Provided by: cman_1.20060222-0ubuntu5_i386
cman_tool - Cluster Management Tool
cman_tool join | leave | kill | expected | votes | version | wait |
status | nodes | services [options]
cman_tool is a program that manages the cluster management subsystem
CMAN. cman_tool can be used to join the node to a cluster, leave the
cluster, kill another cluster node or change the value of expected
votes of a cluster.
Be careful that you understand the consequences of the commands issued
via cman_tool as they can affect all nodes in your cluster. Most of the
time the cman_tool will only be invoked from your startup and shutdown
join This is the main use of cman_tool. It instructs the cluster
manager to attempt to join an existing cluster or (if no
existing cluster exists) then to form a new one on its own.
If no options are given to this command then it will take the
cluster configuration information from CCS. However, it is
possible to provide all the information on the command-line or
to override CCS values by using the command line.
leave Tells CMAN to leave the cluster. You cannot do this if there are
subsystems (eg DLM, GFS) active. You should dismount all GFS
filesystems, shutdown CLVM, fenced and anything else using the
cluster manager before using cman_tool leave. Look at
’cman_tool status|services’ to see how many (and which) services
When a node leaves the cluster, the remaining nodes recalculate
quorum and this may block cluster activity if the required
number of votes is not present. If this node is to be down for
an extended period of time and you need to keep the cluster
running, add the remove option, and the remaining nodes will
recalculate quorum such that activity can continue.
kill Tells CMAN to kill another node in the cluster. This will cause
the local node to send a "KILL" message to that node and it will
shut down. Recovery will occur for the killed node as if it had
failed. This is a sort of remote version of "leave force" so
only use if if you really know what you are doing.
Tells CMAN a new value of expected votes and instructs it to
recalculate quorum based on this value.
Use this option if your cluster has lost quorum due to nodes
failing and you need to get it running again in a hurry.
Used alone this will report the major, minor, patch and config
versions used by CMAN (also displayed in ’cman_tool status’). It
can also be used with -r to set a new config version on all
wait Waits until the node is a member of the cluster and then
status Displays the local view of the cluster status.
nodes Displays the local view of the cluster nodes.
Displays the local view of the cluster services.
-w Normally, "cman_tool leave" will fail if the cluster is in
transition (ie another node is joining or leaving the cluster).
By adding the -w flag, cman_tool will wait and retry the leave
operation repeatedly until it succeeds or a more serious error
If -w is also specified then -t dictates the maximum amount of
time cman_tool is prepared to wait. If the operation times out
then a status of 2 is returned.
force Shuts down the cluster manager without first telling any of the
subsystems to close down. Use this option with extreme care as
it could easily cause data loss.
remove Tells the rest of the cluster to recalculate quorum such that
activity can continue without this node.
The new value of expected votes to use. This will usually be
enough to bring the cluster back to life. Values that would
cause incorrect quorum will be rejected.
The node name of the node to be killed. This should be the
unqualified node name as it appears in ’cman_tool nodes’.
The new config version.
-q Waits until the cluster is quorate before returning. -t
<seconds> Dictates the maximum amount of time cman_tool is
prepared to wait. If the operation times out then a status of 2
-X Tells cman_tool to ignore CCS altogether. All of the information
necessary to join the cluster must be provided on the command-
line. Note that if you get this wrong, it is possible that the
node will form a cluster on it’s own and ignore a cluster it is
supposed to be joining, so this method of invocation is not
Provides a text name for the cluster. You can have several
clusters on one LAN and they are distinguished by this name.
Note that the name is hashed to provide a unique number which is
what actually distinguishes the cluster, so it is possible that
two different names can clash. If this happens, the node will
not be allowed into the existing cluster and you will have to
pick another name or use different port number for cluster
UDP port number used for cluster communication. This defaults to
Number of votes this node has in the cluster. Defaults to 1.
-e <expected votes>
Number of expected votes for the whole cluster. If different
nodes provide different values then the highest is used. The
cluster will only operate when quorum is reached - that is more
than half the available votes are available to the cluster.
There is no default for this value. If you are using CCS then
ccs_tool will use the total number of votes for all nodes in the
-2 Sets the cluster up for a special "two node only" mode. Because
of the quorum requirements mentioned above, a two-node cluster
cannot be valid. This option tells the cluster manager that
there will only ever be two nodes in the cluster and relies on
fencing to ensure cluster integrity. If you specify this you
cannot add more nodes without taking down the existing cluster
and reconfiguring it. Expected votes should be set to 1 for a
Overrides the node name. By default the unqualified hostname is
used. This option can also be used to specify which interface is
used for cluster communication as cman_tool will (unless
multicast is specified below) use the broadcast address
associated with that hostname. If you are using IPv6 then you
will have to use multicast rather than broadcast.
Overrides the node ID for this node. Normally, nodes are
assigned a node id by the cluster join mechanism. If you want to
ensure that your nodes always have the same number regardless of
the order in which they join the cluster then you can hard-code
these IDs. Setting node IDs in CCS is a far better way to do
this though. Note that the node’s application to join the
cluster may be rejected if you try to set the nodeid to one that
has already been used, or if the node was previously a member of
the cluster but with a different nodeid.
Specifies a multicast address to use for cluster communication.
This is required for IPv6 operation. You should also specify an
ethernet interface to bind to this multicast address using the
Used in conjunction with -m above to specify the interface for
multicast to use.
-w Join and wait until the node is a cluster member.
-q Join and wait until the cluster is quorate. If the cluster join
fails and -w (or -q) is specified, then it will be retried. Note
that cman_tool cannot tell whether the cluster join was rejected
by another node for a good reason or that it timed out for some
benign reason; so it is strongly recommended that a timeout is
also given with the wait options to join. If you don’t want join
to retry on failure but do want to wait, use the cman_tool join
command without -w followed by cman_tool wait.
If -w or -q is also specified then -t dictates the maximum
amount of time cman_tool is prepared to wait. If the operation
times out then a status of 2 is returned. Note that just
because cman_tool has given up, does not mean that cman itself
has stopped trying to join a cluster.