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2cman(5)             cluster.conf cman configuration section            cman(5)
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NAME

7       cman - cluster.conf cman configuration section
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DESCRIPTION

11              Cman  configuration values are placed in the <cman> </cman> sec‐
12              tion of cluster.conf.  Per-node configuration related to cman is
13              placed  in  the  standard <clusternode> </clusternode> sections.
14              All cman configuration settings are optional; usually  none  are
15              used.   The <cman> section is placed under the <cluster> section
16              in cluster.conf.
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18                <cluster>
19                  <cman>
20                  </cman>
21                  ...
22                </cluster>
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24
25       UDP port
26              By default, cman will use UDP port 5405/5404 for internode  com‐
27              munication.   This  can  be  changed by setting a port number as
28              follows:
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30                <cman port="6809">
31                </cman>
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33              This will cause cman to use ports 6809 and 6808 for cluster com‐
34              munications.
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38       Expected votes
39              The  expected  votes  value is used by cman to determine quorum.
40              The cluster is quorate if the sum of votes of  existing  members
41              is over half of the expected votes value.  By default, cman sets
42              the expected votes value to be the sum of  votes  of  all  nodes
43              listed  in  cluster.conf.   This can be overridden by setting an
44              explicit expected_votes value as follows:
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46                <cman expected_votes="3">
47                </cman>
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49              If the cluster becomes partitioned, improper use of this  option
50              can  result  in more than one partition gaining quorum.  In that
51              event, nodes in each partition will enable cluster services.
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54       Two node clusters
55              Ordinarily, the loss of quorum after one out of two nodes  fails
56              will  prevent  the remaining node from continuing (if both nodes
57              have one vote.)  Special configuration options  can  be  set  to
58              allow  the one remaining node to continue operating if the other
59              fails.  To do this only two nodes, each with one  vote,  can  be
60              defined in cluster.conf.  The two_node and expected_votes values
61              must then be set to 1 in the cman section as follows.
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63                <cman two_node="1" expected_votes="1">
64                </cman>
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66
67       Node votes
68              By default, a node is given one vote toward the  calculation  of
69              quorum.   This can be changed by giving a node a specific number
70              of votes as follows:
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72                <clusternode name="nd1" votes="2">
73                </clusternode>
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75
76       Node ID
77
78              All nodes must have a unique node ID. This is a  single  integer
79              that identifies it to the cluster.  A node's application to join
80              the cluster may be rejected if you try to set the nodeid to  one
81              that is already used.
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83                <clusternode name="nd1" nodeid="1">
84                </clusternode>
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86       Multi-home configuration
87              It is quite common to use multiple ethernet adapters for cluster
88              nodes, so they will tolerate the failure of one link.  A  common
89              way to do this is to use ethernet bonding. Alternatively you can
90              get corosync to run in redundant  ring  mode  by  specifying  an
91              'altname' for the node. This is an alternative name by which the
92              node is known, that resolves to another IP address used  on  the
93              other  ethernet adapter(s). You can optionally specify a differ‐
94              ent port and/or multicast address for each altname in use. Up to
95              9 altnames (10 interfaces in total) can be used.
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97              Note  that  if you are using the DLM with cman/corosync then you
98              MUST tell it to use SCTP as it's communications protocol as  TCP
99              does not support multihoming.
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101                <clusternode name="nd1" nodeid="1">
102                   <altname name="nd1a" port="6809" mcast="239.192.0.2"/>
103                </clusternode>
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105                <dlm protocol="sctp"/>
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107
108       Multicast network configuration
109              cman  uses multicast UDP packets to communicate with other nodes
110              in the cluster.  By default it will generate a multicast address
111              using 239.192.x.x where x.x is the 16bit cluster ID number split
112              into bytes. This, in turn is generated from a hash of the  clus‐
113              ter  name  though it can be specified explicitly. The purpose of
114              this is to allow multiple clusters to share the  same  subnet  -
115              they  will  each  use  a  different multicast address. You might
116              also/instead want to isolate clusters using the port  number  as
117              shown above.
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119              It  is  possible to override the multicast address by specifying
120              it in cluster.conf as shown:
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122                <cman>
123                    <multicast addr="239.192.0.1"/>
124                </cman>
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126
127       Cluster ID
128              The cluster ID number is used to isolate clusters  in  the  same
129              subnet. Usually it is generated from a hash of the cluster name,
130              but it can be overridden here if you feel  the  need.  Sometimes
131              cluster names can hash to the same ID.
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133                <cman cluster_id="669">
134                </cman>
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136
137       corosync security key
138              All  traffic  sent out by cman/corosync is encrypted. By default
139              the security key used is simply the cluster name.  If  you  need
140              more  security  you can specify a key file that contains the key
141              used to encrypt cluster communications.  Of course, the contents
142              of the key file must be the same on all nodes in the cluster. It
143              is up to you to securely copy the file to the nodes.
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145                <cman keyfile="/etc/cluster/corosync.key">
146                </cman>
147
148              Note that this only applies to cluster  communication.  The  DLM
149              does not encrypt traffic.
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151
152       Other corosync parameters
153              When  corosync is started by cman (cman_tool runs corosync), the
154              corosync.conf file is  not  used.   Many  of  the  configuration
155              parameters  listed  in  corosync.conf can be set in cluster.conf
156              instead.  Cman will read corosync parameters from the  following
157              sections in cluster.conf and load them into corosync:
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159                <cluster>
160                  <totem />
161                  <event />
162                  <aisexec />
163                  <group />
164                </cluster>
165
166              See  the  corosync.conf(5) man page for more information on keys
167              that are valid for these sections.  Note that  settings  in  the
168              <clusternodes>  section  will  override settings in the sections
169              above, and options on the cman_tool command line  will  override
170              both.   In  particular,  settings  like  bindnetaddr, mcastaddr,
171              mcastport and nodeid will always be replaced by values in <clus‐
172              ternodes>.
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174              Cman uses different defaults for some of the corosync parameters
175              listed in corosync.conf(5).  If you wish to  use  a  non-default
176              setting,  they can be configured in cluster.conf as shown above.
177              Cman uses the following default values:
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179                <totem
180                  vsftype="none"
181                  token="10000"
182                  token_retransmits_before_loss_const="20"
183                  join="60"
184                  consensus="4800"
185                  rrp_mode="none"
186                  <!-- or rrp_mode="active" if altnames are present >
187                />
188                <aisexec user="root" group="root" />
189
190              Here's how to set the token timeout to five seconds:
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192                <totem token="5000"/>
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SEE ALSO

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