Abstract:
Each LDIF entry of a directory tree is read, split to a domain of LDIF fragments (corresponding to backend servers) and written to each LDIF fragment. The split may be accomplished through a hash function, establishing, for that iteration of LDIF entry, a write file. The LDIF entry is appended to the write file. A subsequent LDIF entry is read. A corresponding LDIF fragment is determined, which need not be different from the LDIF fragment to which the first LDIF entry was written. The current LDIF entry is written to the currently selected write file. The process continues until all LDIF entries are exhausted from the directory tree. LDIF fragments are each copied to distinct backend servers, where, each LDIF fragment may be loaded into a distributed directory data structure.

Description:
This application is a continuation of application Ser. No. 11/106,396, filed Apr. 14, 2005, status, allowed. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to the field of configuring and provisioning additional computing resources, and more particularly to an improved conversion from single computer directory service to a distributed directory service. 
     2. Description of Related Art 
     X.500 directory model is a distributed collection of independent systems which cooperate to provide a logical data base of information to provide a global Directory Service. Directory information about a particular organization is maintained locally in a Directory System Agent (DSA) or directory server. This information is structured within specified standards. Adherence to these standards makes the distributed model possible. It is possible for one organization to keep information about other organizations, and it is possible for an organization to operate independently from the global model as a stand alone system. DSAs that operate within the global model have the ability to exchange information with other DSAs by means of the X*500 protocol. 
     DSAs that are interconnected form the Directory Information Tree (DIT). The DIT is a virtual hierarchical data structure. An X.500 pilot using QUIPU software introduced the concept of a “root” DSA which represents the world; below which “countries” are defined. Defined under the countries are “organizations”. The organizations further define “organizational units” and/or “people”. 
     The lightweight directory access protocol (LDAP) is a streamlined version of the x.500 directory service. It eliminates the ISO protocol stack, defining, instead, a protocol based on the IP protocol suite. LDAP also simplifies the data encoding and command set of X.500 and defines a standard API for directory access. LDAP has undergone several revisions and may be revised again. For example, some versions of LDAP incorporate various measures that improve security. 
     LDAP and the X.500 standard define the information model used in the directory service. All information in the directory is stored in “entries”, each of which belongs to at least one “object class”. As an example, in a white Pages application of X.500, object classes are defined as country, organization, organizational unit and person. 
     The object classes to which an entry belongs defines the attributes associated with a particular entry. Some attributes are mandatory others are optional. System administrators may define their own attributes and register these with regulating authorities, which will in turn make these attributes available on a large scale. 
     Every entry has a Relative Distinguished Name (RDN), which uniquely identifies the entry. A RDN is made up of the DIT information and the actual entry. 
     Deploying a distributed directory has been problematic in the past for a variety of reasons. First, the configuration of each backend server can be complicated, especially as the number of backend servers increases. This often means additional configuration file entries, replication agreements or referral objects which must be added to each backend server by the administrator. 
     Second, the data must be transferred from one main server or LDAP Data Interchange Format (LDIF) file to each backend server. This is often done through a proxy server or servers after the empty distributed directory servers are configured. Loading data into the empty directory is often very slow, as each entry was loaded through the proxy server one by one. Such loading failed to take advantage of the parallelism offered by the incipient distributed directory. Loading would benefit greatly if some parallel copying and loading could be done. 
     Thus, although a running distributed directory rapidly responds to client requests, such a distributed directory is cumbersome to migrate to from the typical single server configured directory support. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method, apparatus and computer instructions for creating at least two LDIF (Lightweight Directory Access Protocol Data Interchange Format) fragments from a directory information tree is shown. A setup configuration file is read having LDIF fragment names that reference places in storage, e.g. LDIF fragment files. Successive LDIF entries from the directory information tree (DIT) are read. A determination is made whether each LDIF entry should be stored to a first LDIF fragment or a second LDIF fragment, based on a split function. Depending on the LDIF fragment selected, the LDIF entry is written to the selected LDIF fragment. Once all LDIF entries have been split or otherwise written, resultant files, including the LDIF fragments are bulkloaded in a concurrent manner, one to each backend server. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  shows a typical distributed directory environment in block form in accordance with an illustrative embodiment of the present invention; 
         FIG. 2  shows a first embodiment setup computer in block form in accordance with an illustrative embodiment of the present invention; 
         FIG. 3  shows an exemplary setup configuration file upon which an embodiment may operate; and 
         FIG. 4  shows a flow diagram of the steps performed by an illustrative embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  shows a block diagram of a typical distributed directory network in accordance with an illustrative embodiment of the present invention. A first backend directory server  103  supports a portion of the overall directory of the domain. The workload is shared with a second backend directory server  105 . Each backend directory server may be simply referred to as a backend. The combined backends may present themselves to the network as if they were a single device with, for example, a common Internet Protocol (IP) address. This is ordinarily accomplished through the use of a proxy server  101 , which may provide security and load-sharing functions. Queries for directory service may arrive to the domain through a network connection  109  that may connect with, among other things, the internet  111 . Frequently, such distributed directory networks are established with more than two backend servers. 
     With reference now to  FIG. 2 , a block diagram illustrating a data processing system is depicted in which the present invention may be implemented. Data processing system  200  is an example of a computer which may operate in the capacity of a backend distributed directory server, a single directory server or a proxy server. Data processing system  200  employs a peripheral component interconnect (PCI) local bus architecture. Although the depicted example employs a PCI bus, other bus architectures such as Accelerated Graphics Port (AGP) and Industry Standard Architecture (ISA) may be used. Processor  202  and main memory  204  are connected to PCI local bus  206  through PCI Bridge  208 . PCI Bridge  208  also may include an integrated memory controller and cache memory for processor  202 . Additional connections to PCI local bus  206  may be made through direct component interconnection or through add-in boards. In the depicted example, local area network (LAN) adapter  210 , small computer system interface (SCSI) host bus adapter  212 , and expansion bus interface  214  are connected to PCI local bus  206  by direct component connection. LAN adapter  210  may interconnect a computer, e.g. the Proxy  101  to one or more backends,  103  and  105  of  FIG. 1 , i.e. one LAN adapter for each of proxy, backend  103  and backend  105 . In contrast, audio adapter  216 , graphics adapter  218 , and audio/video adapter  219  are connected to PCI local bus  206  by add-in boards inserted into expansion slots. Expansion bus interface  214  provides a connection for a keyboard and mouse adapter  220 , modem  222 , and additional memory  224 . SCSI host bus adapter  212  provides a connection for hard disk drive  226 , tape drive  228 , and CD-ROM drive  230 . Typical PCI local bus implementations will support three or four PCI expansion slots or add-in connectors. 
     An operating system runs on processor  202  and is used to coordinate and provide control of various components within data processing system  200  in  FIG. 2 . The operating system may be a commercially available operating system, such as Windows XP, which is available from Microsoft Corporation. An object oriented programming system such as Java may run in conjunction with the operating system and provide calls to the operating system from Java programs or applications executing on data processing system  200 . “Java” is a trademark of Sun Microsystems, Inc. Instructions for the operating system, the object-oriented programming system, and applications or programs are located on storage devices, such as hard disk drive  226 , and may be loaded into main memory  204  for execution by processor  202 . 
       FIG. 3  shows an example of a setup configuration file  300  that may be established to guide the operation of the embodiment. A setup configuration file may include an input file name  303 ; a first fragment file name  305 ; and a second fragment file name  307 . A baseDN  302  specifies a node in the directory information tree, wherein the baseDN  302  specifies a split point of the DIT. In the case of the setup configuration file  300 , the baseDN  302  has two attribute pairs, “o=ibm, c=US”. The node defined by the attribute pair “c=US” is a parent. In this case there are no parent nodes to “c=US”, since that is the root node to the DIT. Child nodes to “o=ibm, c=US” are nodes that have distinguished names that include an additional attribute pair to the left of “o=ibm”. Children of the child nodes would have yet another attribute pair added to the left. All nodes of the DIT that have the split point described in baseDN  302  among the attribute pairs, is considered a descendant of the baseDN  302 . Nodes of the DIT that lack one or more attribute pairs of the baseDN are said to be ancestors of the baseDN. This includes the parent “c=US”. 
     Optionally, the setup configuration file may include a first backend server Uniform Resource Locator (URL)  309  and a second backend server URL  311 . It is appreciated that many of the details mentioned in the setup configuration file may alternatively be presented on a command line or otherwise be available to a running program in a data structure called a setup configuration. Consequently, the setup configuration may be edited by hand prior to running a program implementing the embodiment, or the setup configuration may be provided at the time of running. 
       FIG. 4  shows initial steps in accordance with an embodiment. The steps of  FIG. 4  may be executed by a proxy  101 , backend distributed directory server  103  or backend distributed directory server  105 . When operating the embodiment, the computer that operates the steps may be called the setup computer. An embodiment may receive important options and files upon which it operates on the command line. The setup program may parse (step  401 ) the command line to locate and obtain a setup configuration file of  FIG. 3  from the command line. In addition, debug levels may also be parsed from the command line. In order to rapidly reference data for repeated access, the setup program may read, parse and assign to variables data from the setup configuration file in a process generally known as constructing a configuration object (step  402 ). A configuration object may be a data structure. 
     The setup computer may read a setup configuration file, such as described in  FIG. 3 , or otherwise access a file or data structure that designates at least two files: a first fragment file name, and a second fragment file name. As a data structure, the configuration object may serve as a setup configuration, which the setup computer may read. Having done that, the setup computer may read (step  403 ) a LDIF entry of an input file, e.g. specified by input file name  303 , or directory information tree. Each LDIF entry may be read (step  403 ) in consecutive order, i.e. a successive LDIF entry. An initial step determines if the successive LDIF entry is a descendant (step  407 ) of the baseDN,  302  of  FIG. 3 . Provided the successive LDIF entry is a descendant, the setup computer may use a hash function operating on the distinguished name (DN) of the successive LDIF entry in such a way as to identify the LDIF fragment to write to as a write file (step  413 ). Such an LDIF fragment may be chosen from a set of fragments comprising a first LDIF fragment name, and a second LDIF fragment name, e.g. SERVERA, as specified in more detail by first backend server URL  309 , and SERVERB. Each choice for each LDIF entry is a selected write file. Such LDIF fragment names may be specified in the setup configuration file. These files are the targets within which all the descendant LDIF entries will be placed, but initially, it is expected that the LDIF fragments will be empty. 
     The hash function maps each descendant LDIF entry to the domain of LDIF fragment names or backend servers into which the LDIF entry may be placed. It is appreciated that backend servers may be enumerated, 1, 2, 3, etc., and that a simple array may contain the LDIF fragment name or other unique identifier with which the output file is accessed, such array indexed by integers. So, the domain that the hash function maps to (step  413 ) may merely be integers from one to the number “n”, wherein “n” is the number of servers that are to be setup to form the distributed directory. 
     The setup computer then writes or appends the LDIF entry to the selected write file (step  415 ). A write may be to a hard drive ( 226  of  FIG. 2 ) or may be to a storage beyond the setup computer, e.g. as may occur by transmitting a stream of data to a serving computer through the facility of the LAN adapter ( 210  of  FIG. 2 ). Provided there are another LDIF entries (step  417 ) another LDIF entry is read (step  403 ) by the setup computer. Thus each reading may advance the next LDIF entry, and the next LDIF entry, or successive LDIF entry, changes with each occurrence of read (step  403 ). Absent additional LDIF entries being available (step  417 ), processing passes to the bulkloading steps  421  and  423 . 
     If a successive LDIF entry fails to be a descendant of the baseDN (step  407 ) the entry is handled specially. The entry is written (step  409 ) to a default output file, e.g. root fragment  308  of  FIG. 3 . Following the write, a determination whether there are other LDIF entries is made (step  417 ). If yes, more successive LDIF entry or entries are read (step  403 ). If not, bulkloading steps  421  and  423  are executed. One or more steps of  FIG. 4  may be accomplished by a processor ( 202  of  FIG. 2 ). 
     A high speed offline loader is the “bulkload” utility. Executing the bulkload utility is called “bulkloading”. Bulkloading refers to the transference of at least two distinct data structures from one long term storage, e.g. a hard drive, to another long term storage, often located in another computer. 
     A first step of the bulkload, is the step of copying each LDIF fragment (step  421 ) to a backend server. The designated backend server to copy to may be specified in the setup configuration file. The second step of the bulkload is to load (step  423 ) each LDIF fragment to the backend where it is located. 
     Since a program may accumulate a series of write operations to a buffer before committing such writes to long term storage, the setup computer may receive a first LDIF entry of the directory information tree and a second LDIF entry of the directory information tree for writing, wherein the first LDIF entry and the second LDIF entry are non-consecutive in the directory information tree from which it originates. By non-consecutive, it is meant that at least one LDIF entry appears between the first LDIF entry and the second LDIF entry. After receiving the first LDIF entry and the second LDIF entry, the bulkload may copy the combined LDIF entries to the backend server. The copy of the combined LDIF entries may be such that the first LDIF entry and the second LDIF entry are consecutive, when they arrive at the backend server. Bulkload may also load the first LDIF entry and the second LDIF entry to the backend server. 
     The copy (step  421 ) may be several concurrent copies in the sense that a microprocessor may share time processing a copy operation of the first LDIF fragment and the copy operation of the second LDIF fragment. As such, the copying from the embodiment to a backend server may accomplish multiple copyings to multiple backend servers during a time interval—in effect, causing a parallel copying to occur vis-à-vis the two or more LDIF fragments. Likewise, the load (step  423 ) may be several concurrent loadings of LDIF fragments into their respective backend servers. 
     
       
         
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
             
             
               
                   
                  dn: cn = ServerA, cn = ProxyDB, cn = Proxy Backends, 
               
               
                   
                 cn = IBM Directory, cn = Schemas, cn = Configuration 
               
               
                   
                  cn: ServerA 
               
               
                   
                  ibm-slapdProxyBindMethod: Simple 
               
               
                   
                  ibm-slapdProxyConnectionPoolSize: 5 
               
               
                   
                  ibm-slapdProxyDN: cn = root 
               
               
                   
                  ibm-slapdProxyPW: secret 
               
               
                   
                  ibm-slapdProxyTargetURL: ldap://serverA:389 
               
               
                   
                  objectClass: top 
               
               
                   
                  objectClass: ibm-slapdProxyBackendServer 
               
               
                   
                  objectClass: ibm-slapdConfigEntry 
               
               
                   
                  dn: cn = ServerB cn = ProxyDB, cn = Proxy Backends, cn = IBM 
               
               
                   
                 Directory, cn = Schemas, cn = Configuration 
               
               
                   
                  cn: ServerB 
               
               
                   
                  ibm-slapdProxyBindMethod: Simple 
               
               
                   
                  ibm-slapdProxyConnectionPoolSize: 5 
               
               
                   
                  ibm-slapdProxyDN: cn = root 
               
               
                   
                  ibm-slapdProxyPW: secret 
               
               
                   
                  ibm-slapdProxyTargetURL: ldap://serverB:389 
               
               
                   
                  objectClass: top 
               
               
                   
                  objectClass: ibm-slapdProxyBackendServer 
               
               
                   
                  objectClass: ibm-slapdConfigEntry 
               
               
                   
                  dn: cn = ibm split, cn = ProxyDB, cn = Proxy Backends, 
               
               
                   
                 cn = IBM Directory, cn = Schemas, cn = Configuration 
               
               
                   
                  cn: ibm split 
               
               
                   
                  ibm-slapdProxyNumPartitions: 2 
               
               
                   
                  ibm-slapdProxyPartitionBase: o = ibm, c = us 
               
               
                   
                  objectclass: top 
               
               
                   
                  objectclass: ibm-slapdConfigEntry 
               
               
                   
                  objectclass: ibm-slapdProxyBackendSplitContainer 
               
               
                   
                  dn: cn = split1, cn = ibm split, cn = ProxyDB, cn = Proxy 
               
               
                   
                 Backends, cn = IBM Directory, cn = Schemas, cn = Configuration 
               
               
                   
                  cn: split1 
               
               
                   
                  ibm-slapdProxyBackendServerDN: 
               
               
                   
                 cn = ServerA, cn = ProxyDB, cn = Proxy Backends, cn = IBM 
               
               
                   
                 Directory, cn = Schemas, cn = Configuration 
               
               
                   
                  ibm-slapdProxyPartitionIndex: 1 
               
               
                   
                  objectclass: top 
               
               
                   
                  objectclass: ibm-slapdConfigEntry 
               
               
                   
                  objectclass: ibm-slapdProxyBackendSplit 
               
               
                   
                  dn: cn = split2, cn = ibm split, cn = ProxyDB, cn = Proxy 
               
               
                   
                 Backends, cn = IBM Directory, cn = Schemas, cn = Configuration 
               
               
                   
                  cn: split2 
               
               
                   
                  ibm-slapdProxyBackendServerDN: 
               
               
                   
                 cn = ServerB, cn = ProxyDB, cn = Proxy Backends, cn = IBM 
               
               
                   
                 Directory, cn = Schemas, cn = Configuration 
               
               
                   
                  ibm-slapdProxyPartitionIndex: 2 
               
               
                   
                  objectclass: top 
               
               
                   
                  objectclass: ibm-slapdConfigEntry 
               
               
                   
                  objectclass: ibm-slapdProxyBackendSplit 
               
               
                   
                   
               
             
          
         
       
     
     Table 1 shows an example of a proxy configuration file which an embodiment of the invention may generate, providing a command line option or other input requests such a file. The proxy configuration file is known in the art to specify the manner in which a proxy computer should direct traffic to a supporting set of computer or computers. 
     Generally, the proxy configuration file is derived from the setup configuration file. The first entry is the LDIF entry containing the connection information for the first server holding the first LDIF fragment. The second entry is the same, but for the second server. Thus, the first two entries describe to the proxy the ServerA and ServerB specified in the  FIG. 3 , and are found to the right hand side of ibm-slapdProxyTragetURL in each entry. A proxy configuration file varies in format from manufacturer to manufacturer. Suffice it that the proxy configuration file describes to the proxy server the logical interconnectivity and division of labor among the servers that jointly provide the directory information service. 
     The third entry is the top level entry for the o=ibm, c=us split point. It identifies the number of partitions, two, in the case of  FIG. 3 , and the baseDN. 
     The fourth entry represents the first portion of the split or partition between sibling nodes of the DIT prior to split. The fifth entry represents the second portion of the split. The attributes in the fourth and fifth entries mean the following. ibm-slapdProxyBackendServerDN refers to the entry that contains the connection information for a partition held by a backend server. ibm-slapdProxyPartitionIndex refers to an integer that uniquely identifies the partition. In our example, where there is two partitions, ibm-slapdProxyPartitionIndex may be 1 or 2, referring to the first partition portion of the DIT and to the second partition portion of the DIT, respectively. 
     In addition to a command line invocation, it is appreciated that the setup configuration file may provide a command to generate the proxy configuration file. For example the “ActionType” line in  FIG. 3 , may be assigned the value “SplitConfig” or similar text keyword that requests at least a proxy configuration file be generated alone or together with the generation of LDIF fragments. 
     The efficiency of the bulkload is realized in the present invention in that, in general, LDIF entries are aggregated into substantial LDIF fragments prior to loading into the distributed directory data structure of each backend server. Thus a much more rapid deployment of the distributed directory among several backend servers may be achieved as compared to the piecemeal methods of the past. 
     It is important to note that while the present invention has been described in the context of a fully functioning data processing system, those of ordinary skill in the art will appreciate that the processes of the present invention are capable of being distributed in the form of a computer readable medium of instructions and a variety of forms and that the present invention applies equally regardless of the particular type of signal bearing media actually used to carry out the distribution. Examples of computer readable media include recordable-type media, such as a floppy disk, a hard disk drive, a RAM, CD-ROMs, DVD-ROMs, and transmission-type media, such as digital and analog communications links, wired or wireless communications links using transmission forms, such as, for example, radio frequency and light wave transmissions. The computer readable media may take the form of coded formats that are decoded for actual use in a particular data processing system. 
     The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.