Ribbon Loadbalance核心接口
接口列表
- IRule
- ILoadBalancer
- ServerList
- ServerListFilter
- IPing
功能介紹
配置入口:RibbonClientConfiguration
合適的方式選擇合適的節點
ILoadBalancer
接口定義:com.netflix.loadbalancer.ILoadBalancer
核心方法:
/**
* Choose a server from load balancer.
*
* @param key An object that the load balancer may use to determine which server to return. null if
* the load balancer does not use this parameter.
* @return server chosen
*/
public Server chooseServer(Object key);
/**
* @return Only the servers that are up and reachable.
*/
public List<Server> getReachableServers();
/**
* @return All known servers, both reachable and unreachable.
*/
public List<Server> getAllServers();
核心作用:維護全量服務列表及可用列表,依賴IPing接口標記失效節點,標識失效依賴IPing實現
默認實現:ZoneAwareLoadBalancer
IRule
接口定義:com.netflix.loadbalancer.IRule
核心方法:
/*
* choose one alive server from lb.allServers or
* lb.upServers according to key
*
* @return choosen Server object. NULL is returned if none
* server is available
*/
public Server choose(Object key);
核心作用:從loadbalance裏面選取一個server;提供多種選擇策略
默認實現:ZoneAvoidanceRule
ServerList
接口定義:com.netflix.loadbalancer.ServerList
核心方法:
/**
* Return updated list of servers. This is called say every 30 secs
* (configurable) by the Loadbalancer's Ping cycle
*
*/
public List<T> getUpdatedListOfServers();
核心作用:獲取更新服務列表
默認實現:ConfigurationBasedServerList
ServerListFilter
接口定義:com.netflix.loadbalancer.ServerListFilter
核心方法:
public List<T> getFilteredListOfServers(List<T> servers);
核心作用:
默認實現:ZonePreferenceServerListFilter
IPing
接口定義:com.netflix.loadbalancer.IPing
核心方法:
/**
* Checks whether the given <code>Server</code> is "alive" i.e. should be
* considered a candidate while loadbalancing
*
*/
public boolean isAlive(Server server);
核心作用:檢測特定服務是否活着,在ILoadBalance中做失效服務檢測作用
默認實現:DummyPing
擴展思考
Ribbon最大的有點就是允許用戶定製化各種規則,很好的管理了節點狀態及訪問規則,基於規則擴展做一些好用的產品,比如灰度管理、目標節點能力不對等下的權重控制