In an E-MapReduce (EMR) cluster, you can run Kudu-related commands to perform operations. This topic describes the common commands of Kudu.
Prerequisites
- An EMR cluster is created, and Kudu is selected from the optional services when you create the cluster. For more information, see Create a cluster.
- You have logged on to the cluster. For more information, see Log on to a cluster.
Background information
You can run the following commands:
- kudu master list: queries master nodes
- kudu tserver list: queries tablet servers
- kudu cluster ksck: checks the health of a cluster
- kudu table list: queries all tables
- kudu table describe: describes a table
- kudu-tserver --dump_metrics_json and kudu-master --dump_metrics_json: check the metrics of a Kudu cluster
Limits
Kudu must be deployed in the cluster that you created.
kudu master list: queries master nodes
- Syntax
kudu master list <your_Intranet_IP>
Note<your_Intranet_IP>
specifies the internal IP address of a Kudu cluster. Separate multiple IP addresses with commas (,). Example:192.168.10.59,192.168.10.60,192.168.10.61
. - Example: Run the following command to query master nodes:
kudu master list 192.168.10.59,192.168.10.60,192.168.10.61
Information similar to the following output is returned:uuid | rpc-addresses | role ----------------------------------+----------------------------------+---------- 3ebef6e84e0d45b2b6b5d24a2911**** | emr-header-1.cluster-23****:7051 | LEADER a4e0160acd804e8d83b4448183f6**** | emr-header-3.cluster-23****:7051 | FOLLOWER 0d9fdf59efce48e58f18cf212c2c**** | emr-header-2.cluster-23****:7051 | FOLLOWER
kudu tserver list: queries tablet servers
- Syntax
kudu tserver list <your_Intranet_IP>
- Example: Run the following command to query tablet servers:
kudu tserver list 192.168.10.59,192.168.10.60,192.168.10.61
Information similar to the following output is returned:uuid | rpc-addresses ----------------------------------+---------------------------------- be173a301ea24997a4a7a0f78815**** | emr-worker-2.cluster-23****:7050 2a8257107d0048728707e783035e**** | emr-worker-1.cluster-23****:7050
kudu cluster ksck: checks the health of a cluster
- Syntax
kudu cluster ksck <your_Intranet_IP>
- Example: Run the following command to check the health of your cluster:
kudu cluster ksck 192.168.10.59,192.168.10.60,192.168.10.61
Information similar to the following output is returned:Master Summary UUID | Address | Status ----------------------------------+---------------+--------- 0d9fdf59efce48e58f18cf212c2c**** | 192.168.10.60 | HEALTHY 3ebef6e84e0d45b2b6b5d24a2911**** | 192.168.10.61 | HEALTHY a4e0160acd804e8d83b4448183f6**** | 192.168.10.59 | HEALTHY Flag | Value | Tags | Master -----------------------------------+--------+--------+------------------------- raft_get_node_instance_timeout_ms | 300000 | hidden | all 3 server(s) checked Tablet Server Summary UUID | Address | Status | Location ----------------------------------+----------------------------------+---------+---------- 2a8257107d0048728707e783035e**** | emr-worker-1.cluster-234593:7050 | HEALTHY | <none> be173a301ea24997a4a7a0f78815**** | emr-worker-2.cluster-234593:7050 | HEALTHY | <none> Tablet Server Location Summary Location | Count ----------+--------- <none> | 2 Flag | Value | Tags | Tablet Server -----------------------------------+--------+--------+------------------------- raft_get_node_instance_timeout_ms | 300000 | hidden | all 2 server(s) checked Version Summary Version | Servers ---------+------------------------- 1.10.0 | all 5 server(s) checked The cluster doesn't have any matching tablets The cluster doesn't have any matching tables Tablet Replica Count Summary Statistic | Replica Count ----------------+--------------- Minimum | 0 First Quartile | 0 Median | 0 Third Quartile | 0 Maximum | 0 ================== Warnings: ================== Some masters have unsafe, experimental, or hidden flags set Some tablet servers have unsafe, experimental, or hidden flags set OK
kudu table list: queries all tables
- Syntax
kudu table list <your_Intranet_IP>
- Example: Run the following command to query all tables:
kudu table list 192.168.10.59,192.168.10.60,192.168.10.61
Information similar to the following output is returned:impala::default.my_first_table
kudu table describe: describes a table
- Syntax
kudu table describe <your_Intranet_IP> <your_tablename>
Note<your_tablename>
specifies the name of a table. You can run the kudu table list command to obtain the name of the table whose content you want to describe. For more information about the kudu table list command, see kudu table list: queries all tables. Example:impala::default.my_first_table
. - Example: Run the following command to describe a table:
kudu table describe 192.168.10.59,192.168.10.60,192.168.10.61 impala::default.my_first_table
Information similar to the following output is returned:ABLE impala::default.my_first_table ( id INT64 NOT NULL, name STRING NULLABLE, PRIMARY KEY (id) ) HASH (id) PARTITIONS 16 REPLICAS 1
kudu-tserver --dump_metrics_json and kudu-master --dump_metrics_json: check the metrics of a Kudu cluster
- Check the metrics of tablet servers
kudu-tserver --dump_metrics_json
- Check the metrics of master servers
kudu-master --dump_metrics_json