Take over an OceanBase cluster

Prerequisites

• The OceanBase cluster to be acquired must be Community Edition V4.2.1 BP4 or a later version and must have been started using obshell. For more information, see the steps in View information about the OceanBase cluster.

• The OceanBase cluster to be taken over is running properly.

• If you have installed OBLOBD v2.8.0 or later, it is recommended to use the latest version. For more information, see Install obd.

• The OBD server must be able to access the nodes in the OceanBase cluster.

Take over an OceanBase cluster

1. Take over an OceanBase cluster

   [admin@obtest ~]$ obd cluster takeover test -h 10.10.10.1 -P 2881 -p ****** --ssh-user=admin --ssh-key-file=/home/admin/.ssh/id_rsa
   

   For more information about takeover commands, see obd cluster takeover in Cluster commands.

2. Use obd to check the cluster status.

   [admin@obtest ~]$ obd cluster display test
   

   The output is as follows:

   Get local repositories and plugins ok
   Open ssh connection ok
   Cluster status check ok
   Connect to observer 10.10.10.1:2881 ok
   Wait for observer init ok
   +----------------------------------------------+
   |                oceanbase-ce                  |
   +------------+---------+------+-------+--------+
   | ip         | version | port | zone  | status |
   +------------+---------+------+-------+--------+
   | 10.10.10.1 | 4.3.0.1 | 2881 | zone1 | ACTIVE |
   +------------+---------+------+-------+--------+
   obclient -h10.10.10.1 -P2881 -uroot -p'********' -Doceanbase -A
   
   obshell program health check ok
   display obshell dashboard ok
   +-----------------------------------------------------------+
   |                        obshell Dashboard                  |
   +---------------------------+------+---------------+--------+
   | url                       | user | password      | status |
   +---------------------------+------+---------------+--------+
   | http://10.10.10.1:2886    | root | '********'    | active |
   +---------------------------+------+---------------+--------+
   
   Trace ID: 093ddc0c-039b-11ef-865a-00163e0808cc
   If you want to view detailed obd logs, please run: obd display-trace 093ddc0c-039b-11ef-865a-00163e0808cc
   

View information about an OceanBase cluster

1. Log in to the sys tenant of the OceanBase cluster to be taken over as the root user.

   [admin@obtest ~]$ obclient -h10.10.10.1 -P2883 -uroot@sys#obdemo -p -c -Doceanbase -A
   

   Parameter description:

   • -h: The IP address for connecting to the OceanBase database. Usually, this is the IP address of the ODP. For example, 10.10.10.1. You must replace it with the actual IP address.

   • -u: The account for connecting to the tenant. The format is one of the following: username@tenant name#cluster name, cluster name:tenant name:username, cluster name-tenant name-username, or cluster name.tenant name.username. Here, root@sys#obdemo is used as an example. You need to modify the account according to your actual scenario.

     Note

     • When you use ODP to connect to an OceanBase cluster, you can use the following methods to obtain the cluster name:
       First, connect directly to OceanBase Database and then execute the SHOW PARAMETERS LIKE 'cluster'; command. The result of this command returns the name of the OceanBase cluster in the VALUE field.
     • If ODP is a proxy for multiple clusters, you must specify the cluster name when you connect to ODP. If ODP is a proxy for only one cluster, you do not need to specify the cluster name when you connect to ODP.

   • -P: The port for connecting to OceanBase Database. When a direct connection is established, set this parameter to mysql_port (the default value is 2881). When a connection through ODP is established, set this parameter to listen_port (the default value is 2883). In this example, 2883 is used. You must replace it with the actual port number.

   • -c: Specify that comments are not ignored in the OBClient runtime environment.

     Instructions

     Hints are special comments and are not affected by -c.

   • -A: Indicates whether to automatically obtain statistics when you connect to a database by using OBClient.

   • -D: Specifies the name of the database to access, and the value can be changed to the business database.

2. View the OceanBase Database version.

   obclient [oceanbase]> SELECT OB_VERSION();
   

   The output is as follows:

   +--------------+
   | OB_VERSION() |
   +--------------+
   | 4.3.0.1      |
   +--------------+
   

3. View the obshell information.

   obclient [oceanbase]> select * from ocs.all_agent;
   

   The output is as follows, which indicates that the obshell is running in the cluster:

   +------------+------+---------------+----------------------+-------+--------------+-------+------------+----------+--------------------------------+------------------------------------------------------------------------------------------------------+
   | ip         | port | identity      | version              | os    | architecture | zone  | mysql_port | rpc_port | home_path                      | public_key                                                                                           |
   +------------+------+---------------+----------------------+-------+--------------+-------+------------+----------+--------------------------------+------------------------------------------------------------------------------------------------------+
   | 10.10.10.1 | 2886 | CLUSTER AGENT | 4.2.3.0-102024031414 | linux | x86_64       | zone1 |       2881 |     2882 | /home/admin/oceanbase-ce       | MEgCQQCoegOM/lKWUfz0ZUOg+KK+bpW7jr16xvQy7foOqZc5yB8F+8J5pNvD0pHNH+2IeG2bIMbhnUbV/B0XeqkACD/xAgMBAAE= |
   +------------+------+---------------+----------------------+-------+--------------+-------+------------+----------+--------------------------------+------------------------------------------------------------------------------------------------------+
   

Related documentation

• obd cluster takeover

Take over the seekdb instance

Prerequisites

• The seekdb instance that is to be taken over must be V1.2.0 or later.

• The seekdb instance is running. You can execute the sudo systemctl status seekdb command to verify this. If the status shows Active: active (running) and Status: seekdb is ready and running, the seekdb instance is running.

• You have installed an OBD V4.3.0 or later. We recommend that you install the latest version. For more information, see Install OBD.

• The server on which the obd instance is located has network connectivity to the node where the seekdb instance is located.

Procedure

1. Take over the instance named seekdb

   [admin@obtest ~]$ obd seekdb takeover test -h 10.10.10.1 -P 2881 --ssh-user=root
   

   For more information about the obd seekdb takeover command, see obd SEEK_DB_PLACEHOLDER_94ca31407809423c8f0fae030c306431 takeover in seekdb command group.

2. Check the status of the table seekdb by using the obd tool.

   [admin@obtest ~]$ obd seekdb display test
   

   The output is as follows:

   Get local repositories and plugins ok
   Open ssh connection ok
   Connect to seekdb 10.10.10.1:2881 ok
   Wait for seekdb init ok
   +--------------------------------+
   |             seekdb             |
   +---------------+---------+------+
   | ip            | version | port |
   +---------------+---------+------+
   | 10.10.10.1    | 1.2.0.0 | 2881 |
   +---------------+---------+------+
   obclient -h10.10.10.1 -P2881 -uroot -Doceanbase -A