DS 7.4.0

LDAP-based monitoring

This page covers the LDAP interfaces for monitoring DS servers. For the same capabilities over HTTP, refer to HTTP-based monitoring.

DS servers publish whether the server is alive and able to handle requests in the root DSE. They publish monitoring information over LDAP under the entry cn=monitor.

The following example reads all available monitoring entries:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN cn=monitor \
 "(&)"

The monitoring entries under cn=monitor reflect activity since the server started.

Many types of metrics are exposed. For details, refer to LDAP metrics reference.

Basic availability

Server health (LDAP)

Anonymous clients can monitor the health status of the DS server by reading the alive attribute of the root DSE:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --baseDN "" \
 --searchScope base \
 "(&)" \
 alive

dn:
alive: true

When alive is true, the server’s internal tests have not found any errors requiring administrative action. When it is false, fix the errors and either restart or replace the server.

If the server returns false for this attribute, get error information, as described in Server health details (LDAP).

Server health details (LDAP)

The default monitor user can check whether the server is alive and able to handle requests on cn=health status,cn=monitor:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN "cn=health status,cn=monitor" \
 --searchScope base \
 "(&)"

dn: cn=health status,cn=monitor
ds-mon-alive: true
ds-mon-healthy: true
objectClass: top
objectClass: ds-monitor
objectClass: ds-monitor-health-status
cn: health status

When the server is either not alive or not able to handle requests, this entry includes error diagnostics as strings on the ds-mon-alive-errors and ds-mon-healthy-errors attributes.

Activity

Active users (LDAP)

DS server connection handlers respond to client requests. The following example uses the default monitor user account to read the metrics about active connections on each connection handler:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN cn=monitor \
 "(objectClass=ds-monitor-connection*)" \
 ds-mon-active-connections-count ds-mon-active-persistent-searches ds-mon-connection ds-mon-listen-address

For details about the content of metrics returned, refer to Metric types reference.

Request statistics (LDAP)

DS server connection handlers respond to client requests. The following example uses the default monitor user account to read statistics about client operations on each of the available connection handlers:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN "cn=connection handlers,cn=monitor" \
 "(&)"

For details about the content of metrics returned, refer to Metric types reference.

Work queue (LDAP)

DS servers have a work queue to track request processing by worker threads, and whether the server has rejected any requests due to a full queue. If enough worker threads are available, then no requests are rejected. The following example uses the default monitor user account to read statistics about the work queue:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN "cn=work queue,cn=monitor" \
 "(&)"

For details about the content of metrics returned, refer to Metric types reference. To adjust the number of worker threads, refer to the settings for Traditional Work Queue.

Counts

ACIs (LDAP)

DS maintains counts of ACIs:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN cn=monitor \
 "(objectClass=ds-monitor-aci)" \
 ds-mon-entries-acis-count ds-mon-entries-with-aci-attributes-count ds-mon-global-acis-count

Database size (LDAP)

DS servers maintain counts of the number of entries in each backend and under each base DN. The following example uses the default monitor user account to read the counts:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN cn=monitor \
 "(|(ds-mon-backend-entry-count=*)(ds-mon-base-dn-entry-count=*))" \
 ds-mon-backend-entry-count ds-mon-base-dn-entry-count

Entry caches (LDAP)

DS servers maintain entry cache statistics:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN cn=monitor \
 "(objectClass=ds-monitor-entry-cache)" \

Entry caches for groups have their own monitoring entries.

Groups (LDAP)

The following example reads counts of static, dynamic, and virtual static groups, and statistics on the distribution of static group size:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN cn=monitor \
 "(objectClass=ds-monitor-groups)" \
 ds-mon-dynamic-groups-count ds-mon-static-groups-count ds-mon-virtual-static-groups-count \
 ds-mon-static-group-size-less-or-equal-to-100 \
 ds-mon-static-group-size-less-or-equal-to-1000 \
 ds-mon-static-group-size-less-or-equal-to-10000 \
 ds-mon-static-group-size-less-or-equal-to-100000 \
 ds-mon-static-group-size-less-or-equal-to-1000000 \
 ds-mon-static-group-size-less-or-equal-to-inf

At startup time, DS servers log a message showing the number of different types of groups and the memory allocated to cache static groups.

Subentries (LDAP)

DS maintains counts of LDAP subentries:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN cn=monitor \
 "(objectClass=ds-monitor-subentries)" \
 ds-mon-collective-attribute-subentries-count \
 ds-mon-password-policy-subentries-count

Indexing

Index use (LDAP)

DS maintains metrics about index use. The metrics indicate how often an index was accessed since the DS server started.

The following example demonstrates how to read the metrics for all monitored indexes:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN cn=monitor \
 "(objectClass=ds-monitor-backend-index)" ds-mon-index ds-mon-index-uses

Index cost (LDAP)

DS maintains metrics about index cost. The metrics count the number of updates and how long they took since the DS server started.

The following example demonstrates how to read the metrics for all monitored indexes:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN cn=monitor \
 "(objectClass=ds-monitor-backend-index)" ds-mon-index ds-mon-index-cost

Logging

DS maintains a list of supported logging categories. The following example reads the list:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN cn=monitor \
 "(objectClass=ds-monitor-logging)"

Replication

Monitor the following to ensure replication runs smoothly. Take action as described in these sections and in the troubleshooting documentation for replication problems.

Replication delay (LDAP)

The following example uses the default monitor user account to check the delay in replication:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN cn=monitor \
 "(ds-mon-receive-delay=*)" \
 ds-mon-receive-delay

dn: ds-mon-domain-name=cn=schema,cn=replicas,cn=replication,cn=monitor
ds-mon-receive-delay: <delay>

dn: ds-mon-domain-name=dc=example\,dc=com,cn=replicas,cn=replication,cn=monitor
ds-mon-receive-delay: <delay>

dn: ds-mon-domain-name=uid=monitor,cn=replicas,cn=replication,cn=monitor
ds-mon-receive-delay: <delay>

DS replicas measure replication delay as the local delay when receiving and replaying changes. A replica calculates these local delays based on changes received from other replicas. Therefore, a replica can only calculate delays based on changes it has received. Network outages cause inaccuracy in delay metrics.

A replica calculates delay metrics based on times reflecting the following events:

  • t0: the remote replica records the change in its data

  • t1: the remote replica sends the change to a replica server

  • t2: the local replica receives the change from a replica server

  • t3: the local replica applies the change to its data

This figure illustrates when these events occur:

repl-delay

Replication keeps track of changes using change sequence numbers (CSNs), opaque and unique identifiers for each change that indicate when and where each change first occurred. The tn values are CSNs.

When the CSNs for the last change received and the last change replayed are identical, the replica has applied all the changes it has received. In this case, there is no known delay. The receive and replay delay metrics are set to 0 (zero).

When the last received and last replayed CSNs differ:

  • Receive delay is set to the time t2 - t0 for the last change received.

    Another name for receive delay is current delay.

  • Replay delay is approximately t3 - t2 for the last change replayed. In other words, it is an approximation of how long it took the last change to be replayed.

As long as replication delay tends toward zero regularly and over the long term, temporary spikes and increases in delay measurements are normal. When all replicas remain connected and yet replication delay remains high and increases over the long term, the high replication delay indicates a problem. Steadily high and increasing replication delay shows that replication is not converging, and the service is failing to achieve eventual consistency.

For a current snapshot of replication delays, you can also use the dsrepl status command. For details, refer to Replication status.

Replication status (LDAP)

The following example uses the default monitor user account to check the replication status of the local replica:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN cn=monitor \
 "(ds-mon-status=*)" \
 ds-mon-status

dn: ds-mon-domain-name=dc=example\,dc=com,cn=replicas,cn=replication,cn=monitor
ds-mon-status: Normal

If the status is not Normal, how you react depends on the value of the ds-mon-status attribute for LDAP, or ds_replication_replica_status{status} for Prometheus:

Status Explanation Actions to Take

Bad data

Replication is broken.

Internally, DS replicas store a shorthand form of the initial state called a generation ID. The generation ID is a hash of the first 1000 entries in a backend. If the replicas' generation IDs match, the servers can replicate data without user intervention. If the replicas' generation IDs do not match for a given backend, you must manually initialize replication between them to force the same initial state on all replicas.

This status arises for one of the following reasons:

  • The replica and the replication server have different generation IDs for the data because the replica was not initialized with the same data as its peer replicas.

  • The fractional replication configuration for this replica does not match the backend data. For example, you reconfigured fractional replication to include or exclude different attributes, or you configured fractional replication in an incompatible way on different peer replicas.

DS 7.3 introduced this status. Earlier releases included this state as part of the Bad generation id status.

Whenever this status displays:

  1. If fractional replication is configured, make sure the configuration is compatible on all peer replicas.

    For details, refer to Fractional replication (advanced).

  2. Reinitialize replication to fix the bad generation IDs.

    For details, refer to Manual initialization.

Full update

Replication is operating normally.

You have chosen to initialize replication over the network.

The time to complete the operation depends on the network bandwidth and volume of data to synchronize.

Monitor the server output and wait for initialization to complete.

Invalid

This status arises for one of the following reasons:

  • The replica has encountered a replication protocol error. This status can arise due to faulty network communication between the replica and the replication server.

  • The replica has just started, and is initializing.

If this status happens during normal operation:

  1. Review the replica and replication server error logs, described in About logs, for network-related replication error messages.

  2. Independently verify network communication between the replica and the replication server systems.

Normal

Replication is operating normally.

Nothing to do.

Not connected

This status arises for one of the following reasons:

  • The replica has just started and is not yet connected to the replication server.

  • The replica cannot connect to a replication server.

If this status happens during normal operation:

  1. Review the replica and replication server error logs for network-related replication error messages.

  2. Independently verify network communication between the replica and the replication server systems.

Too late

The replica has fallen further behind the replication server than allowed by the replication-purge-delay. In other words, the replica is missing too many changes, and lacks the historical information required to synchronize with peer replicas.

The replica no longer receives updates from replication servers. Other replicas that recognize this status stop returning referrals to this replica.

DS 7.3 introduced this status. Earlier releases included this state as part of the Bad generation id status.

Whenever this status displays:

  1. Reinitialize replication for the replica that is too late.

    For details, refer to Manual initialization.

Change number indexing (LDAP)

DS replication servers maintain a changelog database to record updates to directory data. The changelog database serves to:

  • Replicate changes, synchronizing data between replicas.

  • Let client applications get change notifications.

DS replication servers purge historical changelog data after the replication-purge-delay in the same way replicas purge their historical data.

Client applications can get changelog notifications using cookies (recommended) or change numbers.

To support change numbers, the servers maintain a change number index to the replicated changes. A replication server maintains the index when its configuration properties include changelog-enabled:enabled. (Cookie-based notifications do not require a change number index.)

The change number indexer must not be interrupted for long. Interruptions can arise when, for example, a DS server:

  • Stays out of contact, not sending any updates or heartbeats.

  • Gets removed without being shut down cleanly.

  • Gets lost in a system crash.

Interruptions prevent the change number indexer from advancing. When a change number indexer cannot advance for almost as long as the purge delay, it may be unable to recover as the servers purge historical data needed to determine globally consistent change numbers.

The following example uses the default monitor user account to check the state of change number indexing:

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=monitor \
 --bindPassword password \
 --baseDN "cn=changelog,cn=replication,cn=monitor" \
 "(objectClass=ds-monitor-change-number-indexing)" \
 ds-mon-indexing-state ds-mon-time-since-last-indexing ds-mon-replicas-preventing-indexing

dn: cn=change number indexing,cn=changelog,cn=replication,cn=monitor
ds-mon-indexing-state: INDEXING
ds-mon-time-since-last-indexing: 0

When ds-mon-indexing-state: BLOCKED_BY_REPLICA_NOT_IN_TOPOLOGY or ds-mon-indexing-state: WAITING_ON_UPDATE_FROM_REPLICA, refer to ds-mon-time-since-last-indexing for the wait time in milliseconds and to ds-mon-replicas-preventing-indexing for the list of problem servers.

Monitor privilege

The following example assigns the required privilege to Kirsten Vaughan’s entry to read monitoring data, and shows monitoring information for the backend holding Example.com data:

$ ldapmodify \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=admin \
 --bindPassword password << EOF
dn: uid=kvaughan,ou=People,dc=example,dc=com
changetype: modify
add: ds-privilege-name
ds-privilege-name: monitor-read
EOF

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=kvaughan,ou=People,dc=example,dc=com \
 --bindPassword bribery \
 --baseDN cn=monitor \
 "(ds-cfg-backend-id=dsEvaluation)"

dn: ds-cfg-backend-id=dsEvaluation,cn=backends,cn=monitor
objectClass: top
objectClass: ds-monitor
objectClass: ds-monitor-backend
objectClass: ds-monitor-backend-pluggable
objectClass: ds-monitor-backend-db
ds-cfg-backend-id: dsEvaluation
ds-mon-backend-degraded-index-count: <number>
ds-mon-backend-entry-count: <number>
ds-mon-backend-entry-size-read: <json>
ds-mon-backend-entry-size-written: <json>
ds-mon-backend-filter-indexed: <number>
ds-mon-backend-filter-unindexed: <number>
ds-mon-backend-filter-use-start-time: <timestamp>
ds-mon-backend-is-private: <boolean>
ds-mon-backend-ttl-entries-deleted: <json>
ds-mon-backend-ttl-is-running: <boolean>
ds-mon-backend-ttl-last-run-time: <timestamp>
ds-mon-backend-ttl-queue-size: <number>
ds-mon-backend-ttl-thread-count: <number>
ds-mon-backend-writability-mode: enabled
ds-mon-db-cache-evict-internal-nodes-count: <number>
ds-mon-db-cache-evict-leaf-nodes-count: <number>
ds-mon-db-cache-leaf-nodes: <boolean>
ds-mon-db-cache-misses-internal-nodes: <number>
ds-mon-db-cache-misses-leaf-nodes: <number>
ds-mon-db-cache-size-active: <number>
ds-mon-db-cache-size-total: <number>
ds-mon-db-cache-total-tries-internal-nodes: <number>
ds-mon-db-cache-total-tries-leaf-nodes: <number>
ds-mon-db-checkpoint-count: <number>
ds-mon-db-log-cleaner-file-deletion-count: <number>
ds-mon-db-log-files-open: <number>
ds-mon-db-log-files-opened: <number>
ds-mon-db-log-size-active: <number>
ds-mon-db-log-size-total: <number>
ds-mon-db-log-utilization-max: <number>
ds-mon-db-log-utilization-min: <number>
ds-mon-db-version: <version>
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