Load Balancing
When deploying multiple FE nodes, users can deploy a load balancing layer on top of the FEs to achieve high availability.
The following are some high availability options:
Code approachβ
One way is to implement code at the application layer to perform retry and load balancing. For example, if a connection is broken, it will automatically retry on other connections. This approach requires users to configure multiple FE node addresses.
JDBC Connectorβ
JDBC connector supports automatic retry:
jdbc:mysql:loadbalance://[host1][:port],[host2][:port][,[host3][:port]]...[/[database]][?propertyName1=propertyValue1[&propertyName2=propertyValue2]...]
ProxySQLβ
ProxySQL is a MySQL proxy layer that supports read/write separation, query routing, SQL caching, dynamic load configuration, failover, and SQL filtering.
StarRocks FE is responsible for receiving connection and query requests, and itβs horizontally scalable and highly available. However FE requires users to set up a proxy layer on top of it to achieve automatic load balancing. See the following steps for setup:
1. Install relevant dependenciesβ
yum install -y gnutls perl-DBD-MySQL perl-DBI perl-devel
2. Download the installation packageβ
wget https://github.com/sysown/proxysql/releases/download/v2.0.14/proxysql-2.0.14-1-centos7.x86_64.rpm
3. Decompress to the current directoryβ
rpm2cpio proxysql-2.0.14-1-centos7.x86_64.rpm | cpio -ivdm
4. Modify the configuration fileβ
vim ./etc/proxysql.cnf
Direct to a directory that the user has privilege to access (absolute path):
datadir="/var/lib/proxysql"
errorlog="/var/lib/proxysql/proxysql.log"
5. Startβ
./usr/bin/proxysql -c ./etc/proxysql.cnf --no-monitor
6. Log inβ
mysql -u admin -padmin -h 127.0.0.1 -P6032
7. Configure the global logβ
SET mysql-eventslog_filename='proxysql_queries.log';
SET mysql-eventslog_default_log=1;
SET mysql-eventslog_format=2;
LOAD MYSQL VARIABLES TO RUNTIME;
SAVE MYSQL VARIABLES TO DISK;
8. Insert into the leader nodeβ
insert into mysql_servers(hostgroup_id, hostname, port) values(1, '172.xx.xx.139', 9030);
9. Insert the observer nodesβ
insert into mysql_servers(hostgroup_id, hostname, port) values(2, '172.xx.xx.139', 9030);
insert into mysql_servers(hostgroup_id, hostname, port) values(2, '172.xx.xx.140', 9030);
10. Load the configurationβ
load mysql servers to runtime;
save mysql servers to disk;
11. Configure the username and passwordβ
insert into mysql_users(username, password, active, default_hostgroup, backend, frontend) values('root', '*94BDCEBE19083CE2A1F959FD02F964C7AF4CFC29', 1, 1, 1, 1);
12. Load the configurationβ
load mysql users to runtime;
save mysql users to disk;
13. Write to the proxy rulesβ
insert into mysql_query_rules(rule_id, active, match_digest, destination_hostgroup, mirror_hostgroup, apply) values(1, 1, '.', 1, 2, 1);
14. Load the configurationβ
load mysql query rules to runtime;
save mysql query rules to disk;