streamtool getzk

Usage

getzk [-s,--short] [-h,--help] [--trace <level>] [-v,--verbose <level>] [--zkconnect {<host>:<port>},... | --embeddedzk]

The streamtool getzk command prints information about the ZooKeeper servers that the domain uses.

Authority

You do not need any authority to run this command.

Description

Streams uses Apache ZooKeeper to maintain configuration and run time state data for domains and instances. You can use an embedded version of ZooKeeper, which is included in the product installation and is managed by Streams. If you are going to use multiple resources in your domain, however, you must configure one or more external ZooKeeper servers.

If you are using external ZooKeeper servers, this command returns the connection string for those servers, which consists of one or more host and port pairs.

Options

--embeddedzk

Specifies to use the embedded copy of ZooKeeper. This option is not supported within the interactive streamtool interface.

If you are not using the interactive streamtool interface and you do not specify either this option or the --zkconnect option, Streams uses the ZooKeeper connection that is associated with the active domain or the domain that is specified in the --domain-id option. Streams determines which connection maps to the domain by using cached information about the domains. In this scenario, if the domain identifier is not unique in the Streams configuration cache, the command fails.

-h,--help
Specifies to show the command syntax.
-s,--short
Specifies to return a shortened list of information. In particular, the command returns only the ZooKeeper connection string.
--trace <level>
Specifies the trace setting. The following valid levels are listed in order of increasing verbosity, which is to say that the first level in the list generates the least amount of information:
  • off
  • error
  • warn
  • info
  • debug
  • trace
The default value is off.
-v,--verbose <level>
Specifies to provide more detailed command output. The verbosity level can be 0-3, where 0 disables detailed reporting and each increment provides more detailed output.
--zkconnect <{<host>:<port>},...>

The name of one or more host and port pairs that specify the configured ZooKeeper servers. This option is not supported within the interactive streamtool interface.

If you are not using the interactive streamtool interface and you do not specify this option, Streams tries to use:

  1. The --embeddedzk option
  2. The value from the STREAMS_ZKCONNECT environment variable
  3. A ZooKeeper connection string that is derived from cached information about the current domain.

Examples

The following command obtains the connection string for Zookeeper in the domain mydomain:

[streamtool <?@StreamsDomain>] getzk 
External Zookeeper connection is set: host1:2100

If you are using the embedded copy of Zookeeper, the command returns the following information: 

Streams embedded ZooKeeper is set: host2:43427