add process --processhosts=
This command adds one or more processes to an existing cluster,
these being specified using a
process_host_list whose format is the
same as that used with the
cluster command. Any hosts referenced in the list must
be members of the site to which the cluster belongs. In
addition, all hosts must be resolvable. If node IDs are
specified, they must be within the allowed range for the type of
Any new processes added by this command must be started
For example, the following
command adds two mysqld processes on hosts
kolja to the
add process --processhosts=mysqld@torsk,mysqld@kolja mycluster;+------------------------------+ | Command result | +------------------------------+ | Processes added successfully | +------------------------------+ 1 row in set (2 min 10.39 sec)
Processes added before the cluster is started for the first time
are started with the cluster. This makes it possible to use this
command to break down what would otherwise be very long
create cluster commands.
Consider the following set of commands which creates and then
starts a cluster named
create cluster --processhosts=ndb_mgmd@host1,ndbd@host1,ndbd@host2, \ mysqld@host3,mysqld@host4 mycluster; start cluster mycluster;
create cluster command
can be divided into a shorter (and more manageable) version of
itself, plus several
add process commands.
This set of commands performs the same task as the previous set,
mycluster with exactly the same
processes and hosts as before, and then starting it:
create cluster --processhosts=ndb_mgmd@host1 mycluster; add process --processhosts=ndbd@host1,ndbd@host2 mycluster; add process --processhosts=mysqld@host3,mysqld@host4 mycluster; start cluster mycluster;
mycluster was never started before
the ndbd and mysqld
processes were added to it using the
process commands shown, it is not necessary to use the
--added option with the
start cluster command in this
case; all 5 processes are started.
A process that is added to a cluster that was created using
--import and before the import takes place is
added with status
import, which means it
cannot be started or stopped using
process before an import has taken place.
You can also manually assign a node ID to the new process you
are adding to the cluster by adding
process_name. For MySQL Cluster Manager
1.3.3 and earlier, trying to manually assign node IDs less than
ndbapi fails with an error; the
restriction, however, has been lifted since MySQL Cluster Manager 1.3.4.
Nevertheless, you are still recommend to follow the best
practice of reserving node ID 1 to 48 for data nodes.
A newly added process inherits its configuration attribute settings from those in effect for its process type on the parent cluster, or assume the default settings for that process type if none apply. Existing attribute settings in the cluster must have process-level scope to be inherited by new processes added later; instance-level settings set for existing process instances prior to adding any new ones do not apply to any of the added processes. (See Configuration attributes, for more information about the scope of attribute settings.)
Inherited attribute settings can be overridden when adding
processes; to do this, use the
This option takes as its argument an attribute assignment list
similar in format to that used with the
set commands. Suppose that the
current ndbd process-level setting in the
mycluster for the
DataDir attribute is
/home/users/ndb/cluster-data, but you wish
to add two new ndbd processes that use
/tmp/cluster/data instead. You can do this
using the following command:
mcm> add process --set=ndbd:DataDir=/tmp/cluster/data > --processhosts=mysqld@torsk,mysqld@kolja > mysite;
The equals sign (
=) immediately following
--set option is required.
When setting attributes in this way which contain paths for
processes running on Windows, you must replace any backslashes
\) used with forward slashes
/), just as with the
set command. See
Setting Attributes Containing Paths on Windows, for more information.
After a process has been added using
process, you can also use the
set command to modify its
configuration attribute settings (or specify additional ones) as
you would with any other cluster process being managed with
MySQL Cluster Manager.
It is currently not possible to drop or delete cluster processes using MySQL Cluster Manager.
When IPv6-enabled Windows systems are used as MySQL Cluster hosts under MySQL Cluster Manager, you must reference these hosts using IPv4 addresses. Otherwise, MySQL Cluster Manager will be unable to connect to the agent processes on those hosts. See Section 5.1, “MySQL Cluster Manager Usage and Design Limitations”.