child workers'
process management.

The class method RingData.load() can be told to only load the ring
metadata (i.e. everything except replica2part2dev_id) with the optional
kwarg, header_only=True.  This is used to keep the parent and all
forked off workers from unnecessarily having full copies of all storage
policy rings in memory.

A new helper class, swift.common.storage_policy.BindPortsCache,
provides a method to return a set of all device ports in all rings for
the server on which it is instantiated (identified by its set of IP
addresses).  The BindPortsCache instance will track mtimes of ring
files, so they are not opened more frequently than necessary.

This patch includes enhancements to the probe tests and
object-replicator/object-reconstructor config plumbing to allow the
probe tests to work correctly both in the "normal" config (same IP but
unique ports for each SAIO "server") and a server-per-port setup where
each SAIO "server" must have a unique IP address and unique port per
disk within each "server".  The main probe tests only work with 4
servers and 4 disks, but you can see the difference in the rings for the
EC probe tests where there are 2 disks per server for a total of 8
disks.  Specifically, swift.common.ring.utils.is_local_device() will
ignore the ports when the "my_port" argument is None.  Then,
object-replicator and object-reconstructor both set self.bind_port to
None if server_per_port is enabled.  Bonus improvement for IPv6
addresses in is_local_device().

This PR for vagrant-swift-all-in-one will aid in testing this patch:
https://github.com/swiftstack/vagrant-swift-all-in-one/pull/16/

Also allow SAIO to answer is_local_device() better; common SAIO setups
have multiple "servers" all on the same host with different ports for
the different "servers" (which happen to match the IPs specified in the
rings for the devices on each of those "servers").

However, you can configure the SAIO to have different localhost IP
addresses (e.g. 127.0.0.1, 127.0.0.2, etc.) in the ring and in the
servers' config files' bind_ip setting.

This new whataremyips() implementation combined with a little plumbing
allows is_local_device() to accurately answer, even on an SAIO.

In the default case (an unspecified bind_ip defaults to '0.0.0.0') as
well as an explict "bind to everything" like '0.0.0.0' or '::',
whataremyips() behaves as it always has, returning all IP addresses for
the server.

Also updated probe tests to handle each "server" in the SAIO having a
unique IP address.

For some (noisy) benchmarks that show servers_per_port=X is at least as
good as the same number of "normal" workers:
https://gist.github.com/dbishop/c214f89ca708a6b1624a#file-summary-md

Benchmarks showing the benefits of I/O isolation with a small number of
slow disks:
https://gist.github.com/dbishop/fd0ab067babdecfb07ca#file-results-md

If you were wondering what the overhead of threads_per_disk looks like:
https://gist.github.com/dbishop/1d14755fedc86a161718#file-tabular_results-md

DocImpact

Change-Id: I2239a4000b41a7e7cc53465ce794af49d44796c6
2015-06-18 12:43:50 -07:00

178 lines
7.5 KiB
Python
Executable File

#!/usr/bin/python -u
# Copyright (c) 2010-2012 OpenStack Foundation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import os
import shutil
import time
from unittest import main
from uuid import uuid4
from swiftclient import client
from swift.common import direct_client
from swift.obj.diskfile import get_data_dir
from swift.common.exceptions import ClientException
from test.probe.common import (
kill_server, ReplProbeTest, start_server, get_server_number)
from swift.common.utils import readconf
from swift.common.manager import Manager
class TestEmptyDevice(ReplProbeTest):
def _get_objects_dir(self, onode):
device = onode['device']
_, node_id = get_server_number((onode['ip'], onode['port']),
self.ipport2server)
obj_server_conf = readconf(self.configs['object-server'][node_id])
devices = obj_server_conf['app:object-server']['devices']
obj_dir = '%s/%s' % (devices, device)
return obj_dir
def test_main(self):
# Create container
container = 'container-%s' % uuid4()
client.put_container(self.url, self.token, container,
headers={'X-Storage-Policy':
self.policy.name})
cpart, cnodes = self.container_ring.get_nodes(self.account, container)
cnode = cnodes[0]
obj = 'object-%s' % uuid4()
opart, onodes = self.object_ring.get_nodes(
self.account, container, obj)
onode = onodes[0]
# Kill one container/obj primary server
kill_server((onode['ip'], onode['port']),
self.ipport2server, self.pids)
# Delete the default data directory for objects on the primary server
obj_dir = '%s/%s' % (self._get_objects_dir(onode),
get_data_dir(self.policy))
shutil.rmtree(obj_dir, True)
self.assertFalse(os.path.exists(obj_dir))
# Create container/obj (goes to two primary servers and one handoff)
client.put_object(self.url, self.token, container, obj, 'VERIFY')
odata = client.get_object(self.url, self.token, container, obj)[-1]
if odata != 'VERIFY':
raise Exception('Object GET did not return VERIFY, instead it '
'returned: %s' % repr(odata))
# Kill other two container/obj primary servers
# to ensure GET handoff works
for node in onodes[1:]:
kill_server((node['ip'], node['port']),
self.ipport2server, self.pids)
# Indirectly through proxy assert we can get container/obj
odata = client.get_object(self.url, self.token, container, obj)[-1]
if odata != 'VERIFY':
raise Exception('Object GET did not return VERIFY, instead it '
'returned: %s' % repr(odata))
# Restart those other two container/obj primary servers
for node in onodes[1:]:
start_server((node['ip'], node['port']),
self.ipport2server, self.pids)
self.assertFalse(os.path.exists(obj_dir))
# We've indirectly verified the handoff node has the object, but
# let's directly verify it.
# Directly to handoff server assert we can get container/obj
another_onode = next(self.object_ring.get_more_nodes(opart))
odata = direct_client.direct_get_object(
another_onode, opart, self.account, container, obj,
headers={'X-Backend-Storage-Policy-Index': self.policy.idx})[-1]
if odata != 'VERIFY':
raise Exception('Direct object GET did not return VERIFY, instead '
'it returned: %s' % repr(odata))
# Assert container listing (via proxy and directly) has container/obj
objs = [o['name'] for o in
client.get_container(self.url, self.token, container)[1]]
if obj not in objs:
raise Exception('Container listing did not know about object')
timeout = time.time() + 5
found_objs_on_cnode = []
while time.time() < timeout:
for cnode in [c for c in cnodes if cnodes not in
found_objs_on_cnode]:
objs = [o['name'] for o in
direct_client.direct_get_container(
cnode, cpart, self.account, container)[1]]
if obj in objs:
found_objs_on_cnode.append(cnode)
if len(found_objs_on_cnode) >= len(cnodes):
break
time.sleep(0.3)
if len(found_objs_on_cnode) < len(cnodes):
missing = ['%s:%s' % (cnode['ip'], cnode['port']) for cnode in
cnodes if cnode not in found_objs_on_cnode]
raise Exception('Container servers %r did not know about object' %
missing)
# Bring the first container/obj primary server back up
start_server((onode['ip'], onode['port']),
self.ipport2server, self.pids)
# Assert that it doesn't have container/obj yet
self.assertFalse(os.path.exists(obj_dir))
try:
direct_client.direct_get_object(
onode, opart, self.account, container, obj, headers={
'X-Backend-Storage-Policy-Index': self.policy.idx})
except ClientException as err:
self.assertEquals(err.http_status, 404)
self.assertFalse(os.path.exists(obj_dir))
else:
self.fail("Expected ClientException but didn't get it")
# Run object replication for first container/obj primary server
_, num = get_server_number(
(onode['ip'], onode.get('replication_port', onode['port'])),
self.ipport2server)
Manager(['object-replicator']).once(number=num)
# Run object replication for handoff node
_, another_num = get_server_number(
(another_onode['ip'],
another_onode.get('replication_port', another_onode['port'])),
self.ipport2server)
Manager(['object-replicator']).once(number=another_num)
# Assert the first container/obj primary server now has container/obj
odata = direct_client.direct_get_object(
onode, opart, self.account, container, obj, headers={
'X-Backend-Storage-Policy-Index': self.policy.idx})[-1]
if odata != 'VERIFY':
raise Exception('Direct object GET did not return VERIFY, instead '
'it returned: %s' % repr(odata))
# Assert the handoff server no longer has container/obj
try:
direct_client.direct_get_object(
another_onode, opart, self.account, container, obj, headers={
'X-Backend-Storage-Policy-Index': self.policy.idx})
except ClientException as err:
self.assertEquals(err.http_status, 404)
else:
self.fail("Expected ClientException but didn't get it")
if __name__ == '__main__':
main()