Deploy OceanBase Database by using systemd

This topic describes how to deploy and manage OceanBase Database on a single server by using systemd.

Prerequisites

Before you start, make sure that the following conditions are met:

• You are using one of the following RPM-based operating systems:

  • CentOS Linux 7.X and 8.X

  • Anolis OS 8.X and 23

  • openSUSE 15.X

  • openEuler 22.03

• The size of available memory in the current environment exceeds 3 GB.

• You have installed jq, a command-line tool, in your environment and configured systemd as the system and service manager.

• You have installed the mysql client or OceanBase Client (OBClient) in your environment for database connection.

• You are going to deploy OceanBase Database V4.2.2 or later.

• You have the permissions to run sudo commands.

Deploy OceanBase Database

Step 1: Install OceanBase Database

You can install OceanBase Database online or offline, depending on whether your environment is connected to the Internet.

Step 2: Start OceanBase Database

You can start OceanBase Database by performing the following steps:

1. (Optional) Modify the configuration file.

   Run the following command to open the configuration file and modify it by referring to this step. If you skip this step, default configurations are used.

   [admin@test001 ~]$ sudo vim /etc/oceanbase.cnf
   

   The configuration file contains the following parameters:

   ip=127.0.0.1
   mysql_port=2881
   rpc_port=2882
   obshell_port=2886
   root_pwd=""
   redo_dir=/var/lib/oceanbase/redo
   data_dir=/var/lib/oceanbase/data
   datafile_size=2G
   cpu_count=16
   memory_limit=6G
   system_memory=1G
   log_disk_size=13G
   

   Note

   • You can add other parameters to the configuration file. For more information about the parameters, see Parameter summary.

   • At present, you cannot modify the zone of an OBServer node, which is zone1 by default.

   The following table describes parameters in the configuration file.

   Parameter	Required	Default value	Description
   ip	No	127.0.0.1	The IP address of the OBServer node. At present, you cannot specify an IPv6 address for an OBServer node.
   mysql_port	No	2881	The SQL port of OceanBase Database.
   rpc_port	No	2882	The RPC port of OceanBase Database.
   obshell_port	No	2886	The O&M port of OceanBase Database.
   root_pwd	No	Empty	The password of the super administrator (root@sys) of the OceanBase cluster. We recommend that you set a complex password.
   redo_dir	No	/var/lib/oceanbase/redo	The directory for storing clogs, ilogs, and slogs. We recommend that you set the directory on a separate disk. Note The available space of the data disk (/var/lib/oceanbase/ by default) must be greater than 15 GB.
   data_dir	No	/var/lib/oceanbase/data	The directory for storing SSTables and other data. We recommend that you use a separate disk. Note The available space of the data disk (/var/lib/oceanbase/ by default) must be greater than 15 GB.
   datafile_size	No	0	The size of the data file block_file on the corresponding OBServer node. If this parameter is not configured, the datafile_disk_percentage parameter takes effect. For more information, see datafile_size and datafile_disk_percentage.
   cpu_count	No	0	The total number of CPU cores that OceanBase Database can use. If you set the parameter to 0, the system will automatically detect the number of CPU cores.
   memory_limit	No	0	The maximum memory that the observer process can obtain from the environment. If this parameter is not configured, the memory_limit_percentage parameter takes effect. For more information about the two parameters, see memory_limit and memory_limit_percentage.
   system_memory	No	0M	The reserved system memory, which is part of memory_limit. If this parameter is not configured, OceanBase Database reserves memory for the system in adaptive mode.
   log_disk_size	No	0	The size of the redo log disk. If this parameter is not configured, the log_disk_percentage parameter takes effect. For more information, see log_disk_size and log_disk_percentage.

2. Modify the owner of the etc directory in the installation directory of OceanBase Database. By default, the installation directory is /home/admin/oceanbase.

   [admin@test001 ~]$ sudo chown root /home/admin/oceanbase/etc
   

3. Start OceanBase Database.

   [admin@test001 ~]$ sudo systemctl start oceanbase
   

4. View the startup status of OceanBase Database.

   [admin@test001 ~]$ sudo systemctl status oceanbase
   

   If Service is ready is displayed, OceanBase Database has been started.

Step 3: Connect to OceanBase Database

In this example, OBClient is used to connect to OceanBase Database. Run the following command:

[admin@test001 ~]$ obclient -h<IP> -uroot@sys -P<Port> -p<Passwd> -A oceanbase

where

• -h specifies the IP address for connecting to OceanBase Database. If you start OceanBase Database by using systemd, the IP address is 127.0.0.1 by default.

• -u specifies the account for connecting to OceanBase Database, in the format of username@tenant name. The default username of the administrator of a MySQL tenant is root.

• -P specifies the port for connecting to OceanBase Database, which is the value of mysqlPort in the oceanbase.cnf configuration file in the etc directory.

• -p specifies the password for connecting to OceanBase Database, which is the value of rootPwd in the oceanbase.cnf configuration file in the etc directory. Instead of providing the password in the command, we recommend that you enter the password as prompted after you run the command. This way, the password is masked.

• -A specifies not to automatically retrieve statistics when connecting to OceanBase Database by using OBClient.

• oceanbase specifies the name of the database to access. You can change it to the name of a business database.

Manage OceanBase Database

Currently, you can use systemd only to start, stop, and view the status of OceanBase Database.

View the status of OceanBase Database

Run the following command to query the status of OceanBase Database:

[admin@test001 ~]$ sudo systemctl status oceanbase

OceanBase Database may be in one of the following states:

• If the value of the Active field is active (running), and that of the Status field is Service is running, OceanBase Database is being started.

• If the value of the Active field is active (running), and that of the Status field is Service is ready, OceanBase Database is successfully started.

• If the value of the Active field is inactive (dead), OceanBase Database is stopped.

• If the value of the Active field is failed, an error occurred to OceanBase Database and you must check the logs for troubleshooting.

View detailed logs of OceanBase Database

When OceanBase Database is abnormal, you can run the following command to view the detailed logs of OceanBase Database:

[admin@test001 ~]$ sudo journalctl -u oceanbase

Actually, systemd sends requests to communicate with the management tool OBShell of OceanBase Database, thereby controlling the status of OBServer nodes. Many trace IDs are recorded in logs. You can use OBShell APIs in conjunction with these trace IDs for troubleshooting. The command is as follows:

[admin@test001 ~]$ curl -X GET http://<ip>:<obshell_port>/api/v1/task/dag/<trace id> | jq

If an error is returned in the observer start or bootstrap phase, you also need to view the logs of the OBServer node, which are stored in the /home/admin/oceanbase/log directory by default.

FAQ

• ERROR: current user(uid=0) that starts observer is not the same with the original one(uid=500)

  A common cause is that the owner of the etc directory in the installation directory of OceanBase Database, which is /home/admin/oceanbase by default, is not the current user. In this case, you can run the following command:

  chown root /home/admin/oceanbase/etc
  

• errcode=-4290, file=“ob_server_log_block_mgr.cpp”, line_no=1127, info=“::fallocate failed”

  A common cause is that the available space of the data disk of OceanBase Database, which is /var/lib/oceanbase/ by default, is insufficient. In this case, you can increase the data disk space.

Clear OceanBase Database

You can perform the following steps to clear OceanBase Database started by using systemd:

1. Stop OceanBase Database.

   [admin@test001 ~]$ sudo systemctl stop oceanbase
   

2. Uninstall OceanBase Database.

   1. Delete the package of OceanBase Database.

      If you have installed OceanBase Database online, run the following command to delete the package:

      [admin@test001 ~]$ sudo yum erase package
      

      You must replace package with the actual name of the package to be deleted. To view the package name, run the yum list | grep oceanbase command.

      If you have installed OceanBase Database offline, run the following command to delete the package:

      [admin@test001 ~]$ sudo rpm -e package
      

      You must replace package with the actual name of the package to be deleted. To view the package name, run the rpm -qa | grep oceanbase command.

   2. (Optional) Delete the data of OceanBase Database.

      After you perform the preceding step, OceanBase Database is uninstalled from your environment, but the database data still exists. If you redeploy OceanBase Database later, you can view and use the data.

      After you perform this step, the data of OceanBase Database is completely deleted.

      Delete the installation directory of OceanBase Database.

      [admin@test001 ~]$ sudo rm -rf /home/admin/oceanbase
      

      Delete the data directory of OceanBase Database.

      [admin@test001 ~]$ sudo rm -rf /var/lib/oceanbase
      

References

• You can log on to the cluster and run the ALTER USER command to modify the user password. For more information, see ALTER USER.

• For more information about how to connect to OceanBase Database after the deployment, see Connect to OceanBase Database.