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yb-ctl

The yb-ctl utility, located in the bin directory of YugabyteDB home, provides a simple command line interface for administering local clusters used for development and learning. It invokes the yb-tserver and yb-master servers to perform the necessary orchestration.

Note

  • yb-ctl is meant for managing local clusters only. This means that a single host machine like a local laptop is used to simulate YugabyteDB clusters even though the YugabyteDB cluster can have 3 nodes or more. For creating multi-host clusters, follow the instructions in the Deploy section.

  • yb-ctl can manage a cluster if and only if it was initially created via yb-ctl. This means that clusters created through any other means including those in the Deploy section cannot be administered using yb-ctl.

Syntax

Run yb-ctl commands from the YugabyteDB home directory.

./bin/yb-ctl [ command ] [ flag1, flag2, ... ]

Online help

To display the online help, run yb-ctl --help from the YugabyteDB home directory.

$ ./bin/yb-ctl --help

Commands

create

Creates a local YugabyteDB cluster. With no flags, creates a 1-node cluster.

For more details and examples, see Create a local cluster, Create a cluster across multiple zones, regions, and clouds, and Create a local cluster with custom flags.

start

Starts the existing cluster or, if not existing, creates and starts the cluster.

stop

Stops the cluster, if running.

destroy

Destroys the current cluster.

For details and examples, see Destroy a local cluster.

status

Displays the current status of the cluster.

For details and examples, see Check cluster status.

restart

Restarts the current cluster all at once.

For details and examples, see Restart a cluster and Restart with custom flags.

wipe_restart

Stops the current cluster, wipes all data files and starts the cluster as before (losing all flags).

For details and examples, see Wipe and restart with placement info flags.

add_node

Adds a new node to the current cluster. It also takes an optional flag --master, which denotes that the server to add is a yb-master.

For details and examples, see Add nodes and Create a cluster across multiple zones, regions, and clouds.

remove_node

Stops a particular node in the running cluster. It also takes an optional flag --master, which denotes that the server is a yb-master.

For details and examples, see Stop and remove nodes.

start_node

Starts a specified node in the running cluster. It also takes an optional flag --master, which denotes that the server is a yb-master.

stop_node

Stops the specified node in the running cluster. It also takes an optional flag --master, which denotes that the server is a yb-master.

For details and examples, see Stop and remove nodes.

restart_node

Restarts the specified node in a running cluster. It also takes an optional flag --master, which denotes that the server is a yb-master.

For details and examples, see Restart node with placement information.

setup_redis

Enables YugabyteDB support for the Redis-compatible YEDIS API.

For details and examples, see Initialize the YEDIS API.

Flags

--help, -h

Shows the help message and then exits.

--binary_dir

Specifies the directory in which to find the YugabyteDB yb-master and yb-tserver binary files.

Default: <yugabyte-installation-dir>/bin/

--data_dir

Specifies the data directory for YugabyteDB.

Default: $HOME/yugabyte-data/

--master_flags

Specifies a list of YB-Master flags, separated by commas.

For details and examples, see Create a local cluster with custom flags.

--tserver_flags

Specifies a list of YB-TServer flags, separated by commas.

For details and examples, see Create a local cluster with custom flags.

Example

To enable YSQL authentication, you can use the --tserver_flags flag to add the yb-tserver --ysql_enable-auth flag to the yb-ctl create | start | restart commands.

$./bin/yb-ctl create --tserver_flags "ysql_enable_auth=true"
--placement_info

Specifies the cloud, region, and zone as cloud.region.zone, separated by commas.

Default: cloud1.datacenter1.rack1

For details and examples, see Create a cluster across multiple zones, regions, and clouds, Restart node with placement information, and Wipe and restart with placement info flags.

--replication_factor, -rf

Specifies the number of replicas for each tablet. This parameter is also known as Replication Factor (RF). Should be an odd number so that a majority consensus can be established. A miniumum value of 3 is needed to create a fault-tolerant cluster since 1 signifies that there is no only 1 replica with no fault tolerance.

This value also sets the default number of YB-Master servers.

Default: 1

--require_clock_sync

Specifies whether YugabyteDB requires clock synchronization between the nodes in the cluster.

Default: false

--listen_ip

Specifies the IP address, or port, for a 1-node cluster to listen on. To enable external access of the YugabyteDB APIs and administration ports, set the value to 0.0.0.0. Note that this flag is not applicable to multi-node clusters.

Default: 127.0.0.1

--num_shards_per_tserver

Number of shards (tablets) to start per tablet server for each table.

Default: 2

--timeout-yb-admin-sec

Timeout, in seconds, for operations that call yb-admin and wait on the cluster.

--timeout-processes-running-sec

Timeout, in seconds, for operations that wait on the cluster.

--verbose

Flag to log internal debug messages to stderr.

Create a local cluster

To create a local YugabyteDB cluster for development and learning, use the yb-ctl create command.

In order to ensure that all of the replicas for a given tablet can be placed on different nodes, the number of nodes created with the initial create command is always equal to the replication factor. To expand or shrink the cluster, use the add_node and remove_node commands.

Each of these initial nodes run a yb-tserver server and a yb-master server. Note that the number of YB-Master servers in a cluster must equal the replication factor for the cluster to be considered operating normally.

Create a local 1-node cluster with replication factor of 1

$ ./bin/yb-ctl create

Note that the default replication factor is 1.

Create a 4-node cluster with replication factor of 3

First create 3-node cluster with replication factor of 3.

$ ./bin/yb-ctl --rf 3 create

Use yb-ctl add_node command to add a node and make it a 4-node cluster.

$ ./bin/yb-ctl add_node

Create a 5-node cluster with replication factor of 5

$ ./bin/yb-ctl --rf 5 create

Default directories for local clusters

YugabyteDB clusters created with the yb-ctl utility are created locally on the same host and simulate a distributed multi-host cluster.

Data directory

YugabyteDB cluster data is installed in $HOME/yugabyte-data/, containing the following:

cluster_config.json
initdb.log
node-#/
node-#/disk-#/

Node directories

For each simulated YugabyteDB node, a yugabyte-data subdirectory, named node-# (where # is the number of the node), is created.

Example: /yugabyte-data/node-#/

Each node-# directory contains the following:

yugabyte-data/node-#/disk-#/

Disk directories

For each simulated disk, a disk-# subdirectory is created in each /yugabyte-data/node-# directory.

Each disk-# directory contains the following:

master.err
master.out
pg_data/
tserver.err
tserver.out
yb-data/

Logs

YB-Master logs are added in the following location:

yugabyte-data/node-#/disk-#/yb-data/master.out
yugabyte-data/node-#/disk-#/yb-data/master/logs

YB-TServer logs are added in the following location:

yugabyte-data/node-#/disk-#/yb-data/tserver.out
yugabyte-data/node-#/disk-#/yb-data/tserver/logs

Enable external access

There are essentially two modes with yb-ctl.

  • 1-node RF1 cluster where the bind IP address for all ports can be bound to 0.0.0.0 using the listen_ip flag. This is the mode you use if you want to have external access for the database APIs and admin UIs.
$ ./bin/yb-ctl create --listen_ip=0.0.0.0
  • Multi-node (say 3-node RF3) cluster where the bind IP addresses are the loopback IP addresses since binding to 0.0.0.0 is no longer possible. Hence, this mode is only meant for internal access.

Check cluster status

To get the status of your local cluster, including the Admin UI URLs for the YB-Master and YB-TServer, run the yb-ctl status command.

$ ./bin/yb-ctl status

Following is the output shown for a 3-node RF3 cluster.

----------------------------------------------------------------------------------------------------
| Node Count: 3 | Replication Factor: 3                                                            |
----------------------------------------------------------------------------------------------------
| JDBC                : jdbc:postgresql://127.0.0.1:5433/yugabyte                                  |
| YSQL Shell          : bin/ysqlsh                                                                 |
| YCQL Shell          : bin/ycqlsh                                                                 |
| YEDIS Shell         : bin/redis-cli                                                              |
| Web UI              : http://127.0.0.1:7000/                                                     |
| Cluster Data        : /Users/testuser12/yugabyte-data                                            |
----------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------
| Node 1: yb-tserver (pid 27389), yb-master (pid 27380)                                            |
----------------------------------------------------------------------------------------------------
| JDBC                : jdbc:postgresql://127.0.0.1:5433/yugabyte                                  |
| YSQL Shell          : bin/ysqlsh                                                                 |
| YCQL Shell          : bin/ycqlsh                                                                 |
| YEDIS Shell         : bin/redis-cli                                                              |
| data-dir[0]         : /Users/testuser12/yugabyte-data/node-1/disk-1/yb-data                      |
| yb-tserver Logs     : /Users/testuser12/yugabyte-data/node-1/disk-1/yb-data/tserver/logs         |
| yb-master Logs      : /Users/testuser12/yugabyte-data/node-1/disk-1/yb-data/master/logs          |
----------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------
| Node 2: yb-tserver (pid 27392), yb-master (pid 27383)                                            |
----------------------------------------------------------------------------------------------------
| JDBC                : jdbc:postgresql://127.0.0.2:5433/yugabyte                                  |
| YSQL Shell          : bin/ysqlsh -h 127.0.0.2                                                    |
| YCQL Shell          : bin/ycqlsh 127.0.0.2                                                       |
| YEDIS Shell         : bin/redis-cli -h 127.0.0.2                                                 |
| data-dir[0]         : /Users/testuser12/yugabyte-data/node-2/disk-1/yb-data                      |
| yb-tserver Logs     : /Users/testuser12/yugabyte-data/node-2/disk-1/yb-data/tserver/logs         |
| yb-master Logs      : /Users/testuser12/yugabyte-data/node-2/disk-1/yb-data/master/logs          |
----------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------
| Node 3: yb-tserver (pid 27395), yb-master (pid 27386)                                            |
----------------------------------------------------------------------------------------------------
| JDBC                : jdbc:postgresql://127.0.0.3:5433/yugabyte                                  |
| YSQL Shell          : bin/ysqlsh -h 127.0.0.3                                                    |
| YCQL Shell          : bin/ycqlsh 127.0.0.3                                                       |
| YEDIS Shell         : bin/redis-cli -h 127.0.0.3                                                 |
| data-dir[0]         : /Users/testuser12/yugabyte-data/node-3/disk-1/yb-data                      |
| yb-tserver Logs     : /Users/testuser12/yugabyte-data/node-3/disk-1/yb-data/tserver/logs         |
| yb-master Logs      : /Users/testuser12/yugabyte-data/node-3/disk-1/yb-data/master/logs          |
----------------------------------------------------------------------------------------------------

Start and stop an existing cluster

Start the existing cluster, or create and start a cluster (if one doesn't exist) by running the yb-ctl start command.

$ ./bin/yb-ctl start

Stop a cluster so that you can start it later by running the yb-ctl stop command.

$ ./bin/yb-ctl stop

Add and remove nodes

Add nodes

This will start a new YB-TServer server and give it a new node_id for tracking purposes.

$ ./bin/yb-ctl add_node

Stop and remove nodes

We can stop a node by executing the yb-ctl stop command. The command takes the node_id of the node that has to be removed as input. Stop node command expects a node id which denotes the index of the server that needs to be stopped. It also takes an optional flag --master, which denotes that the server is a yb-master.

$ ./bin/yb-ctl stop_node 3

We can also pass an optional flag --master, which denotes that the server is a yb-master.

$ ./bin/yb-ctl stop_node 3 --master

Currently stop_node and remove_node implement exactly the same behavior. So they can be used interchangeably.

Test failure of a node

You can test the failure of a node in a 3-node RF3 cluster by killing 1 instance of yb-tserver and 1 instance of yb-master by using the following commands.

./bin/yb-ctl destroy
./bin/yb-ctl --rf 3 create
./bin/yb-ctl stop_node 3
./bin/yb-ctl stop_node 3 --master
./bin/yb-ctl start_node 3
./bin/yb-ctl start_node 3 --master

The command ./bin/yb-ctl start_node 3 will start yb-tserver3. However, it will throw an error even though the command will succeed. This is because there are only 2 yb-masters present in the cluster at this point. This is not an error in the cluster configuration but rather a warning to highlight that the cluster is under-replicated and does not have enough yb-masters to ensure continued fault tolerance. Following GitHub issue tracks the work to convert this error into a user-friendly warning.

Initialize the YEDIS API

The setup_redis command to initialize YugabyteDB's Redis-compatible YEDIS API.

$ ./bin/yb-ctl setup_redis

Destroy a local cluster

This command stops all the nodes and deletes the data directory of the cluster.

$ ./bin/yb-ctl destroy

Advanced commands

Create a cluster across multiple zones, regions, and clouds

You can pass the placement information for nodes in a cluster from the command line. The placement information is provided as a set of (cloud, region, zone) tuples separated by commas. Each cloud, region and zone entry is separated by dots.

$ ./bin/yb-ctl --rf 3 create --placement_info "cloud1.region1.zone1,cloud2.region2.zone2"

The total number of placement information entries cannot be more than the replication factor (this is because you would not be able to satisfy the data placement constraints for this replication factor). If the total number of placement information entries is lesser than the replication factor, the placement information is passed down to the node in a round robin approach.

To add a node:

$ ./bin/yb-ctl add_node --placement_info "cloud1.region1.zone1"

Create a local cluster with custom flags

When you use yb-ctl, you can pass "custom" flags (flags unavailable directly in yb-ctl) to the YB-Master and YB-TServer servers.

$ ./bin/yb-ctl --rf 1 create --master_flags "log_cache_size_limit_mb=128,log_min_seconds_to_retain=20,master_backup_svc_queue_length=70" --tserver_flags "log_inject_latency=false,log_segment_size_mb=128,raft_heartbeat_interval_ms=1000"

To add a node with custom YB-TServer flags:

$ ./bin/yb-ctl add_node --tserver_flags "log_inject_latency=false,log_segment_size_mb=128"

To add a node with custom YB-Master flags:

$ ./bin/yb-ctl add_node --master_flags "log_cache_size_limit_mb=128,log_min_seconds_to_retain=20"

To handle flags whose value contains commas or equals, quote the whole key-value pair with double-quotes:

$ ./bin/yb-ctl create --tserver_flags 'ysql_enable_auth=false,"vmodule=tablet_service=1,pg_doc_op=1",ysql_prefetch_limit=1000'

Restart a cluster

The yb-ctl restart command can be used to restart a cluster. Please note that if you restart the cluster, all custom defined flags and placement information will be lost. Nevertheless, you can pass the placement information and custom flags in the same way as they are passed in the yb-ctl create command.

$ ./bin/yb-ctl restart
  • Restart with cloud, region and zone flags
$ ./bin/yb-ctl restart --placement_info "cloud1.region1.zone1"

Restart with custom flags

$ ./bin/yb-ctl restart --master_flags "log_cache_size_limit_mb=128,log_min_seconds_to_retain=20,master_backup_svc_queue_length=70" --tserver_flags "log_inject_latency=false,log_segment_size_mb=128,raft_heartbeat_interval_ms=1000"

Restart a node

The yb-ctl restart first stops the node and then starts it again. At this point of time, the node is not decommissioned from the cluster. Thus one of the primary advantages of this command is that it can be used to clear old flags and pass in new ones. Just like create, you can pass the cloud/region/zone and custom flags in the yb-ctl restart command.

$ ./bin/yb-ctl restart_node 2

Restart yb-master on a node

$ ./bin/yb-ctl restart_node 2 --master

Restart node with placement information

$ ./bin/yb-ctl restart_node 2 --placement_info "cloud1.region1.zone1"

Restart node with flags

$ ./bin/yb-ctl restart_node 2 --master --master_flags "log_cache_size_limit_mb=128,log_min_seconds_to_retain=20"

Wipe and restart a cluster

The yb-ctl wipe_restart command stops all the nodes, removes the underlying data directories, and then restarts with the same number of nodes that you had in your previous configuration.

Just like the yb-ctl restart command, the custom-defined flags and placement information will be lost during wipe_restart, though you can pass placement information and custom flags in the same way as they are passed in the yb-ctl create command.

$ ./bin/yb-ctl wipe_restart

Wipe and restart with placement info flags

$ ./bin/yb-ctl wipe_restart --placement_info "cloud1.region1.zone1"

Wipe and restart with custom flags

$ ./bin/yb-ctl wipe_restart --master_flags "log_cache_size_limit_mb=128,log_min_seconds_to_retain=20,master_backup_svc_queue_length=70" --tserver_flags "log_inject_latency=false,log_segment_size_mb=128,raft_heartbeat_interval_ms=1000"
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