Removed findbugs from the hadoop build images and added spotbugs instead.
Upgraded SpotBugs to 4.2.2 and spotbugs-maven-plugin to 4.2.0.
Reviewed-by: Masatake Iwasaki <iwasakims@apache.org>
(cherry picked from commit 23b343aed1)
Conflicts:
dev-support/docker/Dockerfile
hadoop-project/pom.xml
Adds an Abortable.abort() interface for streams to enable output streams to be terminated; this
is implemented by the S3A connector's output stream. It allows for commit protocols
to be implemented which commit/abort work by writing to the final destination and
using the abort() call to cancel any write which is not intended to be committed.
Consult the specification document for information about the interface and its use.
Contributed by Jungtaek Lim and Steve Loughran.
Change-Id: I7fcc25e9dd8c10ce6c29f383529f3a2642a201ae
This defines what output streams and especially those which implement
Syncable are meant to do, and documents where implementations (HDFS; S3)
don't. With tests.
The file:// FileSystem now supports Syncable if an application calls
FileSystem.setWriteChecksum(false) before creating a file -checksumming
and Syncable.hsync() are incompatible.
Contributed by Steve Loughran.
Change-Id: I892d768de6268f4dd6f175b3fe3b7e5bcaa91194
The ABFS connector now implements listStatusIterator() with
asynchronous prefetching of the next page(s) of results.
For listing large directories this can provide tangible speedups.
If for any reason this needs to be disabled, set
fs.azure.enable.abfslistiterator to false.
Contributed by Bilahari T H.
Change-Id: Ic9a52b80df1d0ffed4c81beae92c136e2a12698c
When 403 is returned from an ABFS HTTP call, an AccessDeniedException is raised.
The exception text is unchanged, for any application string matching on the getMessage() contents.
Contributed by Steve Loughran.
Change-Id: I519d50ccd657968fd8ee72d132518099de901e15
* core-default.xml updated so that fs.s3a.committer.magic.enabled = true
* CommitConstants updated to match
* All tests which previously enabled the magic committer now rely on
default settings. This helps make sure it is enabled.
* Docs cover the switch, mention its enabled and explain why you may
want to disable it.
Note: this doesn't switch to using the committer -it just enables the path
rewriting magic which it depends on.
Contributed by Steve Loughran.
This needs SPARK-33739 in the matching spark branch in order to work
Contributed by Steve Loughran.
Change-Id: I4fe75b057159e35aacc072da3cb7343467c0c3f1
Caused by HADOOP-16830 and HADOOP-17271.
Fixes tests which fail intermittently based on configs and
in the case of the HugeFile tests, bulk runs with existing
FS instances meant statistic probes sometimes ended up probing those
of a previous FS.
Contributed by Steve Loughran.
Change-Id: I65ba3f44444e59d298df25ac5c8dc5a8781dfb7d
S3A connector to support the IOStatistics API of HADOOP-16830,
This is a major rework of the S3A Statistics collection to
* Embrace the IOStatistics APIs
* Move from direct references of S3AInstrumention statistics
collectors to interface/implementation classes in new packages.
* Ubiquitous support of IOStatistics, including:
S3AFileSystem, input and output streams, RemoteIterator instances
provided in list calls.
* Adoption of new statistic names from hadoop-common
Regarding statistic collection, as well as all existing
statistics, the connector now records min/max/mean durations
of HTTP GET and HEAD requests, and those of LIST operations.
Contributed by Steve Loughran.
Change-Id: I182d34b6ac39e017a8b4a221dad8e930882b39cf
DETAILS:
The previous commit for HADOOP-17397 was not the correct fix. DelegationSASGenerator.getDelegationSAS
should return sp=p for the set-permission and set-acl operations. The tests have also been updated as
follows:
1. When saoid and suoid are not specified, skoid must have an RBAC role assignment which grants
Microsoft.Storage/storageAccounts/blobServices/containers/blobs/modifyPermissions/action and sp=p
to set permissions or set ACL.
2. When saoid or suiod is specified, same as 1) but furthermore the saoid or suoid must be an owner of
the file or directory in order for the operation to succeed.
3. When saoid or suiod is specified, the ownership check is bypassed by also including 'o' (ownership)
in the SAS permission (for example, sp=op). Note that 'o' grants the saoid or suoid the ability to
change the file or directory owner to themself, and they can also change the owning group. Generally
speaking, if a trusted authorizer would like to give a user the ability to change the permissions or
ACL, then that user should be the file or directory owner.
TEST RESULTS:
namespace.enabled=true
auth.type=SharedKey
-------------------
$mvn -T 1C -Dparallel-tests=abfs -Dscale -DtestsThreadCount=8 clean verify
Tests run: 89, Failures: 0, Errors: 0, Skipped: 0
Tests run: 461, Failures: 0, Errors: 0, Skipped: 24
Tests run: 208, Failures: 0, Errors: 0, Skipped: 24
namespace.enabled=true
auth.type=OAuth
-------------------
$mvn -T 1C -Dparallel-tests=abfs -Dscale -DtestsThreadCount=8 clean verify
Tests run: 89, Failures: 0, Errors: 0, Skipped: 0
Tests run: 461, Failures: 0, Errors: 0, Skipped: 70
Tests run: 208, Failures: 0, Errors: 0, Skipped: 141
Contributed by Steve Loughran
The addition of deprecated S3A configuration options in HADOOP-17318
triggered a reload of default (xml resource) configurations, which breaks
tests which fail if there's a per-bucket setting inconsistent with test
setup.
Creating an S3AFS instance before creating the Configuration() instance
for test runs gets that reload out the way before test setup takes
place.
Along with the fix, extra changes in the failing test suite to fail
fast when marker policy isn't as expected, and to log FS state better.
Rather than create and discard an instance, add a new static method
to S3AFS and invoke it in test setup. This forces the load
Change-Id: Id52b1c46912c6fedd2ae270e2b1eb2222a360329
See also [SPARK-33402]: Jobs launched in same second have duplicate MapReduce JobIDs
Contributed by Steve Loughran.
Change-Id: Iae65333cddc84692997aae5d902ad8765b45772a
This adds a semaphore to throttle the number of FileSystem instances which
can be created simultaneously, set in "fs.creation.parallel.count".
This is designed to reduce the impact of many threads in an application calling
FileSystem.get() on a filesystem which takes time to instantiate -for example
to an object where HTTPS connections are set up during initialization.
Many threads trying to do this may create spurious delays by conflicting
for access to synchronized blocks, when simply limiting the parallelism
diminishes the conflict, so speeds up all threads trying to access
the store.
The default value, 64, is larger than is likely to deliver any speedup -but
it does mean that there should be no adverse effects from the change.
If a service appears to be blocking on all threads initializing connections to
abfs, s3a or store, try a smaller (possibly significantly smaller) value.
Contributed by Steve Loughran.
Change-Id: I57161b026f28349e339dc8b9d74f6567a62ce196
This patch
* fixes the inversion
* adds a precondition check
* if the commands are supplied inverted, swaps them with a warning.
This is to stop breaking any tests written to cope with the existing
behavior.
Contributed by Steve Loughran
Change-Id: I15c40863f0db0675c7d60db477cb3bf1693cae49
This fixes the S3Guard/Directory Marker Retention integration so that when
fs.s3a.directory.marker.retention=keep, failures during multipart delete
are handled correctly, as are incremental deletes during
directory tree operations.
In both cases, when a directory marker with children is deleted from
S3, the directory entry in S3Guard is not deleted, because it is still
critical to representing the structure of the store.
Contributed by Steve Loughran.
Change-Id: I4ca133a23ea582cd42ec35dbf2dc85b286297d2f
Unless you explicitly set it, the issue date of a delegation token identifier is 0, which confuses spark renewal (SPARK-33440). This patch makes sure that all S3A DT identifiers have the current time as issue date, fixing the problem as far as S3A tokens are concerned.
Contributed by Jungtaek Lim.
Change-Id: Ic80ac7895612a1aa669459c73a78a9c17ecf0c0d
Fixes read-ahead buffer management issues introduced by HADOOP-16852,
"ABFS: Send error back to client for Read Ahead request failure".
Contributed by Sneha Vijayarajan
Contributed by Sneha Vijayarajan
DETAILS:
This change adds config key "fs.azure.enable.conditional.create.overwrite" with
a default of true. When enabled, if create(path, overwrite: true) is invoked
and the file exists, the ABFS driver will first obtain its etag and then attempt
to overwrite the file on the condition that the etag matches. The purpose of this
is to mitigate the non-idempotency of this method. Specifically, in the event of
a network error or similar, the client will retry and this can result in the file
being created more than once which may result in data loss. In essense this is
like a poor man's file handle, and will be addressed more thoroughly in the future
when support for lease is added to ABFS.
TEST RESULTS:
namespace.enabled=true
auth.type=SharedKey
-------------------
$mvn -T 1C -Dparallel-tests=abfs -Dscale -DtestsThreadCount=8 clean verify
Tests run: 87, Failures: 0, Errors: 0, Skipped: 0
Tests run: 457, Failures: 0, Errors: 0, Skipped: 42
Tests run: 207, Failures: 0, Errors: 0, Skipped: 24
namespace.enabled=true
auth.type=OAuth
-------------------
$mvn -T 1C -Dparallel-tests=abfs -Dscale -DtestsThreadCount=8 clean verify
Tests run: 87, Failures: 0, Errors: 0, Skipped: 0
Tests run: 457, Failures: 0, Errors: 0, Skipped: 74
Tests run: 207, Failures: 0, Errors: 0, Skipped: 140
Adds the options to control the size of the per-output-stream threadpool
when writing data through the abfs connector
* fs.azure.write.max.concurrent.requests
* fs.azure.write.max.requests.to.queue
Contributed by Bilahari T H
This reverts changes in HADOOP-13230 to use S3Guard TTL in choosing when
to issue a HEAD request; fixing tests to compensate.
New org.apache.hadoop.fs.s3a.performance.OperationCost cost,
S3GUARD_NONAUTH_FILE_STATUS_PROBE for use in cost tests.
Contributed by Steve Loughran.
Change-Id: I418d55d2d2562a48b2a14ec7dee369db49b4e29e
S3AFileSystem.listStatus() is optimized for invocations
where the path supplied is a non-empty directory.
The number of S3 requests is significantly reduced, saving
time, money, and reducing the risk of S3 throttling.
Contributed by Mukund Thakur.
Change-Id: I7cc5f87aa16a4819e245e0fbd2aad226bd500f3f
This changes directory tree deletion so that only files are incrementally deleted
from S3Guard after the objects are deleted; the directories are left alone
until metadataStore.deleteSubtree(path) is invoke.
This avoids directory tombstones being added above files/child directories,
which stop the treewalk and delete phase from working.
Also:
* Callback to delete objects splits files and dirs so that
any problems deleting the dirs doesn't trigger s3guard updates
* New statistic to measure #of objects deleted, alongside request count.
* Callback listFilesAndEmptyDirectories renamed listFilesAndDirectoryMarkers
to clarify behavior.
* Test enhancements to replicate the failure and verify the fix
Contributed by Steve Loughran
Change-Id: I0e6ea2c35e487267033b1664228c8837279a35c7
Now skips ITestS3AEncryptionWithDefaultS3Settings.testEncryptionOverRename
when server side encryption is not set to sse:kms
Contributed by Mukund Thakur
Change-Id: Ifd83d353e9c7c6f7e1195a2c2f138d85cf876bb1
This adds an option to disable "empty directory" marker deletion,
so avoid throttling and other scale problems.
This feature is *not* backwards compatible.
Consult the documentation and use with care.
Contributed by Steve Loughran.
Change-Id: I69a61e7584dc36e485d5e39ff25b1e3e559a1958
Contributed by Steve Loughran.
Fixes a condition which can cause job commit to fail if a task was
aborted < 60s before the job commit commenced: the task abort
will shut down the thread pool with a hard exit after 60s; the
job commit POST requests would be scheduled through the same pool,
so be interrupted and fail. At present the access is synchronized,
but presumably the executor shutdown code is calling wait() and releasing
locks.
Task abort is triggered from the AM when task attempts succeed but
there are still active speculative task attempts running. Thus it
only surfaces when speculation is enabled and the final tasks are
speculating, which, given they are the stragglers, is not unheard of.
Note: this problem has never been seen in production; it has surfaced
in the hadoop-aws tests on a heavily overloaded desktop
Change-Id: I3b433356d01fcc50d88b4353dbca018484984bc8
Contributed by Thomas Marquardt
DETAILS: WASB depends on the Azure Storage Java SDK. There is a concurrency
bug in the Azure Storage Java SDK that can cause the results of a list blobs
operation to appear empty. This causes the Filesystem listStatus and similar
APIs to return empty results. This has been seen in Spark work loads when jobs
use more than one executor core.
See Azure/azure-storage-java#546 for details on the bug in the Azure Storage SDK.
TESTS: A new test was added to validate the fix. All tests are passing:
wasb:
mvn -T 1C -Dparallel-tests=wasb -Dscale -DtestsThreadCount=8 clean verify
Tests run: 248, Failures: 0, Errors: 0, Skipped: 11
Tests run: 651, Failures: 0, Errors: 0, Skipped: 65
abfs:
mvn -T 1C -Dparallel-tests=abfs -Dscale -DtestsThreadCount=8 clean verify
Tests run: 64, Failures: 0, Errors: 0, Skipped: 0
Tests run: 437, Failures: 0, Errors: 0, Skipped: 33
Tests run: 206, Failures: 0, Errors: 0, Skipped: 24
Contributed by Thomas Marquardt.
DETAILS:
1) The authentication version in the service has been updated from Dec19 to Feb20, so need to update the client.
2) Add support and test cases for getXattr and setXAttr.
3) Update DelegationSASGenerator and related to use Duration instead of int for time periods.
4) Cleanup DelegationSASGenerator switch/case statement that maps operations to permissions.
5) Cleanup SASGenerator classes to use String.equals instead of ==.
TESTS:
Added tests for getXAttr and setXAttr.
All tests are passing against my account in eastus2euap:
$mvn -T 1C -Dparallel-tests=abfs -Dscale -DtestsThreadCount=8 clean verify
Tests run: 76, Failures: 0, Errors: 0, Skipped: 0
Tests run: 441, Failures: 0, Errors: 0, Skipped: 33
Tests run: 206, Failures: 0, Errors: 0, Skipped: 24
Contributed by Thomas Marquardt.
DETAILS:
Previously we had a SASGenerator class which generated Service SAS, but we need to add DelegationSASGenerator.
I separated SASGenerator into a base class and two subclasses ServiceSASGenerator and DelegationSASGenreator. The
code in ServiceSASGenerator is copied from SASGenerator but the DelegationSASGenrator code is new. The
DelegationSASGenerator code demonstrates how to use Delegation SAS with minimal permissions, as would be used
by an authorization service such as Apache Ranger. Adding this to the tests helps us lock in this behavior.
Added a MockDelegationSASTokenProvider for testing User Delegation SAS.
Fixed the ITestAzureBlobFileSystemCheckAccess tests to assume oauth client ID so that they are ignored when that
is not configured.
To improve performance, AbfsInputStream/AbfsOutputStream re-use SAS tokens until the expiry is within 120 seconds.
After this a new SAS will be requested. The default period of 120 seconds can be changed using the configuration
setting "fs.azure.sas.token.renew.period.for.streams".
The SASTokenProvider operation names were updated to correspond better with the ADLS Gen2 REST API, since these
operations must be provided tokens with appropriate SAS parameters to succeed.
Support for the version 2.0 AAD authentication endpoint was added to AzureADAuthenticator.
The getFileStatus method was mistakenly calling the ADLS Gen2 Get Properties API which requires read permission
while the getFileStatus call only requires execute permission. ADLS Gen2 Get Status API is supposed to be used
for this purpose, so the underlying AbfsClient.getPathStatus API was updated with a includeProperties
parameter which is set to false for getFileStatus and true for getXAttr.
Added SASTokenProvider support for delete recursive.
Fixed bugs in AzureBlobFileSystem where public methods were not validating the Path by calling makeQualified. This is
necessary to avoid passing null paths and to convert relative paths into absolute paths.
Canonicalized the path used for root path internally so that root path can be used with SAS tokens, which requires
that the path in the URL and the path in the SAS token match. Internally the code was using
"//" instead of "/" for the root path, sometimes. Also related to this, the AzureBlobFileSystemStore.getRelativePath
API was updated so that we no longer remove and then add back a preceding forward / to paths.
To run ITestAzureBlobFileSystemDelegationSAS tests follow the instructions in testing_azure.md under the heading
"To run Delegation SAS test cases". You also need to set "fs.azure.enable.check.access" to true.
TEST RESULTS:
namespace.enabled=true
auth.type=SharedKey
-------------------
$mvn -T 1C -Dparallel-tests=abfs -Dscale -DtestsThreadCount=8 clean verify
Tests run: 63, Failures: 0, Errors: 0, Skipped: 0
Tests run: 432, Failures: 0, Errors: 0, Skipped: 41
Tests run: 206, Failures: 0, Errors: 0, Skipped: 24
namespace.enabled=false
auth.type=SharedKey
-------------------
$mvn -T 1C -Dparallel-tests=abfs -Dscale -DtestsThreadCount=8 clean verify
Tests run: 63, Failures: 0, Errors: 0, Skipped: 0
Tests run: 432, Failures: 0, Errors: 0, Skipped: 244
Tests run: 206, Failures: 0, Errors: 0, Skipped: 24
namespace.enabled=true
auth.type=SharedKey
sas.token.provider.type=MockDelegationSASTokenProvider
enable.check.access=true
-------------------
$mvn -T 1C -Dparallel-tests=abfs -Dscale -DtestsThreadCount=8 clean verify
Tests run: 63, Failures: 0, Errors: 0, Skipped: 0
Tests run: 432, Failures: 0, Errors: 0, Skipped: 33
Tests run: 206, Failures: 0, Errors: 0, Skipped: 24
namespace.enabled=true
auth.type=OAuth
-------------------
$mvn -T 1C -Dparallel-tests=abfs -Dscale -DtestsThreadCount=8 clean verify
Tests run: 63, Failures: 0, Errors: 0, Skipped: 0
Tests run: 432, Failures: 0, Errors: 1, Skipped: 74
Tests run: 206, Failures: 0, Errors: 0, Skipped: 140
Contributed by: Mehakmeet Singh
In some cases, ABFS-prefetch thread runs in the background which returns some bytes from the buffer and gives an extra readOp. Thus, making readOps values arbitrary and giving intermittent failures in some cases. Hence, readOps values of 2 or 3 are seen in different setups.
Contributed by Steve Loughran.
S3A delegation token providers will be asked for any additional
token issuers, an array can be returned,
each one will be asked for tokens when DelegationTokenIssuer collects
all the tokens for a filesystem.
Change-Id: I1bd3035bbff98cbd8e1d1ac7fc615d937e6bb7bb
Contributed by Steve Loughran.
Move the loading to deployUnbonded (where they are required) and add a safety check when a new DT is requested
Change-Id: I03c69aa2e16accfccddca756b2771ff832e7dd58
Contributed by Mukund Thakur and Steve Loughran.
This patch ensures that writes to S3A fail when more than 10,000 blocks are
written. That upper bound still exists. To write massive files, make sure
that the value of fs.s3a.multipart.size is set to a size which is large
enough to upload the files in fewer than 10,000 blocks.
Change-Id: Icec604e2a357ffd38d7ae7bc3f887ff55f2d721a
Contributed by Steve Loughran.
The S3Guard absence warning of HADOOP-16484 has been changed
so that by default the S3A connector only logs at debug
when the connection to the S3 Store does not have S3Guard
enabled.
The option to control this log level is now
fs.s3a.s3guard.disabled.warn.level
and can be one of: silent, inform, warn, fail.
On a failure, an ExitException is raised with exit code 49.
For details on this safety feature, consult the s3guard documentation.
Change-Id: If868671c9260977c2b03b3e475b9c9531c98ce79
Contributed by Steve Loughran.
This is a successor to HADOOP-16346, which enabled the S3A connector
to load the native openssl SSL libraries for better HTTPS performance.
That patch required wildfly.jar to be on the classpath. This
update:
* Makes wildfly.jar optional except in the special case that
"fs.s3a.ssl.channel.mode" is set to "openssl"
* Retains the declaration of wildfly.jar as a compile-time
dependency in the hadoop-aws POM. This means that unless
explicitly excluded, applications importing that published
maven artifact will, transitively, add the specified
wildfly JAR into their classpath for compilation/testing/
distribution.
This is done for packaging and to offer that optional
speedup. It is not mandatory: applications importing
the hadoop-aws POM can exclude it if they choose.
Change-Id: I7ed3e5948d1e10ce21276b3508871709347e113d
Contributed by Mukund Thakur.
If you set the log org.apache.hadoop.fs.s3a.impl.NetworkBinding
to DEBUG, then when the S3A bucket probe is made -the DNS address
of the S3 endpoint is calculated and printed.
This is useful to see if a large set of processes are all using
the same IP address from the pool of load balancers to which AWS
directs clients when an AWS S3 endpoint is resolved.
This can have implications for performance: if all clients
access the same load balancer performance may be suboptimal.
Note: if bucket probes are disabled, fs.s3a.bucket.probe = 0,
the DNS logging does not take place.
Change-Id: I21b3ac429dc0b543f03e357fdeb94c2d2a328dd8
Contributed by Mukund Thakur
Optimize S3AFileSystem.listLocatedStatus() to perform list
operations directly and then fallback to head checks for files
Change-Id: Ia2c0fa6fcc5967c49b914b92f41135d07dab0464
Contributed by Steve Loughran.
This strips out all the -p preservation options which have already been
processed when uploading a file before deciding whether or not to query
the far end for the status of the (existing/uploaded) file to see if any
other attributes need changing.
This will avoid 404 caching-related issues in S3, wherein a newly created
file can have a 404 entry in the S3 load balancer's cache from the
probes for the file's existence prior to the upload.
It partially addresses a regression caused by HADOOP-8143,
"Change distcp to have -pb on by default" that causes a resurfacing
of HADOOP-13145, "In DistCp, prevent unnecessary getFileStatus call when
not preserving metadata"
Change-Id: Ibc25d19e92548e6165eb8397157ebf89446333f7
add unit test, new ITest and then fix the issue: different schema, bucket == skip
factored out the underlying logic for unit testing; also moved
maybeAddTrailingSlash to S3AUtils (while retaining/forwarnding existing method
in S3AFS).
tested: london, sole failure is
testListingDelete[auth=true](org.apache.hadoop.fs.s3a.ITestS3GuardOutOfBandOperations)
filed HADOOP-16853
Change-Id: I4b8d0024469551eda0ec70b4968cba4abed405ed
Contributed by Bilahari T H.
The page limit is set in "fs.azure.list.max.results"; default value is 500.
There's currently a limit of 5000 in the store -there are no range checks
in the client code so that limit can be changed on the server without
any need to update the abfs connector.
Contributed by Ben Roling.
ETag values are unpredictable with some S3 encryption algorithms.
Skip ITestS3AMiscOperations tests which make assertions about etags
when default encryption on a bucket is enabled.
When testing with an AWS an account which lacks the privilege
for a call to getBucketEncryption(), we don't skip the tests.
In the event of failure, developers get to expand the
permissions of the account or relax default encryption settings.
Contributed by Steve Loughran
* move qualify logic to S3AFileSystem.makeQualified()
* make S3AFileSystem.qualify() a private redirect to that
* ITestS3GuardFsShell turned off
Contributed by Steve Loughran.
Not all stores do complete validation here; in particular the S3A
Connector does not: checking up the entire directory tree to see if a path matches
is a file significantly slows things down.
This check does take place in S3A mkdirs(), which walks backwards up the list of
parent paths until it finds a directory (success) or a file (failure).
In practice production applications invariably create destination directories
before writing 1+ file into them -restricting check purely to the mkdirs()
call deliver significant speed up while implicitly including the checks.
Change-Id: I2c9df748e92b5655232e7d888d896f1868806eb0
AreContributed by Mukund Thakur.
This addresses an issue which surfaced with KMS encryption: the wrong
KMS key could be picked up in the S3 COPY operation, so
renamed files, while encrypted, would end up with the
bucket default key.
As well as adding tests in the new suite
ITestS3AEncryptionWithDefaultS3Settings,
AbstractSTestS3AHugeFiles has a new test method to
verify that the encryption settings also work
for large files copied via multipart operations.
Contributed by Sergei Poganshev.
Catches Exception instead of IOException in closeStream()
and so handle exceptions such as SdkClientException by
aborting the wrapped stream. This will increase resilience
to failures, as any which occuring during stream closure
will be caught. Furthermore, because the
underlying HTTP connection is aborted, rather than closed,
it will not be recycled to cause problems on subsequent
operations.
Akira Ajisaka
sumangala-patki
Pierrick Hymbert
Ahmed Hussein
Anoop Sam John
Inigo Goiri
Steve Loughran
bilaharith
Mehakmeet Singh
Sneha Vijayarajan
Sumangala
Maksim Bober
yzhangal
Chao Sun
Mukund Thakur
Ayush Saxena
Ankit Kumar
Thomas Marquardt
Jungtaek Lim
Jim Brennan
Doroszlai, Attila
Eric E Payne
Sneha Vijayarajan
Dongjoon Hyun
swamirishi
ishaniahuja
Karthik Amarnath
jimmy-zuber-amzn
Sebastian Nagel
Mehakmeet Singh
Masatake Iwasaki
Mukund Thakur
Sunil G
Nicholas Chammas
Gabor Bota
Weiwei Yang
spoganshev