Metadb Master-Slave Configuration

• Standalone/Cluster Deployment
• Container Deployment
• K8s Deployment

Configuration Instructions

1. Metadb master-slave configuration, applicable to Metadb database versions higher than 13.5. For Metadb services below this version, refer to Database Service Upgrade.

Standalone/Cluster Deployment

Preparation Work

1. Configure the export PG_METASLAVE_HOST=(10.10.10.xx 10.10.10.xx) parameter in the /opt/hengshi/conf/hengshi-sense-env.sh file, where 10.10.10.xx represents the IP address of the slave node.
   Multiple slave configurations are supported, allowing you to choose one or multiple slave nodes, and horizontal scaling of the number of slave nodes is supported.
2. Ensure that the slave server can log in to the master server without a password.
3. Before executing the initialization operation for the slave node, ensure that the master node's metadb service is in a running state.
   Note: The slave node port cannot be configured; it uses the HS_PG_PORT value configured on the master node. Please ensure that this port is available on the slave node.

Initialization Operations

Note

1. Before initializing metaslave, ensure that the metadb service is running.
2. The initialized slave database has read-only permissions without write permissions and cannot be directly connected for use as a database.

cd /opt/hengshi
bin/hengshi-sense-bin init metaslave

Startup Operations

cd /opt/hengshi
bin/hengshi-sense-bin start metaslave

Stop Operation

cd /opt/hengshi
bin/hengshi-sense-bin stop metaslave

Switching Slave Database Operations

1. Promote write permissions for the slave database. This operation needs to be executed on the server with the original slave database address configured in HS_PG_HOST.

cd /opt/hengshi
bin/hengshi-sense-bin promote metadb

2. When the following prompt appears, enter Y to confirm the operation. The successful operation interface is shown below:
3. Modify the HS_PG_HOST parameter in the /opt/hengshi/conf/hengshi-sense-env.sh file to the slave database address you want to switch to as the master database. Note
   1. If the HS_ENGINE_HOST parameter is not configured, please configure it. Using the default parameter will reference the HS_PG_HOST parameter information, which may lead to an incorrect engine address.
   2. After switching to the slave database, please reconfigure the PG_METASLAVE_HOST parameter. The previously configured master-slave relationship will become invalid, and you will need to perform initialization operations again.
4. Restart the HENGSHI service to complete the master-slave switching operation.

cd /opt/hengshi
bin/hengshi-sense-bin restart hengshi

Cluster Deployment Notes

1. Uncomment the following content in /opt/hengshi/ansible/hosts on the cluster operation node (default Node-A):

[metaslave] #metadb database slave (optional) can be used as a backup when the master database is down
Node-B

2. Specify the export PG_METASLAVE_HOST=(Node-B) parameter in /opt/hengshi/conf/hengshi-sense-env.sh on the machine node where the metadb slave resides (default Node-B) as Node-B. Use spaces to separate multiple hosts.

Alternatively, you can directly modify /opt/hengshi/conf/hengshi-sense-env.sh on Node-A, and then use the following command to synchronize the configuration file to other nodes:

./hs_install -m config  -c ../cluster-conf/

3. Execute initialization and startup operations on the cluster operation node (default Node-A):

/opt/hengshi/bin/hengshi-sense-bin init metaslave
/opt/hengshi/bin/hengshi-sense-bin start metaslave

You will see the word "streaming," indicating that the master-slave configuration is successful.

Container Deployment

Preparation Work

1. Deploy Metadb master-slave using a specific docker-compose.yaml file. Please contact support personnel.
2. Configure the hsenv file:
   • HS_MASTER_PG_HOST: Deployment service node, server IP information (not the internal IP of the docker container).
   • HS_SLAVE_PG_HOST: Deployment slave node, server IP information (not the internal IP of the docker container).
3. Ensure that the HS_MASTER_PG_HOST and HS_SLAVE_PG_HOST servers can communicate normally and that the HS_PG_EXPOSE_PORT is mutually open.

Initialization Operations

Note

1. Before initializing metaslave, ensure that the metadb service is running.
2. The initialized slave database has read-only permissions and no write permissions. It cannot be directly connected for use as a database.

cd single
docker-compose run --rm metadb init metaslave

Start Operation

cd single
docker-compose up -d

Stop Operation

cd single
docker-compose down

Switching Slave Operations

1. Promote the read-write permissions of the slave. This operation needs to be executed on the server with the original slave address configured in HS_SLAVE_PG_HOST.

cd single
docker-compose run --rm metadb promote metadb

2. When the following prompt appears, enter Y to confirm the operation. The successful operation interface is shown below:
3. Modify the hengshi docker-compose/.env configuration file, changing HS_PG_HOST:xxx to the IP of the slave server.
4. Restart the HENGSHI service to complete the master-slave switching operation.

cd single
docker-compose down
docker-compose up

k8s Deployment

Preparation Work

1. Please contact the after-sales personnel to obtain the metaslave.yaml configuration file.

Startup Operations

Note

1. Before executing the metaslave operation, ensure that the metadb service is in a running state.
2. The initialized slave database has read-only permissions and no write permissions; it cannot be directly connected for use as a database.
3. Please confirm that the LOCAL_HOST_NAME parameter is configured in the configmap.yaml file.

kubectl -n hengshi apply -f configmap.yaml
kubectl -n hengshi apply -f metaslave.yaml

Switching Slave Database Operations

1. Promote slave database read-write permissions

kubectl -n hengshi exec -it metaslave-0 -- /docker-entrypoint.sh promote metadb single

2. When the following prompt appears, enter Y to confirm the operation. The successful operation interface is shown below:
3. Modify the configmap.yaml file, change the parameter HS_PG_HOST: **metadb-0.hengshi-hs** to metaslave-0.hengshi-hs.
4. Restart the HENGSHI service to complete the master-slave switching operation:

kubectl -n hengshi apply -f hengshi.yaml