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cman(5)		    cluster.conf cman configuration section	       cman(5)

       cman - cluster.conf cman configuration section

	      Cman  configuration values are placed in the <cman> </cman> sec‐
	      tion of cluster.conf.  Per-node configuration related to cman is
	      placed  in  the  standard <clusternode> </clusternode> sections.
	      All cman configuration settings are optional; usually  none  are
	      used.   The <cman> section is placed under the <cluster> section
	      in cluster.conf.


       UDP port
	      By default, cman will use UDP port 5405/5404 for internode  com‐
	      munication.   This  can  be  changed by setting a port number as

		<cman port="6809">

	      This will cause cman to use ports 6809 and 6808 for cluster com‐

       Expected votes
	      The  expected  votes  value is used by cman to determine quorum.
	      The cluster is quorate if the sum of votes of  existing  members
	      is over half of the expected votes value.	 By default, cman sets
	      the expected votes value to be the sum of	 votes	of  all	 nodes
	      listed  in  cluster.conf.	  This can be overridden by setting an
	      explicit expected_votes value as follows:

		<cman expected_votes="3">

	      If the cluster becomes partitioned, improper use of this	option
	      can  result  in more than one partition gaining quorum.  In that
	      event, nodes in each partition will enable cluster services.

       Two node clusters
	      Ordinarily, the loss of quorum after one out of two nodes	 fails
	      will  prevent  the remaining node from continuing (if both nodes
	      have one vote.)  Special configuration options  can  be  set  to
	      allow  the one remaining node to continue operating if the other
	      fails.  To do this only two nodes, each with one	vote,  can  be
	      defined in cluster.conf.	The two_node and expected_votes values
	      must then be set to 1 in the cman section as follows.

		<cman two_node="1" expected_votes="1">

       Node votes
	      By default, a node is given one vote toward the  calculation  of
	      quorum.	This can be changed by giving a node a specific number
	      of votes as follows:

		<clusternode name="nd1" votes="2">

       Node ID

	      All nodes must have a unique node ID. This is a  single  integer
	      that identifies it to the cluster.  A node's application to join
	      the cluster may be rejected if you try to set the nodeid to  one
	      that is already used.

		<clusternode name="nd1" nodeid="1">

       Multi-home configuration
	      It is quite common to use multiple ethernet adapters for cluster
	      nodes, so they will tolerate the failure of one link.  A	common
	      way to do this is to use ethernet bonding. Alternatively you can
	      get corosync to run in redundant	ring  mode  by	specifying  an
	      'altname' for the node. This is an alternative name by which the
	      node is known, that resolves to another IP address used  on  the
	      other  ethernet adapter(s). You can optionally specify a differ‐
	      ent port and/or multicast address for each altname in use. Up to
	      9 altnames (10 interfaces in total) can be used.

	      Note  that  if you are using the DLM with cman/corosync then you
	      MUST tell it to use SCTP as it's communications protocol as  TCP
	      does not support multihoming.

		<clusternode name="nd1" nodeid="1">
		   <altname name="nd1a" port="6809" mcast=""/>

		<dlm protocol="sctp"/>

       Multicast network configuration
	      cman  uses multicast UDP packets to communicate with other nodes
	      in the cluster.  By default it will generate a multicast address
	      using 239.192.x.x where x.x is the 16bit cluster ID number split
	      into bytes. This, in turn is generated from a hash of the	 clus‐
	      ter  name	 though it can be specified explicitly. The purpose of
	      this is to allow multiple clusters to share the  same  subnet  -
	      they  will  each	use  a	different multicast address. You might
	      also/instead want to isolate clusters using the port  number  as
	      shown above.

	      It  is  possible to override the multicast address by specifying
	      it in cluster.conf as shown:

		    <multicast addr=""/>

       Cluster ID
	      The cluster ID number is used to isolate clusters	 in  the  same
	      subnet. Usually it is generated from a hash of the cluster name,
	      but it can be overridden here if you feel	 the  need.  Sometimes
	      cluster names can hash to the same ID.

		<cman cluster_id="669">

       corosync security key
	      All  traffic  sent out by cman/corosync is encrypted. By default
	      the security key used is simply the cluster name.	 If  you  need
	      more  security  you can specify a key file that contains the key
	      used to encrypt cluster communications.  Of course, the contents
	      of the key file must be the same on all nodes in the cluster. It
	      is up to you to securely copy the file to the nodes.

		<cman keyfile="/etc/cluster/corosync.key">

	      Note that this only applies to cluster  communication.  The  DLM
	      does not encrypt traffic.

       Other corosync parameters
	      When  corosync is started by cman (cman_tool runs corosync), the
	      corosync.conf file is  not  used.	  Many	of  the	 configuration
	      parameters  listed  in  corosync.conf can be set in cluster.conf
	      instead.	Cman will read corosync parameters from the  following
	      sections in cluster.conf and load them into corosync:

		  <totem />
		  <event />
		  <aisexec />
		  <group />

	      See  the	corosync.conf(5) man page for more information on keys
	      that are valid for these sections.  Note that  settings  in  the
	      <clusternodes>  section  will  override settings in the sections
	      above, and options on the cman_tool command line	will  override
	      both.   In  particular,  settings	 like  bindnetaddr, mcastaddr,
	      mcastport and nodeid will always be replaced by values in <clus‐

	      Cman uses different defaults for some of the corosync parameters
	      listed in corosync.conf(5).  If you wish to  use	a  non-default
	      setting,	they can be configured in cluster.conf as shown above.
	      Cman uses the following default values:

		  <!-- or rrp_mode="active" if altnames are present >
		<aisexec user="root" group="root" />

	      Here's how to set the token timeout to five seconds:

		<totem token="5000"/>

       cluster.conf(5), corosync.conf(5), cman_tool(8)


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