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     <h2 class="title">
      <a name="mysql-cluster-management">
      </a>
      25.6 Management of NDB Cluster
     </h2>
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   </div>
  </div>
  <div class="toc">
   <dl class="toc">
    <dt>
     <span class="section">
      <a href="mysql-cluster-mgm-client-commands.html">
       25.6.1 Commands in the NDB Cluster Management Client
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-logs-ndb-messages.html">
       25.6.2 NDB Cluster Log Messages
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-event-reports.html">
       25.6.3 Event Reports Generated in NDB Cluster
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-start-phases.html">
       25.6.4 Summary of NDB Cluster Start Phases
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-rolling-restart.html">
       25.6.5 Performing a Rolling Restart of an NDB Cluster
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-single-user-mode.html">
       25.6.6 NDB Cluster Single User Mode
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-online-add-node.html">
       25.6.7 Adding NDB Cluster Data Nodes Online
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-backup.html">
       25.6.8 Online Backup of NDB Cluster
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-importing-data.html">
       25.6.9 Importing Data Into MySQL Cluster
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-mysqld.html">
       25.6.10 MySQL Server Usage for NDB Cluster
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-disk-data.html">
       25.6.11 NDB Cluster Disk Data Tables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-online-operations.html">
       25.6.12 Online Operations with ALTER TABLE in NDB Cluster
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-privilege-synchronization.html">
       25.6.13 Privilege Synchronization and NDB_STORED_USER
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-tde.html">
       25.6.14 File System Encryption for NDB Cluster
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-tls.html">
       25.6.15 TLS Link Encryption for NDB Cluster
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-ndb-api-statistics.html">
       25.6.16 NDB API Statistics Counters and Variables
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-ndbinfo.html">
       25.6.17 ndbinfo: The NDB Cluster Information Database
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-information-schema-tables.html">
       25.6.18 INFORMATION_SCHEMA Tables for NDB Cluster
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-ps-tables.html">
       25.6.19 NDB Cluster and the Performance Schema
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-sql-statements.html">
       25.6.20 Quick Reference: NDB Cluster SQL Statements
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="mysql-cluster-security.html">
       25.6.21 NDB Cluster Security Issues
      </a>
     </span>
    </dt>
   </dl>
  </div>
  <a class="indexterm" name="idm46045094663792">
  </a>
  <a class="indexterm" name="idm46045094662304">
  </a>
  <p>
   Managing an NDB Cluster involves a number of tasks, the first of
    which is to configure and start NDB Cluster. This is covered in
   <a class="xref" href="mysql-cluster-configuration.html" title="25.4 Configuration of NDB Cluster">
    Section 25.4, “Configuration of NDB Cluster”
   </a>
   , and
   <a class="xref" href="mysql-cluster-programs.html" title="25.5 NDB Cluster Programs">
    Section 25.5, “NDB Cluster Programs”
   </a>
   .
  </p>
  <p>
   The next few sections cover the management of a running NDB Cluster.
  </p>
  <p>
   For information about security issues relating to management and
    deployment of an NDB Cluster, see
   <a class="xref" href="mysql-cluster-security.html" title="25.6.21 NDB Cluster Security Issues">
    Section 25.6.21, “NDB Cluster Security Issues”
   </a>
   .
  </p>
  <p>
   There are essentially two methods of actively managing a running NDB
    Cluster. The first of these is through the use of commands entered
    into the management client whereby cluster status can be checked,
    log levels changed, backups started and stopped, and nodes stopped
    and started. The second method involves studying the contents of the
    cluster log
   <code class="filename">
    ndb_
    <em class="replaceable">
     <code>
      node_id
     </code>
    </em>
    _cluster.log
   </code>
   ;
    this is usually found in the management server's
   <a class="link" href="mysql-cluster-mgm-definition.html#ndbparam-mgmd-datadir">
    <code class="literal">
     DataDir
    </code>
   </a>
   directory, but this
    location can be overridden using the
   <a class="link" href="mysql-cluster-mgm-definition.html#ndbparam-mgmd-logdestination">
    <code class="literal">
     LogDestination
    </code>
   </a>
   option.
    (Recall that
   <em class="replaceable">
    <code>
     node_id
    </code>
   </em>
   represents the
    unique identifier of the node whose activity is being logged.) The
    cluster log contains event reports generated by
   <a class="link" href="mysql-cluster-programs-ndbd.html" title="25.5.1 ndbd — The NDB Cluster Data Node Daemon">
    <span class="command">
     <strong>
      ndbd
     </strong>
    </span>
   </a>
   . It is also possible to send cluster log
    entries to a Unix system log.
  </p>
  <p>
   Some aspects of the cluster's operation can be also be
    monitored from an SQL node using the
   <a class="link" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
    <code class="literal">
     SHOW ENGINE NDB
    STATUS
    </code>
   </a>
   statement.
  </p>
  <p>
   More detailed information about NDB Cluster operations is available
    in real time through an SQL interface using the
   <a class="link" href="mysql-cluster-ndbinfo.html" title="25.6.17 ndbinfo: The NDB Cluster Information Database">
    <code class="literal">
     ndbinfo
    </code>
   </a>
   database. For more
    information, see
   <a class="xref" href="mysql-cluster-ndbinfo.html" title="25.6.17 ndbinfo: The NDB Cluster Information Database">
    Section 25.6.17, “ndbinfo: The NDB Cluster Information Database”
   </a>
   .
  </p>
  <p>
   NDB statistics counters provide improved monitoring using the
   <a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
    <span class="command">
     <strong>
      mysql
     </strong>
    </span>
   </a>
   client. These counters, implemented in the
    NDB kernel, relate to operations performed by or affecting
   <a class="ulink" href="/doc/ndbapi/en/ndb-ndb.html" target="_top">
    <code class="literal">
     Ndb
    </code>
   </a>
   objects, such as starting,
    closing, and aborting transactions; primary key and unique key
    operations; table, range, and pruned scans; blocked threads waiting
    for various operations to complete; and data and events sent and
    received by NDB Cluster. The counters are incremented by the NDB
    kernel whenever NDB API calls are made or data is sent to or
    received by the data nodes.
  </p>
  <p>
   <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
    <span class="command">
     <strong>
      mysqld
     </strong>
    </span>
   </a>
   exposes the NDB API statistics counters as
    system status variables, which can be identified from the prefix
    common to all of their names (
   <code class="literal">
    Ndb_api_
   </code>
   ). The
    values of these variables can be read in the
   <a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
    <span class="command">
     <strong>
      mysql
     </strong>
    </span>
   </a>
   client from the output of a
   <a class="link" href="show-status.html" title="15.7.7.37 SHOW STATUS Statement">
    <code class="literal">
     SHOW STATUS
    </code>
   </a>
   statement, or by querying
    either the Performance Schema
   <a class="link" href="performance-schema-status-variable-tables.html" title="29.12.15 Performance Schema Status Variable Tables">
    <code class="literal">
     session_status
    </code>
   </a>
   or
   <a class="link" href="performance-schema-status-variable-tables.html" title="29.12.15 Performance Schema Status Variable Tables">
    <code class="literal">
     global_status
    </code>
   </a>
   table. By comparing the
    values of the status variables before and after the execution of an
    SQL statement that acts on
   <a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
    <code class="literal">
     NDB
    </code>
   </a>
   tables,
    you can observe the actions taken on the NDB API level that
    correspond to this statement, which can be beneficial for monitoring
    and performance tuning of NDB Cluster.
  </p>
  <p>
   MySQL Cluster Manager provides an advanced command-line interface that simplifies
    many otherwise complex NDB Cluster management tasks, such as
    starting, stopping, or restarting an NDB Cluster with a large number
    of nodes. The MySQL Cluster Manager client also supports commands for getting and
    setting the values of most node configuration parameters as well as
   <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
    <span class="command">
     <strong>
      mysqld
     </strong>
    </span>
   </a>
   server options and variables relating to
    NDB Cluster. See
   <a class="ulink" href="/doc/mysql-cluster-manager/8.4/en/" target="_top">
    MySQL Cluster Manager 8.4.3 User Manual
   </a>
   , for more information.
  </p>
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