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="opt">--lvs</arg>
32 <arg choice="req">--nlist=<filename></arg>
33 <arg choice="opt">--no-lmaster</arg>
34 <arg choice="opt">--no-recmaster</arg>
35 <arg choice="opt">--nosetsched</arg>
36 <arg choice="req">--notification-script=<filename></arg>
37 <arg choice="opt">--public-addresses=<filename></arg>
38 <arg choice="opt">--public-interface=<interface></arg>
39 <arg choice="req">--reclock=<filename></arg>
40 <arg choice="opt">--single-public-ip=<address></arg>
41 <arg choice="opt">--socket=<filename></arg>
42 <arg choice="opt">--start-as-disabled</arg>
43 <arg choice="opt">--start-as-stopped</arg>
44 <arg choice="opt">--syslog</arg>
45 <arg choice="opt">--log-ringbuf-size=<num-entries></arg>
46 <arg choice="opt">--torture</arg>
47 <arg choice="opt">--transport=<STRING></arg>
48 <arg choice="opt">--usage</arg>
53 <refsect1><title>DESCRIPTION</title>
55 ctdbd is the main ctdb daemon.
58 ctdbd provides a clustered version of the TDB database with automatic rebuild/recovery of the databases upon nodefailures.
61 Combined with a cluster filesystem ctdbd provides a full HA environment for services such as clustered Samba and NFS as well as other services.
64 ctdbd provides monitoring of all nodes in the cluster and automatically reconfigures the cluster and recovers upon node failures.
67 ctdbd is the main component in clustered Samba that provides a high-availability load-sharing CIFS server cluster.
73 <title>OPTIONS</title>
76 <varlistentry><term>-? --help</term>
79 Print some help text to the screen.
84 <varlistentry><term>-d --debug=<DEBUGLEVEL></term>
87 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.
92 <varlistentry><term>--dbdir=<directory></term>
95 This is the directory on local storage where ctdbd keeps the local
96 copy of the TDB databases. This directory is local for each node and should not be stored on the shared cluster filesystem.
99 This directory would usually be /var/ctdb .
104 <varlistentry><term>--dbdir-persistent=<directory></term>
107 This is the directory on local storage where ctdbd keeps the local
108 copy of the persistent TDB databases. This directory is local for each node and should not be stored on the shared cluster filesystem.
111 This directory would usually be /etc/ctdb/persistent .
116 <varlistentry><term>--event-script-dir=<directory></term>
119 This option is used to specify the directory where the CTDB event
123 This will normally be /etc/ctdb/events.d which is part of the ctdb distribution.
128 <varlistentry><term>-i --interactive</term>
131 By default ctdbd will detach itself from the shell and run in
132 the background as a daemon. This option makes ctdbd to start in interactive mode.
137 <varlistentry><term>--listen=<address></term>
140 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.
143 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.
148 <varlistentry><term>--logfile=<filename></term>
151 This is the file where ctdbd will write its log. This is usually /var/log/log.ctdb .
156 <varlistentry><term>--lvs</term>
159 This option is used to activate the LVS capability on a CTDB node.
160 Please see the LVS section.
165 <varlistentry><term>--nlist=<filename></term>
168 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.
171 This file is usually /etc/ctdb/nodes .
176 <varlistentry><term>--no-lmaster</term>
179 This argument specifies that this node can NOT become an lmaster
180 for records in the database. This means that it will never show up
181 in the vnnmap. This feature is primarily used for making a cluster
182 span across a WAN link and use CTDB as a WAN-accelerator.
185 Please see the "remote cluster nodes" section for more information.
190 <varlistentry><term>--no-recmaster</term>
193 This argument specifies that this node can NOT become a recmaster
194 for the database. This feature is primarily used for making a cluster
195 span across a WAN link and use CTDB as a WAN-accelerator.
198 Please see the "remote cluster nodes" section for more information.
203 <varlistentry><term>--nosetsched</term>
206 This is a ctdbd debugging option. this option is only used when
210 Normally ctdb will change its scheduler to run as a real-time
211 process. This is the default mode for a normal ctdbd operation
212 to gurarantee that ctdbd always gets the cpu cycles that it needs.
215 This option is used to tell ctdbd to NOT run as a real-time process
216 and instead run ctdbd as a normal userspace process.
217 This is useful for debugging and when you want to run ctdbd under
218 valgrind or gdb. (You dont want to attach valgrind or gdb to a
224 <varlistentry><term>--notification-script=<filename></term>
227 This specifies a script which will be invoked by ctdb when certain
228 state changes occur in ctdbd and when you may want to trigger this
229 to run certain scripts.
232 This file is usually /etc/ctdb/notify.sh .
235 See the NOTIFICATION SCRIPT section below for more information.
240 <varlistentry><term>--public_addresses=<filename></term>
243 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.
246 This is usually the file /etc/ctdb/public_addresses
251 <varlistentry><term>--public-interface=<interface></term>
254 This option tells ctdb which interface to attach public-addresses
255 to and also where to attach the single-public-ip when used.
258 This is only required when using public ip addresses and only when
259 you dont specify the interface explicitly in /etc/ctdb/public_addresses or when you are using --single-public-ip.
262 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.
267 <varlistentry><term>--reclock=<filename></term>
270 This is the name of the lock file stored of the shared cluster filesystem that ctdbd uses to prevent split brains from occuring.
271 This file must be stored on shared storage.
274 It is possible to run CTDB without a reclock file, but then there
275 will be no protection against split brain if the network becomes
276 partitioned. Using CTDB without a reclock file is strongly
282 <varlistentry><term>--socket=<filename></term>
285 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.
288 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.
293 <varlistentry><term>--start-as-disabled</term>
296 This makes the ctdb daemon to be DISABLED when it starts up.
299 As it is DISABLED it will not get any of the public ip addresses
300 allocated to it, and thus this allow you to start ctdb on a node
301 without causing any ip address to failover from other nodes onto
305 When used, the administrator must keep track of when nodes start and
306 manually enable them again using the "ctdb enable" command, or else
307 the node will not host any services.
310 A node that is DISABLED will not host any services and will not be
311 reachable/used by any clients.
316 <varlistentry><term>--start-as-stopped</term>
319 This makes the ctdb daemon to be STOPPED when it starts up.
322 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.
325 To restart and activate a STOPPED node, the command "ctdb continue" is used.
328 A node that is STOPPED will not host any services and will not be
329 reachable/used by any clients.
334 <varlistentry><term>--syslog</term>
337 Send all log messages to syslog instead of to the ctdb logfile.
342 <varlistentry><term>--log-ringbuf-size=<num-entries></term>
345 In addition to the normal loggign to a log file,
346 CTDBD also keeps a in-memory ringbuffer containing the most recent
347 log entries for all log levels (except DEBUG).
350 This is useful since it allows for keeping continous logs to a file
351 at a reasonable non-verbose level, but shortly after an incident has
352 occured, a much more detailed log can be pulled from memory. This
353 can allow you to avoid having to reproduce an issue due to the
354 on-disk logs being of insufficient detail.
357 This in-memory ringbuffer contains a fixed number of the most recent
358 entries. This is settable at startup either through the
359 --log-ringbuf-size argument, or preferably by using
360 CTDB_LOG_RINGBUF_SIZE in the sysconfig file.
363 Use the "ctdb getlog" command to access this log.
369 <varlistentry><term>--torture</term>
372 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.
375 You do NOT want to use this option unless you are developing and testing new functionality in ctdbd.
380 <varlistentry><term>--transport=<STRING></term>
383 This option specifies which transport to use for ctdbd internode communications. The default is "tcp".
386 Currently only "tcp" is supported but "infiniband" might be
387 implemented in the future.
392 <varlistentry><term>--usage</term>
395 Print useage information to the screen.
404 <refsect1><title>Private vs Public addresses</title>
406 When used for ip takeover in a HA environment, each node in a ctdb
407 cluster has multiple ip addresses assigned to it. One private and one or more public.
410 <refsect2><title>Private address</title>
412 This is the physical ip address of the node which is configured in
413 linux and attached to a physical interface. This address uniquely
414 identifies a physical node in the cluster and is the ip addresses
415 that ctdbd will use to communicate with the ctdbd daemons on the
416 other nodes in the cluster.
419 The private addresses are configured in /etc/ctdb/nodes
420 (unless the --nlist option is used) and contain one line for each
421 node in the cluster. Each line contains the private ip address for one
422 node in the cluster. This file must be the same on all nodes in the
426 Since the private addresses are only available to the network when the
427 corresponding node is up and running you should not use these addresses
428 for clients to connect to services provided by the cluster. Instead
429 client applications should only attach to the public addresses since
430 these are guaranteed to always be available.
433 When using ip takeover, it is strongly recommended that the private
434 addresses are configured on a private network physically separated
435 from the rest of the network and that this private network is dedicated
438 Example /etc/ctdb/nodes for a four node cluster:
439 <screen format="linespecific">
446 <refsect2><title>Public address</title>
448 A public address on the other hand is not attached to an interface.
449 This address is managed by ctdbd itself and is attached/detached to
450 a physical node at runtime.
453 The ctdb cluster will assign/reassign these public addresses across the
454 available healthy nodes in the cluster. When one node fails, its public address
455 will be migrated to and taken over by a different node in the cluster
456 to ensure that all public addresses are always available to clients as
457 long as there are still nodes available capable of hosting this address.
460 These addresses are not physically attached to a specific node.
461 The 'ctdb ip' command can be used to view the current assignment of
462 public addresses and which physical node is currently serving it.
465 On each node this file contains a list of the public addresses that
466 this node is capable of hosting.
467 The list also contain the netmask and the
468 interface where this address should be attached for the case where you
469 may want to serve data out through multiple different interfaces.
471 Example /etc/ctdb/public_addresses for a node that can host 4 public addresses:
472 <screen format="linespecific">
480 In most cases this file would be the same on all nodes in a cluster but
481 there are exceptions when one may want to use different files
484 Example: 4 nodes partitioned into two subgroups :
485 <screen format="linespecific">
486 Node 0:/etc/ctdb/public_addresses
490 Node 1:/etc/ctdb/public_addresses
494 Node 2:/etc/ctdb/public_addresses
498 Node 3:/etc/ctdb/public_addresses
503 In this example nodes 0 and 1 host two public addresses on the
504 10.1.1.x network while nodes 2 and 3 host two public addresses for the
508 Ip address 10.1.1.1 can be hosted by either of nodes 0 or 1 and will be
509 available to clients as long as at least one of these two nodes are
511 If both nodes 0 and node 1 become unavailable 10.1.1.1 also becomes
512 unavailable. 10.1.1.1 can not be failed over to node 2 or node 3 since
513 these nodes do not have this ip address listed in their public
520 <refsect1><title>Node status</title>
522 The current status of each node in the cluster can be viewed by the
523 'ctdb status' command.
526 There are five possible states for a node.
530 OK - This node is fully functional.
534 DISCONNECTED - This node could not be connected through the network
535 and is currently not particpating in the cluster. If there is a
536 public IP address associated with this node it should have been taken
537 over by a different node. No services are running on this node.
541 DISABLED - This node has been administratively disabled. This node is
542 still functional and participates in the CTDB cluster but its IP
543 addresses have been taken over by a different node and no services are
544 currently being hosted.
548 UNHEALTHY - A service provided by this node is malfunctioning and should
549 be investigated. The CTDB daemon itself is operational and participates
550 in the cluster. Its public IP address has been taken over by a different
551 node and no services are currently being hosted. All unhealthy nodes
552 should be investigated and require an administrative action to rectify.
556 BANNED - This node failed too many recovery attempts and has been banned
557 from participating in the cluster for a period of RecoveryBanPeriod
558 seconds. Any public IP address has been taken over by other nodes. This
559 node does not provide any services. All banned nodes should be
560 investigated and require an administrative action to rectify. This node
561 does not perticipate in the CTDB cluster but can still be communicated
562 with. I.e. ctdb commands can be sent to it.
566 STOPPED - A node that is stopped does not host any public ip addresses,
567 nor is it part of the VNNMAP. A stopped node can not become LVSMASTER,
569 This node does not perticipate in the CTDB cluster but can still be
570 communicated with. I.e. ctdb commands can be sent to it.
575 <title>PUBLIC TUNABLES</title>
577 These are the public tuneables that can be used to control how ctdb behaves.
580 <refsect2><title>KeepaliveInterval</title>
581 <para>Default: 1</para>
583 How often should the nodes send keepalives to eachother.
586 <refsect2><title>KeepaliveLimit</title>
587 <para>Default: 5</para>
589 After how many keepalive intervals without any traffic should a node
590 wait until marking the peer as DISCONNECTED.
593 <refsect2><title>MonitorInterval</title>
594 <para>Default: 15</para>
596 How often should ctdb run the event scripts to check for a nodes health.
599 <refsect2><title>TickleUpdateInterval</title>
600 <para>Default: 20</para>
602 How often will ctdb record and store the "tickle" information used to
603 kickstart stalled tcp connections after a recovery.
606 <refsect2><title>EventScriptTimeout</title>
607 <para>Default: 20</para>
609 How long should ctdb let an event script run before aborting it and
610 marking the node unhealthy.
613 <refsect2><title>RecoveryBanPeriod</title>
614 <para>Default: 300</para>
616 If a node becomes banned causing repetitive recovery failures. The node will
617 eventually become banned from the cluster.
618 This controls how long the culprit node will be banned from the cluster
619 before it is allowed to try to join the cluster again.
620 Dont set to small. A node gets banned for a reason and it is usually due
621 to real problems with the node.
624 <refsect2><title>DatabaseHashSize</title>
625 <para>Default: 100000</para>
627 Size of the hash chains for the local store of the tdbs that ctdb manages.
630 <refsect2><title>RerecoveryTimeout</title>
631 <para>Default: 10</para>
633 Once a recovery has completed, no additional recoveries are permitted until this timeout has expired.
636 <refsect2><title>EnableBans</title>
637 <para>Default: 1</para>
639 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.
642 <refsect2><title>DeterministicIPs</title>
643 <para>Default: 1</para>
645 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.
648 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.
651 <refsect2><title>DisableWhenUnhealthy</title>
652 <para>Default: 0</para>
654 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'.
657 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.
660 <refsect2><title>NoIPFailback</title>
661 <para>Default: 0</para>
663 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.
666 Use with caution! Normally when a node becomes available to the cluster
667 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.
670 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.
675 <refsect1><title>LVS</title>
677 LVS is a mode where CTDB presents one single IP address for the entire
678 cluster. This is an alternative to using public IP addresses and round-robin
679 DNS to loadbalance clients across the cluster.
683 This is similar to using a layer-4 loadbalancing switch but with some restrictions.
687 In this mode the cluster select a set of nodes in the cluster and loadbalance
688 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
689 all LVS capable nodes regardless of health status.
690 LVS will however never loadbalance traffic to nodes that are BANNED,
691 STOPPED, DISABLED or DISCONNECTED. The "ctdb lvs" command is used to show
692 which nodes are currently load-balanced across.
696 One of the these nodes are elected as the LVSMASTER. This node receives all
697 traffic from clients coming in to the LVS address and multiplexes it
698 across the internal network to one of the nodes that LVS is using.
699 When responding to the client, that node will send the data back
700 directly to the client, bypassing the LVSMASTER node.
701 The command "ctdb lvsmaster" will show which node is the current
706 The path used for a client i/o is thus :
707 <screen format="linespecific">
708 (1) Client sends request packet to LVSMASTER
709 (2) LVSMASTER passes the request on to one node across the internal network.
710 (3) Selected node processes the request.
711 (4) Node responds back to client.
716 This means that all incoming traffic to the cluster will pass through
717 one physical node, which limits scalability. You can send more data to the
718 LVS address that one physical node can multiplex. This means that you
719 should not use LVS if your I/O pattern is write-intensive since you will be
720 limited in the available network bandwidth that node can handle.
721 LVS does work wery well for read-intensive workloads where only smallish
722 READ requests are going through the LVSMASTER bottleneck and the majority
723 of the traffic volume (the data in the read replies) goes straight from
724 the processing node back to the clients. For read-intensive i/o patterns you can acheive very high throughput rates in this mode.
728 Note: you can use LVS and public addresses at the same time.
731 <refsect2><title>Configuration</title>
733 To activate LVS on a CTDB node you must specify CTDB_PUBLIC_INTERFACE and
734 CTDB_LVS_PUBLIC_ADDRESS in /etc/sysconfig/ctdb.
738 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.
743 <screen format="linespecific">
744 CTDB_PUBLIC_INTERFACE=eth0
745 CTDB_LVS_PUBLIC_IP=10.0.0.237
752 If you use LVS, you must still have a real/permanent address configured
753 for the public interface on each node. This address must be routable
754 and the cluster nodes must be configured so that all traffic back to client
755 hosts are routed through this interface. This is also required in order
756 to allow samba/winbind on the node to talk to the domain controller.
757 (we can not use the lvs IP address to initiate outgoing traffic)
760 I.e. make sure that you can "ping" both the domain controller and also
761 all of the clients from the node BEFORE you enable LVS. Also make sure
762 that when you ping these hosts that the traffic is routed out through the
768 <refsect1><title>REMOTE CLUSTER NODES</title>
770 It is possible to have a CTDB cluster that spans across a WAN link.
771 For example where you have a CTDB cluster in your datacentre but you also
772 want to have one additional CTDB node located at a remote branch site.
773 This is similar to how a WAN accelerator works but with the difference
774 that while a WAN-accelerator often acts as a Proxy or a MitM, in
775 the ctdb remote cluster node configuration the Samba instance at the remote site
776 IS the genuine server, not a proxy and not a MitM, and thus provides 100%
777 correct CIFS semantics to clients.
781 See the cluster as one single multihomed samba server where one of
782 the NICs (the remote node) is very far away.
786 NOTE: This does require that the cluster filesystem you use can cope
787 with WAN-link latencies. Not all cluster filesystems can handle
788 WAN-link latencies! Whether this will provide very good WAN-accelerator
789 performance or it will perform very poorly depends entirely
790 on how optimized your cluster filesystem is in handling high latency
791 for data and metadata operations.
795 To activate a node as being a remote cluster node you need to set
796 the following two parameters in /etc/sysconfig/ctdb for the remote node:
797 <screen format="linespecific">
798 CTDB_CAPABILITY_LMASTER=no
799 CTDB_CAPABILITY_RECMASTER=no
804 Verify with the command "ctdb getcapabilities" that that node no longer
805 has the recmaster or the lmaster capabilities.
811 <refsect1><title>NAT-GW</title>
813 Sometimes it is desireable to run services on the CTDB node which will
814 need to originate outgoing traffic to external servers. This might
815 be contacting NIS servers, LDAP servers etc. etc.
818 This can sometimes be problematic since there are situations when a
819 node does not have any public ip addresses assigned. This could
820 be due to the nobe just being started up and no addresses have been
821 assigned yet or it could be that the node is UNHEALTHY in which
822 case all public addresses have been migrated off.
825 If then the service status of CTDB depends on such services being
826 able to always being able to originate traffic to external resources
827 this becomes extra troublesome. The node might be UNHEALTHY because
828 the service can not be reached, and the service can not be reached
829 because the node is UNHEALTHY.
832 There are two ways to solve this problem. The first is by assigning a
833 static ip address for one public interface on every node which will allow
834 every node to be able to route traffic to the public network even
835 if there are no public addresses assigned to the node.
836 This is the simplest way but it uses up a lot of ip addresses since you
837 have to assign both static and also public addresses to each node.
839 <refsect2><title>NAT-GW</title>
841 A second way is to use the built in NAT-GW feature in CTDB.
842 With NAT-GW you assign one public NATGW address for each natgw group.
843 Each NATGW group is a set of nodes in the cluster that shares the same
844 NATGW address to talk to the outside world. Normally there would only be
845 one NATGW group spanning the entire cluster, but in situations where one
846 ctdb cluster spans multiple physical sites it is useful to have one
847 NATGW group for each of the two sites.
850 There can be multiple NATGW groups in one cluster but each node can only
851 be member of one NATGW group.
854 In each NATGW group, one of the nodes is designated the NAT Gateway
855 through which all traffic that is originated by nodes in this group
856 will be routed through if a public addresses are not available.
860 <refsect2><title>Configuration</title>
862 NAT-GW is configured in /etc/sysconfigctdb by setting the following
865 <screen format="linespecific">
866 # NAT-GW configuration
867 # Some services running on nthe CTDB node may need to originate traffic to
868 # remote servers before the node is assigned any IP addresses,
869 # This is problematic since before the node has public addresses the node might
870 # not be able to route traffic to the public networks.
871 # One solution is to have static public addresses assigned with routing
872 # in addition to the public address interfaces, thus guaranteeing that
873 # a node always can route traffic to the external network.
874 # This is the most simple solution but it uses up a large number of
875 # additional ip addresses.
877 # A more complex solution is NAT-GW.
878 # In this mode we only need one additional ip address for the cluster from
879 # the exsternal public network.
880 # One of the nodes in the cluster is elected to be hosting this ip address
881 # so it can reach the external services. This node is also configured
882 # to use NAT MASQUERADING for all traffic from the internal private network
883 # to the external network. This node is the NAT-GW node.
885 # All other nodes are set up with a default rote with a metric of 10 to point
886 # to the nat-gw node.
888 # The effect of this is that only when a node does not have a public address
889 # and thus no proper routes to the external world it will instead
890 # route all packets through the nat-gw node.
892 # CTDB_NATGW_NODES is the list of nodes that belong to this natgw group.
893 # You can have multiple natgw groups in one cluster but each node
894 # can only belong to one single natgw group.
896 # CTDB_NATGW_PUBLIC_IP=10.0.0.227/24
897 # CTDB_NATGW_PUBLIC_IFACE=eth0
898 # CTDB_NATGW_DEFAULT_GATEWAY=10.0.0.1
899 # CTDB_NATGW_PRIVATE_NETWORK=10.1.1.0/24
900 # CTDB_NATGW_NODES=/etc/ctdb/natgw_nodes
904 <refsect2><title>CTDB_NATGW_PUBLIC_IP</title>
906 This is an ip address in the public network that is used for all outgoing
907 traffic when the public addresses are not assigned.
908 This address will be assigned to one of the nodes in the cluster which
909 will masquerade all traffic for the other nodes.
912 Format of this parameter is IPADDRESS/NETMASK
916 <refsect2><title>CTDB_NATGW_PUBLIC_IFACE</title>
918 This is the physical interface where the CTDB_NATGW_PUBLIC_IP will be
919 assigned to. This should be an interface connected to the public network.
922 Format of this parameter is INTERFACE
926 <refsect2><title>CTDB_NATGW_DEFAULT_GATEWAY</title>
928 This is the default gateway to use on the node that is elected to host
929 the CTDB_NATGW_PUBLIC_IP. This is the default gateway on the public network.
932 Format of this parameter is IPADDRESS
936 <refsect2><title>CTDB_NATGW_PRIVATE_NETWORK</title>
938 This is the network/netmask used for the interal private network.
941 Format of this parameter is IPADDRESS/NETMASK
945 <refsect2><title>CTDB_NATGW_NODES</title>
947 This is the list of all nodes that belong to the same NATGW group
948 as this node. The default is /etc/ctdb/natgw_nodes.
952 <refsect2><title>Operation</title>
954 When the NAT-GW functionality is used, one of the nodes is elected
955 to act as a NAT router for all the other nodes in the group when
956 they need to originate traffic to the external public network.
959 The NAT-GW node is assigned the CTDB_NATGW_PUBLIC_IP to the designated
960 interface and the provided default route. The NAT-GW is configured
961 to act as a router and to masquerade all traffic it receives from the
962 internal private network and which is destined to the external network(s).
965 All other nodes in the group are configured with a default route of
966 metric 10 pointing to the designated NAT GW node.
969 This is implemented in the 11.natgw eventscript. Please see the
970 eventscript for further information.
975 <refsect2><title>Removing/Changing NATGW at runtime</title>
977 The following are the procedures to change/remove a NATGW configuration
978 at runtime, without having to restart ctdbd.
982 If you want to remove NATGW completely from a node, use these steps:
984 <screen format="linespecific">
985 1, Run 'CTDB_BASE=/etc/ctdb /etc/ctdb/events.d/11.natgw removenatgw'
986 2, Then remove the configuration from /etc/sysconfig/ctdb
990 If you want to change the NATGW configuration on a node :
992 <screen format="linespecific">
993 1, Run 'CTDB_BASE=/etc/ctdb /etc/ctdb/events.d/11.natgw removenatgw'
994 2, Then change the configuration in /etc/sysconfig/ctdb
995 3, Run 'CTDB_BASE=/etc/ctdb /etc/ctdb/events.d/11.natgw updatenatgw'
1002 <refsect1><title>NOTIFICATION SCRIPT</title>
1004 Notification scripts are used with ctdb to have a call-out from ctdb
1005 to a user-specified script when certain state changes occur in ctdb.
1006 This is commonly to set up either sending SNMP traps or emails
1007 when a node becomes unhealthy and similar.
1010 This is activated by setting CTDB_NOTIFY_SCRIPT=<your script> in the
1011 sysconfig file, or by adding --notification-script=<your script>.
1014 See /etc/ctdb/notify.sh for an example script.
1017 CTDB currently generates notifications on these state changes:
1020 <refsect2><title>unhealthy</title>
1022 This call-out is triggered when the node changes to UNHEALTHY state.
1026 <refsect2><title>healthy</title>
1028 This call-out is triggered when the node changes to HEALTHY state.
1032 <refsect2><title>startup</title>
1034 This call-out is triggered when ctdb has started up and all managed services are up and running.
1041 <refsect1><title>ClamAV Daemon</title>
1043 CTDB has support to manage the popular anti-virus daemon ClamAV.
1044 This support is implemented through the
1045 eventscript : /etc/ctdb/events.d/31.clamd.
1048 <refsect2><title>Configuration</title>
1050 Start by configuring CLAMAV normally and test that it works. Once this is
1051 done, copy the configuration files over to all the nodes so that all nodes
1052 share identical CLAMAV configurations.
1053 Once this is done you can proceed with the intructions below to activate
1054 CTDB support for CLAMAV.
1058 First, to activate CLAMAV support in CTDB, edit /etc/sysconfig/ctdb and add the two lines :
1060 <screen format="linespecific">
1061 CTDB_MANAGES_CLAMD=yes
1062 CTDB_CLAMD_SOCKET="/path/to/clamd.socket"
1066 Second, activate the eventscript
1068 <screen format="linespecific">
1069 ctdb enablescript 31.clamd
1073 Third, CTDB will now be starting and stopping this service accordingly,
1074 so make sure that the system is not configured to start/stop this service
1076 On RedHat systems you can disable the system starting/stopping CLAMAV automatically by running :
1077 <screen format="linespecific">
1084 Once you have restarted CTDBD, use
1085 <screen format="linespecific">
1088 and verify that the 31.clamd eventscript is listed and that it was executed successfully.
1097 <refsect1><title>SEE ALSO</title>
1100 <ulink url="http://ctdb.samba.org/"/>
1104 <refsect1><title>COPYRIGHT/LICENSE</title>
1106 Copyright (C) Andrew Tridgell 2007
1107 Copyright (C) Ronnie sahlberg 2007
1109 This program is free software; you can redistribute it and/or modify
1110 it under the terms of the GNU General Public License as published by
1111 the Free Software Foundation; either version 3 of the License, or (at
1112 your option) any later version.
1114 This program is distributed in the hope that it will be useful, but
1115 WITHOUT ANY WARRANTY; without even the implied warranty of
1116 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
1117 General Public License for more details.
1119 You should have received a copy of the GNU General Public License
1120 along with this program; if not, see http://www.gnu.org/licenses/.