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>
8 <refmiscinfo class="source">ctdb</refmiscinfo>
9 <refmiscinfo class="manual">CTDB - clustered TDB database</refmiscinfo>
14 <refname>ctdbd</refname>
15 <refpurpose>The CTDB cluster daemon</refpurpose>
20 <command>ctdbd</command>
24 <command>ctdbd</command>
25 <arg choice="opt">-? --help</arg>
26 <arg choice="opt">-d --debug=<INTEGER></arg>
27 <arg choice="req">--dbdir=<directory></arg>
28 <arg choice="req">--dbdir-persistent=<directory></arg>
29 <arg choice="opt">--event-script-dir=<directory></arg>
30 <arg choice="opt">-i --interactive</arg>
31 <arg choice="opt">--listen=<address></arg>
32 <arg choice="opt">--logfile=<filename></arg>
33 <arg choice="opt">--lvs</arg>
34 <arg choice="req">--nlist=<filename></arg>
35 <arg choice="opt">--no-lmaster</arg>
36 <arg choice="opt">--no-recmaster</arg>
37 <arg choice="opt">--nosetsched</arg>
38 <arg choice="req">--notification-script=<filename></arg>
39 <arg choice="opt">--public-addresses=<filename></arg>
40 <arg choice="opt">--public-interface=<interface></arg>
41 <arg choice="req">--reclock=<filename></arg>
42 <arg choice="opt">--single-public-ip=<address></arg>
43 <arg choice="opt">--socket=<filename></arg>
44 <arg choice="opt">--start-as-disabled</arg>
45 <arg choice="opt">--start-as-stopped</arg>
46 <arg choice="opt">--syslog</arg>
47 <arg choice="opt">--log-ringbuf-size=<num-entries></arg>
48 <arg choice="opt">--torture</arg>
49 <arg choice="opt">--transport=<STRING></arg>
50 <arg choice="opt">--usage</arg>
55 <refsect1><title>DESCRIPTION</title>
57 ctdbd is the main ctdb daemon.
60 ctdbd provides a clustered version of the TDB database with automatic rebuild/recovery of the databases upon nodefailures.
63 Combined with a cluster filesystem ctdbd provides a full HA environment for services such as clustered Samba and NFS as well as other services.
66 ctdbd provides monitoring of all nodes in the cluster and automatically reconfigures the cluster and recovers upon node failures.
69 ctdbd is the main component in clustered Samba that provides a high-availability load-sharing CIFS server cluster.
75 <title>OPTIONS</title>
78 <varlistentry><term>-? --help</term>
81 Print some help text to the screen.
86 <varlistentry><term>-d --debug=<DEBUGLEVEL></term>
89 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.
94 <varlistentry><term>--dbdir=<directory></term>
97 This is the directory on local storage where ctdbd keeps the local
98 copy of the TDB databases. This directory is local for each node and should not be stored on the shared cluster filesystem.
101 This directory would usually be /var/ctdb .
106 <varlistentry><term>--dbdir-persistent=<directory></term>
109 This is the directory on local storage where ctdbd keeps the local
110 copy of the persistent TDB databases. This directory is local for each node and should not be stored on the shared cluster filesystem.
113 This directory would usually be /etc/ctdb/persistent .
118 <varlistentry><term>--event-script-dir=<directory></term>
121 This option is used to specify the directory where the CTDB event
125 This will normally be /etc/ctdb/events.d which is part of the ctdb distribution.
130 <varlistentry><term>-i --interactive</term>
133 By default ctdbd will detach itself from the shell and run in
134 the background as a daemon. This option makes ctdbd to start in interactive mode.
139 <varlistentry><term>--listen=<address></term>
142 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.
145 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.
150 <varlistentry><term>--logfile=<filename></term>
153 This is the file where ctdbd will write its log. This is usually /var/log/log.ctdb .
158 <varlistentry><term>--lvs</term>
161 This option is used to activate the LVS capability on a CTDB node.
162 Please see the LVS section.
167 <varlistentry><term>--nlist=<filename></term>
170 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.
173 This file is usually /etc/ctdb/nodes .
178 <varlistentry><term>--no-lmaster</term>
181 This argument specifies that this node can NOT become an lmaster
182 for records in the database. This means that it will never show up
183 in the vnnmap. This feature is primarily used for making a cluster
184 span across a WAN link and use CTDB as a WAN-accelerator.
187 Please see the "remote cluster nodes" section for more information.
192 <varlistentry><term>--no-recmaster</term>
195 This argument specifies that this node can NOT become a recmaster
196 for the database. This feature is primarily used for making a cluster
197 span across a WAN link and use CTDB as a WAN-accelerator.
200 Please see the "remote cluster nodes" section for more information.
205 <varlistentry><term>--nosetsched</term>
208 This is a ctdbd debugging option. this option is only used when
212 Normally ctdb will change its scheduler to run as a real-time
213 process. This is the default mode for a normal ctdbd operation
214 to gurarantee that ctdbd always gets the cpu cycles that it needs.
217 This option is used to tell ctdbd to NOT run as a real-time process
218 and instead run ctdbd as a normal userspace process.
219 This is useful for debugging and when you want to run ctdbd under
220 valgrind or gdb. (You don't want to attach valgrind or gdb to a
226 <varlistentry><term>--notification-script=<filename></term>
229 This specifies a script which will be invoked by ctdb when certain
230 state changes occur in ctdbd and when you may want to trigger this
231 to run certain scripts.
234 This file is usually /etc/ctdb/notify.sh .
237 See the NOTIFICATION SCRIPT section below for more information.
242 <varlistentry><term>--public_addresses=<filename></term>
245 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.
248 This is usually the file /etc/ctdb/public_addresses
253 <varlistentry><term>--public-interface=<interface></term>
256 This option tells ctdb which interface to attach public-addresses
257 to and also where to attach the single-public-ip when used.
260 This is only required when using public ip addresses and only when
261 you don't specify the interface explicitly in /etc/ctdb/public_addresses or when you are using --single-public-ip.
264 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.
269 <varlistentry><term>--reclock=<filename></term>
272 This is the name of the lock file stored of the shared cluster filesystem that ctdbd uses to prevent split brains from occuring.
273 This file must be stored on shared storage.
276 It is possible to run CTDB without a reclock file, but then there
277 will be no protection against split brain if the network becomes
278 partitioned. Using CTDB without a reclock file is strongly
284 <varlistentry><term>--socket=<filename></term>
287 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.
290 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.
295 <varlistentry><term>--start-as-disabled</term>
298 This makes the ctdb daemon to be DISABLED when it starts up.
301 As it is DISABLED it will not get any of the public ip addresses
302 allocated to it, and thus this allow you to start ctdb on a node
303 without causing any ip address to failover from other nodes onto
307 When used, the administrator must keep track of when nodes start and
308 manually enable them again using the "ctdb enable" command, or else
309 the node will not host any services.
312 A node that is DISABLED will not host any services and will not be
313 reachable/used by any clients.
318 <varlistentry><term>--start-as-stopped</term>
321 This makes the ctdb daemon to be STOPPED when it starts up.
324 A node that is STOPPED does not host any public addresses. It is not part of the VNNMAP so it does act as an LMASTER. It also has all databases locked in recovery mode until restarted.
327 To restart and activate a STOPPED node, the command "ctdb continue" is used.
330 A node that is STOPPED will not host any services and will not be
331 reachable/used by any clients.
336 <varlistentry><term>--syslog</term>
339 Send all log messages to syslog instead of to the ctdb logfile.
344 <varlistentry><term>--log-ringbuf-size=<num-entries></term>
347 In addition to the normal loggign to a log file,
348 CTDBD also keeps a in-memory ringbuffer containing the most recent
349 log entries for all log levels (except DEBUG).
352 This is useful since it allows for keeping continous logs to a file
353 at a reasonable non-verbose level, but shortly after an incident has
354 occured, a much more detailed log can be pulled from memory. This
355 can allow you to avoid having to reproduce an issue due to the
356 on-disk logs being of insufficient detail.
359 This in-memory ringbuffer contains a fixed number of the most recent
360 entries. This is settable at startup either through the
361 --log-ringbuf-size argument, or preferably by using
362 CTDB_LOG_RINGBUF_SIZE in the sysconfig file.
365 Use the "ctdb getlog" command to access this log.
371 <varlistentry><term>--torture</term>
374 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.
377 You do NOT want to use this option unless you are developing and testing new functionality in ctdbd.
382 <varlistentry><term>--transport=<STRING></term>
385 This option specifies which transport to use for ctdbd internode communications. The default is "tcp".
388 Currently only "tcp" is supported but "infiniband" might be
389 implemented in the future.
394 <varlistentry><term>--usage</term>
397 Print useage information to the screen.
406 <refsect1><title>Private vs Public addresses</title>
408 When used for ip takeover in a HA environment, each node in a ctdb
409 cluster has multiple ip addresses assigned to it. One private and one or more public.
412 <refsect2><title>Private address</title>
414 This is the physical ip address of the node which is configured in
415 linux and attached to a physical interface. This address uniquely
416 identifies a physical node in the cluster and is the ip addresses
417 that ctdbd will use to communicate with the ctdbd daemons on the
418 other nodes in the cluster.
421 The private addresses are configured in /etc/ctdb/nodes
422 (unless the --nlist option is used) and contain one line for each
423 node in the cluster. Each line contains the private ip address for one
424 node in the cluster. This file must be the same on all nodes in the
428 Since the private addresses are only available to the network when the
429 corresponding node is up and running you should not use these addresses
430 for clients to connect to services provided by the cluster. Instead
431 client applications should only attach to the public addresses since
432 these are guaranteed to always be available.
435 When using ip takeover, it is strongly recommended that the private
436 addresses are configured on a private network physically separated
437 from the rest of the network and that this private network is dedicated
440 Example /etc/ctdb/nodes for a four node cluster:
441 <screen format="linespecific">
448 <refsect2><title>Public address</title>
450 A public address on the other hand is not attached to an interface.
451 This address is managed by ctdbd itself and is attached/detached to
452 a physical node at runtime.
455 The ctdb cluster will assign/reassign these public addresses across the
456 available healthy nodes in the cluster. When one node fails, its public address
457 will be migrated to and taken over by a different node in the cluster
458 to ensure that all public addresses are always available to clients as
459 long as there are still nodes available capable of hosting this address.
462 These addresses are not physically attached to a specific node.
463 The 'ctdb ip' command can be used to view the current assignment of
464 public addresses and which physical node is currently serving it.
467 On each node this file contains a list of the public addresses that
468 this node is capable of hosting.
469 The list also contain the netmask and the
470 interface where this address should be attached for the case where you
471 may want to serve data out through multiple different interfaces.
473 Example /etc/ctdb/public_addresses for a node that can host 4 public addresses:
474 <screen format="linespecific">
482 In most cases this file would be the same on all nodes in a cluster but
483 there are exceptions when one may want to use different files
486 Example: 4 nodes partitioned into two subgroups :
487 <screen format="linespecific">
488 Node 0:/etc/ctdb/public_addresses
492 Node 1:/etc/ctdb/public_addresses
496 Node 2:/etc/ctdb/public_addresses
500 Node 3:/etc/ctdb/public_addresses
505 In this example nodes 0 and 1 host two public addresses on the
506 10.1.1.x network while nodes 2 and 3 host two public addresses for the
510 Ip address 10.1.1.1 can be hosted by either of nodes 0 or 1 and will be
511 available to clients as long as at least one of these two nodes are
513 If both nodes 0 and node 1 become unavailable 10.1.1.1 also becomes
514 unavailable. 10.1.1.1 can not be failed over to node 2 or node 3 since
515 these nodes do not have this ip address listed in their public
522 <refsect1><title>Node status</title>
524 The current status of each node in the cluster can be viewed by the
525 'ctdb status' command.
528 There are five possible states for a node.
532 OK - This node is fully functional.
536 DISCONNECTED - This node could not be connected through the network
537 and is currently not particpating in the cluster. If there is a
538 public IP address associated with this node it should have been taken
539 over by a different node. No services are running on this node.
543 DISABLED - This node has been administratively disabled. This node is
544 still functional and participates in the CTDB cluster but its IP
545 addresses have been taken over by a different node and no services are
546 currently being hosted.
550 UNHEALTHY - A service provided by this node is malfunctioning and should
551 be investigated. The CTDB daemon itself is operational and participates
552 in the cluster. Its public IP address has been taken over by a different
553 node and no services are currently being hosted. All unhealthy nodes
554 should be investigated and require an administrative action to rectify.
558 BANNED - This node failed too many recovery attempts and has been banned
559 from participating in the cluster for a period of RecoveryBanPeriod
560 seconds. Any public IP address has been taken over by other nodes. This
561 node does not provide any services. All banned nodes should be
562 investigated and require an administrative action to rectify. This node
563 does not perticipate in the CTDB cluster but can still be communicated
564 with. I.e. ctdb commands can be sent to it.
568 STOPPED - A node that is stopped does not host any public ip addresses,
569 nor is it part of the VNNMAP. A stopped node can not become LVSMASTER,
571 This node does not perticipate in the CTDB cluster but can still be
572 communicated with. I.e. ctdb commands can be sent to it.
577 <title>PUBLIC TUNABLES</title>
579 These are the public tuneables that can be used to control how ctdb behaves.
582 <refsect2><title>KeepaliveInterval</title>
583 <para>Default: 1</para>
585 How often should the nodes send keepalives to eachother.
588 <refsect2><title>KeepaliveLimit</title>
589 <para>Default: 5</para>
591 After how many keepalive intervals without any traffic should a node
592 wait until marking the peer as DISCONNECTED.
595 <refsect2><title>MonitorInterval</title>
596 <para>Default: 15</para>
598 How often should ctdb run the event scripts to check for a nodes health.
601 <refsect2><title>TickleUpdateInterval</title>
602 <para>Default: 20</para>
604 How often will ctdb record and store the "tickle" information used to
605 kickstart stalled tcp connections after a recovery.
608 <refsect2><title>EventScriptTimeout</title>
609 <para>Default: 20</para>
611 How long should ctdb let an event script run before aborting it and
612 marking the node unhealthy.
615 <refsect2><title>RecoveryBanPeriod</title>
616 <para>Default: 300</para>
618 If a node becomes banned causing repetitive recovery failures. The node will
619 eventually become banned from the cluster.
620 This controls how long the culprit node will be banned from the cluster
621 before it is allowed to try to join the cluster again.
622 Don't set to small. A node gets banned for a reason and it is usually due
623 to real problems with the node.
626 <refsect2><title>DatabaseHashSize</title>
627 <para>Default: 100000</para>
629 Size of the hash chains for the local store of the tdbs that ctdb manages.
632 <refsect2><title>RerecoveryTimeout</title>
633 <para>Default: 10</para>
635 Once a recovery has completed, no additional recoveries are permitted until this timeout has expired.
638 <refsect2><title>EnableBans</title>
639 <para>Default: 1</para>
641 When set to 0, this disables BANNING completely in the cluster and thus nodes can not get banned, even it they break. Don't set to 0.
644 <refsect2><title>DeterministicIPs</title>
645 <para>Default: 1</para>
647 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.
650 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.
653 <refsect2><title>DisableWhenUnhealthy</title>
654 <para>Default: 0</para>
656 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'.
659 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.
662 <refsect2><title>NoIPFailback</title>
663 <para>Default: 0</para>
665 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.
668 Use with caution! Normally when a node becomes available to the cluster
669 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.
672 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.
677 <refsect1><title>LVS</title>
679 LVS is a mode where CTDB presents one single IP address for the entire
680 cluster. This is an alternative to using public IP addresses and round-robin
681 DNS to loadbalance clients across the cluster.
685 This is similar to using a layer-4 loadbalancing switch but with some restrictions.
689 In this mode the cluster select a set of nodes in the cluster and loadbalance
690 all client access to the LVS address across this set of nodes. This set of nodes are all LVS capable nodes that are HEALTHY, or if no HEALTHY nodes exists
691 all LVS capable nodes regardless of health status.
692 LVS will however never loadbalance traffic to nodes that are BANNED,
693 STOPPED, DISABLED or DISCONNECTED. The "ctdb lvs" command is used to show
694 which nodes are currently load-balanced across.
698 One of the these nodes are elected as the LVSMASTER. This node receives all
699 traffic from clients coming in to the LVS address and multiplexes it
700 across the internal network to one of the nodes that LVS is using.
701 When responding to the client, that node will send the data back
702 directly to the client, bypassing the LVSMASTER node.
703 The command "ctdb lvsmaster" will show which node is the current
708 The path used for a client i/o is thus :
709 <screen format="linespecific">
710 (1) Client sends request packet to LVSMASTER
711 (2) LVSMASTER passes the request on to one node across the internal network.
712 (3) Selected node processes the request.
713 (4) Node responds back to client.
718 This means that all incoming traffic to the cluster will pass through
719 one physical node, which limits scalability. You can send more data to the
720 LVS address that one physical node can multiplex. This means that you
721 should not use LVS if your I/O pattern is write-intensive since you will be
722 limited in the available network bandwidth that node can handle.
723 LVS does work wery well for read-intensive workloads where only smallish
724 READ requests are going through the LVSMASTER bottleneck and the majority
725 of the traffic volume (the data in the read replies) goes straight from
726 the processing node back to the clients. For read-intensive i/o patterns you can acheive very high throughput rates in this mode.
730 Note: you can use LVS and public addresses at the same time.
733 <refsect2><title>Configuration</title>
735 To activate LVS on a CTDB node you must specify CTDB_PUBLIC_INTERFACE and
736 CTDB_LVS_PUBLIC_ADDRESS in /etc/sysconfig/ctdb.
740 You must also specify the "--lvs" command line argument to ctdbd to activete LVS as a capability of the node. This should be done automatically for you by the /etc/init.d/ctdb script.
745 <screen format="linespecific">
746 CTDB_PUBLIC_INTERFACE=eth0
747 CTDB_LVS_PUBLIC_IP=10.0.0.237
754 If you use LVS, you must still have a real/permanent address configured
755 for the public interface on each node. This address must be routable
756 and the cluster nodes must be configured so that all traffic back to client
757 hosts are routed through this interface. This is also required in order
758 to allow samba/winbind on the node to talk to the domain controller.
759 (we can not use the lvs IP address to initiate outgoing traffic)
762 I.e. make sure that you can "ping" both the domain controller and also
763 all of the clients from the node BEFORE you enable LVS. Also make sure
764 that when you ping these hosts that the traffic is routed out through the
770 <refsect1><title>REMOTE CLUSTER NODES</title>
772 It is possible to have a CTDB cluster that spans across a WAN link.
773 For example where you have a CTDB cluster in your datacentre but you also
774 want to have one additional CTDB node located at a remote branch site.
775 This is similar to how a WAN accelerator works but with the difference
776 that while a WAN-accelerator often acts as a Proxy or a MitM, in
777 the ctdb remote cluster node configuration the Samba instance at the remote site
778 IS the genuine server, not a proxy and not a MitM, and thus provides 100%
779 correct CIFS semantics to clients.
783 See the cluster as one single multihomed samba server where one of
784 the NICs (the remote node) is very far away.
788 NOTE: This does require that the cluster filesystem you use can cope
789 with WAN-link latencies. Not all cluster filesystems can handle
790 WAN-link latencies! Whether this will provide very good WAN-accelerator
791 performance or it will perform very poorly depends entirely
792 on how optimized your cluster filesystem is in handling high latency
793 for data and metadata operations.
797 To activate a node as being a remote cluster node you need to set
798 the following two parameters in /etc/sysconfig/ctdb for the remote node:
799 <screen format="linespecific">
800 CTDB_CAPABILITY_LMASTER=no
801 CTDB_CAPABILITY_RECMASTER=no
806 Verify with the command "ctdb getcapabilities" that that node no longer
807 has the recmaster or the lmaster capabilities.
813 <refsect1><title>NAT-GW</title>
815 Sometimes it is desireable to run services on the CTDB node which will
816 need to originate outgoing traffic to external servers. This might
817 be contacting NIS servers, LDAP servers etc. etc.
820 This can sometimes be problematic since there are situations when a
821 node does not have any public ip addresses assigned. This could
822 be due to the nobe just being started up and no addresses have been
823 assigned yet or it could be that the node is UNHEALTHY in which
824 case all public addresses have been migrated off.
827 If then the service status of CTDB depends on such services being
828 able to always being able to originate traffic to external resources
829 this becomes extra troublesome. The node might be UNHEALTHY because
830 the service can not be reached, and the service can not be reached
831 because the node is UNHEALTHY.
834 There are two ways to solve this problem. The first is by assigning a
835 static ip address for one public interface on every node which will allow
836 every node to be able to route traffic to the public network even
837 if there are no public addresses assigned to the node.
838 This is the simplest way but it uses up a lot of ip addresses since you
839 have to assign both static and also public addresses to each node.
841 <refsect2><title>NAT-GW</title>
843 A second way is to use the built in NAT-GW feature in CTDB.
844 With NAT-GW you assign one public NATGW address for each natgw group.
845 Each NATGW group is a set of nodes in the cluster that shares the same
846 NATGW address to talk to the outside world. Normally there would only be
847 one NATGW group spanning the entire cluster, but in situations where one
848 ctdb cluster spans multiple physical sites it is useful to have one
849 NATGW group for each of the two sites.
852 There can be multiple NATGW groups in one cluster but each node can only
853 be member of one NATGW group.
856 In each NATGW group, one of the nodes is designated the NAT Gateway
857 through which all traffic that is originated by nodes in this group
858 will be routed through if a public addresses are not available.
862 <refsect2><title>Configuration</title>
864 NAT-GW is configured in /etc/sysconfigctdb by setting the following
867 <screen format="linespecific">
868 # NAT-GW configuration
869 # Some services running on nthe CTDB node may need to originate traffic to
870 # remote servers before the node is assigned any IP addresses,
871 # This is problematic since before the node has public addresses the node might
872 # not be able to route traffic to the public networks.
873 # One solution is to have static public addresses assigned with routing
874 # in addition to the public address interfaces, thus guaranteeing that
875 # a node always can route traffic to the external network.
876 # This is the most simple solution but it uses up a large number of
877 # additional ip addresses.
879 # A more complex solution is NAT-GW.
880 # In this mode we only need one additional ip address for the cluster from
881 # the exsternal public network.
882 # One of the nodes in the cluster is elected to be hosting this ip address
883 # so it can reach the external services. This node is also configured
884 # to use NAT MASQUERADING for all traffic from the internal private network
885 # to the external network. This node is the NAT-GW node.
887 # All other nodes are set up with a default rote with a metric of 10 to point
888 # to the nat-gw node.
890 # The effect of this is that only when a node does not have a public address
891 # and thus no proper routes to the external world it will instead
892 # route all packets through the nat-gw node.
894 # CTDB_NATGW_NODES is the list of nodes that belong to this natgw group.
895 # You can have multiple natgw groups in one cluster but each node
896 # can only belong to one single natgw group.
898 # CTDB_NATGW_PUBLIC_IP=10.0.0.227/24
899 # CTDB_NATGW_PUBLIC_IFACE=eth0
900 # CTDB_NATGW_DEFAULT_GATEWAY=10.0.0.1
901 # CTDB_NATGW_PRIVATE_NETWORK=10.1.1.0/24
902 # CTDB_NATGW_NODES=/etc/ctdb/natgw_nodes
904 # Normally any node in the natgw group can act as the natgw master.
905 # In some configurations you may have special nodes that is a part of the
906 # cluster/natgw group, but where the node lacks connectivity to the
908 # For these cases, set this variable to make these nodes not able to
909 # become natgw master.
911 # CTDB_NATGW_SLAVE_ONLY=yes
915 <refsect2><title>CTDB_NATGW_PUBLIC_IP</title>
917 This is an ip address in the public network that is used for all outgoing
918 traffic when the public addresses are not assigned.
919 This address will be assigned to one of the nodes in the cluster which
920 will masquerade all traffic for the other nodes.
923 Format of this parameter is IPADDRESS/NETMASK
927 <refsect2><title>CTDB_NATGW_PUBLIC_IFACE</title>
929 This is the physical interface where the CTDB_NATGW_PUBLIC_IP will be
930 assigned to. This should be an interface connected to the public network.
933 Format of this parameter is INTERFACE
937 <refsect2><title>CTDB_NATGW_DEFAULT_GATEWAY</title>
939 This is the default gateway to use on the node that is elected to host
940 the CTDB_NATGW_PUBLIC_IP. This is the default gateway on the public network.
943 Format of this parameter is IPADDRESS
947 <refsect2><title>CTDB_NATGW_PRIVATE_NETWORK</title>
949 This is the network/netmask used for the interal private network.
952 Format of this parameter is IPADDRESS/NETMASK
956 <refsect2><title>CTDB_NATGW_NODES</title>
958 This is the list of all nodes that belong to the same NATGW group
959 as this node. The default is /etc/ctdb/natgw_nodes.
963 <refsect2><title>Operation</title>
965 When the NAT-GW functionality is used, one of the nodes is elected
966 to act as a NAT router for all the other nodes in the group when
967 they need to originate traffic to the external public network.
970 The NAT-GW node is assigned the CTDB_NATGW_PUBLIC_IP to the designated
971 interface and the provided default route. The NAT-GW is configured
972 to act as a router and to masquerade all traffic it receives from the
973 internal private network and which is destined to the external network(s).
976 All other nodes in the group are configured with a default route of
977 metric 10 pointing to the designated NAT GW node.
980 This is implemented in the 11.natgw eventscript. Please see the
981 eventscript for further information.
986 <refsect2><title>Removing/Changing NATGW at runtime</title>
988 The following are the procedures to change/remove a NATGW configuration
989 at runtime, without having to restart ctdbd.
993 If you want to remove NATGW completely from a node, use these steps:
995 <screen format="linespecific">
996 1, Run 'CTDB_BASE=/etc/ctdb /etc/ctdb/events.d/11.natgw removenatgw'
997 2, Then remove the configuration from /etc/sysconfig/ctdb
1001 If you want to change the NATGW configuration on a node :
1003 <screen format="linespecific">
1004 1, Run 'CTDB_BASE=/etc/ctdb /etc/ctdb/events.d/11.natgw removenatgw'
1005 2, Then change the configuration in /etc/sysconfig/ctdb
1006 3, Run 'CTDB_BASE=/etc/ctdb /etc/ctdb/events.d/11.natgw updatenatgw'
1013 <refsect1><title>NOTIFICATION SCRIPT</title>
1015 Notification scripts are used with ctdb to have a call-out from ctdb
1016 to a user-specified script when certain state changes occur in ctdb.
1017 This is commonly to set up either sending SNMP traps or emails
1018 when a node becomes unhealthy and similar.
1021 This is activated by setting CTDB_NOTIFY_SCRIPT=<your script> in the
1022 sysconfig file, or by adding --notification-script=<your script>.
1025 See /etc/ctdb/notify.sh for an example script.
1028 CTDB currently generates notifications on these state changes:
1031 <refsect2><title>unhealthy</title>
1033 This call-out is triggered when the node changes to UNHEALTHY state.
1037 <refsect2><title>healthy</title>
1039 This call-out is triggered when the node changes to HEALTHY state.
1043 <refsect2><title>startup</title>
1045 This call-out is triggered when ctdb has started up and all managed services are up and running.
1052 <refsect1><title>ClamAV Daemon</title>
1054 CTDB has support to manage the popular anti-virus daemon ClamAV.
1055 This support is implemented through the
1056 eventscript : /etc/ctdb/events.d/31.clamd.
1059 <refsect2><title>Configuration</title>
1061 Start by configuring CLAMAV normally and test that it works. Once this is
1062 done, copy the configuration files over to all the nodes so that all nodes
1063 share identical CLAMAV configurations.
1064 Once this is done you can proceed with the intructions below to activate
1065 CTDB support for CLAMAV.
1069 First, to activate CLAMAV support in CTDB, edit /etc/sysconfig/ctdb and add the two lines :
1071 <screen format="linespecific">
1072 CTDB_MANAGES_CLAMD=yes
1073 CTDB_CLAMD_SOCKET="/path/to/clamd.socket"
1077 Second, activate the eventscript
1079 <screen format="linespecific">
1080 ctdb enablescript 31.clamd
1084 Third, CTDB will now be starting and stopping this service accordingly,
1085 so make sure that the system is not configured to start/stop this service
1087 On RedHat systems you can disable the system starting/stopping CLAMAV automatically by running :
1088 <screen format="linespecific">
1095 Once you have restarted CTDBD, use
1096 <screen format="linespecific">
1099 and verify that the 31.clamd eventscript is listed and that it was executed successfully.
1108 <refsect1><title>SEE ALSO</title>
1111 <ulink url="http://ctdb.samba.org/"/>
1115 <refsect1><title>COPYRIGHT/LICENSE</title>
1117 Copyright (C) Andrew Tridgell 2007
1118 Copyright (C) Ronnie sahlberg 2007
1120 This program is free software; you can redistribute it and/or modify
1121 it under the terms of the GNU General Public License as published by
1122 the Free Software Foundation; either version 3 of the License, or (at
1123 your option) any later version.
1125 This program is distributed in the hope that it will be useful, but
1126 WITHOUT ANY WARRANTY; without even the implied warranty of
1127 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
1128 General Public License for more details.
1130 You should have received a copy of the GNU General Public License
1131 along with this program; if not, see http://www.gnu.org/licenses/.