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https://issues.apache.org/jira/browse/FLINK-41435?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
LuChengxiang updated FLINK-41435:
---------------------------------
Description:
*Background*
Flink periodically obtains HDFS delegation tokens and distributes them through
HadoopDelegationTokenReceiver. The receiver currently adds the new credentials
to UserGroupInformation.getCurrentUser() on the refresh thread. Long-lived
Hadoop clients, such as checkpoint storage and the job-result store, capture a
UGI when their DFSClient is created and use tokens from that UGI for later RPC
connections.
If the refresh thread's current UGI is not the UGI captured by the client, the
client continues using the startup token even after a new token was created
successfully. The job later fails with SecretManager$InvalidToken at the 24h
deadline.
*Observed failure*
This was observed in a Kubernetes application-mode job. The primary failure was
in checkpoint storage:
CheckpointCoordinator.initializeCheckpointLocation
-> FsCheckpointStorageAccess.initializeLocationForCheckpoint
-> HadoopFileSystem.mkdirs
-> DFSClient.mkdirs
The checkpoint storage client reported InvalidToken for the startup token after
the refresh had created a new HDFS token and the receiver reported success. The
same JVM also showed a FileSystemJobResultStore.hasCleanJobResultEntryInternal
stack using the expired token during cleanup. The job-result store is therefore
a secondary long-lived client with the same failure mode, not the primary
trigger.
An earlier test build that skipped the second security installation (`Security
configuration is already installed`) still hit the 24h deadline; install
idempotency alone is therefore not sufficient.
FLINK-27204 (1.19+) moved FileSystemJobResultStore I/O onto the shared
cluster-io executor. DefaultDelegationTokenManager uses the same executor for
periodic token refresh. The provider and receiver are invoked sequentially on
the same refresh thread. The provider's freshUGI.doAs() scope ends before the
receiver runs, so the receiver's getCurrentUser() reflects the Subject
inherited by the cluster-io worker, not the provider's short-lived UGI.
HadoopSecurityContext and the refresh worker are not the same source of truth
for the current UGI. The context holds the UGI captured at security
installation. UserGroupInformation.getCurrentUser() on a pooled thread resolves
the Subject inherited by that worker when it was created. Because
FileSystemJobResultStore I/O and token refresh share cluster-io, the receiver
can run with a Subject from a different lifecycle than the context/login UGI.
The 1.18 path had synchronous FileSystemJobResultStore I/O, so this
worker/Subject interaction was not triggered in the deployments observed. 1.15
did not have the unified delegation-token manager path. These version
differences explain the observed frequency; they do not prove that those
versions are immune.
YARN with ZooKeeper HA uses the same FileSystemJobResultStore(ioExecutor) and
token-refresh code path, but this has not been reproduced on YARN. YARN is not
inherently exempt: its normal application-mode startup does not perform the
early security installation used for artifact fetching, so the first cluster-io
worker is normally created from the login/security context. The decisive
condition is the Subject inherited by that worker, not the platform name. YARN
is therefore not listed as a confirmed affected deployment type.
*Root cause*
HadoopDelegationTokenReceiver targets getCurrentUser() of the refresh thread.
That target is not guaranteed to be the UGI held by HadoopSecurityContext or
the UGI captured by a long-lived checkpoint storage or job-result-store
DFSClient.
*Proposed change*
This issue addresses the case where a token is obtained successfully but the
refreshed credentials do not reach long-lived Hadoop clients, primarily
checkpoint storage.
* Add an accessor for the UGI held by HadoopSecurityContext.
* In HadoopDelegationTokenReceiver, add refreshed credentials to the
security-context UGI and login UGI, with the current UGI as a fallback,
deduplicated by object identity.
* Add a test where the refresh thread's current user differs from the
security-context user, and verify that the security-context/login UGI receives
the credentials.
Out of scope for this issue:
* The separate case where HadoopFSDelegationTokenProvider evaluates
delegation-token requirements against the wrong current UGI and does not obtain
a token at all.
* Closing FileSystem instances created under the short-lived fresh UGI; this is
separate lifecycle cleanup.
* SecurityUtils.install idempotency.
*Testing*
* A JVM probe confirmed that a fixed thread pool created under Subject A but
first submitted under Subject B runs subsequent tasks under Subject B.
* Receiver test as described above.
* A deployed application-mode job should survive the 24h token deadline and
continue checkpointing without SecretManager$InvalidToken. Verify that the
checkpoint storage DFSClient receives the new token; the job-result-store
client should receive the same credentials because it uses the same target UGI.
*Acceptance criteria*
* A token refresh updates the UGI used by checkpoint storage and other
long-lived Hadoop clients.
* Refresh does not depend on the Subject inherited by the shared cluster-io
worker.
* A long-running application-mode job survives the 24h HDFS token deadline.
was:
*Background*
Flink periodically obtains HDFS delegation tokens and distributes them through
HadoopDelegationTokenReceiver. The receiver currently adds the new credentials
to UserGroupInformation.getCurrentUser() on the refresh thread. Long-lived
Hadoop clients capture a UGI when their DFSClient is created and use tokens
from that UGI for later RPC connections.
If the refresh thread's current UGI is not the UGI captured by the client, the
client continues using the startup token even after a new token was created
successfully. The job later fails with SecretManager$InvalidToken at the 24h
deadline.
*Observed failure*
This was observed in a Kubernetes application-mode job. The refresh created a
new HDFS token and the receiver reported success, but FileSystemJobResultStore
and checkpoint storage continued using the startup token. An earlier test build
that skipped the second security installation (`Security configuration is
already installed`) still hit the 24h deadline; install idempotency alone is
therefore not sufficient.
FLINK-27204 (1.19+) moved FileSystemJobResultStore I/O onto the shared
cluster-io executor. DefaultDelegationTokenManager uses the same executor for
periodic token refresh. The provider and receiver are invoked sequentially on
the same refresh thread. The provider's freshUGI.doAs() scope ends before the
receiver runs, so the receiver's getCurrentUser() reflects the Subject
inherited by the cluster-io worker, not the provider's short-lived UGI.
HadoopSecurityContext and the refresh worker are not the same source of truth
for the current UGI. The context holds the UGI captured at security
installation. UserGroupInformation.getCurrentUser() on a pooled thread resolves
the Subject inherited by that worker when it was created. Because
FileSystemJobResultStore I/O and token refresh share cluster-io, the receiver
can run with a Subject from a different lifecycle than the context/login UGI.
The 1.18 path had synchronous FileSystemJobResultStore I/O, so this
worker/Subject interaction was not triggered in the deployments observed. 1.15
did not have the unified delegation-token manager path. These version
differences explain the observed frequency; they do not prove that those
versions are immune.
YARN with ZooKeeper HA uses the same FileSystemJobResultStore(ioExecutor) and
token-refresh code path, but this has not been reproduced on YARN. YARN is not
inherently exempt: its normal application-mode startup does not perform the
early security installation used for artifact fetching, so the first cluster-io
worker is normally created from the login/security context. The decisive
condition is the Subject inherited by that worker, not the platform name. YARN
is therefore not listed as a confirmed affected deployment type.
*Root cause*
HadoopDelegationTokenReceiver targets getCurrentUser() of the refresh thread.
That target is not guaranteed to be the UGI held by HadoopSecurityContext or
the UGI captured by a long-lived FileSystemJobResultStore/checkpoint DFSClient.
*Proposed change*
This issue addresses the case where a token is obtained successfully but the
refreshed credentials do not reach long-lived Hadoop clients.
* Add an accessor for the UGI held by HadoopSecurityContext.
* In HadoopDelegationTokenReceiver, add refreshed credentials to the
security-context UGI and login UGI, with the current UGI as a fallback,
deduplicated by object identity.
* Add a test where the refresh thread's current user differs from the
security-context user, and verify that the security-context/login UGI receives
the credentials.
Out of scope for this issue:
* The separate case where HadoopFSDelegationTokenProvider evaluates
delegation-token requirements against the wrong current UGI and does not obtain
a token at all.
* Closing FileSystem instances created under the short-lived fresh UGI; this is
separate lifecycle cleanup.
* SecurityUtils.install idempotency.
*Testing*
* A JVM probe confirmed that a fixed thread pool created under Subject A but
first submitted under Subject B runs subsequent tasks under Subject B.
* Receiver test as described above.
* A deployed application-mode job should survive the 24h token deadline and
keep checkpointing without SecretManager$InvalidToken.
*Acceptance criteria*
* A token refresh updates the UGI used by FileSystemJobResultStore/checkpoint
DFSClient.
* Refresh does not depend on the Subject inherited by the shared cluster-io
worker.
* A long-running application-mode job survives the 24h HDFS token deadline.
> Hadoop delegation token refresh can target a different UGI than Hadoop clients
> ------------------------------------------------------------------------------
>
> Key: FLINK-41435
> URL: https://issues.apache.org/jira/browse/FLINK-41435
> Project: Flink
> Issue Type: Bug
> Components: Runtime / Configuration
> Affects Versions: 2.0.0, 1.19.0, 1.20.0, 2.1.0, 2.2.0, 2.3.0, 2.4.0
> Environment: Flink 1.19.0 and later (1.19.x, 1.20.x, 2.0 through
> 2.4), plus master (2.5-SNAPSHOT); Kubernetes and standalone application mode
> with Kerberos and HDFS delegation tokens. The mismatch is more likely when
> FileSystemJobResultStore and the token manager share the cluster-io executor
> (FLINK-27204).
> Reporter: LuChengxiang
> Priority: Major
>
> *Background*
> Flink periodically obtains HDFS delegation tokens and distributes them
> through HadoopDelegationTokenReceiver. The receiver currently adds the new
> credentials to UserGroupInformation.getCurrentUser() on the refresh thread.
> Long-lived Hadoop clients, such as checkpoint storage and the job-result
> store, capture a UGI when their DFSClient is created and use tokens from that
> UGI for later RPC connections.
> If the refresh thread's current UGI is not the UGI captured by the client,
> the client continues using the startup token even after a new token was
> created successfully. The job later fails with SecretManager$InvalidToken at
> the 24h deadline.
> *Observed failure*
> This was observed in a Kubernetes application-mode job. The primary failure
> was in checkpoint storage:
> CheckpointCoordinator.initializeCheckpointLocation
> -> FsCheckpointStorageAccess.initializeLocationForCheckpoint
> -> HadoopFileSystem.mkdirs
> -> DFSClient.mkdirs
> The checkpoint storage client reported InvalidToken for the startup token
> after the refresh had created a new HDFS token and the receiver reported
> success. The same JVM also showed a
> FileSystemJobResultStore.hasCleanJobResultEntryInternal stack using the
> expired token during cleanup. The job-result store is therefore a secondary
> long-lived client with the same failure mode, not the primary trigger.
> An earlier test build that skipped the second security installation
> (`Security configuration is already installed`) still hit the 24h deadline;
> install idempotency alone is therefore not sufficient.
> FLINK-27204 (1.19+) moved FileSystemJobResultStore I/O onto the shared
> cluster-io executor. DefaultDelegationTokenManager uses the same executor for
> periodic token refresh. The provider and receiver are invoked sequentially on
> the same refresh thread. The provider's freshUGI.doAs() scope ends before the
> receiver runs, so the receiver's getCurrentUser() reflects the Subject
> inherited by the cluster-io worker, not the provider's short-lived UGI.
> HadoopSecurityContext and the refresh worker are not the same source of truth
> for the current UGI. The context holds the UGI captured at security
> installation. UserGroupInformation.getCurrentUser() on a pooled thread
> resolves the Subject inherited by that worker when it was created. Because
> FileSystemJobResultStore I/O and token refresh share cluster-io, the receiver
> can run with a Subject from a different lifecycle than the context/login UGI.
> The 1.18 path had synchronous FileSystemJobResultStore I/O, so this
> worker/Subject interaction was not triggered in the deployments observed.
> 1.15 did not have the unified delegation-token manager path. These version
> differences explain the observed frequency; they do not prove that those
> versions are immune.
> YARN with ZooKeeper HA uses the same FileSystemJobResultStore(ioExecutor) and
> token-refresh code path, but this has not been reproduced on YARN. YARN is
> not inherently exempt: its normal application-mode startup does not perform
> the early security installation used for artifact fetching, so the first
> cluster-io worker is normally created from the login/security context. The
> decisive condition is the Subject inherited by that worker, not the platform
> name. YARN is therefore not listed as a confirmed affected deployment type.
> *Root cause*
> HadoopDelegationTokenReceiver targets getCurrentUser() of the refresh thread.
> That target is not guaranteed to be the UGI held by HadoopSecurityContext or
> the UGI captured by a long-lived checkpoint storage or job-result-store
> DFSClient.
> *Proposed change*
> This issue addresses the case where a token is obtained successfully but the
> refreshed credentials do not reach long-lived Hadoop clients, primarily
> checkpoint storage.
> * Add an accessor for the UGI held by HadoopSecurityContext.
> * In HadoopDelegationTokenReceiver, add refreshed credentials to the
> security-context UGI and login UGI, with the current UGI as a fallback,
> deduplicated by object identity.
> * Add a test where the refresh thread's current user differs from the
> security-context user, and verify that the security-context/login UGI
> receives the credentials.
> Out of scope for this issue:
> * The separate case where HadoopFSDelegationTokenProvider evaluates
> delegation-token requirements against the wrong current UGI and does not
> obtain a token at all.
> * Closing FileSystem instances created under the short-lived fresh UGI; this
> is separate lifecycle cleanup.
> * SecurityUtils.install idempotency.
> *Testing*
> * A JVM probe confirmed that a fixed thread pool created under Subject A but
> first submitted under Subject B runs subsequent tasks under Subject B.
> * Receiver test as described above.
> * A deployed application-mode job should survive the 24h token deadline and
> continue checkpointing without SecretManager$InvalidToken. Verify that the
> checkpoint storage DFSClient receives the new token; the job-result-store
> client should receive the same credentials because it uses the same target
> UGI.
> *Acceptance criteria*
> * A token refresh updates the UGI used by checkpoint storage and other
> long-lived Hadoop clients.
> * Refresh does not depend on the Subject inherited by the shared cluster-io
> worker.
> * A long-running application-mode job survives the 24h HDFS token deadline.
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