Name

ha.cf — Configuration file for the Heartbeat cluster messaging layer

Description

/etc/ha.d/ha.cf is read by heartbeat(8) upon node start-up. It lists the communication facilities enabled between nodes, enables or disables certain features, and optionally lists the cluster nodes by host name.

This file can safely be made world readable, but should be writable only by root.

Global directives

Some directives in ha.cf are global in nature. The order of these global options is important in configuring the ha.cf file, since each directive is interpreted as it is encountered in ha.cf.

These directives are use_logd and udpport. It is recommended that these be placed first in the ha.cf file when they are entered.

Other directives in this category are baud, logfacility, logfile, and debugfile, but those directives are deprecated and should no longer be used.

Supported directives

The following directives are supported in ha.cf (listed here in alphabetical order):

apiauth

This directive specifies what users and/or groups are allowed to connect to a specific API group name. The syntax is simple:

apiauth apigroupname [uid=uid1,uid2 ...] [gid=gid1,gid2 ...]

You can specify either a uid list, or a gid list, or both. However you must specify either a uid list or a gid list. If you include both a uid list and a gid list, then a process is authorized to connect to that API group if if it is either in the uid-list or it is in the gid-list.

The API group name default has special meaning. If it is specified, it will be used for authorizing clients without any API group name, and all client groups not identified by any other apiauth directive.

Unless you specify otherwise in the ha.cf file, certain services will be provided default authorizations as follows:

Table A.1. Default service authorizations

ServiceDefault apiauth
ipfailuid=hacluster
ccmgid=haclient
pinggid=haclient
cl_statusgid=haclient
lha-snmpagentuid=root
crmuid=hacluster

autojoin

The autojoin directive enables nodes to join automatically just by communicating with the cluster, hence not requiring node directives in the ha.cf file. Since our communication is normally strongly authenticated, only nodes which know the cluster key can join (automatically or otherwise).

The values you can give for the autojoin directive have the following meanings:

  • none: disables automatic joining.

  • other: allows nodes other than ourself who are not listed in ha.cf to join automatically. In other words, our node has to be listed in ha.cf, but other nodes do not.

  • any: allows any node to join automatically without being listed in ha.cf, even the current node.

Note that the set of nodes currently considered part of the cluster is kept in the hostcache file. With autojoin enabled, the node directive is no longer authoritative - the hostcache file is.

bcast

The bcast directive is used to configure which interfaces Heartbeat sends UDP broadcast traffic on. More than one interface can be specified on the line. The udpport directive is used to configure which port is used for these broadcast communications if the udpport directive is specified before the bcast directive, otherwise the default port will be used. A couple of sample bcast lines are shown below.

bcast eth0 eth1  # on Linux systems
bcast le0        # for Solaris systems
[Note]Note

Broadcast links are not supported in Pacemaker clusters on BSD systems.

compression

The compression directive sets which compression method will be used when a message is big and compression is needed.

It could be either zlib or bz2, depending on whether you have the corresponding library in the system. You can check /usr/lib/heartbeat/plugins/HBcompress to see what compression module is available.

If this directive is not set, there will be no compression.

compression_threshold

The compression_threshold directive sets the threshold to compress a message, e.g. if the threshold is 1, then any message with size greater than 1 KB will be compressed. The default is 2 (KB). This directive only makes sense if you have set the compression directive.

conn_logd_time

The conn_logd_time directive specifies the time Heartbeat will reconnect to the logging daemon if the connection between Heartbeat and the logging daemon is broken. The conn_logd_time is specified according to the Heartbeat time syntax, for example:

conn_logd_time 60 #60 seconds

The default is 60 seconds.

[Note]Note

Heartbeat will not automatically reconnect to the logging daemon. It only tries to reconnect when it needs to log a message and conn_logd_time have passed since the last attempt to connect.

coredumps

The coredumps directive tells Heartbeat to do things to enable making core dumps - should it need to dump core.

The allowed values are true and false.

crm

Enables the Pacemaker cluster manager. For historical reasons, the default for this option is off; however, it should always be set to respawn.

When set to respawn, the directive automatically implies:

apiauth stonithd        uid=root
apiauth crmd            uid=hacluster
apiauth cib             uid=hacluster

respawn hacluster       ccm
respawn hacluster       cib
respawn root            stonithd
respawn root            lrmd
respawn hacluster       crmd
deadtime

The deadtime directive is used to specify how quickly Heartbeat should decide that a node in a cluster is dead. Setting this value too low will cause the system to falsely declare itself dead. Setting it too high will delay takeover after the failure of a node in the cluster.

debug

The debug directive is used to set the level of debugging in effect in the system. Production systems should have their debug level set to zero (i.e., turned off). This is the default. Legal values of the debug option are between 0-255. The most useful values are between 0 (off) and 3. Setting the debug level greater than 1 can have an adverse effect on the size of your log files, and on the system's ability to send heartbeats at rapid rates, thus affecting the cluster reliability.

The debug level of the system can also be specified on the command line using the -d option. Additionally, the debug level of the system can be dynamically changed by sending the heartbeat process SIGUSR1 and SIGUSR2 signals. SIGUSR1 raises the debug level, and SIGUSR2 lowers it.

hbgenmethod time|file

The hbgenmethod directive specifies how Heartbeat should compute its current generation number for communications. This is a specialized and obscure directive, used mainly in firewalls which have no local disk, and other devices which do not have a method of storing data persistently across reboots. It defaults to storing the Heartbeat generations in a file. Generation numbers are used by Heartbeat for replay attack protection.

[Warning]Warning

If one specifies the time method, there are certain possible cases where troubles can arise. If a machine restarts Heartbeat and its local time of day clock is less than or equal to than the value of the time of day clock when Heartbeat last started, then that node will be unable to join the cluster.

initdead

The initdead parameter is used to set the time that it takes to declare a cluster node dead when Heartbeat is first started. This parameter generally needs to be set to a higher value, because experience suggests that it sometimes takes operating systems many seconds for their communication systems before they operate correctly. initdead is specified according to the Heartbeat time syntax. A sample initdead value is shown below:

initdead 30

In some switched network environments, switches engage in a spanning tree algorithm whenever a NIC connects to a port. This can take a long time to complete, and it is only necessary if the NIC being connected is another switch. If this is the case, you may be able to configure certain NICs as not being switches and shrink the connection delay significantly. If not, you'll need to raise initdead to make this problem go away.

If this is set too low, you'll see one node declare the other as dead.

keepalive

The keepalive directive sets the interval between heartbeat packets. It is specified according to the Heartbeat time syntax.

logfacility

The logfacility is used to tell Heartbeat which syslog logging facility it should use for logging its messages.

The possible values for logfacility vary by operating system, but some of the most common ones are {auth, authpriv, daemon, syslog, user, local0, local1, local2, local3, local4, local5, local6, local7}.

A sample logfacility directive is shown below:

logfacility local7

If you want to disable logging to syslog:

logfacility none
mcast

The mcast directive is used to configure a multicast communication path. The syntax of an mcast directive is:

mcast dev mcast-group udp-port ttl 0
  • dev - IP device to send/rcv heartbeats on

  • mcast-group - multicast group to join (class D multicast address 224.0.0.0 - 239.255.255.255). For most Heartbeat uses, the first byte should be 239.

  • port - UDP port to sendto/rcvfrom (set this to the same value as udpport)

  • ttl - the ttl value for outbound heartbeats. This affects how far the multicast packet will propagate. (0-255). Set to 1 for the current subnet. Must be greater than zero.

A sample mcast directive is shown below:

mcast eth0 239.0.0.1 694 1 0
msgfmt classic|netstring

The msgfmt directive specifies the format Heartbeat uses in wire.

  • classic - Heartbeat will convert a message into a string and transmit in wire. Binary values are converted with a base64 library.

  • netstring - Binary messages will be transmitted directly. This is more efficient since it avoids conversion between string and binary values.

When in doubt, leave the default (classic).

node

The node directive tells what machines are in the cluster. The syntax of the node directive is simple:

node nodename1 nodename2 ...

Node names in the directive must match the "uname -n" of that machine.

You can declare multiple node names in one directive. You can also use the directive multiple times. Normally every node in the cluster must be listed in the ha.cf file, including the current node, unless the autojoin directive is enabled.

The node directive is not completely authoritative with regard to nodes heartbeat will communicate with. If a node has ever been added in the past, it will tend to remain in the hostcache file more until it's manually removed.

realtime on|off

The realtime directive specifies whether or not Heartbeat should try and take advantage of the operating system's realtime scheduling features. When enabled, Heartbeat will lock itself into memory, and raise its priority to a realtime priority (as set by the rtprio directive). This feature is mainly used for debugging various kinds of loops which might otherwise cripple the system and impair debugging them.

The default is on.

rtprio

The rtprio directive is used to specify the priority at which Heartbeat runs. It does not need to be specified unless other realtime priority programs are also running on the system. The minimum and maximum values for this field can be determined from the sched_get_priority_min(SCHED_FIFO) and sched_get_priority_max(SCHED_FIFO) calls respectively. The default value for rtprio is halfway between the minimum and maximum values.

A sample rtprio directive is shown below:

rtprio 5
ucast

The ucast directive configures Heartbeat to communicate over a UDP unicast communications link. The udpport directive is used to configure which port is used for these unicast communications if the udpport directive is specified before the ucast directive, otherwise the default port will be used.

The general syntax of a ucast directive is:

ucast dev peer-ip-address

Where dev is the device to use when talking to the peer, and peer-ip-address is the IP address we will send packets to.

A sample ucast directive is shown below:

ucast eth0 10.10.10.133

This directive will cause us to send packets to 10.10.10.133 over interface eth0.

Note that ucast directives which go to the local machine are effectively ignored. This allows the ha.cf directives on all machines to be identical.

udpport

The udpport directive specifies which port Heartbeat will use for its UDP intra-cluster communication. There are two common reasons for overriding this value: there are multiple bcast clusters on the same subnet, or this port is already in use in accordance with some locally-established policy.

The default value for this parameter is the the port ha-cluster in /etc/services (if present), or 694 if port ha-cluster is not in /etc/services. 694 is the IANA registered port number for Heartbeat (a.k.a. ha-cluster).

A sample udpport directive is shown below.

udpport 694

You have to configure udpport (in ha.cf) before you configure ucast or bcast, if not heartbeat will use the default port (694).

[Note]Note

Due to a specification error in the syntax of the mcast directive, this directive does not apply to mcast communications.

use_logd on|off

The use_logd directive specifies whether Heartbeat logs its messages through logging daemon or not.

If the logging daemon is used, all log messages will be sent through IPC to the logging daemon, which then writes them into log files. In case the logging daemon dies (for whatever reason), a warning message will be logged and all messages will be written to log files directly.

If the logging daemon is used, logfile/debugfile/logfacility in this file are not meaningful any longer. You should check the config file for logging daemon (the default is /etc/logd.cf).

If use_logd is not used, all log messages will be written to log files directly.

The logging daemon is started/stopped in heartbeat script.

Setting use_logd to "on" is recommended.

uuidfrom

In the normal case, heartbeat generates a UUID for each node in the system as a way of uniquely identifying a node - even if it should change nodenames. This UUID is typically stored in the file /var/lib/heartbeat/hb_uuid.

For certain kinds of installations (those booting from CDs or other read-only media), it is impossible for heartbeat to save a generated to disk as it normally does. In these cases, one can use the uuidfrom directive to instruct heartbeat to use the nodename as though it were a UUID, by specifying uuidfrom nodename.

All possible legal uuidfrom directives are shown below.

uuidfrom file
uuidfrom nodename
warntime

The warntime directive is used to specify how quickly Heartbeat should issue a "late heartbeat" warning.

The warntime value is specified according to the HeartbeatTimeSyntax. A sample warntime specification is shown below.

warntime 10    # 10 seconds

The warntime directive is important for tuning deadtime

Deprecated directives

The following directives are interpreted by the configuration file parser for historical reasons, but should be considered deprecated and should no longer be used.

auto_failback

In legacy Heartbeat clusters, the auto_failback option would determine whether a resource would automatically fail back to its "primary" node, or remain on whatever node is serving it until that node fails, or an administrator intervenes. The possible values for auto_failback were:

  • on - enable automatic failbacks

  • off - disable automatic failback

  • legacy - enable automatic failbacks in systems where all nodes in the cluster do not yet support the auto_failback option.

This option has been replaced the configurable failback policies in Pacemaker, and should no longer be used.

baud

The baud directive is used to set the speed for serial communications. Any of the following speeds can be specified, provided they are supported by your operating system: 9600, 19200, 38400, 57600, 115200, 230400, 460800. The default speed is 19200.

This option is obsolete as serial links should not be used in Pacemaker clusters.

deadping

The deadping directive is used to specify how quickly Heartbeat should decide that a ping node in a cluster is dead. Setting this value too low will cause the system to falsely declare the ping node dead. Setting it too high will delay detection of communication failure.

This feature has been replaced by the more flexible pingd resource agent in Pacemaker, and should no longer be used.

debugfile

The debugfile directive specifies the file Heartbeat will write debug messages to.

This directive is ignored when use_logd is specified. Enabling use_logd is the recommended approach.

hbaping

Hbaping directives are given to declare fiber channel devices as ping nodes.

This directive was never fully supported in Heartbeat (requiring manual modifications to the code base) and should not be used.

hopfudge

The hopfudge directive controls how many nodes a packet can be forwarded through before it is thrown away in the worst case. However, the hopfudge value is added to the number of nodes in the system. It defaults to 1.

This option applies to serial links only, which are deprecated.

logfile

The logfile directive configures a log file. All non-debug messages from Heartbeat will go into this file.

This directive is ignored when use_logd is specified. Enabling use_logd is the recommended approach.

ping

Ping directives are given to declare ping nodes to Heartbeat. The syntax of the ping directive is simple:

ping ip-address ...

Each IP address listed in a ping directive is considered to be independent. That is, connectivity to each node is considered to be equally important.

In order to declare that a group of nodes are equally qualified for a particular function, and that the presence of any of them indicates successful communication, use the ping_group directive.

This feature has been replaced by the more flexible pingd resource agent in Pacemaker, and should no longer be used.

ping_group

Ping group directives are given to declare a group ping node to Heartbeat. syntax of the ping_group directive is as follows:

ping_group group-name ip-address ...

Each IP address listed in a ping_group directive is considered to be related, and connectivity to any one node is considered to be connectivity to the group.

A ping group is considered by Heartbeat to be a single cluster node (group-name). The ability to communicate with any of the group members means that the group-name member is reachable. This is useful when (for example) two different routers may be used to contact the internet, depending on which is up, or when finding an appropriate reliable single ping node is difficult.

This feature has been replaced by the more flexible pingd resource agent in Pacemaker, and should no longer be used.

respawn

The respawn directive is used to specify a program to run and monitor while it runs. If this program exits with anything other than exit code 100, it will be automatically restarted. The first parameter is the user id to run the program under, and the second parameter is the program to run. Subsequent parameters will be given to the program as arguments.

This functionality was primarily designed for the legacy ipfail program, which has been replaced by the more flexible pingd resource agent in Pacemaker. Thus, this directive should no longer be used, except when it is implicitly generated by crm yes.

serial

The serial directive tells Heartbeat to use the specified serial port(s) for its communication. The parameters to the serial directive are the names of tty devices suitable for opening without waiting for carrier first. On Linux, those ports are typically named /dev/ttySX.

A few sample serial directives are shown below:

serial /dev/ttyS0 /dev/ttyS1     # Linux
serial /dev/cuaa0                # FreeBSD
serial /dev/cua/a                # Solaris

The baud directive is used to configure the baud rate for the port(s) if the baud directive is specified before the serial directive, otherwise the default baud rate will be used.

Using this option is strongly discouraged in Pacemaker clusters, as its CIB updates can easily hit practical message size limits for serial links, with undefined results.

stonith

The stonith directive is used to configure Heartbeat's legacy STONITH configuration. It assumes you're going to put in a STONITH configuration file on each machine in the cluster to configure the (single) STONITH device that this node will use to reset the other node in the cluster.

This functionality has been replaced by STONITH agents in Pacemaker.

stonith_host

The stonith_host directive is used to configure Heartbeat's (release 1 only), STONITH configuration. With this directive, you put all the STONITH configuration information for the devices in your cluster in the ha.cf file, rather than in a separate file.

This functionality has been replaced by STONITH agents in Pacemaker.

traditional_compression on|off

This directive enables traditional compression. It is highly recommended that this be set to off (the default); otherwise heartbeat performance can be significantly negatively impacted.

watchdog

The watchdog directive configures Heartbeat to use a watchdog device. In some circumstances, a watchdog device can be used in place of a STONITH device. In any case, it is a reasonable thing to configure if you don't have a STONITH device, or if you wish, in addition to your STONITH device.

It is the purpose of a watchdog device to shut the machine down if Heartbeat does not hear its own heartbeats as often as it thinks it should. This keeps things like scheduler bugs from becoming split-brain configurations.

The general syntax of a watchdog directive is:

watchdog watchdog-device-name

A sample watchdog directive is shown below:

watchdog /dev/watchdog

The most common watchdog device currently used with general Linux systems is the softdog device. The softdog device is a software-based watchdog device and is usually referred to as /dev/watchdog - although like most UNIX devices, this is a convention not a rule.

This functionality has been replaced by cluster self-monitoring and STONITH resource agents in Pacemaker. This directive should no longer be used.

Required directives

The following directives must always be present in ha.cf:

  • At least one communication topology directive (bcast, mcast, or ucast);

  • Either one or more node directives, or autojoin any.

Example

Below is an example ha.cf for a 2-node Pacemaker cluster with redundant network communication paths:

use_logd on
mcast eth0 239.0.0.42 694 1 0
bcast eth1
node alice
node bob
crm respawn