samba-mirror/ctdb/doc/ctdb-script.options.5.xml

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<refentry id="ctdb-script.options.5">

  <refmeta>
    <refentrytitle>ctdb-script.options</refentrytitle>
    <manvolnum>5</manvolnum>
    <refmiscinfo class="source">ctdb</refmiscinfo>
    <refmiscinfo class="manual">CTDB - clustered TDB database</refmiscinfo>
  </refmeta>

  <refnamediv>
    <refname>ctdb-script.options</refname>
    <refpurpose>CTDB scripts configuration files</refpurpose>
  </refnamediv>

  <refsect1>
    <title>DESCRIPTION</title>

    <para>
      Each CTDB script has 2 possible locations for its configuration options:
    </para>

    <variablelist>

      <varlistentry>
	<term>
	  <filename>/usr/local/etc/ctdb/script.options</filename>
	</term>
	<listitem>
	  <para>
	    This is a catch-all global file for general purpose
	    scripts and for options that are used in multiple event
	    scripts.
	  </para>
	</listitem>
      </varlistentry>

      <varlistentry>
	<term>
	  <parameter>SCRIPT</parameter>.options
	</term>
	<listitem>
	  <para>
	    That is, options for
	    <filename><parameter>SCRIPT</parameter></filename> are
	    placed in a file alongside the script, with a ".script"
	    suffix added.  This style is usually recommended for event
	    scripts.
	  </para>

	  <para>
	    Options in this script-specific file override those in
	    the global file.
	  </para>
	</listitem>
      </varlistentry>

    </variablelist>

    <para>
      These files should include simple shell-style variable
      assignments and shell-style comments.
    </para>

  </refsect1>

  <refsect1>
    <title>NETWORK CONFIGURATION</title>

    <refsect2>
      <title>10.interface</title>

      <para>
	This event script handles monitoring of interfaces using by
	public IP addresses.
      </para>

      <variablelist>

	<varlistentry>
	  <term>
	    CTDB_PARTIALLY_ONLINE_INTERFACES=yes|no
	  </term>
	  <listitem>
	    <para>
	      Whether one or more offline interfaces should cause a
	      monitor event to fail if there are other interfaces that
	      are up.  If this is "yes" and a node has some interfaces
	      that are down then <command>ctdb status</command> will
	      display the node as "PARTIALLYONLINE".
	    </para>

	    <para>
	      Note that CTDB_PARTIALLY_ONLINE_INTERFACES=yes is not
	      generally compatible with NAT gateway or LVS.  NAT
	      gateway relies on the interface configured by
	      CTDB_NATGW_PUBLIC_IFACE to be up and LVS replies on
	      CTDB_LVS_PUBLIC_IFACE to be up.  CTDB does not check if
	      these options are set in an incompatible way so care is
	      needed to understand the interaction.
	    </para>

	    <para>
	      Default is "no".
	    </para>
	  </listitem>
	</varlistentry>

      </variablelist>
    </refsect2>

    <refsect2>
      <title>11.natgw</title>

      <para>
	Provides CTDB's NAT gateway functionality.
      </para>

      <para>
	NAT gateway is used to configure fallback routing for nodes
	when they do not host any public IP addresses.  For example,
	it allows unhealthy nodes to reliably communicate with
	external infrastructure.  One node in a NAT gateway group will
	be designated as the NAT gateway leader node and other (follower)
	nodes will be configured with fallback routes via the NAT
	gateway leader node.  For more information, see the
	<citetitle>NAT GATEWAY</citetitle> section in
	<citerefentry><refentrytitle>ctdb</refentrytitle>
	<manvolnum>7</manvolnum></citerefentry>.
      </para>

      <variablelist>

	<varlistentry>
	  <term>CTDB_NATGW_DEFAULT_GATEWAY=<parameter>IPADDR</parameter></term>
	  <listitem>
	    <para>
	      IPADDR is an alternate network gateway to use on the NAT
	      gateway leader node.  If set, a fallback default route
	      is added via this network gateway.
	    </para>
	    <para>
	      No default.  Setting this variable is optional - if not
	      set that no route is created on the NAT gateway leader
	      node.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>CTDB_NATGW_NODES=<parameter>FILENAME</parameter></term>
	  <listitem>
	    <para>
	      FILENAME contains the list of nodes that belong to the
	      same NAT gateway group.
	    </para>
	    <para>
	      File format:
	      <screen>
<parameter>IPADDR</parameter> <optional>follower-only</optional>
	      </screen>
	    </para>
	    <para>
	      IPADDR is the private IP address of each node in the NAT
	      gateway group.
	    </para>
	    <para>
	      If "follower-only" is specified then the corresponding node
	      can not be the NAT gateway leader node.  In this case
	      <varname>CTDB_NATGW_PUBLIC_IFACE</varname> and
	      <varname>CTDB_NATGW_PUBLIC_IP</varname> are optional and
	      unused.
	    </para>
	    <para>
	      No default, usually
	      <filename>/usr/local/etc/ctdb/natgw_nodes</filename> when enabled.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>CTDB_NATGW_PRIVATE_NETWORK=<parameter>IPADDR/MASK</parameter></term>
	  <listitem>
	    <para>
	      IPADDR/MASK is the private sub-network that is
	      internally routed via the NAT gateway leader node.  This
	      is usually the private network that is used for node
	      addresses.
	    </para>
	    <para>
	      No default.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>CTDB_NATGW_PUBLIC_IFACE=<parameter>IFACE</parameter></term>
	  <listitem>
	    <para>
	      IFACE is the network interface on which the
	      CTDB_NATGW_PUBLIC_IP will be configured.
	    </para>
	    <para>
	      No default.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>CTDB_NATGW_PUBLIC_IP=<parameter>IPADDR/MASK</parameter></term>
	  <listitem>
	    <para>
	      IPADDR/MASK indicates the IP address that is used for
	      outgoing traffic (originating from
	      CTDB_NATGW_PRIVATE_NETWORK) on the NAT gateway leader
	      node.  This <emphasis>must not</emphasis> be a
	      configured public IP address.
	    </para>
	    <para>
	      No default.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>CTDB_NATGW_STATIC_ROUTES=<parameter>IPADDR/MASK[@GATEWAY]</parameter> ...</term>
	  <listitem>
	    <para>
	      Each IPADDR/MASK identifies a network or host to which
	      NATGW should create a fallback route, instead of
	      creating a single default route.  This can be used when
	      there is already a default route, via an interface that
	      can not reach required infrastructure, that overrides
	      the NAT gateway default route.
	    </para>
	    <para>
	      If GATEWAY is specified then the corresponding route on
	      the NATGW leader node will be via GATEWAY.  Such routes
	      are created even if
	      <varname>CTDB_NATGW_DEFAULT_GATEWAY</varname> is not
	      specified.  If GATEWAY is not specified for some
	      networks then routes are only created on the NATGW
	      leader node for those networks if
	      <varname>CTDB_NATGW_DEFAULT_GATEWAY</varname> is
	      specified.
	    </para>
	    <para>
	      This should be used with care to avoid causing traffic
	      to unnecessarily double-hop through the NAT gateway
	      leader, even when a node is hosting public IP addresses.
	      Each specified network or host should probably have a
	      corresponding automatically created link route or static
	      route to avoid this.
	    </para>
	    <para>
	      No default.
	    </para>
	  </listitem>
	</varlistentry>

      </variablelist>

      <refsect3>
	<title>Example</title>
	<screen>
CTDB_NATGW_NODES=/usr/local/etc/ctdb/natgw_nodes
CTDB_NATGW_PRIVATE_NETWORK=192.168.1.0/24
CTDB_NATGW_DEFAULT_GATEWAY=10.0.0.1
CTDB_NATGW_PUBLIC_IP=10.0.0.227/24
CTDB_NATGW_PUBLIC_IFACE=eth0
	</screen>

	<para>
	  A variation that ensures that infrastructure (ADS, DNS, ...)
	  directly attached to the public network (10.0.0.0/24) is
	  always reachable would look like this:
	</para>
	<screen>
CTDB_NATGW_NODES=/usr/local/etc/ctdb/natgw_nodes
CTDB_NATGW_PRIVATE_NETWORK=192.168.1.0/24
CTDB_NATGW_PUBLIC_IP=10.0.0.227/24
CTDB_NATGW_PUBLIC_IFACE=eth0
CTDB_NATGW_STATIC_ROUTES=10.0.0.0/24
	</screen>
	<para>
	  Note that <varname>CTDB_NATGW_DEFAULT_GATEWAY</varname> is
	  not specified.
	</para>
      </refsect3>

    </refsect2>

    <refsect2>
      <title>13.per_ip_routing</title>

      <para>
	Provides CTDB's policy routing functionality.
      </para>

      <para>
	A node running CTDB may be a component of a complex network
	topology.  In particular, public addresses may be spread
	across several different networks (or VLANs) and it may not be
	possible to route packets from these public addresses via the
	system's default route.  Therefore, CTDB has support for
	policy routing via the <filename>13.per_ip_routing</filename>
	eventscript.  This allows routing to be specified for packets
	sourced from each public address.  The routes are added and
	removed as CTDB moves public addresses between nodes.
      </para>

      <para>
	For more information, see the <citetitle>POLICY
	ROUTING</citetitle> section in
	<citerefentry><refentrytitle>ctdb</refentrytitle>
	<manvolnum>7</manvolnum></citerefentry>.
      </para>

      <variablelist>
	<varlistentry>
	  <term>CTDB_PER_IP_ROUTING_CONF=<parameter>FILENAME</parameter></term>
	  <listitem>
	    <para>
	      FILENAME contains elements for constructing the desired
	      routes for each source address.
	    </para>

	    <para>
	      The special FILENAME value
	      <constant>__auto_link_local__</constant> indicates that no
	      configuration file is provided and that CTDB should
	      generate reasonable link-local routes for each public IP
	      address.
	    </para>

	    <para>
	      File format:
	      <screen>
		<parameter>IPADDR</parameter> <parameter>DEST-IPADDR/MASK</parameter> <optional><parameter>GATEWAY-IPADDR</parameter></optional>
	      </screen>
	    </para>

	    <para>
	      No default, usually
	      <filename>/usr/local/etc/ctdb/policy_routing</filename>
	      when enabled.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>
	    CTDB_PER_IP_ROUTING_RULE_PREF=<parameter>NUM</parameter>
	  </term>
	<listitem>
	  <para>
	    NUM sets the priority (or preference) for the routing
	    rules that are added by CTDB.
	  </para>

	  <para>
	    This should be (strictly) greater than 0 and (strictly)
	    less than 32766.  A priority of 100 is recommended, unless
	    this conflicts with a priority already in use on the
	    system.  See
	    <citerefentry><refentrytitle>ip</refentrytitle>
	    <manvolnum>8</manvolnum></citerefentry>, for more details.
	  </para>
	</listitem>
	</varlistentry>

	<varlistentry>
	  <term>
	    CTDB_PER_IP_ROUTING_TABLE_ID_LOW=<parameter>LOW-NUM</parameter>,
	    CTDB_PER_IP_ROUTING_TABLE_ID_HIGH=<parameter>HIGH-NUM</parameter>
	  </term>
	  <listitem>
	    <para>
	      CTDB determines a unique routing table number to use for
	      the routing related to each public address.  LOW-NUM and
	      HIGH-NUM indicate the minimum and maximum routing table
	      numbers that are used.
	    </para>

	    <para>
	      <citerefentry><refentrytitle>ip</refentrytitle>
	      <manvolnum>8</manvolnum></citerefentry> uses some
	      reserved routing table numbers below 255.  Therefore,
	      CTDB_PER_IP_ROUTING_TABLE_ID_LOW should be (strictly)
	      greater than 255.
	    </para>

	    <para>
	      CTDB uses the standard file
	      <filename>/etc/iproute2/rt_tables</filename> to maintain
	      a mapping between the routing table numbers and labels.
	      The label for a public address
	      <replaceable>ADDR</replaceable> will look like
	      ctdb.<replaceable>addr</replaceable>.  This means that
	      the associated rules and routes are easy to read (and
	      manipulate).
	    </para>

	    <para>
	      No default, usually 1000 and 9000.
	    </para>
	  </listitem>
	</varlistentry>
      </variablelist>

      <refsect3>
	<title>Example</title>
	<screen>
CTDB_PER_IP_ROUTING_CONF=/usr/local/etc/ctdb/policy_routing
CTDB_PER_IP_ROUTING_RULE_PREF=100
CTDB_PER_IP_ROUTING_TABLE_ID_LOW=1000
CTDB_PER_IP_ROUTING_TABLE_ID_HIGH=9000
	</screen>
      </refsect3>

    </refsect2>

    <refsect2>
      <title>91.lvs</title>

      <para>
	Provides CTDB's LVS functionality.
      </para>

      <para>
	For a general description see the <citetitle>LVS</citetitle>
	section in <citerefentry><refentrytitle>ctdb</refentrytitle>
	<manvolnum>7</manvolnum></citerefentry>.
      </para>

      <variablelist>

	<varlistentry>
	  <term>
	    CTDB_LVS_NODES=<parameter>FILENAME</parameter>
	  </term>
	  <listitem>
	    <para>
	      FILENAME contains the list of nodes that belong to the
	      same LVS group.
	    </para>
	    <para>
	      File format:
	      <screen>
<parameter>IPADDR</parameter> <optional>follower-only</optional>
	      </screen>
	    </para>
	    <para>
	      IPADDR is the private IP address of each node in the LVS
	      group.
	    </para>
	    <para>
	      If "follower-only" is specified then the corresponding node
	      can not be the LVS leader node.  In this case
	      <varname>CTDB_LVS_PUBLIC_IFACE</varname> and
	      <varname>CTDB_LVS_PUBLIC_IP</varname> are optional and
	      unused.
	    </para>
	    <para>
	      No default, usually
	      <filename>/usr/local/etc/ctdb/lvs_nodes</filename> when enabled.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>
	    CTDB_LVS_PUBLIC_IFACE=<parameter>INTERFACE</parameter>
	  </term>
	  <listitem>
	    <para>
	      INTERFACE is the network interface that clients will use
	      to connection to <varname>CTDB_LVS_PUBLIC_IP</varname>.
	      This is optional for follower-only nodes.
	      No default.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>
	    CTDB_LVS_PUBLIC_IP=<parameter>IPADDR</parameter>
	  </term>
	  <listitem>
	    <para>
	      CTDB_LVS_PUBLIC_IP is the LVS public address.  No
	      default.
	  </para>
	  </listitem>
	</varlistentry>

      </variablelist>
    </refsect2>

  </refsect1>

  <refsect1>
    <title>SERVICE CONFIGURATION</title>

    <para>
      CTDB can be configured to manage and/or monitor various NAS (and
      other) services via its eventscripts.
    </para>

    <para>
      In the simplest case CTDB will manage a service.  This means the
      service will be started and stopped along with CTDB, CTDB will
      monitor the service and CTDB will do any required
      reconfiguration of the service when public IP addresses are
      failed over.
    </para>

    <refsect2>
      <title>20.multipathd</title>

      <para>
	Provides CTDB's Linux multipathd service management.
      </para>

      <para>
	It can monitor multipath devices to ensure that active paths
	are available.
      </para>

      <variablelist>
	<varlistentry>
	  <term>
	    CTDB_MONITOR_MPDEVICES=<parameter>MP-DEVICE-LIST</parameter>
	  </term>
	  <listitem>
	    <para>
	      MP-DEVICE-LIST is a list of multipath devices for CTDB to monitor?
	    </para>
	    <para>
	      No default.
	    </para>
	  </listitem>
	</varlistentry>
      </variablelist>
    </refsect2>

    <refsect2>
      <title>31.clamd</title>

      <para>
	This event script provide CTDB's ClamAV anti-virus service
	management.
      </para>

      <para>
	This eventscript is not enabled by default.  Use <command>ctdb
	enablescript</command> to enable it.
      </para>

      <variablelist>

	<varlistentry>
	  <term>
	    CTDB_CLAMD_SOCKET=<parameter>FILENAME</parameter>
	  </term>
	  <listitem>
	    <para>
	      FILENAME is the socket to monitor ClamAV.
	    </para>
	    <para>
	      No default.
	    </para>
	  </listitem>
	</varlistentry>

      </variablelist>

    </refsect2>

    <refsect2>
      <title>48.netbios</title>

      <para>
	Provides CTDB's NetBIOS service management.
      </para>

      <variablelist>
	<varlistentry>
	  <term>
	    CTDB_SERVICE_NMB=<parameter>SERVICE</parameter>
	  </term>
	  <listitem>
	    <para>
	      Distribution specific SERVICE for managing nmbd.
	    </para>
	    <para>
	      Default is distribution-dependant.
	    </para>
	  </listitem>
	</varlistentry>

      </variablelist>

    </refsect2>

    <refsect2>
      <title>49.winbind</title>

      <para>
	Provides CTDB's Samba winbind service management.
      </para>

      <variablelist>

	<varlistentry>
	  <term>
	    CTDB_SERVICE_WINBIND=<parameter>SERVICE</parameter>
	  </term>
	  <listitem>
	    <para>
	      Distribution specific SERVICE for managing winbindd.
	    </para>
	    <para>
	      Default is "winbind".
	    </para>
	  </listitem>
	</varlistentry>

      </variablelist>

    </refsect2>

    <refsect2>
      <title>50.samba</title>

      <para>
	Provides the core of CTDB's Samba file service management.
      </para>

      <variablelist>

	<varlistentry>
	  <term>
	    CTDB_SAMBA_CHECK_PORTS=<parameter>PORT-LIST</parameter>
	  </term>
	  <listitem>
	    <para>
	      When monitoring Samba, check TCP ports in
	      space-separated PORT-LIST.
	    </para>
	    <para>
	      Default is to monitor ports that Samba is configured to listen on.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>
	    CTDB_SAMBA_SKIP_SHARE_CHECK=yes|no
	  </term>
	  <listitem>
	    <para>
	      As part of monitoring, should CTDB skip the check for
	      the existence of each directory configured as share in
	      Samba.  This may be desirable if there is a large number
	      of shares.
	    </para>
	    <para>
	      Default is no.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>
	    CTDB_SERVICE_SMB=<parameter>SERVICE</parameter>
	  </term>
	  <listitem>
	    <para>
	      Distribution specific SERVICE for managing smbd.
	    </para>
	    <para>
	      Default is distribution-dependant.
	    </para>
	  </listitem>
	</varlistentry>

      </variablelist>

    </refsect2>

    <refsect2>
      <title>60.nfs</title>

      <para>
	This event script (along with 06.nfs) provides CTDB's NFS
	service management.
      </para>

      <para>
	This includes parameters for the kernel NFS server.
	Alternative NFS subsystems (such as <ulink
	url="https://github.com/nfs-ganesha/nfs-ganesha/wiki">NFS-Ganesha</ulink>)
	can be integrated using <varname>CTDB_NFS_CALLOUT</varname>.
      </para>

      <variablelist>

	<varlistentry>
	  <term>
	    CTDB_NFS_CALLOUT=<parameter>COMMAND</parameter>
	  </term>
	  <listitem>
	    <para>
	      COMMAND specifies the path to a callout to handle
	      interactions with the configured NFS system, including
	      startup, shutdown, monitoring.
	    </para>
	    <para>
	      Default is the included
	      <command>nfs-linux-kernel-callout</command>.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>
	    CTDB_NFS_CHECKS_DIR=<parameter>DIRECTORY</parameter>
	  </term>
	  <listitem>
	    <para>
	      Specifies the path to a DIRECTORY containing files that
	      describe how to monitor the responsiveness of NFS RPC
	      services.  See the README file for this directory for an
	      explanation of the contents of these "check" files.
	    </para>
	    <para>
	      CTDB_NFS_CHECKS_DIR can be used to point to different
	      sets of checks for different NFS servers.
	    </para>
	    <para>
	      One way of using this is to have it point to, say,
	      <filename>/usr/local/etc/ctdb/nfs-checks-enabled.d</filename>
	      and populate it with symbolic links to the desired check
	      files.  This avoids duplication and is upgrade-safe.
	    </para>
	    <para>
	      Default is
	      <filename>/usr/local/etc/ctdb/nfs-checks.d</filename>,
	      which contains NFS RPC checks suitable for Linux kernel
	      NFS.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>
	    CTDB_NFS_SKIP_SHARE_CHECK=yes|no
	  </term>
	  <listitem>
	    <para>
	      As part of monitoring, should CTDB skip the check for
	      the existence of each directory exported via NFS.  This
	      may be desirable if there is a large number of exports.
	    </para>
	    <para>
	      Default is no.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>
	    CTDB_RPCINFO_LOCALHOST=<parameter>IPADDR</parameter>|<parameter>HOSTNAME</parameter>
	  </term>
	  <listitem>
	    <para>
	      IPADDR or HOSTNAME indicates the address that
	      <command>rpcinfo</command> should connect to when doing
	      <command>rpcinfo</command> check on IPv4 RPC service during
	      monitoring.  Optimally this would be "localhost".
	      However, this can add some performance overheads.
	    </para>
	    <para>
	      Default is "127.0.0.1".
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>
	    CTDB_RPCINFO_LOCALHOST6=<parameter>IPADDR</parameter>|<parameter>HOSTNAME</parameter>
	  </term>
	  <listitem>
	    <para>
	      IPADDR or HOSTNAME indicates the address that
	      <command>rpcinfo</command> should connect to when doing
	      <command>rpcinfo</command> check on IPv6 RPC service
	      during monitoring.  Optimally this would be "localhost6"
	      (or similar).  However, this can add some performance
	      overheads.
	    </para>
	    <para>
	      Default is "::1".
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>
	    CTDB_NFS_STATE_FS_TYPE=<parameter>TYPE</parameter>
	  </term>
	  <listitem>
	    <para>
	      The type of filesystem used for a clustered NFS' shared
	      state. No default.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>
	    CTDB_NFS_STATE_MNT=<parameter>DIR</parameter>
	  </term>
	  <listitem>
	    <para>
	      The directory where a clustered NFS' shared state will be
	      located. No default.
	    </para>
	  </listitem>
	</varlistentry>

      </variablelist>

    </refsect2>

    <refsect2>
      <title>70.iscsi</title>

      <para>
	Provides CTDB's Linux iSCSI tgtd service management.
      </para>

      <variablelist>

	<varlistentry>
	  <term>
	    CTDB_START_ISCSI_SCRIPTS=<parameter>DIRECTORY</parameter>
	  </term>
	  <listitem>
	    <para>
	      DIRECTORY on shared storage containing scripts to start
	      tgtd for each public IP address.
	    </para>
	    <para>
	      No default.
	    </para>
	  </listitem>
	</varlistentry>
      </variablelist>
    </refsect2>

  </refsect1>

  <refsect1>
    <title>
      DATABASE SETUP
      </title>

      <para>
	CTDB checks the consistency of databases during startup.
      </para>

      <refsect2>
	<title>00.ctdb</title>

	<variablelist>

	  <varlistentry>
	    <term>CTDB_MAX_CORRUPT_DB_BACKUPS=<parameter>NUM</parameter></term>
	    <listitem>
	      <para>
		NUM is the maximum number of volatile TDB database
		backups to be kept (for each database) when a corrupt
		database is found during startup.  Volatile TDBs are
		zeroed during startup so backups are needed to debug
		any corruption that occurs before a restart.
	      </para>
	      <para>
		Default is 10.
	      </para>
	    </listitem>
	  </varlistentry>

	</variablelist>
      </refsect2>

  </refsect1>

  <refsect1>
    <title>SYSTEM RESOURCE MONITORING</title>

    <refsect2>
      <title>
	05.system
      </title>

      <para>
	Provides CTDB's filesystem and memory usage monitoring.
      </para>

      <para>
	CTDB can experience seemingly random (performance and other)
	issues if system resources become too constrained.  Options in
	this section can be enabled to allow certain system resources
	to be checked.  They allows warnings to be logged and nodes to
	be marked unhealthy when system resource usage reaches the
	configured thresholds.
      </para>

      <para>
	Some checks are enabled by default.  It is recommended that
	these checks remain enabled or are augmented by extra checks.
	There is no supported way of completely disabling the checks.
      </para>

      <variablelist>

	<varlistentry>
	  <term>
	    CTDB_MONITOR_FILESYSTEM_USAGE=<parameter>FS-LIMIT-LIST</parameter>
	  </term>
	  <listitem>
	    <para>
	      FS-LIMIT-LIST is a space-separated list of
	      <parameter>FILESYSTEM</parameter>:<parameter>WARN_LIMIT</parameter><optional>:<parameter>UNHEALTHY_LIMIT</parameter></optional>
	      triples indicating that warnings should be logged if the
	      space used on FILESYSTEM reaches WARN_LIMIT%.  If usage
	      reaches UNHEALTHY_LIMIT then the node should be flagged
	      unhealthy.  Either WARN_LIMIT or UNHEALTHY_LIMIT may be
	      left blank, meaning that check will be omitted.
	    </para>

	    <para>
	      Default is to warn for each filesystem containing a
	      database directory
	      (<literal>volatile&nbsp;database&nbsp;directory</literal>,
	      <literal>persistent&nbsp;database&nbsp;directory</literal>,
	      <literal>state&nbsp;database&nbsp;directory</literal>)
	      with a threshold of 90%.
	    </para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>
	    CTDB_MONITOR_MEMORY_USAGE=<parameter>MEM-LIMITS</parameter>
	  </term>
	  <listitem>
	    <para>
	      MEM-LIMITS takes the form
	      <parameter>WARN_LIMIT</parameter><optional>:<parameter>UNHEALTHY_LIMIT</parameter></optional>
	      indicating that warnings should be logged if memory
	      usage reaches WARN_LIMIT%.  If usage reaches
	      UNHEALTHY_LIMIT then the node should be flagged
	      unhealthy.  Either WARN_LIMIT or UNHEALTHY_LIMIT may be
	      left blank, meaning that check will be omitted.
	    </para>
	    <para>
	      Default is 80, so warnings will be logged when memory
	      usage reaches 80%.
	    </para>
	  </listitem>
	</varlistentry>

      </variablelist>
    </refsect2>

  </refsect1>


  <refsect1>
    <title>EVENT SCRIPT DEBUGGING</title>

    <refsect2>
      <title>
	debug-hung-script.sh
      </title>

      <variablelist>

	<varlistentry>
	  <term>CTDB_DEBUG_HUNG_SCRIPT_STACKPAT=<parameter>REGEXP</parameter></term>
	  <listitem>
	    <para>
	      REGEXP specifies interesting processes for which stack
	      traces should be logged when debugging hung eventscripts
	      and those processes are matched in pstree output.
	      REGEXP is an extended regexp so choices are separated by
	      pipes ('|').  However, REGEXP should not contain
	      parentheses.  See also the <citerefentry><refentrytitle>ctdb.conf</refentrytitle>
	      <manvolnum>5</manvolnum></citerefentry>
	      [event] "debug&nbsp;script" option.
	    </para>
	    <para>
	      Default is "exportfs|rpcinfo".
	    </para>
	  </listitem>
	</varlistentry>

      </variablelist>
    </refsect2>

  </refsect1>

  <refsect1>
    <title>FILES</title>

    <simplelist>
      <member><filename>/usr/local/etc/ctdb/script.options</filename></member>
    </simplelist>
  </refsect1>

  <refsect1>
    <title>SEE ALSO</title>
    <para>
      <citerefentry><refentrytitle>ctdbd</refentrytitle>
      <manvolnum>1</manvolnum></citerefentry>,

      <citerefentry><refentrytitle>ctdb</refentrytitle>
      <manvolnum>7</manvolnum></citerefentry>,

      <ulink url="http://ctdb.samba.org/"/>
    </para>
  </refsect1>

  <refentryinfo>
    <author>
      <contrib>
	This documentation was written by
	Amitay Isaacs,
	Martin Schwenke
      </contrib>
    </author>

    <copyright>
      <year>2007</year>
      <holder>Andrew Tridgell</holder>
      <holder>Ronnie Sahlberg</holder>
    </copyright>
    <legalnotice>
      <para>
	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License as
	published by the Free Software Foundation; either version 3 of
	the License, or (at your option) any later version.
      </para>
      <para>
	This program is distributed in the hope that it will be
	useful, but WITHOUT ANY WARRANTY; without even the implied
	warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
	PURPOSE.  See the GNU General Public License for more details.
      </para>
      <para>
	You should have received a copy of the GNU General Public
	License along with this program; if not, see
	<ulink url="http://www.gnu.org/licenses"/>.
      </para>
    </legalnotice>
  </refentryinfo>

</refentry>