[
https://issues.apache.org/jira/browse/HDFS-17906?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
dzcxzl updated HDFS-17906:
--------------------------
Description:
HDFS-16942 introduced `InvalidBlockReportLeaseException`, which the NameNode
now throws back to the DataNode via RPC when a block report is rejected due to
an invalid lease. On a DataNode that also includes HDFS-16942, the exception is
caught and `fullBlockReportLeaseId` is reset to 0, allowing the DN to request a
new lease on the next heartbeat and retry.
However, during a rolling upgrade where the NameNode has been upgraded (with
HDFS-16942) but DataNodes are still running an older version (without
HDFS-16942), the old DataNode code does not have the
`InvalidBlockReportLeaseException` handling branch in
`BPServiceActor.offerService()`. This causes the DN to enter an infinite
failure loop where it can never successfully send a full block report.
was:
## Description
HDFS-16942 introduced `InvalidBlockReportLeaseException`, which the NameNode
now throws back to the DataNode via RPC when a block report is rejected due to
an invalid lease. On a DataNode that also includes HDFS-16942, the exception is
caught and `fullBlockReportLeaseId` is reset to 0, allowing the DN to request a
new lease on the next heartbeat and retry.
However, during a rolling upgrade where the NameNode has been upgraded (with
HDFS-16942) but DataNodes are still running an older version (without
HDFS-16942), the old DataNode code does not have the
`InvalidBlockReportLeaseException` handling branch in
`BPServiceActor.offerService()`. This causes the DN to enter an infinite
failure loop where it can never successfully send a full block report.
## Root Cause
In `BPServiceActor.offerService()`, the logic works as follows:
1. The DN requests a block report lease during heartbeat only when
`fullBlockReportLeaseId == 0`:
```java
boolean requestBlockReportLease = (fullBlockReportLeaseId == 0) &&
scheduler.isBlockReportDue(startTime);
```
2. After sending the block report, `fullBlockReportLeaseId` is reset to 0:
```java
if ((fullBlockReportLeaseId != 0) || forceFullBr) {
cmds = blockReport(fullBlockReportLeaseId);
fullBlockReportLeaseId = 0; // not reached if blockReport() throws
}
```
3. When the upgraded NN throws `InvalidBlockReportLeaseException`,
`blockReport()` propagates the exception. The `fullBlockReportLeaseId = 0` line
after the call is never executed.
4. The exception is caught by the generic `RemoteException` catch block. The
old DN code does not recognize `InvalidBlockReportLeaseException`, so
`fullBlockReportLeaseId` remains set to the stale invalid value.
5. On the next heartbeat iteration, because `fullBlockReportLeaseId != 0`,
`requestBlockReportLease` is `false` — the DN does not request a new lease. It
then attempts `blockReport()` again with the same stale lease, which the NN
rejects again. This repeats indefinitely.
> Rolling upgrade: old DataNodes get stuck in infinite invalid block report
> lease loop
> ------------------------------------------------------------------------------------
>
> Key: HDFS-17906
> URL: https://issues.apache.org/jira/browse/HDFS-17906
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: datanode
> Reporter: dzcxzl
> Priority: Major
>
>
> HDFS-16942 introduced `InvalidBlockReportLeaseException`, which the NameNode
> now throws back to the DataNode via RPC when a block report is rejected due
> to an invalid lease. On a DataNode that also includes HDFS-16942, the
> exception is caught and `fullBlockReportLeaseId` is reset to 0, allowing the
> DN to request a new lease on the next heartbeat and retry.
> However, during a rolling upgrade where the NameNode has been upgraded (with
> HDFS-16942) but DataNodes are still running an older version (without
> HDFS-16942), the old DataNode code does not have the
> `InvalidBlockReportLeaseException` handling branch in
> `BPServiceActor.offerService()`. This causes the DN to enter an infinite
> failure loop where it can never successfully send a full block report.
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