1SLAPO-UNIQUE(5) File Formats Manual SLAPO-UNIQUE(5)
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6 slapo-unique - Attribute Uniqueness overlay to slapd
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9 /etc/openldap/slapd.conf
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12 The Attribute Uniqueness overlay can be used with a backend database
13 such as slapd-mdb(5) to enforce the uniqueness of some or all at‐
14 tributes within a scope. This subtree defaults to all objects within
15 the subtree of the database for which the Uniqueness overlay is config‐
16 ured.
17 Uniqueness is enforced by searching the subtree to ensure that the val‐
19 ues of all attributes presented with an add, modify or modrdn operation
20 are unique within the scope. For example, if uniqueness were enforced
21 for the uid attribute, the subtree would be searched for any other
22 records which also have a uid attribute containing the same value. If
23 any are found, the request is rejected.
24 The search is performed using the rootdn of the database, to avoid is‐
26 sues with ACLs preventing the overlay from seeing all of the relevant
27 data. As such, the database must have a rootdn configured.
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30 These slapd.conf options apply to the Attribute Uniqueness overlay.
31 They should appear after the overlay directive.
32 unique_uri <[strict ][ignore ][serialize ]URI[[ URI...]...]>
34 Configure the base, attributes, scope, and filter for uniqueness
35 checking. Multiple URIs may be specified within a domain, al‐
36 lowing complex selections of objects. Multiple unique_uri
37 statements or olcUniqueURI attribute values will create indepen‐
38 dent domains, each with their own independent lists of URIs and
39 ignore/strict settings.
40 Keywords strict, ignore, and serialize have to be enclosed in
42 quotes (") together with the URI.
43 The LDAP URI syntax is a subset of RFC-4516, and takes the form:
45 ldap:///[base dn]?[attributes...]?scope[?filter]
47 The base dn defaults to that of the back-end database. Speci‐
49 fied base dns must be within the subtree of the back-end data‐
50 base.
51 If no attributes are specified, the URI applies to all non-oper‐
53 ational attributes.
54 The scope component is effectively mandatory, because LDAP URIs
56 default to base scope, which is not valid for uniqueness, be‐
57 cause groups of one object are always unique. Scopes of sub
58 (for subtree) and one for one-level are valid.
59 The filter component causes the domain to apply uniqueness con‐
61 straints only to matching objects. e.g.
62 ldap:///?cn?sub?(sn=e*) would require unique cn attributes for
63 all objects in the subtree of the back-end database whose sn
64 starts with an e.
65 It is possible to assert uniqueness upon all non-operational at‐
67 tributes except those listed by prepending the keyword ignore If
68 not configured, all non-operational (e.g., system) attributes
69 must be unique. Note that the attributes list of an ignore URI
70 should generally contain the objectClass, dc, ou and o at‐
71 tributes, as these will generally not be unique, nor are they
72 operational attributes.
73 It is possible to set strict checking for the uniqueness domain
75 by prepending the keyword strict. By default, uniqueness is not
76 enforced for null values. Enabling strict mode extends the con‐
77 cept of uniqueness to include null values, such that only one
78 attribute within a subtree will be allowed to have a null value.
79 Strictness applies to all URIs within a uniqueness domain, but
80 some domains may be strict while others are not.
81 It is possible to enforce strict serialization of modifications
83 by prepending the keyword serialize. By default, no serializa‐
84 tion is performed, so multiple modifications occurring nearly
85 simultaneously may see incomplete uniqueness results. Using se‐
86 rialize will force individual write operations to fully complete
87 before allowing any others to proceed, to ensure that each oper‐
88 ation's uniqueness checks are consistent.
89 It is not possible to set both URIs and legacy slapo-unique configura‐
91 tion parameters simultaneously. In general, the legacy configuration
92 options control pieces of a single unfiltered subtree domain.
93 unique_base <basedn>
95 This legacy configuration parameter should be converted to the
96 base dn component of the above unique_uri style of parameter.
97 unique_ignore <attribute...>
99 This legacy configuration parameter should be converted to a
100 unique_uri parameter with ignore keyword as described above.
101 unique_attributes <attribute...>
103 This legacy configuration parameter should be converted to a
104 unique_uri parameter, as described above.
105 unique_strict <attribute...>
107 This legacy configuration parameter should be converted to a
108 strict keyword prepended to a unique_uri parameter, as described
109 above.
110
112 unique_uri cannot be used with the old-style of configuration, and vice
113 versa. unique_uri can implement everything the older system can do,
114 however.
115 Typical attributes for the ignore ldap:///... URIs are intentionally
117 not hardcoded into the overlay to allow for maximum flexibility in
118 meeting site-specific requirements.
119 Replication and operations with the relax control are allowed to bypass
121 this enforcement. It is therefore important that all servers accepting
122 writes have this overlay configured in order to maintain uniqueness in
123 a replicated DIT.
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126 /etc/openldap/slapd.conf
127 default slapd configuration file
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130 slapd.conf(5), slapd-config(5).
131OpenLDAP 2.6.2 2022/05/04 SLAPO-UNIQUE(5)