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CTDB-SCRIPT.OPTIO(5) CTDB - clustered TDB database CTDB-SCRIPT.OPTIO(5)

NAME

ctdb-script.options - CTDB scripts configuration files

DESCRIPTION

Location

Each CTDB script has 2 possible locations for its configuration options:

/etc/ctdb/script.options

This is a catch-all global file for general purpose scripts and for options that are used in multiple event scripts.

SCRIPT.options

That is, options for SCRIPT are placed in a file alongside the script, with a ".script" suffix added. This style is usually recommended for event scripts.

Options in this script-specific file override those in the global file.

Contents

These files should include simple shell-style variable assignments and shell-style comments.

Monitoring Thresholds

Event scripts can monitor resources or services. When a problem is detected, it may be better to warn about a problem rather than to immediately fail monitoring and mark a node as unhealthy. CTDB provides support for event scripts to do threshold-based monitoring.

A threshold setting looks like WARNING_THRESHOLD[:ERROR_THRESHOLD]. If the number of problems is ≥ WARNING_THRESHOLD then the script will log a warning and continue. If the number problems is ≥ ERROR_THRESHOLD then the script will log an error and exit with failure, causing monitoring to fail. Note that ERROR_THRESHOLD is optional, and follows the optional colon (:) separator.

NETWORK CONFIGURATION

10.interface

This event script handles monitoring of interfaces using by public IP addresses.

CTDB_PARTIALLY_ONLINE_INTERFACES=yes|no

Whether one or more offline interfaces should cause a monitor event to fail if there are other interfaces that are up. If this is "yes" and a node has some interfaces that are down then ctdb status will display the node as "PARTIALLYONLINE".

Note that CTDB_PARTIALLY_ONLINE_INTERFACES=yes is not generally compatible with NAT gateway or LVS. NAT gateway relies on the interface configured by CTDB_NATGW_PUBLIC_IFACE to be up and LVS replies on CTDB_LVS_PUBLIC_IFACE to be up. CTDB does not check if these options are set in an incompatible way so care is needed to understand the interaction.

Default is "no".

11.natgw

Provides CTDB's NAT gateway functionality.

NAT gateway is used to configure fallback routing for nodes when they do not host any public IP addresses. For example, it allows unhealthy nodes to reliably communicate with external infrastructure. One node in a NAT gateway group will be designated as the NAT gateway leader node and other (follower) nodes will be configured with fallback routes via the NAT gateway leader node. For more information, see the NAT GATEWAY section in ctdb(7).

CTDB_NATGW_DEFAULT_GATEWAY=IPADDR

IPADDR is an alternate network gateway to use on the NAT gateway leader node. If set, a fallback default route is added via this network gateway.

No default. Setting this variable is optional - if not set that no route is created on the NAT gateway leader node.

CTDB_NATGW_NODES=FILENAME

FILENAME contains the list of nodes that belong to the same NAT gateway group.

File format:

IPADDR [follower-only]

IPADDR is the private IP address of each node in the NAT gateway group.

If "follower-only" is specified then the corresponding node can not be the NAT gateway leader node. In this case CTDB_NATGW_PUBLIC_IFACE and CTDB_NATGW_PUBLIC_IP are optional and unused.

No default, usually /etc/ctdb/natgw_nodes when enabled.

CTDB_NATGW_PRIVATE_NETWORK=IPADDR/MASK

IPADDR/MASK is the private sub-network that is internally routed via the NAT gateway leader node. This is usually the private network that is used for node addresses.

No default.

CTDB_NATGW_PUBLIC_IFACE=IFACE

IFACE is the network interface on which the CTDB_NATGW_PUBLIC_IP will be configured.

No default.

CTDB_NATGW_PUBLIC_IP=IPADDR/MASK

IPADDR/MASK indicates the IP address that is used for outgoing traffic (originating from CTDB_NATGW_PRIVATE_NETWORK) on the NAT gateway leader node. This must not be a configured public IP address.

No default.

CTDB_NATGW_STATIC_ROUTES=IPADDR/MASK[@GATEWAY] ...

Each IPADDR/MASK identifies a network or host to which NATGW should create a fallback route, instead of creating a single default route. This can be used when there is already a default route, via an interface that can not reach required infrastructure, that overrides the NAT gateway default route.

If GATEWAY is specified then the corresponding route on the NATGW leader node will be via GATEWAY. Such routes are created even if CTDB_NATGW_DEFAULT_GATEWAY is not specified. If GATEWAY is not specified for some networks then routes are only created on the NATGW leader node for those networks if CTDB_NATGW_DEFAULT_GATEWAY is specified.

This should be used with care to avoid causing traffic to unnecessarily double-hop through the NAT gateway leader, even when a node is hosting public IP addresses. Each specified network or host should probably have a corresponding automatically created link route or static route to avoid this.

No default.

Example 

CTDB_NATGW_NODES=/etc/ctdb/natgw_nodes
CTDB_NATGW_PRIVATE_NETWORK=192.168.1.0/24
CTDB_NATGW_DEFAULT_GATEWAY=10.0.0.1
CTDB_NATGW_PUBLIC_IP=10.0.0.227/24
CTDB_NATGW_PUBLIC_IFACE=eth0

A variation that ensures that infrastructure (ADS, DNS, ...) directly attached to the public network (10.0.0.0/24) is always reachable would look like this:

CTDB_NATGW_NODES=/etc/ctdb/natgw_nodes
CTDB_NATGW_PRIVATE_NETWORK=192.168.1.0/24
CTDB_NATGW_PUBLIC_IP=10.0.0.227/24
CTDB_NATGW_PUBLIC_IFACE=eth0
CTDB_NATGW_STATIC_ROUTES=10.0.0.0/24

Note that CTDB_NATGW_DEFAULT_GATEWAY is not specified.

13.per_ip_routing

Provides CTDB's policy routing functionality.

A node running CTDB may be a component of a complex network topology. In particular, public addresses may be spread across several different networks (or VLANs) and it may not be possible to route packets from these public addresses via the system's default route. Therefore, CTDB has support for policy routing via the 13.per_ip_routing eventscript. This allows routing to be specified for packets sourced from each public address. The routes are added and removed as CTDB moves public addresses between nodes.

For more information, see the POLICY ROUTING section in ctdb(7).

CTDB_PER_IP_ROUTING_CONF=FILENAME

FILENAME contains elements for constructing the desired routes for each source address.

The special FILENAME value __auto_link_local__ indicates that no configuration file is provided and that CTDB should generate reasonable link-local routes for each public IP address.

File format:

		IPADDR DEST-IPADDR/MASK [GATEWAY-IPADDR]

No default, usually /etc/ctdb/policy_routing when enabled.

CTDB_PER_IP_ROUTING_RULE_PREF=NUM

NUM sets the priority (or preference) for the routing rules that are added by CTDB.

This should be (strictly) greater than 0 and (strictly) less than 32766. A priority of 100 is recommended, unless this conflicts with a priority already in use on the system. See ip(8), for more details.

CTDB_PER_IP_ROUTING_TABLE_ID_LOW=LOW-NUM, CTDB_PER_IP_ROUTING_TABLE_ID_HIGH=HIGH-NUM

CTDB determines a unique routing table number to use for the routing related to each public address. LOW-NUM and HIGH-NUM indicate the minimum and maximum routing table numbers that are used.

ip(8) uses some reserved routing table numbers below 255. Therefore, CTDB_PER_IP_ROUTING_TABLE_ID_LOW should be (strictly) greater than 255.

CTDB uses the standard file /etc/iproute2/rt_tables to maintain a mapping between the routing table numbers and labels. The label for a public address ADDR will look like ctdb.addr. This means that the associated rules and routes are easy to read (and manipulate).

No default, usually 1000 and 9000.

Example 

CTDB_PER_IP_ROUTING_CONF=/etc/ctdb/policy_routing
CTDB_PER_IP_ROUTING_RULE_PREF=100
CTDB_PER_IP_ROUTING_TABLE_ID_LOW=1000
CTDB_PER_IP_ROUTING_TABLE_ID_HIGH=9000

91.lvs

Provides CTDB's LVS functionality.

For a general description see the LVS section in ctdb(7).

CTDB_LVS_NODES=FILENAME

FILENAME contains the list of nodes that belong to the same LVS group.

File format:

IPADDR [follower-only]

IPADDR is the private IP address of each node in the LVS group.

If "follower-only" is specified then the corresponding node can not be the LVS leader node. In this case CTDB_LVS_PUBLIC_IFACE and CTDB_LVS_PUBLIC_IP are optional and unused.

No default, usually /etc/ctdb/lvs_nodes when enabled.

CTDB_LVS_PUBLIC_IFACE=INTERFACE

INTERFACE is the network interface that clients will use to connection to CTDB_LVS_PUBLIC_IP. This is optional for follower-only nodes. No default.

CTDB_LVS_PUBLIC_IP=IPADDR

CTDB_LVS_PUBLIC_IP is the LVS public address. No default.

SERVICE CONFIGURATION

CTDB can be configured to manage and/or monitor various NAS (and other) services via its eventscripts.

In the simplest case CTDB will manage a service. This means the service will be started and stopped along with CTDB, CTDB will monitor the service and CTDB will do any required reconfiguration of the service when public IP addresses are failed over.

20.multipathd

Provides CTDB's Linux multipathd service management.

It can monitor multipath devices to ensure that active paths are available.

CTDB_MONITOR_MPDEVICES=MP-DEVICE-LIST

MP-DEVICE-LIST is a list of multipath devices for CTDB to monitor?

No default.

31.clamd

This event script provide CTDB's ClamAV anti-virus service management.

This eventscript is not enabled by default. Use ctdb enablescript to enable it.

CTDB_CLAMD_SOCKET=FILENAME

FILENAME is the socket to monitor ClamAV.

No default.

40.vsftpd

Provides CTDB's vsftpd service management.

CTDB_VSFTPD_MONITOR_THRESHOLDS=THRESHOLDS

THRESHOLDS indicates how many consecutive monitoring attempts need to report that vsftpd is not listening on TCP port 21 before a warning is logged and before monitoring fails. See the Monitoring Thresholds for a description of how monitoring thresholds work.

Default is 1:2.

48.netbios

Provides CTDB's NetBIOS service management.

CTDB_SERVICE_NMB=SERVICE

Distribution specific SERVICE for managing nmbd.

Default is distribution-dependant.

49.winbind

Provides CTDB's Samba winbind service management.

CTDB_SERVICE_WINBIND=SERVICE

Distribution specific SERVICE for managing winbindd.

Default is "winbind".

CTDB_SAMBA_INTERFACES_FILE=FILENAME

Generates FILENAME, containing an smb.conf snippet with an interfaces setting that includes interfaces for configured CTDB public IP addresses. This file then needs to be explicitly included in smb.conf.

For example, if public IP addresses are defined on interfaces eth0 and eth1, and this is set to /etc/samba/interfaces.conf, then that file will contain the following before smbd is started:



     bind interfaces only = yes


     interfaces = lo eth0 eth1

This can be useful for limiting the interfaces used by SMB multichannel.

Default is to not generate a file.

CTDB_SAMBA_INTERFACES_EXTRA=INTERFACE-LIST

A space separated list to provide additional interfaces to bind.

Default is empty - no extra interfaces are added.

50.samba

Provides the core of CTDB's Samba file service management.

CTDB_SAMBA_CHECK_PORTS=PORT-LIST

When monitoring Samba, check TCP ports in space-separated PORT-LIST.

Default is to monitor ports that Samba is configured to listen on.

CTDB_SAMBA_SKIP_SHARE_CHECK=yes|no

As part of monitoring, should CTDB skip the check for the existence of each directory configured as share in Samba. This may be desirable if there is a large number of shares.

Default is no.

CTDB_SERVICE_SMB=SERVICE

Distribution specific SERVICE for managing smbd.

Default is distribution-dependant.

60.nfs

This event script provides CTDB's NFS service management.

This includes parameters for the kernel NFS server. Alternative NFS subsystems (such as NFS-Ganesha[1]) can be integrated using CTDB_NFS_CALLOUT.

CTDB_NFS_CALLOUT=COMMAND

COMMAND specifies the path to a callout to handle interactions with the configured NFS system, including startup, shutdown, monitoring.

Default is the included nfs-linux-kernel-callout.

CTDB_NFS_CHECKS_DIR=DIRECTORY

Specifies the path to a DIRECTORY containing files that describe how to monitor the responsiveness of NFS RPC services. See the README file for this directory for an explanation of the contents of these "check" files.

CTDB_NFS_CHECKS_DIR can be used to point to different sets of checks for different NFS servers.

One way of using this is to have it point to, say, /etc/ctdb/nfs-checks-enabled.d and populate it with symbolic links to the desired check files. This avoids duplication and is upgrade-safe.

Default is /etc/ctdb/nfs-checks.d, which contains NFS RPC checks suitable for Linux kernel NFS.

CTDB_NFS_EXPORTS_FILE=FILE

Set FILE as the path of the file containing NFS exports, for use by the NFS callout (see CTDB_NFS_CALLOUT, above). This is used for share checks when CTDB_NFS_SKIP_SHARE_CHECK is not set to "yes". This is most useful with NFS-Ganesha, since it supports configuration include files and exports may be stored in a separate file.

Default is /var/lib/nfs/etab for nfs-linux-kernel-callout, /etc/ganesha/ganesha.conf for nfs-ganesha-callout.

CTDB_NFS_SKIP_SHARE_CHECK=yes|no

As part of monitoring, should CTDB skip the check for the existence of each directory exported via NFS. This may be desirable if there is a large number of exports.

Default is no.

CTDB_RPCINFO_LOCALHOST=IPADDR|HOSTNAME

IPADDR or HOSTNAME indicates the address that rpcinfo should connect to when doing rpcinfo check on IPv4 RPC service during monitoring. Optimally this would be "localhost". However, this can add some performance overheads.

Default is "127.0.0.1".

CTDB_RPCINFO_LOCALHOST6=IPADDR|HOSTNAME

IPADDR or HOSTNAME indicates the address that rpcinfo should connect to when doing rpcinfo check on IPv6 RPC service during monitoring. Optimally this would be "localhost6" (or similar). However, this can add some performance overheads.

Default is "::1".

CTDB_NFS_STATE_FS_TYPE=TYPE

The type of filesystem used for a clustered NFS' shared state. No default.

CTDB_NFS_STATE_MNT=DIR

The directory where a clustered NFS' shared state will be located. No default.

70.iscsi

Provides CTDB's Linux iSCSI tgtd service management.

CTDB_START_ISCSI_SCRIPTS=DIRECTORY

DIRECTORY on shared storage containing scripts to start tgtd for each public IP address.

No default.

DATABASE SETUP

CTDB checks the consistency of databases during startup.

00.ctdb

CTDB_MAX_CORRUPT_DB_BACKUPS=NUM

NUM is the maximum number of volatile TDB database backups to be kept (for each database) when a corrupt database is found during startup. Volatile TDBs are zeroed during startup so backups are needed to debug any corruption that occurs before a restart.

Default is 10.

SYSTEM RESOURCE MONITORING

05.system

Provides CTDB's filesystem and memory usage monitoring.

CTDB can experience seemingly random (performance and other) issues if system resources become too constrained. Options in this section can be enabled to allow certain system resources to be checked. They allows warnings to be logged and nodes to be marked unhealthy when system resource usage reaches the configured thresholds.

Some checks are enabled by default. It is recommended that these checks remain enabled or are augmented by extra checks. There is no supported way of completely disabling the checks.

CTDB_MONITOR_FILESYSTEM_USAGE=FS-LIMIT-LIST

FS-LIMIT-LIST is a space-separated list of FILESYSTEM:WARN_LIMIT[:UNHEALTHY_LIMIT] triples indicating that warnings should be logged if the space used on FILESYSTEM reaches WARN_LIMIT%. If usage reaches UNHEALTHY_LIMIT then the node should be flagged unhealthy. Either WARN_LIMIT or UNHEALTHY_LIMIT may be left blank, meaning that check will be omitted.

Default is to warn for each filesystem containing a database directory (volatile database directory, persistent database directory, state database directory) with a threshold of 90%.

CTDB_MONITOR_MEMORY_USAGE=MEM-LIMITS

MEM-LIMITS takes the form WARN_LIMIT[:UNHEALTHY_LIMIT] indicating that warnings should be logged if memory usage reaches WARN_LIMIT%. If usage reaches UNHEALTHY_LIMIT then the node should be flagged unhealthy. Either WARN_LIMIT or UNHEALTHY_LIMIT may be left blank, meaning that check will be omitted.

Default is 80, so warnings will be logged when memory usage reaches 80%.

EVENT SCRIPT DEBUGGING

debug-hung-script.sh

CTDB_DEBUG_HUNG_SCRIPT_STACKPAT=REGEXP

REGEXP specifies interesting processes for which stack traces should be logged when debugging hung eventscripts and those processes are matched in pstree output. REGEXP is an extended regexp so choices are separated by pipes ('|'). However, REGEXP should not contain parentheses. See also the ctdb.conf(5) [event] "debug script" option.

Default is "exportfs|rpcinfo".

FILES

/etc/ctdb/script.options

SEE ALSO

ctdbd(1), ctdb(7), http://ctdb.samba.org/

AUTHOR

This documentation was written by Amitay Isaacs, Martin Schwenke

COPYRIGHT

Copyright © 2007 Andrew Tridgell, Ronnie Sahlberg

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, see http://www.gnu.org/licenses.

NOTES

1.
NFS-Ganesha
https://github.com/nfs-ganesha/nfs-ganesha/wiki
12/01/2024 ctdb