MySQL :: MySQL 8.0 Reference Manual :: 22.4.30 ndb_waiter — Wait for NDB Cluster to Reach a Given Status

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22.4.30 ndb_waiter — Wait for NDB Cluster to Reach a Given Status

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 22.4.31, “Options Common to NDB Cluster Programs — Options Common to NDB Cluster Programs”.

Table 22.359 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	All NDB 8.0 releases
`--not-started`	Wait for cluster to reach NOT STARTED state	All NDB 8.0 releases
`--single-user`	Wait for cluster to enter single user mode	All NDB 8.0 releases
`--timeout=#`, `-t`	Wait this many seconds, then exit whether or not cluster has reached desired state; default is 2 minutes (120 seconds)	All NDB 8.0 releases
`--nowait-nodes=list`	List of nodes not to be waited for.	All NDB 8.0 releases
`--wait-nodes=list`, `-w`	List of nodes to be waited for.	All NDB 8.0 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

NDBT_ProgramExit: 0 - OK

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).

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