负载均衡策略示例

以下示例演示了连接负载均衡策略的一些常见用例。

启用来自多个网络的客户端连接

假设您有一个可从两个（或更多）不同网络访问的 Vertica 群集。下面是这种情形的一些示例：

您有一个内部网络和一个外部网络。在这种配置中，您的数据库节点通常有两个或多个 IP 地址，每个地址只能从其中一个网络访问。在云环境中运行 Vertica 时，此配置很常见。在许多情况下，您可以创建适用于所有 IP 地址的全方位规则，然后为内部子网添加其他路由规则。
无论客户端使用 IPv4 还是 IPv6 协议，您都希望客户端进行负载均衡。从数据库的角度来看，IPv4 和 IPv6 连接是不同的网络，因为每个节点都有单独的 IPv4 和 IPv6 IP 地址。

在为可从多个网络访问的数据库创建负载均衡策略时，必须将客户端连接定向到网络上可供它们访问的 IP 地址。最好的解决方案是为分配给节点的每组 IP 地址创建负载均衡组。然后创建路由规则，将客户端连接重定向到可从其所在的网络访问的 IP 地址。

下面的例子：

创建两组网络地址：一组用于内部网络，另一组用于外部网络。
创建两个负载均衡组：一个用于内部网络，一个用于外部网络。
创建三个路由规则：一个用于内部网络，两个用于外部网络。内部路由规则涵盖其中一个外部规则涵盖的一部分网络。
使用内部和外部 IP 地址测试路由规则。

=> CREATE NETWORK ADDRESS node01_int ON v_vmart_node0001 WITH '192.168.0.1';
CREATE NETWORK ADDRESS

=> CREATE NETWORK ADDRESS node01_ext ON v_vmart_node0001 WITH '203.0.113.1';
CREATE NETWORK ADDRESS

=> CREATE NETWORK ADDRESS node02_int ON v_vmart_node0002 WITH '192.168.0.2';
CREATE NETWORK ADDRESS

=> CREATE NETWORK ADDRESS node02_ext ON v_vmart_node0002 WITH '203.0.113.2';
CREATE NETWORK ADDRESS

=> CREATE NETWORK ADDRESS node03_int ON v_vmart_node0003 WITH '192.168.0.3';
CREATE NETWORK ADDRESS

=> CREATE NETWORK ADDRESS node03_ext ON v_vmart_node0003 WITH '203.0.113.3';
CREATE NETWORK ADDRESS

=> CREATE LOAD BALANCE GROUP internal_group WITH ADDRESS node01_int, node02_int, node03_int;
CREATE LOAD BALANCE GROUP

=> CREATE LOAD BALANCE GROUP external_group WITH ADDRESS node01_ext, node02_ext, node03_ext;
CREATE LOAD BALANCE GROUP

=> CREATE ROUTING RULE internal_rule ROUTE '192.168.0.0/24' TO internal_group;
CREATE ROUTING RULE

=> CREATE ROUTING RULE external_rule ROUTE '0.0.0.0/0' TO external_group;
CREATE ROUTING RULE

=> SELECT DESCRIBE_LOAD_BALANCE_DECISION('198.51.100.10');
                         DESCRIBE_LOAD_BALANCE_DECISION
-------------------------------------------------------------------------------
 Describing load balance decision for address [198.51.100.10]
Load balance cache internal version id (node-local): [3]
Considered rule [internal_rule] source ip filter [192.168.0.0/24]... input
address does not match source ip filter for this rule.
Considered rule [external_rule] source ip filter [0.0.0.0/0]... input
address matches this rule
Matched to load balance group [external_group] the group has policy [ROUNDROBIN]
number of addresses [3]
(0) LB Address: [203.0.113.1]:5433
(1) LB Address: [203.0.113.2]:5433
(2) LB Address: [203.0.113.3]:5433
Chose address at position [2]
Routing table decision: Success. Load balance redirect to: [203.0.113.3] port [5433]

(1 row)

=> SELECT DESCRIBE_LOAD_BALANCE_DECISION('198.51.100.10');

                         DESCRIBE_LOAD_BALANCE_DECISION
-------------------------------------------------------------------------------
 Describing load balance decision for address [192.168.0.79]
Load balance cache internal version id (node-local): [3]
Considered rule [internal_rule] source ip filter [192.168.0.0/24]... input
address matches this rule
Matched to load balance group [internal_group] the group has policy [ROUNDROBIN]
number of addresses [3]
(0) LB Address: [192.168.0.1]:5433
(1) LB Address: [192.168.0.3]:5433
(2) LB Address: [192.168.0.2]:5433
Chose address at position [2]
Routing table decision: Success. Load balance redirect to: [192.168.0.2] port
[5433]

(1 row)

隔离工作负载

您可能希望控制特定类型的客户端使用群集中的哪些节点。例如，您可能希望将执行数据加载任务的客户端限制为一组节点，并保留其余节点来运行查询。以这种方式分离工作负载对于 Eon 模式数据库尤为常见。有关在 Eon 模式数据库中使用负载均衡策略来控制客户端连接到哪个子群集的示例，请参阅控制查询的运行位置。

如果执行某些任务类型的客户端始终源自有限的 IP 地址范围，您可以创建支持工作负载隔离的客户端负载均衡策略。例如，如果用来将数据加载到系统中的客户端始终属于特定子网，则可以创建一个策略来限制这些客户端可以访问哪些节点。

在以下示例中：

通过两个容错组（group_a 和 group_b）来分离 Eon 模式数据库中的工作负载。这些组用作负载均衡组的基础。
ETL 客户端连接全部源自 203.0.113.0/24 子网。
用户连接源自 192.0.0.0 到 199.255.255.255 的范围。

=> CREATE NETWORK ADDRESS node01 ON v_vmart_node0001 WITH '192.0.2.1';
CREATE NETWORK ADDRESS
=> CREATE NETWORK ADDRESS node02 ON v_vmart_node0002 WITH '192.0.2.2';
CREATE NETWORK ADDRESS
=> CREATE NETWORK ADDRESS node03 ON v_vmart_node0003 WITH '192.0.2.3';
CREATE NETWORK ADDRESS
=> CREATE NETWORK ADDRESS node04 ON v_vmart_node0004 WITH '192.0.2.4';
CREATE NETWORK ADDRESS
=> CREATE NETWORK ADDRESS node05 ON v_vmart_node0005 WITH '192.0.2.5';
CREATE NETWORK ADDRESS
                                                     ^
=> CREATE LOAD BALANCE GROUP lb_users WITH FAULT GROUP group_a FILTER '192.0.2.0/24';
CREATE LOAD BALANCE GROUP
=> CREATE LOAD BALANCE GROUP lb_etl WITH FAULT GROUP group_b FILTER '192.0.2.0/24';
CREATE LOAD BALANCE GROUP
=> CREATE ROUTING RULE users_rule ROUTE '192.0.0.0/5' TO lb_users;
CREATE ROUTING RULE
=> CREATE ROUTING RULE etl_rule ROUTE '203.0.113.0/24' TO lb_etl;
CREATE ROUTING RULE

=> SELECT DESCRIBE_LOAD_BALANCE_DECISION('198.51.200.129');
                          DESCRIBE_LOAD_BALANCE_DECISION
-------------------------------------------------------------------------------
 Describing load balance decision for address [198.51.200.129]
Load balance cache internal version id (node-local): [6]
Considered rule [etl_rule] source ip filter [203.0.113.0/24]... input address
does not match source ip filter for this rule.
Considered rule [users_rule] source ip filter [192.0.0.0/5]... input address
matches this rule
Matched to load balance group [lb_users] the group has policy [ROUNDROBIN]
number of addresses [3]
(0) LB Address: [192.0.2.1]:5433
(1) LB Address: [192.0.2.2]:5433
(2) LB Address: [192.0.2.3]:5433
Chose address at position [1]
Routing table decision: Success. Load balance redirect to: [192.0.2.2] port
[5433]

(1 row)

=> SELECT DESCRIBE_LOAD_BALANCE_DECISION('203.0.113.24');
                             DESCRIBE_LOAD_BALANCE_DECISION
-------------------------------------------------------------------------------
 Describing load balance decision for address [203.0.113.24]
Load balance cache internal version id (node-local): [6]
Considered rule [etl_rule] source ip filter [203.0.113.0/24]... input address
matches this rule
Matched to load balance group [lb_etl] the group has policy [ROUNDROBIN] number
of addresses [2]
(0) LB Address: [192.0.2.4]:5433
(1) LB Address: [192.0.2.5]:5433
Chose address at position [1]
Routing table decision: Success. Load balance redirect to: [192.0.2.5] port
[5433]

(1 row)

=> SELECT DESCRIBE_LOAD_BALANCE_DECISION('10.20.100.25');
                           DESCRIBE_LOAD_BALANCE_DECISION
-------------------------------------------------------------------------------
 Describing load balance decision for address [10.20.100.25]
Load balance cache internal version id (node-local): [6]
Considered rule [etl_rule] source ip filter [203.0.113.0/24]... input address
does not match source ip filter for this rule.
Considered rule [users_rule] source ip filter [192.0.0.0/5]... input address
does not match source ip filter for this rule.
Routing table decision: No matching routing rules: input address does not match
any routing rule source filters. Details: [Tried some rules but no matching]
No rules matched. Falling back to classic load balancing.
Classic load balance decision: Classic load balancing considered, but either the
policy was NONE or no target was available. Details: [NONE or invalid]

(1 row)

启用默认子群集内部负载均衡策略

如果没有其他负载均衡策略适用于传入连接并且未启用经典负载均衡，Vertica 会尝试应用默认的子群集内部负载均衡策略。有关此规则的说明，请参阅默认子群集内部负载均衡策略。

要启用默认子群集内部负载均衡，必须为子群集中的节点创建网络地址。创建地址后，Vertica 会在没有其他规则适用时尝试应用此规则来对子群集内的连接进行负载均衡。

以下示例确认数据库没有负载均衡组或规则。然后它将可公开访问的网络地址添加到主子群集中的节点。添加这些地址后，Vertica 应用默认的子群集内部负载均衡策略。

=> SELECT * FROM LOAD_BALANCE_GROUPS;
 name | policy | filter | type | object_name
------+--------+--------+------+-------------
(0 rows)

=> SELECT * FROM ROUTING_RULES;
 name | source_address | destination_name
------+----------------+------------------
(0 rows)

=> CREATE NETWORK ADDRESS node01_ext ON v_verticadb_node0001 WITH '203.0.113.1';
CREATE NETWORK ADDRESS
=> CREATE NETWORK ADDRESS node02_ext ON v_verticadb_node0002 WITH '203.0.113.2';
CREATE NETWORK ADDRESS
=> CREATE NETWORK ADDRESS node03_ext ON v_verticadb_node0003 WITH '203.0.113.3';
CREATE NETWORK ADDRESS

=> SELECT describe_load_balance_decision('11.0.0.100');
                                describe_load_balance_decision
-----------------------------------------------------------------------------------------------
Describing load balance decision for address [11.0.0.100] on subcluster [default_subcluster]
Load balance cache internal version id (node-local): [2]
Considered rule [auto_rr_default_subcluster] subcluster interior filter  [default_subcluster]...
current subcluster matches this rule
Matched to load balance group [auto_lbg_sc_default_subcluster] the group has policy
[ROUNDROBIN] number of addresses [3]
(0) LB Address: [203.0.113.1]:5433
(1) LB Address: [203.0.113.2]:5433
(2) LB Address: [203.0.113.3]:5433
Chose address at position [1]
Routing table decision: Success. Load balance redirect to: [203.0.113.2] port [5433]

(1 row)

对 IPv4 和 IPv6 连接进行负载均衡

连接负载均衡策略将 IPv4 和 IPv6 连接视为不同的网络。要对两种类型的传入客户端连接进行负载均衡，请创建两组网络地址、至少两个负载均衡组和两个负载均衡，对于每个网络地址系列各创建一次。

以下示例为默认子群集创建两个负载均衡策略：一个用于 IPv4 网络地址（192.168.111.31 到 192.168.111.33），另一个用于 IPv6 网络地址（fd9b:1fcc:1dc4:78d3::31 到 fd9b:1fcc:1dc4:78d3::33）。

=> SELECT node_name,node_address,subcluster_name FROM NODES;
      node_name       |  node_address  |  subcluster_name
----------------------+----------------+--------------------
 v_verticadb_node0001 | 192.168.111.31 | default_subcluster
 v_verticadb_node0002 | 192.168.111.32 | default_subcluster
 v_verticadb_node0003 | 192.168.111.33 | default_subcluster

=> CREATE NETWORK ADDRESS node01 ON v_verticadb_node0001 WITH
   '192.168.111.31';
CREATE NETWORK ADDRESS
=> CREATE NETWORK ADDRESS node01_ipv6 ON v_verticadb_node0001 WITH
   'fd9b:1fcc:1dc4:78d3::31';
CREATE NETWORK ADDRESS
=> CREATE NETWORK ADDRESS node02 ON v_verticadb_node0002 WITH
   '192.168.111.32';
CREATE NETWORK ADDRESS
=> CREATE NETWORK ADDRESS node02_ipv6 ON v_verticadb_node0002 WITH
   'fd9b:1fcc:1dc4:78d3::32';
CREATE NETWORK ADDRESS
=> CREATE NETWORK ADDRESS node03 ON v_verticadb_node0003 WITH
   '192.168.111.33';
CREATE NETWORK ADDRESS
=> CREATE NETWORK ADDRESS node03_ipv6 ON v_verticadb_node0003 WITH
   'fd9b:1fcc:1dc4:78d3::33';
CREATE NETWORK ADDRESS

=> CREATE LOAD BALANCE GROUP group_ipv4 WITH SUBCLUSTER default_subcluster
   FILTER '192.168.111.0/24';
CREATE LOAD BALANCE GROUP
=> CREATE LOAD BALANCE GROUP group_ipv6 WITH SUBCLUSTER default_subcluster
   FILTER 'fd9b:1fcc:1dc4:78d3::0/64';
CREATE LOAD BALANCE GROUP

=> CREATE ROUTING RULE all_ipv4 route '0.0.0.0/0' TO group_ipv4;
CREATE ROUTING RULE
=> CREATE ROUTING RULE all_ipv6 route '0::0/0' TO group_ipv6;
CREATE ROUTING RULE

=> SELECT describe_load_balance_decision('203.0.113.50');
                                                                                                                                                                                                                                                                                   describe_load_balance_decision
-----------------------------------------------------------------------------------------------
Describing load balance decision for address [203.0.113.50] on subcluster [default_subcluster]
Load balance cache internal version id (node-local): [3]
Considered rule [all_ipv4] source ip filter [0.0.0.0/0]... input address matches this rule
Matched to load balance group [ group_ipv4] the group has policy [ROUNDROBIN] number of addresses [3]
(0) LB Address: [192.168.111.31]:5433
(1) LB Address: [192.168.111.32]:5433
(2) LB Address: [192.168.111.33]:5433
Chose address at position [2]
Routing table decision: Success. Load balance redirect to: [192.168.111.33] port [5433]

(1 row)

=> SELECT describe_load_balance_decision('2001:0DB8:EA04:8F2C::1');
                                                                                                                                                                                                                                                                                                                                                                    describe_load_balance_decision
---------------------------------------------------------------------------------------------------------
Describing load balance decision for address [2001:0DB8:EA04:8F2C::1] on subcluster [default_subcluster]
Load balance cache internal version id (node-local): [3]
Considered rule [all_ipv4] source ip filter [0.0.0.0/0]... input address does not match source ip filter for this rule.
Considered rule [all_ipv6] source ip filter [0::0/0]... input address matches this rule
Matched to load balance group [ group_ipv6] the group has policy [ROUNDROBIN] number of addresses [3]
(0) LB Address: [fd9b:1fcc:1dc4:78d3::31]:5433
(1) LB Address: [fd9b:1fcc:1dc4:78d3::32]:5433
(2) LB Address: [fd9b:1fcc:1dc4:78d3::33]:5433
Chose address at position [2]
Routing table decision: Success. Load balance redirect to: [fd9b:1fcc:1dc4:78d3::33] port [5433]

(1 row)

其他示例

有关使用连接负载均衡的其他示例，请参阅以下主题：