CuratorFrameworkFactory有四种重连策略,均实现了RetryPolicy接口.

zk server端timeout参数
tickTime：zk的心跳间隔(heartbeat interval）,也是session timeout基本单位.单位为毫秒.
minSessionTimeout:最小超时时间,zk设置的默认值为2*tickTime.
maxSessionTimeout:最大超时时间,zk设置的默认值为20*tickTime.

客户端实际的超时时间.

int minSessionTimeout = zk.getMinSessionTimeout();
if (sessionTimeout < minSessionTimeout) {
sessionTimeout = minSessionTimeout;
}
int maxSessionTimeout = zk.getMaxSessionTimeout();
if (sessionTimeout > maxSessionTimeout) {
sessionTimeout = maxSessionTimeout;
}

如果sessionTimeout的设置小于minSessionTimeout,则采用服务器的minSessionTimeout配置
如果sessionTimeout的设置大于maxSessionTimeout,则采用服务器的maxSessionTimeout配置.
客户端的超时设置,不能超过服务器端配置的范围

Curator 的客户端超时设置.
CuratorFrameworkFactory.newClient
连接超时15s
Session超时60s

private static final int DEFAULT_SESSION_TIMEOUT_MS = Integer.getInteger("curator-default-session-timeout", 60 * 1000);
private static final int DEFAULT_CONNECTION_TIMEOUT_MS = Integer.getInteger("curator-default-connection-timeout", 15 * 1000);
public static CuratorFramework newClient(String connectString, RetryPolicy retryPolicy)
{
return newClient(connectString, DEFAULT_SESSION_TIMEOUT_MS, DEFAULT_CONNECTION_TIMEOUT_MS, retryPolicy);
}

Curator 四种重连策略
1.RetryUntilElapsed(int maxElapsedTimeMs, int sleepMsBetweenRetries)
以sleepMsBetweenRetries的间隔重连,直到超过maxElapsedTimeMs的时间设置

2.RetryNTimes(int n, int sleepMsBetweenRetries)
指定重连次数

3.RetryOneTime(int sleepMsBetweenRetry)
重连一次,简单粗暴

4.ExponentialBackoffRetry
ExponentialBackoffRetry(int baseSleepTimeMs, int maxRetries)
ExponentialBackoffRetry(int baseSleepTimeMs, int maxRetries, int maxSleepMs)

时间间隔 = baseSleepTimeMs * Math.max(1, random.nextInt(1 << (retryCount + 1)))

ITPub博客

Curator 重连策略与超时

最新文章