MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
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 Section 20.4.32, “Options Common to NDB Cluster Programs — Options Common to NDB Cluster Programs”.
Table 20.47 Command-line options for the ndb_waiter program
| Format | Description | Added, Deprecated, or Removed |
|---|---|---|
| Wait for cluster to reach NO CONTACT state | (Supported in all MySQL 5.7 based releases) |
|
| Wait for cluster to reach NOT STARTED state | (Supported in all MySQL 5.7 based releases) |
|
| Wait for cluster to enter single user mode | (Supported in all MySQL 5.7 based releases) |
|
| Wait this many seconds, then exit whether or not cluster has reached desired state | (Supported in all MySQL 5.7 based releases) |
|
| List of nodes not to be waited for | (Supported in all MySQL 5.7 based releases) |
|
| List of nodes to be waited for | (Supported in all MySQL 5.7 based releases) |
ndb_waiter [-c connection_string]
Instead of waiting for the STARTED state,
ndb_waiter continues running until the
cluster reaches NO_CONTACT status before
exiting.
Instead of waiting for the STARTED state,
ndb_waiter continues running until the
cluster reaches NOT_STARTED status before
exiting.
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).
The program waits for the cluster to enter single user mode.
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
Do not use this option together with
the --wait-nodes
option.
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
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
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 -
upon completion of
its run, due to an unnecessary dependency on the
statusNDBT testing library. This dependency is has
now been removed, eliminating the extraneous output.