1
<?xml version="1.0" encoding="iso-8859-1"?>
2
<!DOCTYPE refentry PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
3
<refentry id="ctdbd.1">
6
<refentrytitle>ctdbd</refentrytitle>
7
<manvolnum>1</manvolnum>
12
<refname>ctdbd</refname>
13
<refpurpose>The CTDB cluster daemon</refpurpose>
18
<command>ctdbd</command>
22
<command>ctdbd</command>
23
<arg choice="opt">-? --help</arg>
24
<arg choice="opt">-d --debug=<INTEGER></arg>
25
<arg choice="req">--dbdir=<directory></arg>
26
<arg choice="req">--dbdir-persistent=<directory></arg>
27
<arg choice="opt">--event-script-dir=<directory></arg>
28
<arg choice="opt">-i --interactive</arg>
29
<arg choice="opt">--listen=<address></arg>
30
<arg choice="opt">--logfile=<filename></arg>
31
<arg choice="req">--nlist=<filename></arg>
32
<arg choice="opt">--nosetsched</arg>
33
<arg choice="opt">--public-addresses=<filename></arg>
34
<arg choice="opt">--public-interface=<interface></arg>
35
<arg choice="req">--reclock=<filename></arg>
36
<arg choice="opt">--single-public-ip=<address></arg>
37
<arg choice="opt">--socket=<filename></arg>
38
<arg choice="opt">--start-as-disabled</arg>
39
<arg choice="opt">--syslog</arg>
40
<arg choice="opt">--torture</arg>
41
<arg choice="opt">--transport=<STRING></arg>
42
<arg choice="opt">--usage</arg>
47
<refsect1><title>DESCRIPTION</title>
49
ctdbd is the main ctdb daemon.
52
ctdbd provides a clustered version of the TDB database with automatic rebuild/recovery of the databases upon nodefailures.
55
Combined with a cluster filesystem ctdbd provides a full HA environment for services such as clustered Samba and NFS as well as other services.
58
ctdbd provides monitoring of all nodes in the cluster and automatically reconfigures the cluster and recovers upon node failures.
61
ctdbd is the main component in clustered Samba that provides a high-awailability load-sharing CIFS server cluster.
67
<title>OPTIONS</title>
70
<varlistentry><term>-? --help</term>
73
Print some help text to the screen.
78
<varlistentry><term>-d --debug=<DEBUGLEVEL></term>
81
This option sets the debuglevel on the ctdbd daemon which controls what will be written to the logfile. The default is 0 which will only log important events and errors. A larger number will provide additional logging.
86
<varlistentry><term>--dbdir=<directory></term>
89
This is the directory on local storage where ctdbd keeps the local
90
copy of the TDB databases. This directory is local for each node and should not be stored on the shared cluster filesystem.
93
This directory would usually be /var/ctdb .
98
<varlistentry><term>--dbdir-persistent=<directory></term>
101
This is the directory on local storage where ctdbd keeps the local
102
copy of the persistent TDB databases. This directory is local for each node and should not be stored on the shared cluster filesystem.
105
This directory would usually be /etc/ctdb/persistent .
110
<varlistentry><term>--event-script-dir=<directory></term>
113
This option is used to specify the directory where the CTDB event
117
This will normally be /etc/ctdb/events.d which is part of the ctdb distribution.
122
<varlistentry><term>-i --interactive</term>
125
By default ctdbd will detach itself from the shell and run in
126
the background as a daemon. This option makes ctdbd to start in interactive mode.
131
<varlistentry><term>--listen=<address></term>
134
This specifies which ip address ctdb will bind to. By default ctdbd will bind to the first address it finds in the /etc/ctdb/nodes file and which is also present on the local system in which case you do not need to provide this option.
137
This option is only required when you want to run multiple ctdbd daemons/nodes on the same physical host in which case there would be multiple entries in /etc/ctdb/nodes what would match a local interface.
142
<varlistentry><term>--logfile=<filename></term>
145
This is the file where ctdbd will write its log. This is usually /var/log/log.ctdb .
150
<varlistentry><term>--nlist=<filename></term>
153
This file contains a list of the private ip addresses of every node in the cluster. There is one line/ip address for each node. This file must be the same for all nodes in the cluster.
156
This file is usually /etc/ctdb/nodes .
161
<varlistentry><term>--nosetsched</term>
164
This is a ctdbd debugging option. this option is only used when
168
Normally ctdb will change its scheduler to run as a real-time
169
process. This is the default mode for a normal ctdbd operation
170
to gurarantee that ctdbd always gets the cpu cycles that it needs.
173
This option is used to tell ctdbd to NOT run as a real-time process
174
and instead run ctdbd as a normal userspace process.
175
This is useful for debugging and when you want to run ctdbd under
176
valgrind or gdb. (You dont want to attach valgrind or gdb to a
182
<varlistentry><term>--public_addresses=<filename></term>
185
When used with IP takeover this specifies a file containing the public ip addresses to use on the cluster. This file contains a list of ip addresses netmasks and interfaces. When ctdb is operational it will distribute these public ip addresses evenly across the available nodes.
188
This is usually the file /etc/ctdb/public_addresses
193
<varlistentry><term>--public-interface=<interface></term>
196
This option tells ctdb which interface to attach public-addresses
197
to and also where to attach the single-public-ip when used.
200
This is only required when using public ip addresses and only when
201
you dont specify the interface explicitely on in /etc/ctdb/public_addresses or when you are using --single-public-ip.
204
If you omit this argument when using public addresses or single public ip, ctdb will not be able to send out Gratious ARPs correctly or be able to kill tcp connections correctly which will lead to application failures.
209
<varlistentry><term>--reclock=<filename></term>
212
This is the name of the lock file stored of the shared cluster filesystem that ctdbd uses to arbitrate which node has the role of recovery-master.
213
This file must be stored on shared storage.
218
<varlistentry><term>--single-public-ip=<address></term>
221
This option is used to activate the "ipmux" or the "lvs"
222
functionality of ctdb where the cluster provides a single
223
public ip address for the entire cluster. When using this option
224
you must also use the --public-interface option.
227
In this mode, all nodes of the cluster will expose a single
228
ip address from all nodes with all incoming traffic to the cluster
229
being passed through the current recmaster. This functionality
230
is similar to using a load-balancing switch.
233
All incoming packets are sent to the recmaster which will multiplex
234
the clients across all available nodes and pass the packets on to
235
a different node in the cluster to manage the connection based
236
on the clients ip address. Outgoing packets however are sent
237
directly from the node that was choosen back to the client.
238
Since all incoming packets are sent through the recmaster this will
239
have a throughput and performance impact when used. This impact
240
in performance primarily affects write-performance while
241
read-performance should be mainly unaffected.
242
Only use this feature if your environment is mostly-read
243
(i.e. most traffic is from the nodes back to the clients) or
244
if it is not important to get maximum write-performance to the
248
This feature is completely controlled from the eventscripts and
249
does not require any CTDBD involvement. However, the CTDBD daemon
250
does need to know that the "single public ip" exists so that the
251
CTDBD daemon will allow clients to set up killtcp to work on this
255
CTDBD only allows clients to use killtcp to kill off (RST) tcp
256
connections to/from an ip address that is either a normal public
257
address or to/from the ip address specified by --single-public-ip.
258
No other tcp connections are allowed to be specified with killtcp.
263
<varlistentry><term>--socket=<filename></term>
266
This specifies the name of the domain socket that ctdbd will create. This socket is used for local clients to attach to and communicate with the ctdbd daemon.
269
The default is /tmp/ctdb.socket . You only need to use this option if you plan to run multiple ctdbd daemons on the same physical host.
274
<varlistentry><term>--start-as-disabled</term>
277
This makes the ctdb daemon to be DISABLED when it starts up.
280
As it is DISABLED it will not get any of the public ip addresses
281
allocated to it, and thus this allow you to start ctdb on a node
282
without causing any ip address to failover from other nodes onto
286
When used, the administrator must keep track of when nodes start and
287
manually enable them again using the "ctdb enable" command, or else
288
the node will not host any services.
291
A node that is DISABLED will not host any services and will not be
292
reachable/used by any clients.
297
<varlistentry><term>--syslog</term>
300
Send all log messages to syslog instead of to the ctdb logfile.
305
<varlistentry><term>--torture</term>
308
This option is only used for development and testing of ctdbd. It adds artificial errors and failures to the common codepaths in ctdbd to verify that ctdbd can recover correctly for failures.
311
You do NOT want to use this option unless you are developing and testing new functionality in ctdbd.
316
<varlistentry><term>--transport=<STRING></term>
319
This option specifies which transport to use for ctdbd internode communications. The default is "tcp".
322
Currently only "tcp" is supported but "infiniband" might be
323
implemented in the future.
328
<varlistentry><term>--usage</term>
331
Print useage information to the screen.
340
<refsect1><title>Private vs Public addresses</title>
342
When used for ip takeover in a HA environment, each node in a ctdb
343
cluster has multiple ip addresses assigned to it. One private and one or more public.
346
<refsect2><title>Private address</title>
348
This is the physical ip address of the node which is configured in
349
linux and attached to a physical interface. This address uniquely
350
identifies a physical node in the cluster and is the ip addresses
351
that ctdbd will use to communicate with the ctdbd daemons on the
352
other nodes in the cluster.
355
The private addresses are configured in /etc/ctdb/nodes
356
(unless the --nlist option is used) and contain one line for each
357
node in the cluster. Each line contains the private ip address for one
358
node in the cluster. This file must be the same on all nodes in the
362
Since the private addresses are only available to the network when the
363
corresponding node is up and running you should not use these addresses
364
for clients to connect to services provided by the cluster. Instead
365
client applications should only attach to the public addresses since
366
these are guaranteed to always be available.
369
When using ip takeover, it is strongly recommended that the private
370
addresses are configured on a private network physically separated
371
from the rest of the network and that this private network is dedicated
374
Example /etc/ctdb/nodes for a four node cluster:
375
<screen format="linespecific">
382
<refsect2><title>Public address</title>
384
A public address on the other hand is not attached to an interface.
385
This address is managed by ctdbd itself and is attached/detached to
386
a physical node at runtime.
389
The ctdb cluster will assign/reassign these public addresses across the
390
available healthy nodes in the cluster. When one node fails, its public address
391
will be migrated to and taken over by a different node in the cluster
392
to ensure that all public addresses are always available to clients as
393
long as there are still nodes available capable of hosting this address.
396
These addresses are not physically attached to a specific node.
397
The 'ctdb ip' command can be used to view the current assignment of
398
public addresses and which physical node is currently serving it.
401
On each node this file contains a list of the public addresses that
402
this node is capable of hosting.
403
The list also contain the netmask and the
404
interface where this address should be attached for the case where you
405
may want to serve data out through multiple different interfaces.
407
Example /etc/ctdb/public_addresses for a node that can host 4 public addresses:
408
<screen format="linespecific">
416
In most cases this file would be the same on all nodes in a cluster but
417
there are exceptions when one may want to use different files
420
Example: 4 nodes partitioned into two subgroups :
421
<screen format="linespecific">
422
Node 0:/etc/ctdb/public_addresses
426
Node 1:/etc/ctdb/public_addresses
430
Node 2:/etc/ctdb/public_addresses
434
Node 3:/etc/ctdb/public_addresses
439
In this example nodes 0 and 1 host two public addresses on the
440
10.1.1.x network while nodes 2 and 3 host two public addresses for the
444
Ip address 10.1.1.1 can be hosted by either of nodes 0 or 1 and will be
445
available to clients as long as at least one of these two nodes are
447
If both nodes 0 and node 1 become unavailable 10.1.1.1 also becomes
448
unavailable. 10.1.1.1 can not be failed over to node 2 or node 3 since
449
these nodes do not have this ip address listed in their public
456
<refsect1><title>Node status</title>
458
The current status of each node in the cluster can be viewed by the
459
'ctdb status' command.
462
There are five possible for a node.
466
OK - This node is fully functional.
470
DISCONNECTED - This node could not be connected through the network
471
and is currently not particpating in the cluster. If there is a
472
public IP address associated with this node it should have been taken
473
over by a different node. No services are running on this node.
477
DISABLED - This node has been administratively disabled. This node is
478
still functional and participates in the CTDB cluster but its IP
479
addresses have been taken over by a different node and no services are
480
currently being hosted.
484
UNHEALTHY - A service provided by this node is malfunctioning and should
485
be investigated. The CTDB daemon itself is operational and participates
486
in the cluster. Its public IP address has been taken over by a different
487
node and no services are currently being hosted. All unhealthy nodes
488
should be investigated and require an administrative action to rectify.
492
BANNED - This node failed too many recovery attempts and has been banned
493
from participating in the cluster for a period of RecoveryBanPeriod
494
seconds. Any public IP address has been taken over by other nodes. This
495
node does not provide any services. All banned nodes should be
496
investigated and require an administrative action to rectify. This node
497
does not perticipate in the CTDB cluster but can still be communicated
498
with. I.e. ctdb commands can be sent to it.
503
<title>PUBLIC TUNABLES</title>
505
These are the public tuneables that can be used to control how ctdb behaves.
508
<refsect2><title>KeepaliveInterval</title>
509
<para>Default: 1</para>
511
How often should the nodes send keepalives to eachother.
514
<refsect2><title>KeepaliveLimit</title>
515
<para>Default: 5</para>
517
After how many keepalive intervals without any traffic should a node
518
wait until marking the peer as DISCONNECTED.
521
<refsect2><title>MonitorInterval</title>
522
<para>Default: 15</para>
524
How often should ctdb run the event scripts to check for a nodes health.
527
<refsect2><title>TickleUpdateInterval</title>
528
<para>Default: 20</para>
530
How often will ctdb record and store the "tickle" information used to
531
kickstart stalled tcp connections after a recovery.
534
<refsect2><title>EventScriptTimeout</title>
535
<para>Default: 20</para>
537
How long should ctdb let an event script run before aborting it and
538
marking the node unhealthy.
541
<refsect2><title>RecoveryBanPeriod</title>
542
<para>Default: 300</para>
544
If a node becomes banned causing repetitive recovery failures. The node will
545
eventually become banned from the cluster.
546
This controls how long the culprit node will be banned from the cluster
547
before it is allowed to try to join the cluster again.
548
Dont set to small. A node gets banned for a reason and it is usually due
549
to real problems with the node.
552
<refsect2><title>DatabaseHashSize</title>
553
<para>Default: 100000</para>
555
Size of the hash chains for the local store of the tdbs that ctdb manages.
558
<refsect2><title>RerecoveryTimeout</title>
559
<para>Default: 10</para>
561
Once a recovery has completed, no additional recoveries are permitted until this timeout has expired.
564
<refsect2><title>EnableBans</title>
565
<para>Default: 1</para>
567
When set to 0, this disables BANNING completely in the cluster and thus nodes can not get banned, even it they break. Dont set to 0.
570
<refsect2><title>DeterministicIPs</title>
571
<para>Default: 1</para>
573
When enabled, this tunable makes ctdb try to keep public ip addresses locked to specific nodes as far as possible. This makes it easier for debugging since you can know that as long as all nodes are healthy public ip X will always be hosted by node Y.
576
The cost of using deterministic ip address assignment is that it disables part of the logic where ctdb tries to reduce the number of public ip assignment changes in the cluster. This tunable may increase the number of ip failover/failbacks that are performed on the cluster by a small margin.
579
<refsect2><title>DisableWhenUnhealthy</title>
580
<para>Default: 0</para>
582
When set, As soon as a node becomes unhealthy, that node will also automatically become permanently DISABLED. Once a node is DISABLED, the only way to make it participate in the cluster again and host services is by manually enabling the node again using 'ctdb enable'.
585
This disables parts of the resilience and robustness of the cluster and should ONLY be used when the system administrator is actively monitoring the cluster, so that nodes can be enabled again.
588
<refsect2><title>NoIPFailback</title>
589
<para>Default: 0</para>
591
When set to 1, ctdb will not perform failback of ip addresses when a node becomes healthy. Ctdb WILL perform failover of public ip addresses when a node becomes UNHEALTHY, but when the node becomes HEALTHY again, ctdb will not fail the addresses back.
594
Use with caution! Normally when a node becomes available to the cluster
595
ctdb will try to reassign public ip addresses onto the new node as a way to distribute the workload evenly across the clusternode. Ctdb tries to make sure that all running nodes have approximately the same number of public addresses it hosts.
598
When you enable this tunable, CTDB will no longer attempt to rebalance the cluster by failing ip addresses back to the new nodes. An unbalanced cluster will therefore remain unbalanced until there is manual intervention from the administrator. When this parameter is set, you can manually fail public ip addresses over to the new node(s) using the 'ctdb moveip' command.
605
<refsect1><title>SEE ALSO</title>
608
<ulink url="http://ctdb.samba.org/"/>
612
<refsect1><title>COPYRIGHT/LICENSE</title>
614
Copyright (C) Andrew Tridgell 2007
615
Copyright (C) Ronnie sahlberg 2007
617
This program is free software; you can redistribute it and/or modify
618
it under the terms of the GNU General Public License as published by
619
the Free Software Foundation; either version 3 of the License, or (at
620
your option) any later version.
622
This program is distributed in the hope that it will be useful, but
623
WITHOUT ANY WARRANTY; without even the implied warranty of
624
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
625
General Public License for more details.
627
You should have received a copy of the GNU General Public License
628
along with this program; if not, see http://www.gnu.org/licenses/.