[
https://issues.apache.org/jira/browse/HDDS-9342?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17794305#comment-17794305
]
Sammi Chen commented on HDDS-9342:
----------------------------------
Together with [~wanghongbing] and [~z-bb] , we find the root cause of this.
There are three major issues shown in this case.
The first is a long full GC which caused OM to terminate itself,
{code:java}
2023-10-24 11:40:08,542 [JvmPauseMonitor0] WARN
org.apache.ratis.util.JvmPauseMonitor: JvmPauseMonitor-om2: Detected pause in
JVM or host machine approximately 131.539s with 131.735s GC time.
GC pool 'ParNew' had collection(s): count=1 time=1422ms
GC pool 'ConcurrentMarkSweep' had collection(s): count=1 time=130313ms
...
2023-10-24 11:40:08,552 [JvmPauseMonitor0] ERROR
org.apache.ratis.server.RaftServer: om2: JVM pause detected 131.539s longer
than the close-threshold 120s, shutting down ... {code}
The second is the gap between snapshot index taken during OM shutdown and
commitIndex in Raft is too huge, which leads to many raft logs need replay in
next OM start, and which also caused the third issue.
{code:java}
// Some comments here
2023-10-24 11:40:08,557 [om2-impl-thread2] INFO
org.apache.ratis.server.impl.StateMachineUpdater:
om2@group-197E298202B9-StateMachineUpdater: set stopIndex = 405823932
...
2023-10-24 11:40:13,773 [om2@group-197E298202B9-StateMachineUpdater] INFO
org.apache.ratis.server.impl.StateMachineUpdater:
om2@group-197E298202B9-StateMachineUpdater: Took a snapshot at index 206114616
2023-10-24 11:40:13,776 [om2@group-197E298202B9-StateMachineUpdater] INFO
org.apache.ratis.server.impl.StateMachineUpdater:
om2@group-197E298202B9-StateMachineUpdater: snapshotIndex: updateIncreasingly
205866698 -> 206114616
...
2023-10-24 12:02:58,532 [om2-impl-thread1] INFO
org.apache.ratis.server.raftlog.segmented.SegmentedRaftLogWorker:
om2@group-197E298202B9-SegmentedRaftLogWorker: flushIndex: setUnconditionally 0
-> 405823932
2023-10-24 12:02:58,532 [om2-impl-thread1] INFO
org.apache.ratis.server.raftlog.segmented.SegmentedRaftLogWorker:
om2@group-197E298202B9-SegmentedRaftLogWorker: safeCacheEvictIndex:
setUnconditionally 0 -> 206114616
2023-10-24 12:02:58,619 [om2-impl-thread1] INFO
org.apache.ratis.server.raftlog.RaftLog:
om2@group-197E298202B9-SegmentedRaftLog: commitIndex: updateToMax
old=206114616, new=405823931, updated? true
2023-10-24 12:02:58,619 [om2-impl-thread1] INFO
org.apache.ratis.server.raftlog.RaftLog:
om2@group-197E298202B9-SegmentedRaftLog: purgeIndex: updateIncreasingly -1 ->
206094557
{code}
The third is the OM start failure due to raft log replay failure,
{code:java}
2023-10-24 12:02:59,086 [OM StateMachine ApplyTransaction Thread - 0] ERROR
org.apache.hadoop.ozone.om.ratis.OzoneManagerStateMachine: Terminating with
exit status 1: Request cmdType: RenameKey
traceID: ""
clientId: "client-9300289B92FF"
userInfo {
userName: "weisuonan"
remoteAddress: "10.83.99.62"
hostName: "bigdata-apache-tool1.nmg01.diditaxi.com"
}
version: 3
renameKeyRequest {
keyArgs {
volumeName: "vol-bigdata-offline"
bucketName: "weisuonan"
keyName: "checkative/english-book_Ozone"
dataSize: 0
modificationTime: 1697627113034
}
toKeyName:
".Trash/weisuonan/Current/vol-bigdata-offline/weisuonan/checkative/english-book_Ozone1697627113026"
}
failed with exception
java.lang.IllegalArgumentException: Trying to set updateID to 206114651 which
is not greater than the current value of 405823931 for
OMKeyInfo{volume='vol-bigdata-offline', bucket='weisuonan',
key='checkative/english-book_Ozone', dataSize='23124',
creationTime='1698118516546', objectID='-9223371932963850495',
parentID='-9223372036604311807', replication='RATIS/THREE', fileChecksum='null}
at
org.apache.hadoop.ozone.om.helpers.WithObjectID.setUpdateID(WithObjectID.java:107)
at
org.apache.hadoop.ozone.om.request.key.OMKeyRenameRequestWithFSO.renameKey(OMKeyRenameRequestWithFSO.java:286)
at
org.apache.hadoop.ozone.om.request.key.OMKeyRenameRequestWithFSO.validateAndUpdateCache(OMKeyRenameRequestWithFSO.java:219)
at
org.apache.hadoop.ozone.protocolPB.OzoneManagerRequestHandler.handleWriteRequest(OzoneManagerRequestHandler.java:382)
at
org.apache.hadoop.ozone.om.ratis.OzoneManagerStateMachine.runCommand(OzoneManagerStateMachine.java:572)
at
org.apache.hadoop.ozone.om.ratis.OzoneManagerStateMachine.lambda$1(OzoneManagerStateMachine.java:362)
at
java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
{code}
After an analysis, all the issues are one root cause. HDDS-2680 introduced a
logic in OzoneManagerStateMachine to calculate the lastAppliedTermIndex based
on two maps, applyTransactionMap and ratisTransactionMap. Any write request
from RATIS through applyTransaction will add its trxLogIndex into
applyTransactionMap. And any write request which is flushed by
OzoneManagerDoubleBuffer#flushBatch will have its trxLogIndex removed from
applyTransactionMap during flushBatch call
ozoneManagerRatisSnapShot.updateLastAppliedIndex(flushedEpochs).
If any write request from RATIS not going through
OzoneManagerDoubleBuffer#flushBatch, then its trxLogIndex will be left in the
applyTransactionMap forever. Since lastApplicedIndex can only be updated
incrementally, any trxLogIndex not confirmed by OzoneManagerDoubleBuffer flush
will make the lastApplicedIndex grow stops before it, and although write
requests after that unconfirmed one could be flushed, but their trxLogIndex
will be added to the ratisTransactionMap, which causes the ratisTransactionMap
grow bigger and bigger. These explains the full GC, the huge gap between
snapshot index and commit index.
How a write request will not be confirmed by OzoneManagerDoubleBuffer flush?
Here is one case reproduced locally.
T1: create bucket1
T2: client1 sends delete bucket "bucket1" request to OM. OM verify bucket1
exists, then send request to RATIS to handle the request.
T3: client2 sends create key "bucket1/key1" request to OM. OM verify bucket2
exists, then send request to RATIS
T4: OzoneManagerStateMachine executes delete bucket "bucket1" success, return
response to client1
T5: OzoneManagerStateMachine executes create key "bucket1/key1" request,
"bucket1" cannot be found, execution fails, return failure to client2
In T5, the failure stack is
{code:java}
2023-10-18 19:04:10,131 [OM StateMachine ApplyTransaction Thread - 0] WARN
org.apache.hadoop.ozone.om.ratis.OzoneManagerStateMachine: Failed to write,
Exception occurred
BUCKET_NOT_FOUND org.apache.hadoop.ozone.om.exceptions.OMException: Bucket not
found: s3v/prod-voyager
at
org.apache.hadoop.ozone.om.OzoneManagerUtils.reportNotFound(OzoneManagerUtils.java:87)
at
org.apache.hadoop.ozone.om.OzoneManagerUtils.getBucketInfo(OzoneManagerUtils.java:72)
at
org.apache.hadoop.ozone.om.OzoneManagerUtils.resolveBucketInfoLink(OzoneManagerUtils.java:148)
at
org.apache.hadoop.ozone.om.OzoneManagerUtils.getResolvedBucketInfo(OzoneManagerUtils.java:124)
at
org.apache.hadoop.ozone.om.OzoneManagerUtils.getBucketLayout(OzoneManagerUtils.java:106)
at
org.apache.hadoop.ozone.om.request.BucketLayoutAwareOMKeyRequestFactory.createRequest(BucketLayoutAwareOMKeyRequestFactory.java:230)
at
org.apache.hadoop.ozone.om.ratis.utils.OzoneManagerRatisUtils.createClientRequest(OzoneManagerRatisUtils.java:336)
at
org.apache.hadoop.ozone.protocolPB.OzoneManagerRequestHandler.handleWriteRequest(OzoneManagerRequestHandler.java:380)
at
org.apache.hadoop.ozone.om.ratis.OzoneManagerStateMachine.runCommand(OzoneManagerStateMachine.java:572)
at
org.apache.hadoop.ozone.om.ratis.OzoneManagerStateMachine.lambda$1(OzoneManagerStateMachine.java:362)
at
java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
{code}
In OzoneManagerStateMachine.runCommand, when IOException is throw out from
OzoneManagerRequestHandler.handleWriteRequest, it constructs and returns
OMResponse to client, it doesn't add the response into
OzoneManagerDoubleBuffer, so OzoneManagerDoubleBuffer doesn't aware of this
request and its trxLogIndex. The consequence is this trxLogIndex will be stay
in applyTransactionMap forever. The failed OM logs confirmed that.
> OM restart failed due to transactionLogIndex smaller than current updateID
> --------------------------------------------------------------------------
>
> Key: HDDS-9342
> URL: https://issues.apache.org/jira/browse/HDDS-9342
> Project: Apache Ozone
> Issue Type: Bug
> Components: OM, OM HA
> Affects Versions: 1.3.0
> Reporter: Hongbing Wang
> Priority: Critical
> Attachments: HDDS-9342_testUpdateId.patch,
> HDDS-9342_testUpdateId_reproduce.patch, clipboard_image_1700795744614.png,
> om.shutdown-20230922.log
>
>
> OM restart failed, log as follow:
> create failed:
> {noformat}
> java.lang.IllegalArgumentException: Trying to set updateID to 2901863625
> which is not greater than the current value of 2901863627 for
> OMKeyInfo{volume='vol-xxx', bucket='xxx', key='user/xxx/platform/xxx',
> dataSize='268435456', creationTime='1695088210914',
> objectID='-9223371293977687808', parentID='0', replication='RATIS/THREE',
> fileChecksum='null}
> at
> org.apache.hadoop.ozone.om.helpers.WithObjectID.setUpdateID(WithObjectID.java:105)
> at
> org.apache.hadoop.ozone.om.request.key.OMKeyRequest.prepareFileInfo(OMKeyRequest.java:665)
> at
> org.apache.hadoop.ozone.om.request.key.OMKeyRequest.prepareKeyInfo(OMKeyRequest.java:623)
> at
> org.apache.hadoop.ozone.om.request.file.OMFileCreateRequest.validateAndUpdateCache(OMFileCreateRequest.java:255)
> at
> org.apache.hadoop.ozone.protocolPB.OzoneManagerRequestHandler.handleWriteRequest(OzoneManagerRequestHandler.java:311)
> at
> org.apache.hadoop.ozone.protocolPB.OzoneManagerRouterRequestHandler.handleWriteRequest(OzoneManagerRouterRequestHandler.java:806)
> at
> org.apache.hadoop.ozone.om.ratis.OzoneManagerStateMachine.runCommand(OzoneManagerStateMachine.java:535)
> at
> org.apache.hadoop.ozone.om.ratis.OzoneManagerStateMachine.lambda$1(OzoneManagerStateMachine.java:326)
> at
> java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:745)
> {noformat}
> rename failed:
> {noformat}
> java.lang.IllegalArgumentException: Trying to set updateID to 2901863669
> which is not greater than the current value of 3076345041 for
> OMKeyInfo{volume='vol-xxx', bucket='xxx', key='checkative/xxx',
> dataSize='23124', creationTime='1695380440059',
> objectID='-9223371249310446848', parentID='0', replication='RATIS/THREE',
> fileChecksum='null}
> at
> org.apache.hadoop.ozone.om.helpers.WithObjectID.setUpdateID(WithObjectID.java:105)
> at
> org.apache.hadoop.ozone.om.request.key.OMKeyRenameRequest.validateAndUpdateCache(OMKeyRenameRequest.java:190)
> at
> org.apache.hadoop.ozone.protocolPB.OzoneManagerRequestHandler.handleWriteRequest(OzoneManagerRequestHandler.java:311)
> at
> org.apache.hadoop.ozone.protocolPB.OzoneManagerRouterRequestHandler.handleWriteRequest(OzoneManagerRouterRequestHandler.java:806)
> at
> org.apache.hadoop.ozone.om.ratis.OzoneManagerStateMachine.runCommand(OzoneManagerStateMachine.java:535)
> at
> org.apache.hadoop.ozone.om.ratis.OzoneManagerStateMachine.lambda$1(OzoneManagerStateMachine.java:326)
> at
> java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:745)
> {noformat}
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
