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       cman - cluster.conf cman configuration section


              Cman  configuration  values  are  placed  in  the <cman> </cman>
              section 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
              communication.   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

       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
              different 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
              cluster  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

              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)