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">
6 <refentrytitle>ctdb</refentrytitle>
7 <manvolnum>1</manvolnum>
12 <refname>ctdb</refname>
13 <refpurpose>clustered tdb database management utility</refpurpose>
18 <command>ctdb [ OPTIONS ] COMMAND ...</command>
22 <command>ctdb</command>
23 <arg choice="opt">-n <node></arg>
24 <arg choice="opt">-Y</arg>
25 <arg choice="opt">-t <timeout></arg>
26 <arg choice="opt">-T <timelimit></arg>
27 <arg choice="opt">-? --help</arg>
28 <arg choice="opt">--usage</arg>
29 <arg choice="opt">-d --debug=<INTEGER></arg>
30 <arg choice="opt">--socket=<filename></arg>
35 <refsect1><title>DESCRIPTION</title>
37 ctdb is a utility to view and manage a ctdb cluster.
43 <title>OPTIONS</title>
46 <varlistentry><term>-n <pnn></term>
49 This specifies the physical node number on which to execute the
50 command. Default is to run the command on the deamon running on
54 The physical node number is an integer that describes the node in the
55 cluster. The first node has physical node number 0.
60 <varlistentry><term>-Y</term>
63 Produce output in machine readable form for easier parsing by scripts. Not all commands support this option.
68 <varlistentry><term>-t <timeout></term>
71 How long should ctdb wait for the local ctdb daemon to respond to a command before timing out. Default is 3 seconds.
76 <varlistentry><term>-T <timelimit></term>
79 A limit on how long the ctdb command will run for before it will
80 be aborted. When this timelimit has been exceeded the ctdb command will
86 <varlistentry><term>-? --help</term>
89 Print some help text to the screen.
94 <varlistentry><term>--usage</term>
97 Print useage information to the screen.
102 <varlistentry><term>-d --debug=<debuglevel></term>
105 Change the debug level for the command. Default is 0.
110 <varlistentry><term>--socket=<filename></term>
113 Specify the socketname to use when connecting to the local ctdb
114 daemon. The default is /tmp/ctdb.socket .
117 You only need to specify this parameter if you run multiple ctdb
118 daemons on the same physical host and thus can not use the default
119 name for the domain socket.
128 <refsect1><title>Administrative Commands</title>
130 These are commands used to monitor and administrate a CTDB cluster.
133 <refsect2><title>pnn</title>
135 This command displays the pnn of the current node.
139 <refsect2><title>status</title>
141 This command shows the current status of the ctdb node.
144 <refsect3><title>node status</title>
146 Node status reflects the current status of the node. There are four possible states:
149 OK - This node is fully functional.
152 DISCONNECTED - This node could not be connected through the network and is currently not participating in the cluster. If there is a public IP address associated with this node it should have been taken over by a different node. No services are running on this node.
155 DISABLED - This node has been administratively disabled. This node is still functional and participates in the CTDB cluster but its IP addresses have been taken over by a different node and no services are currently being hosted.
158 UNHEALTHY - A service provided by this node is malfunctioning and should be investigated. The CTDB daemon itself is operational and participates in the cluster. Its public IP address has been taken over by a different node and no services are currnetly being hosted. All unhealthy nodes should be investigated and require an administrative action to rectify.
161 BANNED - This node failed too many recovery attempts and has been banned from participating in the cluster for a period of RecoveryBanPeriod seconds. Any public IP address has been taken over by other nodes. This node does not provide any services. All banned nodes should be investigated and require an administrative action to rectify. This node does not perticipate in the CTDB cluster but can still be communicated with. I.e. ctdb commands can be sent to it.
165 <refsect3><title>generation</title>
167 The generation id is a number that indicates the current generation
168 of a cluster instance. Each time a cluster goes through a
169 reconfiguration or a recovery its generation id will be changed.
172 This number does not have any particular meaning other than to keep
173 track of when a cluster has gone through a recovery. It is a random
174 number that represents the current instance of a ctdb cluster
176 CTDBD uses this number internally to be able to tell when commands
177 to operate on the cluster and the databases was issued in a different
178 generation of the cluster, to ensure that commands that operate
179 on the databases will not survive across a cluster database recovery.
180 After a recovery, all old outstanding commands will automatically
184 Sometimes this number will be shown as "INVALID". This only means that
185 the ctdbd daemon has started but it has not yet merged with the cluster through a recovery.
186 All nodes start with generation "INVALID" and are not assigned a real
187 generation id until they have successfully been merged with a cluster
192 <refsect3><title>VNNMAP</title>
194 The list of Virtual Node Numbers. This is a list of all nodes that actively participates in the cluster and that share the workload of hosting the Clustered TDB database records.
195 Only nodes that are participating in the vnnmap can become lmaster or dmaster for a database record.
199 <refsect3><title>Recovery mode</title>
201 This is the current recovery mode of the cluster. There are two possible modes:
204 NORMAL - The cluster is fully operational.
207 RECOVERY - The cluster databases have all been frozen, pausing all services while the cluster awaits a recovery process to complete. A recovery process should finish within seconds. If a cluster is stuck in the RECOVERY state this would indicate a cluster malfunction which needs to be investigated.
210 Once the recovery master detects an inconsistency, for example a node
211 becomes disconnected/connected, the recovery daemon will trigger a
212 cluster recovery process, where all databases are remerged across the
213 cluster. When this process starts, the recovery master will first
214 "freeze" all databases to prevent applications such as samba from
215 accessing the databases and it will also mark the recovery mode as
219 When CTDBD starts up, it will start in RECOVERY mode.
220 Once the node has been merged into a cluster and all databases
221 have been recovered, the node mode will change into NORMAL mode
222 and the databases will be "thawed", allowing samba to access the
227 <refsect3><title>Recovery master</title>
229 This is the cluster node that is currently designated as the recovery master. This node is responsible of monitoring the consistency of the cluster and to perform the actual recovery process when reqired.
232 Only one node at a time can be the designated recovery master. Which
233 node is designated the recovery master is decided by an election
234 process in the recovery daemons running on each node.
241 <para>Example output:</para>
242 <screen format="linespecific">
244 pnn:0 11.1.2.200 OK (THIS NODE)
248 Generation:1362079228
254 Recovery mode:NORMAL (0)
259 <refsect2><title>ping</title>
261 This command will "ping" all CTDB daemons in the cluster to verify that they are processing commands correctly.
269 <screen format="linespecific">
270 response from 0 time=0.000054 sec (3 clients)
271 response from 1 time=0.000144 sec (2 clients)
272 response from 2 time=0.000105 sec (2 clients)
273 response from 3 time=0.000114 sec (2 clients)
277 <refsect2><title>ip</title>
279 This command will display the list of public addresses that are provided by the cluster and which physical node is currently serving this ip.
287 <screen format="linespecific">
288 Number of addresses:4
296 <refsect2><title>getvar <name></title>
298 Get the runtime value of a tuneable variable.
301 Example: ctdb getvar MaxRedirectCount
306 <screen format="linespecific">
311 <refsect2><title>setvar <name> <value></title>
313 Set the runtime value of a tuneable variable.
316 Example: ctdb setvar MaxRedirectCount 5
320 <refsect2><title>listvars</title>
322 List all tuneable variables.
325 Example: ctdb listvars
330 <screen format="linespecific">
335 KeepaliveInterval = 2
343 EventScriptTimeout = 20
344 RecoveryGracePeriod = 60
345 RecoveryBanPeriod = 300
349 <refsect2><title>lvsmaster</title>
351 This command shows which node is currently the LVSMASTER. The
352 LVSMASTER is the node in the cluster which drives the LVS system and
353 which receives all incoming traffic from clients.
356 LVS is the mode where the entire CTDB/Samba cluster uses a single
357 ip address for the entire cluster. In this mode all clients connect to
358 one specific node which will then multiplex/loadbalance the clients
359 evenly onto the other nodes in the cluster. This is an alternative to using
360 public ip addresses. See the manpage for ctdbd for more information
365 <refsect2><title>lvs</title>
367 This command shows which nodes in the cluster are currently active in the
368 LVS configuration. I.e. which nodes we are currently loadbalancing
369 the single ip address across.
373 LVS will by default only loadbalance across those nodes that are both
374 LVS capable and also HEALTHY. Except if all nodes are UNHEALTHY in which
375 case LVS will loadbalance across all UNHEALTHY nodes as well.
376 LVS will never use nodes that are DISCONNECTED, BANNED or DISABLED.
382 <screen format="linespecific">
390 <refsect2><title>getcapabilities</title>
392 This command shows the capabilities of the current node.
393 Please see manpage for ctdbd for a full list of all capabilities and
394 more detailed description.
398 RECMASTER and LMASTER capabilities are primarily used when CTDBD
399 is used to create a cluster spanning across WAN links. In which case
400 ctdbd acts as a WAN accelerator.
404 LVS capabile means that the node is participating in LVS, a mode
405 where the entire CTDB cluster uses one single ip address for the
406 entire cluster instead of using public ip address failover.
407 This is an alternative to using a loadbalancing layer-4 switch.
413 <screen format="linespecific">
421 <refsect2><title>statistics</title>
423 Collect statistics from the CTDB daemon about how many calls it has served.
426 Example: ctdb statistics
431 <screen format="linespecific">
436 client_packets_sent 360489
437 client_packets_recv 360466
438 node_packets_sent 480931
439 node_packets_recv 240120
440 keepalive_packets_sent 4
441 keepalive_packets_recv 3
462 pending_lockwait_calls 0
465 max_call_latency 4.948321 sec
466 max_lockwait_latency 0.000000 sec
470 <refsect2><title>statisticsreset</title>
472 This command is used to clear all statistics counters in a node.
475 Example: ctdb statisticsreset
479 <refsect2><title>getdebug</title>
481 Get the current debug level for the node. the debug level controls what information is written to the log file.
484 The debug levels are mapped to the corresponding syslog levels.
485 When a debug level is set, only those messages at that level and higher
486 levels will be printed.
489 The list of debug levels from highest to lowest are :
492 EMERG ALERT CRIT ERR WARNING NOTICE INFO DEBUG
496 <refsect2><title>setdebug <debuglevel></title>
498 Set the debug level of a node. This controls what information will be logged.
501 The debuglevel is one of EMERG ALERT CRIT ERR WARNING NOTICE INFO DEBUG
505 <refsect2><title>getpid</title>
507 This command will return the process id of the ctdb daemon.
511 <refsect2><title>disable</title>
513 This command is used to administratively disable a node in the cluster.
514 A disabled node will still participate in the cluster and host
515 clustered TDB records but its public ip address has been taken over by
516 a different node and it no longer hosts any services.
520 <refsect2><title>enable</title>
522 Re-enable a node that has been administratively disabled.
526 <refsect2><title>ban <bantime|0></title>
528 Administratively ban a node for bantime seconds. A bantime of 0 means that the node should be permanently banned.
531 A banned node does not participate in the cluster and does not host any records for the clustered TDB. Its ip address has been taken over by an other node and no services are hosted.
534 Nodes are automatically banned if they are the cause of too many
539 <refsect2><title>moveip <public_ip> <node></title>
541 This command can be used to manually fail a public ip address to a
545 In order to manually override the "automatic" distribution of public
546 ip addresses that ctdb normally provides, this command only works
547 when you have changed the tunables for the daemon to:
557 <refsect2><title>unban</title>
559 This command is used to unban a node that has either been
560 administratively banned using the ban command or has been automatically
561 banned by the recovery daemon.
565 <refsect2><title>shutdown</title>
567 This command will shutdown a specific CTDB daemon.
571 <refsect2><title>recover</title>
573 This command will trigger the recovery daemon to do a cluster
578 <refsect2><title>killtcp <srcip:port> <dstip:port></title>
580 This command will kill the specified TCP connection by issuing a
581 TCP RST to the srcip:port endpoint.
585 <refsect2><title>reloadnodes</title>
587 This command is used when adding new nodes to an existing cluster and
588 to reduce the disruption of this operation. This command should never
589 be used except when expanding an existing cluster.
590 This can only be used to expand a cluster. To remove a node from the
591 cluster you still need to shut down ctdb on all nodes, edit the nodes file
598 1, To expand an existing cluster, first ensure with 'ctdb status' that
599 all nodes are up and running and that they are all healthy.
600 Do not try to expand a cluster unless it is completely healthy!
603 2, On all nodes, edit /etc/ctdb/nodes and add the new node as the last
604 entry to the file. The new node MUST be added to the end of this file!
607 3, Verify that all the nodes have identical /etc/ctdb/nodes files after you edited them and added the new node!
610 4, Run 'ctdb reloadnodes' to force all nodes to reaload the nodesfile.
613 5, Use 'ctdb status' on all nodes and verify that they now show the additional node.
616 6, Install and configure the new node and bring it online.
620 <refsect2><title>tickle <srcip:port> <dstip:port></title>
622 This command will will send a TCP tickle to the source host for the
623 specified TCP connection.
624 A TCP tickle is a TCP ACK packet with an invalid sequence and
625 acknowledge number and will when received by the source host result
626 in it sending an immediate correct ACK back to the other end.
629 TCP tickles are useful to "tickle" clients after a IP failover has
630 occured since this will make the client immediately recognize the
631 TCP connection has been disrupted and that the client will need
632 to reestablish. This greatly speeds up the time it takes for a client
633 to detect and reestablish after an IP failover in the ctdb cluster.
637 <refsect2><title>repack [max_freelist]</title>
639 Over time, when records are created and deleted in a TDB, the TDB list of free space will become fragmented. This can lead to a slowdown in accessing TDB records.
640 This command is used to defragment a TDB database and pruning the freelist.
644 If [max_freelist] is specified, then a database will only be repacked if it has more than this number of entries in the freelist.
647 During repacking of the database, the entire TDB database will be locked to prevent writes. If samba tries to write to a record in the database during a repack operation, samba will block until the repacking has completed.
651 This command can be disruptive and can cause samba to block for the duration of the repack operation. In general, a repack operation will take less than one second to complete.
655 A repack operation will only defragment the local TDB copy of the CTDB database. You need to run this command on all of the nodes to repack a CTDB database completely.
659 Example: ctdb repack 1000
663 By default, this operation is issued from the 00.ctdb event script every 5 minutes.
668 <refsect2><title>vacuum [max_records]</title>
670 Over time CTDB databases will fill up with empty deleted records which will lead to a progressive slow down of CTDB database access.
671 This command is used to prune all databases and delete all empty records from the cluster.
675 By default, vacuum will delete all empty records from all databases.
676 If [max_records] is specified, the command will only delete the first
677 [max_records] empty records for each database.
681 Vacuum only deletes records where the local node is the lmaster.
682 To delete all records from the entire cluster you need to run a vacuum from each node.
684 This command is not disruptive. Samba is unaffected and will still be able to read/write records normally while the database is being vacuumed.
692 By default, this operation is issued from the 00.ctdb event script every 5 minutes.
699 <refsect1><title>Debugging Commands</title>
701 These commands are primarily used for CTDB development and testing and
702 should not be used for normal administration.
704 <refsect2><title>process-exists <pid></title>
706 This command checks if a specific process exists on the CTDB host. This is mainly used by Samba to check if remote instances of samba are still running or not.
710 <refsect2><title>getdbmap</title>
712 This command lists all clustered TDB databases that the CTDB daemon has attached to. Some databases are flagged as PERSISTENT, this means that the database stores data persistently and the data will remain across reboots. One example of such a database is secrets.tdb where information about how the cluster was joined to the domain is stored.
715 Most databases are not persistent and only store the state information that the currently running samba daemons need. These databases are always wiped when ctdb/samba starts and when a node is rebooted.
718 Example: ctdb getdbmap
723 <screen format="linespecific">
724 Number of databases:10
725 dbid:0x435d3410 name:notify.tdb path:/var/ctdb/notify.tdb.0
726 dbid:0x42fe72c5 name:locking.tdb path:/var/ctdb/locking.tdb.0 dbid:0x1421fb78 name:brlock.tdb path:/var/ctdb/brlock.tdb.0
727 dbid:0x17055d90 name:connections.tdb path:/var/ctdb/connections.tdb.0
728 dbid:0xc0bdde6a name:sessionid.tdb path:/var/ctdb/sessionid.tdb.0
729 dbid:0x122224da name:test.tdb path:/var/ctdb/test.tdb.0
730 dbid:0x2672a57f name:idmap2.tdb path:/var/ctdb/persistent/idmap2.tdb.0 PERSISTENT
731 dbid:0xb775fff6 name:secrets.tdb path:/var/ctdb/persistent/secrets.tdb.0 PERSISTENT
732 dbid:0xe98e08b6 name:group_mapping.tdb path:/var/ctdb/persistent/group_mapping.tdb.0 PERSISTENT
733 dbid:0x7bbbd26c name:passdb.tdb path:/var/ctdb/persistent/passdb.tdb.0 PERSISTENT
737 <refsect2><title>catdb <dbname></title>
739 This command will dump a clustered TDB database to the screen. This is a debugging command.
743 <refsect2><title>getmonmode</title>
745 This command returns the monutoring mode of a node. The monitoring mode is either ACTIVE or DISABLED. Normally a node will continously monitor that all other nodes that are expected are in fact connected and that they respond to commands.
748 ACTIVE - This is the normal mode. The node is actively monitoring all other nodes, both that the transport is connected and also that the node responds to commands. If a node becomes unavailable, it will be marked as DISCONNECTED and a recovery is initiated to restore the cluster.
751 DISABLED - This node is not monitoring that other nodes are available. In this mode a node failure will not be detected and no recovery will be performed. This mode is useful when for debugging purposes one wants to attach GDB to a ctdb process but wants to prevent the rest of the cluster from marking this node as DISCONNECTED and do a recovery.
756 <refsect2><title>setmonmode <0|1></title>
758 This command can be used to explicitely disable/enable monitoring mode on a node. The main purpose is if one wants to attach GDB to a running ctdb daemon but wants to prevent the other nodes from marking it as DISCONNECTED and issuing a recovery. To do this, set monitoring mode to 0 on all nodes before attaching with GDB. Remember to set monitoring mode back to 1 afterwards.
762 <refsect2><title>attach <dbname></title>
764 This is a debugging command. This command will make the CTDB daemon create a new CTDB database and attach to it.
768 <refsect2><title>dumpmemory</title>
770 This is a debugging command. This command will make the ctdb
771 daemon to write a fill memory allocation map to standard output.
775 <refsect2><title>freeze</title>
777 This command will lock all the local TDB databases causing clients
778 that are accessing these TDBs such as samba3 to block until the
779 databases are thawed.
782 This is primarily used by the recovery daemon to stop all samba
783 daemons from accessing any databases while the database is recovered
788 <refsect2><title>thaw</title>
790 Thaw a previously frozen node.
797 <refsect1><title>SEE ALSO</title>
800 <ulink url="http://ctdb.samba.org/"/>
803 <refsect1><title>COPYRIGHT/LICENSE</title>
805 Copyright (C) Andrew Tridgell 2007
806 Copyright (C) Ronnie sahlberg 2007
808 This program is free software; you can redistribute it and/or modify
809 it under the terms of the GNU General Public License as published by
810 the Free Software Foundation; either version 3 of the License, or (at
811 your option) any later version.
813 This program is distributed in the hope that it will be useful, but
814 WITHOUT ANY WARRANTY; without even the implied warranty of
815 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
816 General Public License for more details.
818 You should have received a copy of the GNU General Public License
819 along with this program; if not, see http://www.gnu.org/licenses/.