big-data/hadoop
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

给BPServiceActor增加注释

Browse Source
This commit is contained in:
LingZhaoHui 2024-07-28 20:24:00 +08:00
parent 629d31909f
commit ddc50a86f7
Signed by: zeekling
GPG Key ID: D96E4E75267CA2CC
1 changed files with 8 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BPServiceActor.java
View File

@ -532,7 +532,8 @@ private int calculateBlockReportPBSize(
} }
return reportSize; return reportSize;
} }
// 向NN发送心跳的主要实现
HeartbeatResponse sendHeartBeat(boolean requestBlockReportLease) HeartbeatResponse sendHeartBeat(boolean requestBlockReportLease)
throws IOException { throws IOException {
scheduler.scheduleNextHeartbeat(); scheduler.scheduleNextHeartbeat();
@ -587,6 +588,7 @@ void sendLifelineForTests() throws IOException {
} }
//This must be called only by BPOfferService //This must be called only by BPOfferService
// 入口函数，开始向NN注册当前DN
void start() { void start() {
if ((bpThread != null) && (bpThread.isAlive())) { if ((bpThread != null) && (bpThread.isAlive())) {
//Thread is started already //Thread is started already
@ -827,6 +829,7 @@ void register(NamespaceInfo nsInfo) throws IOException {
while (shouldRun()) { while (shouldRun()) {
try { try {
// Use returned registration from namenode with updated fields // Use returned registration from namenode with updated fields
// 向NN注册DataNodde
newBpRegistration = bpNamenode.registerDatanode(newBpRegistration); newBpRegistration = bpNamenode.registerDatanode(newBpRegistration);
newBpRegistration.setNamespaceInfo(nsInfo); newBpRegistration.setNamespaceInfo(nsInfo);
bpRegistration = newBpRegistration; bpRegistration = newBpRegistration;
@ -858,6 +861,7 @@ void register(NamespaceInfo nsInfo) throws IOException {
fullBlockReportLeaseId = 0; fullBlockReportLeaseId = 0;
// random short delay - helps scatter the BR from all DNs // random short delay - helps scatter the BR from all DNs
// 定时汇报block块信息给NN
scheduler.scheduleBlockReport(dnConf.initialBlockReportDelayMs, true); scheduler.scheduleBlockReport(dnConf.initialBlockReportDelayMs, true);
} }
@ -875,6 +879,7 @@ private void sleepAndLogInterrupts(int millis,
* No matter what kind of exception we get, keep retrying to offerService(). * No matter what kind of exception we get, keep retrying to offerService().
* That's the loop that connects to the NameNode and provides basic DataNode * That's the loop that connects to the NameNode and provides basic DataNode
* functionality. * functionality.
* 当前类本身就是一个异步线程，当前函数为线程的入口函数，线程由start函数启动。
* *
* Only stop when "shouldRun" or "shouldServiceRun" is turned off, which can * Only stop when "shouldRun" or "shouldServiceRun" is turned off, which can
* happen either at shutdown or due to refreshNamenodes. * happen either at shutdown or due to refreshNamenodes.
@ -888,6 +893,7 @@ public void run() {
// init stuff // init stuff
try { try {
// setup storage // setup storage
// 开始连接NN并且注册当前DN,主要分为两个阶段：1、握手，并且校验NS等信息。2、向NN注册当前DN。
connectToNNAndHandshake(); connectToNNAndHandshake();
break; break;
} catch (IOException ioe) { } catch (IOException ioe) {
@ -1527,4 +1533,4 @@ void stopCommandProcessingThread() {
commandProcessingThread.interrupt(); commandProcessingThread.interrupt();
} }
} }
} }