Four-letter-words commands are simple diagnostics commands that can be used over
telnet for ZooKeeper. These commands can be configured with Cloudera Manager.
You can configure which four-letter-words commands you want to enable in ZooKeeper.
By default the wchp and the wchc commands are disabled.
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In Cloudera Manager, select the ZooKeeper service.
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Click the Configuration tab.
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Search for
4lw.
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Find the ZooKeeper 'Four Letter Word' Command Whitelist
property.
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Use the minus and plus icon to remove or add four-letter-word commands to the
allowlist.
By default the following commands are on the allowlist:
conf, cons, crst,
dirs, dump, envi,
gtmk, ruok, stmk,
srst, stat, wchs,
mntr, and isro.
The wchp and wchc commands are not enabled
by default because of their known DOS vulnerability. For more information,
see ZOOKEEPER-2693and Zookeeper 3.5.2 - Denial of Service.
If * is set, all commands are enabled.
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Click Save Changes.
