NDB_WAITER(1)

NAME
ndb_waiter - wait for NDB Cluster to reach a given status

SYNOPSIS

ndb_waiter options

DESCRIPTION

ndb_waiter repeatedly (each 100 milliseconds) prints out the status of all cluster data nodes until either the cluster reaches a given status or the --timeout limit is exceeded, then exits. By default, it waits for the cluster to achieve STARTED status, in which all nodes have started and connected to the cluster. This can be overridden using the --no-contact and --not-started options.

The node states reported by this utility are as follows:

    • NO_CONTACT: The node cannot be contacted.

    • UNKNOWN: The node can be contacted, but its status is not yet known. Usually, this means that the node has received a START or RESTART command from the management server, but has not yet acted on it.

    • NOT_STARTED: The node has stopped, but remains in contact with the cluster. This is seen when restarting the node using the management client's RESTART command.

    • STARTING: The node's ndbd process has started, but the node has not yet joined the cluster.

    • STARTED: The node is operational, and has joined the cluster.

    • SHUTTING_DOWN: The node is shutting down.

    • SINGLE USER MODE: This is shown for all cluster data nodes when the cluster is in single user mode.

The following table includes options that are specific to the NDB Cluster native backup restoration program ndb_waiter. Additional descriptions follow the table. For options common to most NDB Cluster programs (including ndb_waiter), see Options Common to NDB Cluster Programs(1).

Table 21.263. Command-line options for the ndb_waiter program
Format | Description | Added, Deprecated, or Removed
--no-contact, -n | Wait for cluster to reach NO CONTACT state | (Supported in all MySQL 5.7 based releases)
--not-started | Wait for cluster to reach NOT STARTED state | (Supported in all MySQL 5.7 based releases)
--single-user | Wait for cluster to enter single user mode | (Supported in all MySQL 5.7 based releases)
--timeout=#, -t | Wait this many seconds, then exit whether or not cluster has reached desired state; default is 2 minutes (120 seconds) | (Supported in all MySQL 5.7 based releases)
--nowait-nodes=list | List of nodes not to be waited for | (Supported in all MySQL 5.7 based releases)
--wait-nodes=list, -w | List of nodes to be waited for | (Supported in all MySQL 5.7 based releases)

Usage

    ndb_waiter [-c connection_string]

Additional Options

    • --no-contact, -n

    Instead of waiting for the STARTED state, ndb_waiter continues running until the cluster reaches NO_CONTACT status before exiting.

    • --not-started

    Instead of waiting for the STARTED state, ndb_waiter continues running until the cluster reaches NOT_STARTED status before exiting.

    • --timeout=seconds, -t seconds

    Time to wait. The program exits if the desired state is not achieved within this number of seconds. The default is 120 seconds (1200 reporting cycles).

    • --single-user

    The program waits for the cluster to enter single user mode.

    • --nowait-nodes=list

    When this option is used, ndb_waiter does not wait for the nodes whose IDs are listed. The list is comma-delimited; ranges can be indicated by dashes, as shown here:

        shell> ndb_waiter --nowait-nodes=1,3,7-9

        Important
        Do not use this option together with the --wait-nodes option.

    • --wait-nodes=list, -w list

    When this option is used, ndb_waiter waits only for the nodes whose IDs are listed. The list is comma-delimited; ranges can be indicated by dashes, as shown here:

        shell> ndb_waiter --wait-nodes=2,4-6,10

        Important
        Do not use this option together with the --nowait-nodes option.

Sample Output. Shown here is the output from ndb_waiter when run against a 4-node cluster in which two nodes have been shut down and then started again manually. Duplicate reports (indicated by ...) are omitted.

    shell> ./ndb_waiter -c localhost
    Connecting to mgmsrv at (localhost)
    State node 1 STARTED
    State node 2 NO_CONTACT
    State node 3 STARTED
    State node 4 NO_CONTACT
    Waiting for cluster enter state STARTED
    ...
    State node 1 STARTED
    State node 2 UNKNOWN
    State node 3 STARTED
    State node 4 NO_CONTACT
    Waiting for cluster enter state STARTED
    ...
    State node 1 STARTED
    State node 2 STARTING
    State node 3 STARTED
    State node 4 NO_CONTACT
    Waiting for cluster enter state STARTED
    ...
    State node 1 STARTED
    State node 2 STARTING
    State node 3 STARTED
    State node 4 UNKNOWN
    Waiting for cluster enter state STARTED
    ...
    State node 1 STARTED
    State node 2 STARTING
    State node 3 STARTED
    State node 4 STARTING
    Waiting for cluster enter state STARTED
    ...
    State node 1 STARTED
    State node 2 STARTED
    State node 3 STARTED
    State node 4 STARTING
    Waiting for cluster enter state STARTED
    ...
    State node 1 STARTED
    State node 2 STARTED
    State node 3 STARTED
    State node 4 STARTED
    Waiting for cluster enter state STARTED

    Note

    If no connection string is specified, then ndb_waiter tries to connect to a management on localhost, and reports Connecting to mgmsrv at (null).

Prior to NDB 7.5.18 and 7.6.14, this program printed NDBT_ProgramExit - status upon completion of its run, due to an unnecessary dependency on the NDBT testing library. This dependency is has now been removed, eliminating the extraneous output.

COPYRIGHT

Copyright © 1997, 2020, Oracle and/or its affiliates. All rights reserved.

This documentation is free software; you can redistribute it and/or modify it only under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License.

This documentation is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with the program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see http://www.gnu.org/licenses/.

SEE ALSO
For more information, please refer to the MySQL Reference Manual, which may already be installed locally and which is also available online at http://dev.mysql.com/doc/.

AUTHOR
Oracle Corporation (http://dev.mysql.com/).