Harsh J created HADOOP-12970:
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Summary: Intermittent signature match failures in S3AFileSystem
due connection closure
Key: HADOOP-12970
URL: https://issues.apache.org/jira/browse/HADOOP-12970
Project: Hadoop Common
Issue Type: Bug
Components: fs/s3
Affects Versions: 2.7.0
Reporter: Harsh J
Assignee: Harsh J
S3AFileSystem's use of {{ObjectMetadata#clone()}} method inside the
{{copyFile}} implementation may fail in circumstances where the connection used
for obtaining the metadata is closed by the server (i.e. response carries a
{{Connection: close}} header). Due to this header not being stripped away when
the {{ObjectMetadata}} is created, and due to us cloning it for use in the next
{{CopyObjectRequest}}, it causes the request to use {{Connection: close}}
headers as a part of itself.
This causes signer related exceptions because the client now includes the
{{Connection}} header as part of the {{SignedHeaders}}, but the S3 server does
not receive the same value for it ({{Connection}} headers are likely stripped
away before the S3 Server tries to match signature hashes), causing a failure
like below:
{code}
2016-03-29 19:59:30,120 DEBUG [s3a-transfer-shared--pool1-t35]
org.apache.http.wire: >> "Authorization: AWS4-HMAC-SHA256
Credential=XXX/20160329/eu-central-1/s3/aws4_request,
SignedHeaders=accept-ranges;connection;content-length;content-type;etag;host;last-modified;user-agent;x-amz-acl;x-amz-content-sha256;x-amz-copy-source;x-amz-date;x-amz-metadata-directive;x-amz-server-side-encryption;x-amz-version-id,
Signature=MNOPQRSTUVWXYZ[\r][\n]"
…
com.amazonaws.services.s3.model.AmazonS3Exception: The request signature we
calculated does not match the signature you provided. Check your key and
signing method. (Service: Amazon S3; Status Code: 403; Error Code:
SignatureDoesNotMatch; Request ID: ABC), S3 Extended Request ID: XYZ
{code}
This is intermittent because the S3 Server does not always add a {{Connection:
close}} directive in its response, but whenever we receive it AND we clone it,
the above exception would happen for the copy request. The copy request is
often used in the context of FileOutputCommitter, when a lot of the MR attempt
files on {{s3a://}} destination filesystem are to be moved to their parent
directories post-commit.
I've also submitted a fix upstream with AWS Java SDK to strip out the
{{Connection}} headers when dealing with {{ObjectMetadata}}, which is pending
acceptance and release at: https://github.com/aws/aws-sdk-java/pull/669, but
until that release is available and can be used by us, we'll need to workaround
the clone approach by manually excluding the {{Connection}} header (not
straight-forward due to the {{metadata}} object being private with no mutable
access). We can remove such a change in future when there's a release available
with the upstream fix.
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