Followup patch to HADOOP-18456 as part of HADOOP-18521,
ABFS ReadBufferManager buffer sharing across concurrent HTTP requests
Add probes of readahead fix aid in checking safety of
hadoop ABFS client across different releases.
* ReadBufferManager constructor logs the fact it is safe at TRACE
* AbfsInputStream declares it is fixed in toString()
by including fs.azure.capability.readahead.safe" in the
result.
The ABFS FileSystem hasPathCapability("fs.azure.capability.readahead.safe")
probe returns true to indicate the client's readahead manager has been fixed
to be safe when prefetching.
All Hadoop releases for which probe this returns false
and for which the probe "fs.capability.etags.available"
returns true at risk of returning invalid data when reading
ADLS Gen2/Azure storage data.
Contributed by Steve Loughran.
This is a followup to the original HADOOP-18546
patch; cherry-picks of that should include this
or follow up with it.
Removes risk of race conditions in assertions
of ITestReadBufferManager on the state of the in-progress
and completed queues by removing assertions brittle
to race conditions in scheduling/network IO
* Waits for all the executor pool shutdown to complete before
making any assertions
* Assertions that there are no in progress reads MUST be
cut as there may be some and they won't be cancelled.
* Assertions that the completed list is without buffers
of a closed stream are brittle because if there was
an in progress stream which completed after stream.close()
then it will end up in the list.
Contributed by Steve Loughran
This addresses HADOOP-18521, "ABFS ReadBufferManager buffer sharing
across concurrent HTTP requests" by not trying to cancel
in progress reads.
It supercedes HADOOP-18528, which disables the prefetching.
If that patch is applied *after* this one, prefetching
will be disabled.
As well as changing the default value in the code,
core-default.xml is updated to set
fs.azure.enable.readahead = true
As a result, if Configuration.get("fs.azure.enable.readahead")
returns a non-null value, then it can be inferred that
it was set in or core-default.xml (the fix is present)
or in core-site.xml (someone asked for it).
Contributed by Pranav Saxena.
This allows abfs request throttling to be shared across all
abfs connections talking to containers belonging to the same abfs storage
account -as that is the level at which IO throttling is applied.
The option is enabled/disabled in the configuration option
"fs.azure.account.throttling.enabled";
The default is "true"
Contributed by Anmol Asrani
This commit parses SAS Tokens and removes the unwanted prefix of '?' from them, if present.
At present, SAS Tokens are provided to the driver through customer implementations of the SASTokenProvider interface. The SAS token providers should not assume that the token will be the first query parameter in the URIs that communicate with the backend. However, it was observed that certain public interfaces provided by Storage to generate SAS can include the '?' as the first character of the SAS Token, which would ideally be the case when it is the first query parameter. Thus, tokens that contain this prefix will lead to an error in the driver due to a clash of query parameters.
To avoid failures for use of such SAS tokens, after receiving the SAS Token from the provider, the code checks for whether any ? prefix is present or not. If yes, it is removed before further usage of the token. This way, users would not have to manually remove the prefix before passing it on as a configuration.
Contributed by Sree Bhattacharya
Disables block prefetching on ABFS InputStreams, by setting
fs.azure.enable.readahead to false in core-default.xml and
the matching java constant.
This prevents
HADOOP-18521. ABFS ReadBufferManager buffer sharing across concurrent HTTP requests.
Once a fix for that is committed, this change can be reverted.
Contributed by Mehakmeet Singh.
* HADOOP-18517. ABFS: Add fs.azure.enable.readahead option to disable readahead
Adds new config option to turn off readahead
* also allows it to be passed in through openFile(),
* extends ITestAbfsReadWriteAndSeek to use the option, including one
replicated test...that shows that turning it off is slower.
Important: this does not address the critical data corruption issue
HADOOP-18521. ABFS ReadBufferManager buffer sharing across concurrent HTTP requests
What is does do is provide a way to completely bypass the ReadBufferManager.
To mitigate the problem, either fs.azure.enable.readahead needs to be set to false,
or set "fs.azure.readaheadqueue.depth" to 0 -this still goes near the (broken)
ReadBufferManager code, but does't trigger the bug.
For safe reading of files through the ABFS connector, readahead MUST be disabled
or the followup fix to HADOOP-18521 applied
Contributed by Steve Loughran
ABFS rename fails intermittently when the Storage-blob tracking
metadata is in an incomplete state. This surfaces as the error code
404 and an error message of "RenameDestinationParentPathNotFound"
To mitigate this issue, when a request fails with this response.
the ABFS client issues a HEAD call on the source file
and then retries the rename operation again
ABFS filesystem statistics track when this occurs with new counters
rename_recovery
metadata_incomplete_rename_failures
rename_path_attempts
This is very rare occurrence and appears to be triggered under certain
heavy load conditions, just as with HADOOP-18163.
Contributed by Mehakmeet Singh.
Stops the abfs connector warning if openFile().withFileStatus()
is invoked with a FileStatus is not an abfs VersionedFileStatus.
Contributed by Steve Loughran.
Change-Id: I85076b365eb30aaef2ed35139fa8714efd4d048e
Follow-on patch to MAPREDUCE-7341, adding ABFS support and tests
* resilient rename
* tests for job commit through the manifest committer.
contains
- HADOOP-17976. ABFS etag extraction inconsistent between LIST and HEAD calls
- HADOOP-16204. ABFS tests to include terasort
Contributed by Steve Loughran.
Change-Id: I0a7d4043bdf19bcb00c033fc389730109b93b77f
Completely removes S3Guard support from the S3A codebase.
If the connector is configured to use any metastore other than
the null and local stores (i.e. DynamoDB is selected) the s3a client
will raise an exception and refuse to initialize.
This is to ensure that there is no mix of S3Guard enabled and disabled
deployments with the same configuration but different hadoop releases
-it must be turned off completely.
The "hadoop s3guard" command has been retained -but the supported
subcommands have been reduced to those which are not purely S3Guard
related: "bucket-info" and "uploads".
This is major change in terms of the number of files
changed; before cherry picking subsequent s3a patches into
older releases, this patch will probably need backporting
first.
Goodbye S3Guard, your work is done. Time to die.
Contributed by Steve Loughran.
Cut modtime-based rename recovery as object modification time
is not updated during rename operation.
Applications will have to use etag API of HADOOP-17979
and implement it themselves.
Why not do the HEAD and etag recovery in ABFS client?
Cuts the IO capacity in half so kills job commit performance.
The manifest committer of MAPREDUCE-7341 will do this recovery
and act as the reference implementation of the algorithm.
Contributed by: Steve Loughran
Addresses transient failures in the following test classes:
* ITestAbfsStreamStatistics: Uses a filesystem level static instance to record read/write statistics, which also tracks these operations in other tests running in parallel. Marked for sequential-only run to avoid transient failure
* ITestAbfsRestOperationException: The use of a static member to track retry count causes transient failures when two tests of this class happen to run together. Switch to non-static variable for assertions on retry count
closes#3341
Contributed by Sumangala Patki
Addresses the problem of processes running out of memory when
there are many ABFS output streams queuing data to upload,
especially when the network upload bandwidth is less than the rate
data is generated.
ABFS Output streams now buffer their blocks of data to
"disk", "bytebuffer" or "array", as set in
"fs.azure.data.blocks.buffer"
When buffering via disk, the location for temporary storage
is set in "fs.azure.buffer.dir"
For safe scaling: use "disk" (default); for performance, when
confident that upload bandwidth will never be a bottleneck,
experiment with the memory options.
The number of blocks a single stream can have queued for uploading
is set in "fs.azure.block.upload.active.blocks".
The default value is 20.
Contributed by Mehakmeet Singh.
This migrates the fs.s3a-server-side encryption configuration options
to a name which covers client-side encryption too.
fs.s3a.server-side-encryption-algorithm becomes fs.s3a.encryption.algorithm
fs.s3a.server-side-encryption.key becomes fs.s3a.encryption.key
The existing keys remain valid, simply deprecated and remapped
to the new values. If you want server-side encryption options
to be picked up regardless of hadoop versions, use
the old keys.
(the old key also works for CSE, though as no version of Hadoop
with CSE support has shipped without this remapping, it's less
relevant)
Contributed by: Mehakmeet Singh
This patch cuts down the size of directory trees used for
distcp contract tests against object stores, so making
them much faster against distant/slow stores.
On abfs, the test only runs with -Dscale (as was the case for s3a already),
and has the larger scale test timeout.
After every test case, the FileSystem IOStatistics are logged,
to provide information about what IO is taking place and
what it's performance is.
There are some test cases which upload files of 1+ MiB; you can
increase the size of the upload in the option
"scale.test.distcp.file.size.kb"
Set it to zero and the large file tests are skipped.
Contributed by Steve Loughran.
Introducing fs.azure.readahead.range parameter which can be set by the user.
Data will be populated in buffer for random reads as well which leads to fewer
remote calls.
This patch also changes the seek implementation to perform a lazy seek. The
actual seek is done when a read is initiated and data is not present in the buffer else
data is returned from the buffer thus reducing the number of remote storage calls.
Contributed By: Mukund Thakur
