第30课 Master的注册机制和状态管理解密

一 、master对其他组件注册的处理

1， master接受注册的对象主要就是：driver，application，worker；需要补充说明executor不会注册给master，executor是注册给driver中的schedulerbackbend的；

2， worker是再启动后主动向master注册的，所以如果在生产环境下加入新的worker到已经正在运行的Spark集群上，此时不需要重新启动spark集群就能够使用新加入的worker以提升处理能力；

<code class="hljs perl has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">case RegisterWorker(    id, workerHost, workerPort, workerRef, cores, memory, workerUiPort, publicAddress)=> {  logInfo(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Registeringworker <span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">%s</span>:<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">%d</span> with <span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">%d</span> cores, <span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">%s</span> RAM"</span>.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">format</span>(    workerHost, workerPort, cores, Utils.megabytesToString(memory)))  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">state</span> == RecoveryState.STANDBY) {    context.reply(MasterInStandby)  } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (idToWorker.contains(id)) {    context.reply(RegisterWorkerFailed(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Duplicate worker ID"</span>))  } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {    val worker = new WorkerInfo(id, workerHost, workerPort, cores, memory,      workerRef, workerUiPort, publicAddress)    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (registerWorker(worker)) {      persistenceEngine.addWorker(worker)      context.reply(RegisteredWorker(self, masterWebUiUrl))      schedule()    } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {      val workerAddress = worker.endpoint.address      logWarning(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Workerregistration failed. Attempted to re-register worker at same "</span> +        <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"address:"</span> + workerAddress)      context.reply(RegisterWorkerFailed(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Attempted to re-register worker at sameaddress: "</span>        + workerAddress))    }  }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li></ul>

3， master在接收到worker注册的请求后，首先会判断一下当前的master是否是standby的模式，如果是的话就不处理；然后会判断当前master的内存数据结构idToWorker中是否已经有该worker的注册信息，如果有的话此时不会重复注册；

4， master如果决定接收注册的worker，首先会创建workerInfo对象来保存注册的worker信息；

<code class="hljs fsharp has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span>[spark] <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> WorkerInfo(    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">val</span> id: String,    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">val</span> host: String,    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">val</span> port: Int,    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">val</span> cores: Int,    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">val</span> memory: Int,    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">val</span> endpoint: RpcEndpointRef,    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">val</span> webUiPort: Int,    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">val</span> publicAddress: String)  extends Serializable {  }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li></ul>

然后调用registerWorker来执行具体的注册过程，如果worker的状态是否是dead的状态则直接过滤掉，对于unknown装的内容调用removeWorker进行清理（包括清理worker下的executors和driver）

5， 注册时候是先注册driver然后在注册application；

二 master对driver和executor状态变化的处理

1， 对driver状态变化的处理

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">case DriverState<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ERROR</span> | DriverState<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.FINISHED</span> | DriverState<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.KILLED</span> | DriverState<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.FAILED</span> =>  removeDriver(driverId, state, exception)</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

2， Executor挂掉的时候系统会尝试一定次数的重启（最多重试10次重启）