## Name

ctdb — clustered tdb database management utility

## Synopsis

`ctdb [ OPTIONS ] COMMAND ...`

`ctdb` [-n <node>] [-Y] [-t <timeout>] [-? --help] [--usage] [-d --debug=<INTEGER>] [--socket=<filename>]

## DESCRIPTION

ctdb is a utility to view and manage a ctdb cluster.

## OPTIONS

-n <node>

  This specifies on which node to execute the command. Default is to run the command on the deamon running on the local host.

-Y

  Produce output in machinereadable form for easier parsing by scripts. Not all commands support this option.

-t <timeout>

  How long should ctdb wait for a command to complete before timing out. Default is 3 seconds.

-? --help

  Print some help text to the screen.

--usage

  Print useage information to the screen.

-d --debug=<debuglevel>

  Change the debug level for the command. Default is 0.

--socket=<filename>

  Specify the socketname to use when connecting to the local ctdb daemon. The default is /tmp/ctdb.socket .

  You only need to specify this parameter if you run multiple ctdb daemons on the same physical host and thus can not use the default name for the domain socket.

## Administrative Commands

These are commands used to monitor and administrate a CTDB cluster.

### status

This command shows the current status of the ctdb node.

#### node status

Node status reflects the current status of the node. There are four possible states:

OK - This node is fully functional.

DISCONNECTED - This node could not be connected through the network and is currently not parcipitating 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.

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.

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.

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.

#### generation

The generation id is a number that indicates the current generation of a cluster instance. Each time a cluster goes through a reconfiguration or a recovery its generation id will be changed.

#### VNNMAP

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. Only nodes that are parcipitating in the vnnmap can become lmaster or dmaster for a database record.

#### Recovery mode

This is the current recovery mode of the cluster. There are two possible modes:

NORMAL - The cluster is fully operational.

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.

#### Recovery master

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.

Example: ctdb status

Example output:

    Number of nodes:4
    vnn:0 11.1.2.200       OK (THIS NODE)
    vnn:1 11.1.2.201       OK
    vnn:2 11.1.2.202       OK
    vnn:3 11.1.2.203       OK
    Generation:1362079228
    Size:4
    hash:0 lmaster:0
    hash:1 lmaster:1
    hash:2 lmaster:2
    hash:3 lmaster:3
    Recovery mode:NORMAL (0)
    Recovery master:0

### ping

This command will "ping" all CTDB daemons in the cluster to verify that they are processing commands correctly.

Example: ctdb ping

Example output:

    response from 0 time=0.000054 sec  (3 clients)
    response from 1 time=0.000144 sec  (2 clients)
    response from 2 time=0.000105 sec  (2 clients)
    response from 3 time=0.000114 sec  (2 clients)

### ip

This command will display the list of public addresses that are provided by the cluster and which physical node is currently serving this ip.

Example: ctdb ip

Example output:

    Number of nodes:4
    12.1.1.1         0
    12.1.1.2         1
    12.1.1.3         2
    12.1.1.4         3

### getvar <name>

Get the runtime value of a tuneable variable.

Example: ctdb getvar MaxRedirectCount

Example output:

    MaxRedirectCount    = 3

### setvar <name> <value>

Set the runtime value of a tuneable variable.

Example: ctdb setvar MaxRedirectCount 5

### listvars

List all tuneable variables.

Example: ctdb listvars

Example output:

    MaxRedirectCount    = 5
    SeqnumFrequency     = 1
    ControlTimeout      = 60
    TraverseTimeout     = 20
    KeepaliveInterval   = 2
    KeepaliveLimit      = 3
    MaxLACount          = 7
    RecoverTimeout      = 5
    RecoverInterval     = 1
    ElectionTimeout     = 3
    TakeoverTimeout     = 5
    MonitorInterval     = 15
    EventScriptTimeout  = 20
    RecoveryGracePeriod = 60
    RecoveryBanPeriod   = 300

### statistics

Collect statistics from the CTDB daemon about how many calls it has served.

Example: ctdb statistics

Example output:

    CTDB version 1
     num_clients                        3
     frozen                             0
     recovering                         0
     client_packets_sent           360489
     client_packets_recv           360466
     node_packets_sent             480931
     node_packets_recv             240120
     keepalive_packets_sent             4
     keepalive_packets_recv             3
     node
         req_call                       2
         reply_call                     2
         req_dmaster                    0
         reply_dmaster                  0
         reply_error                    0
         req_message                   42
         req_control               120408
         reply_control             360439
     client
         req_call                       2
         req_message                   24
         req_control               360440
     timeouts
         call                           0
         control                        0
         traverse                       0
     total_calls                        2
     pending_calls                      0
     lockwait_calls                     0
     pending_lockwait_calls             0
     memory_used                     5040
     max_hop_count                      0
     max_call_latency                   4.948321 sec
     max_lockwait_latency               0.000000 sec

### statisticsreset

This command is used to clear all statistics counters in a node.

Example: ctdb statisticsreset

### getdebug

Get the current debug level for the node. the debug level controls what information is written to the log file.

### setdebug <debuglevel>

Set the debug level of a node. This is a number between 0 and 9 and controls what information will be written to the logfile.

### getpid

This command will return the process id of the ctdb daemon.

### disable

This command is used to administratively disable a node in the cluster. A disabled node will still participate in the cluster and host clustered TDB records but its public ip address has been taken over by a different node and it no longer hosts any services.

### enable

Re-enable a node that has been administratively disabled.

### ban <bantime|0>

Administratively ban a node for bantime seconds. A bantime of 0 means that the node should be permanently banned.

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.

Nodes are automatically banned if they are the cause of too many cluster recoveries.

### unban

This command is used to unban a node that has either been administratively banned using the ban command or has been automatically banned by the recovery daemon.

### shutdown

This command will shutdown a specific CTDB daemon.

### recover

This command will trigger the recovery daemon to do a cluster recovery.

### killtcp <srcip:port> <dstip:port>

This command will kill the specified TCP connection by issuing a TCP RST to the srcip:port endpoint.

### tickle <srcip:port> <dstip:port>

This command will will send a TCP tickle to the source host for the specified TCP connection. A TCP tickle is a TCP ACK packet with an invalid sequence and acknowledge number and will when received by the source host result in it sending an immediate correct ACK back to the other end.

TCP tickles are useful to "tickle" clients after a IP failover has occured since this will make the client immediately recognize the TCP connection has been disrupted and that the client will need to reestablish. This greatly speeds up the time it takes for a client to detect and reestablish after an IP failover in the ctdb cluster.

## Debugging Commands

These commands are primarily used for CTDB development and testing and should not be used for normal administration.

### process-exists <pid>

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.

### getdbmap

This command lists all clustered TDB databases that the CTDB daemon has attahced to.

Example: ctdb getdbmap

Example output:

    Number of databases:4
    dbid:0x42fe72c5 name:locking.tdb path:/var/ctdb/locking.tdb.0
    dbid:0x1421fb78 name:brlock.tdb path:/var/ctdb/brlock.tdb.0
    dbid:0x17055d90 name:connections.tdb path:/var/ctdb/connections.tdb.0
    dbid:0xc0bdde6a name:sessionid.tdb path:/var/ctdb/sessionid.tdb.0

### catdb <dbname>

This command will dump a clustered TDB database to the screen. This is a debugging command.

### getmonmode

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.

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.

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.

### setmonmode <0|1>

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.

### attach <dbname>

This is a debugging command. This command will make the CTDB daemon create a new CTDB database and attach to it.

### dumpmemory

This is a debugging command. This command will make the ctdb daemon to write a fill memory allocation map to the log file.

### freeze

This command will lock all the local TDB databases causing clients that are accessing these TDBs such as samba3 to block until the databases are thawed.

This is primarily used by the recovery daemon to stop all samba daemons from accessing any databases while the database is recovered and rebuilt.

### thaw

Thaw a previously frozen node.

## SEE ALSO

ctdbd(1), onnode(1) http://ctdb.samba.org/

## COPYRIGHT/LICENSE

Copyright (C) Andrew Tridgell 2007
Copyright (C) Ronnie sahlberg 2007
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, see http://www.gnu.org/licenses/.