This section details commonly used configuration directives. For a complete list, see the slapd-config(5) manual page. This section will treat the configuration directives in a top-down order, starting with the global directives in the cn=config entry. Each directive will be described along with its default value (if any) and an example of its use.
Directives contained in this entry generally apply to the server as a whole. Most of them are system or connection oriented, not database related. This entry must have the olcGlobal objectClass.
Specify the number of seconds to wait before forcibly closing an idle client connection. A value of 0, the default, disables this feature.
This directive specifies the level at which debugging statements and operation statistics should be syslogged (currently logged to the syslogd(8) LOG_LOCAL4 facility). You must have configured OpenLDAP --enable-debug (the default) for this to work (except for the two statistics levels, which are always enabled). Log levels may be specified as integers or by keyword. Multiple log levels may be used and the levels are additive. To display what levels correspond to what kind of debugging, invoke slapd with -? or consult the table below. The possible values for <level> are:
Table 5.1: Debugging Levels
|
Level
|
Keyword
|
Description
|
|
-1
|
Any
|
enable all debugging
|
|
0
|
|
no debugging
|
|
1
|
Trace
|
trace function calls
|
|
2
|
Packets
|
debug packet handling
|
|
4
|
Args
|
heavy trace debugging
|
|
8
|
Conns
|
connection management
|
|
16
|
BER
|
print out packets sent and received
|
|
32
|
Filter
|
search filter processing
|
|
64
|
Config
|
configuration processing
|
|
128
|
ACL
|
access control list processing
|
|
256
|
Stats
|
stats log connections/operations/results
|
|
512
|
Stats2
|
stats log entries sent
|
|
1024
|
Shell
|
print communication with shell backends
|
|
2048
|
Parse
|
print entry parsing debugging
|
|
4096
|
Cache
|
database cache processing
|
|
8192
|
Index
|
database indexing
|
|
16384
|
Sync
|
syncrepl consumer processing
|
Example:
olcLogLevel: -1
This will cause lots and lots of debugging information to be logged.
olcLogLevel: Conns Filter
Just log the connection and search filter processing.
Default:
olcLogLevel: Stats
This directive specifies the referral to pass back when slapd cannot find a local database to handle a request.
Example:
olcReferral: ldap://root.openldap.org
This will refer non-local queries to the global root LDAP server at the OpenLDAP Project. Smart LDAP clients can re-ask their query at that server, but note that most of these clients are only going to know how to handle simple LDAP URLs that contain a host part and optionally a distinguished name part.
dn: cn=config
objectClass: olcGlobal
cn: config
olcIdleTimeout: 30
olcLogLevel: Stats
olcReferral: ldap://root.openldap.org
If support for dynamically loaded modules was enabled when configuring slapd, cn=module entries may be used to specify sets of modules to load. Module entries must have the olcModuleList objectClass.
Specify the name of a dynamically loadable module to load. The filename may be an absolute path name or a simple filename. Non-absolute names are searched for in the directories specified by the olcModulePath directive.
Specify a list of directories to search for loadable modules. Typically the path is colon-separated but this depends on the operating system.
dn: cn=module{0},cn=config
objectClass: olcModuleList
cn: module{0}
olcModuleLoad: /usr/local/lib/smbk5pwd.la
dn: cn=module{1},cn=config
objectClass: olcModuleList
cn: module{1}
olcModulePath: /usr/local/lib:/usr/local/lib/slapd
olcModuleLoad: accesslog.la
olcModuleLoad: pcache.la
The cn=schema entry holds all of the schema definitions that are hard-coded in slapd. As such, the values in this entry are generated by slapd so no schema values need to be provided in the config file. The entry must still be defined though, to serve as a base for the user-defined schema to add in underneath. Schema entries must have the olcSchemaConfig objectClass.
5.2.3.1. olcAttributeTypes: <RFC4512 Attribute Type Description>
This directive defines an attribute type. Please see the Schema Specification chapter for information regarding how to use this directive.
5.2.3.2. olcObjectClasses: <RFC4512 Object Class Description>
This directive defines an object class. Please see the Schema Specification chapter for information regarding how to use this directive.
dn: cn=schema,cn=config
objectClass: olcSchemaConfig
cn: schema
dn: cn=test,cn=schema,cn=config
objectClass: olcSchemaConfig
cn: test
olcAttributeTypes: ( 1.1.1
NAME 'testAttr'
EQUALITY integerMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 )
olcAttributeTypes: ( 1.1.2 NAME 'testTwo' EQUALITY caseIgnoreMatch
SUBSTR caseIgnoreSubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.44 )
olcObjectClasses: ( 1.1.3 NAME 'testObject'
MAY ( testAttr $ testTwo ) AUXILIARY )
Backend directives apply to all database instances of the same type and, depending on the directive, may be overridden by database directives. Backend entries must have the olcBackendConfig objectClass.
This directive names a backend-specific configuration entry. <type> should be one of the supported backend types listed in Table 5.2.
Table 5.2: Database Backends
|
Types
|
Description
|
|
bdb
|
Berkeley DB transactional backend
|
|
config
|
Slapd configuration backend
|
|
dnssrv
|
DNS SRV backend
|
|
hdb
|
Hierarchical variant of bdb backend
|
|
ldap
|
Lightweight Directory Access Protocol (Proxy) backend
|
|
ldif
|
Lightweight Data Interchange Format backend
|
|
meta
|
Meta Directory backend
|
|
monitor
|
Monitor backend
|
|
passwd
|
Provides read-only access to passwd(5)
|
|
perl
|
Perl Programmable backend
|
|
shell
|
Shell (extern program) backend
|
|
sql
|
SQL Programmable backend
|
Example:
olcBackend: bdb
There are no other directives defined for this entry. Specific backend types may define additional attributes for their particular use but so far none have ever been defined. As such, these directives usually do not appear in any actual configurations.
dn: olcBackend=bdb,cn=config
objectClass: olcBackendConfig
olcBackend: bdb
Directives in this section are supported by every type of database. Database entries must have the olcDatabaseConfig objectClass.
This directive names a specific database instance. The numeric {<index>} may be provided to distinguish multiple databases of the same type. Usually the index can be omitted, and slapd will generate it automatically. <type> should be one of the supported backend types listed in Table 5.2 or the frontend type.
The frontend is a special database that is used to hold database-level options that should be applied to all the other databases. Subsequent database definitions may also override some frontend settings.
The config database is also special; both the config and the frontend databases are always created implicitly even if they are not explicitly configured, and they are created before any other databases.
Example:
olcDatabase: bdb
This marks the beginning of a new BDB database instance.
This directive grants access (specified by <accesslevel>) to a set of entries and/or attributes (specified by <what>) by one or more requestors (specified by <who>). See the Access Control section of this chapter for a summary of basic usage.
Note: If no
olcAccess directives are specified, the default access control policy,
to * by * read, allows all users (both authenticated and anonymous) read access.
Note: Access controls defined in the frontend are appended to all other databases' controls.
This directive puts the database into "read-only" mode. Any attempts to modify the database will return an "unwilling to perform" error.
Default:
olcReadonly: FALSE
This directive specifies the DN that is not subject to access control or administrative limit restrictions for operations on this database. The DN need not refer to an entry in this database or even in the directory. The DN may refer to a SASL identity.
Entry-based Example:
olcRootDN: "cn=Manager,dc=example,dc=com"
SASL-based Example:
olcRootDN: "uid=root,cn=example.com,cn=digest-md5,cn=auth"
See the SASL Authentication section for information on SASL authentication identities.
This directive can be used to specify a password for the DN for the rootdn (when the rootdn is set to a DN within the database).
Example:
olcRootPW: secret
It is also permissible to provide a hash of the password in RFC2307 form. slappasswd(8) may be used to generate the password hash.
Example:
olcRootPW: {SSHA}ZKKuqbEKJfKSXhUbHG3fG8MDn9j1v4QN
The hash was generated using the command slappasswd -s secret.
This directive specifies the maximum number of entries to return from a search operation.
Default:
olcSizeLimit: 500
This directive specifies the DN suffix of queries that will be passed to this backend database. Multiple suffix lines can be given, and usually at least one is required for each database definition. (Some backend types, such as frontend and monitor use a hard-coded suffix which may not be overridden in the configuration.)
Example:
olcSuffix: "dc=example,dc=com"
Queries with a DN ending in "dc=example,dc=com" will be passed to this backend.
Note: When the backend to pass a query to is selected, slapd looks at the suffix value(s) in each database definition in the order in which they were configured. Thus, if one database suffix is a prefix of another, it must appear after it in the configuration.
olcSyncrepl: rid=<replica ID>
provider=ldap[s]://<hostname>[:port]
[type=refreshOnly|refreshAndPersist]
[interval=dd:hh:mm:ss]
[retry=[<retry interval> <# of retries>]+]
searchbase=<base DN>
[filter=<filter str>]
[scope=sub|one|base]
[attrs=<attr list>]
[attrsonly]
[sizelimit=<limit>]
[timelimit=<limit>]
[schemachecking=on|off]
[bindmethod=simple|sasl]
[binddn=<DN>]
[saslmech=<mech>]
[authcid=<identity>]
[authzid=<identity>]
[credentials=<passwd>]
[realm=<realm>]
[secprops=<properties>]
[starttls=yes|critical]
[tls_cert=<file>]
[tls_key=<file>]
[tls_cacert=<file>]
[tls_cacertdir=<path>]
[tls_reqcert=never|allow|try|demand]
[tls_ciphersuite=<ciphers>]
[tls_crlcheck=none|peer|all]
[logbase=<base DN>]
[logfilter=<filter str>]
[syncdata=default|accesslog|changelog]
This directive specifies the current database as a replica of the master content by establishing the current slapd(8) as a replication consumer site running a syncrepl replication engine. The master database is located at the replication provider site specified by the provider parameter. The replica database is kept up-to-date with the master content using the LDAP Content Synchronization protocol. See RFC4533 for more information on the protocol.
The rid parameter is used for identification of the current syncrepl directive within the replication consumer server, where <replica ID> uniquely identifies the syncrepl specification described by the current syncrepl directive. <replica ID> is non-negative and is no more than three decimal digits in length.
The provider parameter specifies the replication provider site containing the master content as an LDAP URI. The provider parameter specifies a scheme, a host and optionally a port where the provider slapd instance can be found. Either a domain name or IP address may be used for <hostname>. Examples are ldap://provider.example.com:389 or ldaps://192.168.1.1:636. If <port> is not given, the standard LDAP port number (389 or 636) is used. Note that the syncrepl uses a consumer-initiated protocol, and hence its specification is located at the consumer site, whereas the replica specification is located at the provider site. syncrepl and replica directives define two independent replication mechanisms. They do not represent the replication peers of each other.
The content of the syncrepl replica is defined using a search specification as its result set. The consumer slapd will send search requests to the provider slapd according to the search specification. The search specification includes searchbase, scope, filter, attrs, attrsonly, sizelimit, and timelimit parameters as in the normal search specification. The searchbase parameter has no default value and must always be specified. The scope defaults to sub, the filter defaults to (objectclass=*), attrs defaults to "*,+" to replicate all user and operational attributes, and attrsonly is unset by default. Both sizelimit and timelimit default to "unlimited", and only positive integers or "unlimited" may be specified.
The LDAP Content Sychronization protocol has two operation types: refreshOnly and refreshAndPersist. The operation type is specified by the type parameter. In the refreshOnly operation, the next synchronization search operation is periodically rescheduled at an interval time after each synchronization operation finishes. The interval is specified by the interval parameter. It is set to one day by default. In the refreshAndPersist operation, a synchronization search remains persistent in the provider slapd instance. Further updates to the master replica will generate searchResultEntry to the consumer slapd as the search responses to the persistent synchronization search.
If an error occurs during replication, the consumer will attempt to reconnect according to the retry parameter which is a list of the <retry interval> and <# of retries> pairs. For example, retry="60 10 300 3" lets the consumer retry every 60 seconds for the first 10 times and then retry every 300 seconds for the next three times before stop retrying. + in <# of retries> means indefinite number of retries until success.
The schema checking can be enforced at the LDAP Sync consumer site by turning on the schemachecking parameter. If it is turned on, every replicated entry will be checked for its schema as the entry is stored into the replica content. Every entry in the replica should contain those attributes required by the schema definition. If it is turned off, entries will be stored without checking schema conformance. The default is off.
The binddn parameter gives the DN to bind as for the syncrepl searches to the provider slapd. It should be a DN which has read access to the replication content in the master database.
The bindmethod is simple or sasl, depending on whether simple password-based authentication or SASL authentication is to be used when connecting to the provider slapd instance.
Simple authentication should not be used unless adequate data integrity and confidentiality protections are in place (e.g. TLS or IPsec). Simple authentication requires specification of binddn and credentials parameters.
SASL authentication is generally recommended. SASL authentication requires specification of a mechanism using the saslmech parameter. Depending on the mechanism, an authentication identity and/or credentials can be specified using authcid and credentials, respectively. The authzid parameter may be used to specify an authorization identity.
The realm parameter specifies a realm which a certain mechanisms authenticate the identity within. The secprops parameter specifies Cyrus SASL security properties.
The starttls parameter specifies use of the StartTLS extended operation to establish a TLS session before authenticating to the provider. If the critical argument is supplied, the session will be aborted if the StartTLS request fails. Otherwise the syncrepl session continues without TLS. Note that the main slapd TLS settings are not used by the syncrepl engine; by default the TLS parameters from a ldap.conf(5) configuration file will be used. TLS settings may be specified here, in which case any ldap.conf(5) settings will be completely ignored.
Rather than replicating whole entries, the consumer can query logs of data modifications. This mode of operation is referred to as delta syncrepl. In addition to the above parameters, the logbase and logfilter parameters must be set appropriately for the log that will be used. The syncdata parameter must be set to either "accesslog" if the log conforms to the slapo-accesslog(5) log format, or "changelog" if the log conforms to the obsolete changelog format. If the syncdata parameter is omitted or set to "default" then the log parameters are ignored.
The syncrepl replication mechanism is supported by the bdb and hdb backends.
See the LDAP Sync Replication chapter of this guide for more information on how to use this directive.
This directive specifies the maximum number of seconds (in real time) slapd will spend answering a search request. If a request is not finished in this time, a result indicating an exceeded timelimit will be returned.
Default:
olcTimeLimit: 3600
This directive is only applicable in a slave slapd. It specifies the URL to return to clients which submit update requests upon the replica. If specified multiple times, each URL is provided.
Example:
olcUpdateref: ldap://master.example.net
dn: olcDatabase=frontend,cn=config
objectClass: olcDatabaseConfig
objectClass: olcFrontendConfig
olcDatabase: frontend
olcReadOnly: FALSE
dn: olcDatabase=config,cn=config
objectClass: olcDatabaseConfig
olcDatabase: config
olcRootDN: cn=Manager,dc=example,dc=com
Directives in this category apply to both the BDB and the HDB database. They are used in an olcDatabase entry in addition to the generic database directives defined above. For a complete reference of BDB/HDB configuration directives, see slapd-bdb(5). In addition to the olcDatabaseConfig objectClass, BDB and HDB database entries must have the olcBdbConfig and olcHdbConfig objectClass, respectively.
This directive specifies the directory where the BDB files containing the database and associated indices live.
Default:
olcDbDirectory: /usr/local/var/openldap-data
This directive specifies the size in entries of the in-memory cache maintained by the BDB backend database instance.
Default:
olcDbCachesize: 1000
This directive specifies how often to checkpoint the BDB transaction log. A checkpoint operation flushes the database buffers to disk and writes a checkpoint record in the log. The checkpoint will occur if either <kbyte> data has been written or <min> minutes have passed since the last checkpoint. Both arguments default to zero, in which case they are ignored. When the <min> argument is non-zero, an internal task will run every <min> minutes to perform the checkpoint. See the Berkeley DB reference guide for more details.
Example:
olcDbCheckpoint: 1024 10
This attribute specifies a configuration directive to be placed in the DB_CONFIG file of the database directory. At server startup time, if no such file exists yet, the DB_CONFIG file will be created and the settings in this attribute will be written to it. If the file exists, its contents will be read and displayed in this attribute. The attribute is multi-valued, to accommodate multiple configuration directives. No default is provided, but it is essential to use proper settings here to get the best server performance.
Any changes made to this attribute will be written to the DB_CONFIG file and will cause the database environment to be reset so the changes can take immediate effect. If the environment cache is large and has not been recently checkpointed, this reset operation may take a long time. It may be advisable to manually perform a single checkpoint using the Berkeley DB db_checkpoint utility before using LDAP Modify to change this attribute.
Example:
olcDbConfig: set_cachesize 0 10485760 0
olcDbConfig: set_lg_bsize 2097512
olcDbConfig: set_lg_dir /var/tmp/bdb-log
olcDbConfig: set_flags DB_LOG_AUTOREMOVE
In this example, the BDB cache is set to 10MB, the BDB transaction log buffer size is set to 2MB, and the transaction log files are to be stored in the /var/tmp/bdb-log directory. Also a flag is set to tell BDB to delete transaction log files as soon as their contents have been checkpointed and they are no longer needed. Without this setting the transaction log files will continue to accumulate until some other cleanup procedure removes them. See the Berkeley DB documentation for the db_archive command for details.
Ideally the BDB cache must be at least as large as the working set of the database, the log buffer size should be large enough to accommodate most transactions without overflowing, and the log directory must be on a separate physical disk from the main database files. And both the database directory and the log directory should be separate from disks used for regular system activities such as the root, boot, or swap filesystems. See the FAQ-o-Matic and the Berkeley DB documentation for more details.
This option causes on-disk database contents to not be immediately synchronized with in memory changes upon change. Setting this option to TRUE may improve performance at the expense of data integrity. This directive has the same effect as using
olcDbConfig: set_flags DB_TXN_NOSYNC
Specify the size of the in-memory index cache, in index slots. The default is zero. A larger value will speed up frequent searches of indexed entries. The optimal size will depend on the data and search characteristics of the database, but using a number three times the entry cache size is a good starting point.
Example:
olcDbIDLcacheSize: 3000
This directive specifies the indices to maintain for the given attribute. If only an <attrlist> is given, the default indices are maintained. The index keywords correspond to the common types of matches that may be used in an LDAP search filter.
Example:
olcDbIndex: default pres,eq
olcDbIndex: uid
olcDbIndex: cn,sn pres,eq,sub
olcDbIndex: objectClass eq
The first line sets the default set of indices to maintain to present and equality. The second line causes the default (pres,eq) set of indices to be maintained for the uid attribute type. The third line causes present, equality, and substring indices to be maintained for cn and sn attribute types. The fourth line causes an equality index for the objectClass attribute type.
There is no index keyword for inequality matches. Generally these matches do not use an index. However, some attributes do support indexing for inequality matches, based on the equality index.
A substring index can be more explicitly specified as subinitial, subany, or subfinal, corresponding to the three possible components of a substring match filter. A subinitial index only indexes substrings that appear at the beginning of an attribute value. A subfinal index only indexes substrings that appear at the end of an attribute value, while subany indexes substrings that occur anywhere in a value.
Note that by default, setting an index for an attribute also affects every subtype of that attribute. E.g., setting an equality index on the name attribute causes cn, sn, and every other attribute that inherits from name to be indexed.
By default, no indices are maintained. It is generally advised that minimally an equality index upon objectClass be maintained.
olcDbindex: objectClass eq
Additional indices should be configured corresponding to the most common searches that are used on the database. Presence indexing should not be configured for an attribute unless the attribute occurs very rarely in the database, and presence searches on the attribute occur very frequently during normal use of the directory. Most applications don't use presence searches, so usually presence indexing is not very useful.
If this setting is changed while slapd is running, an internal task will be run to generate the changed index data. All server operations can continue as normal while the indexer does its work. If slapd is stopped before the index task completes, indexing will have to be manually completed using the slapindex tool.
If this setting is TRUE slapindex will index one attribute at a time. The default settings is FALSE in which case all indexed attributes of an entry are processed at the same time. When enabled, each indexed attribute is processed individually, using multiple passes through the entire database. This option improves slapindex performance when the database size exceeds the BDB cache size. When the BDB cache is large enough, this option is not needed and will decrease performance. Also by default, slapadd performs full indexing and so a separate slapindex run is not needed. With this option, slapadd does no indexing and slapindex must be used.
This directive specifies the file protection mode that newly created database index files should have.
Default:
olcDbMode: 0600
Specify the depth of the stack used for search filter evaluation. Search filters are evaluated on a stack to accommodate nested AND / OR clauses. An individual stack is allocated for each server thread. The depth of the stack determines how complex a filter can be evaluated without requiring any additional memory allocation. Filters that are nested deeper than the search stack depth will cause a separate stack to be allocated for that particular search operation. These separate allocations can have a major negative impact on server performance, but specifying too much stack will also consume a great deal of memory. Each search uses 512K bytes per level on a 32-bit machine, or 1024K bytes per level on a 64-bit machine. The default stack depth is 16, thus 8MB or 16MB per thread is used on 32 and 64 bit machines, respectively. Also the 512KB size of a single stack slot is set by a compile-time constant which may be changed if needed; the code must be recompiled for the change to take effect.
Default:
olcDbSearchStack: 16
Specify a key for a shared memory BDB environment. By default the BDB environment uses memory mapped files. If a non-zero value is specified, it will be used as the key to identify a shared memory region that will house the environment.
Example:
olcDbShmKey: 42
dn: olcDatabase=hdb,cn=config
objectClass: olcDatabaseConfig
objectClass: olcHdbConfig
olcDatabase: hdb
olcSuffix: "dc=example,dc=com"
olcDbDirectory: /usr/local/var/openldap-data
olcDbCacheSize: 1000
olcDbCheckpoint: 1024 10
olcDbConfig: set_cachesize 0 10485760 0
olcDbConfig: set_lg_bsize 2097152
olcDbConfig: set_lg_dir /var/tmp/bdb-log
olcDbConfig: set_flags DB_LOG_AUTOREMOVE
olcDbIDLcacheSize: 3000
olcDbIndex: objectClass eq
