noble (1) nbdkit-S3-plugin.1.gz

NAME

       nbdkit-S3-plugin - expose data in Amazon S3 or Ceph buckets as block device

SYNOPSIS

        nbdkit S3 [access-key=...] [secret-key=...] [session-token=...]
                  [endpoint-url=...]
                  [size=NN object-size=NN]
                  bucket=BUCKET key=STRING

DESCRIPTION

       "nbdkit-S3-plugin" is a plugin for nbdkit(1) which lets you open objects stored in Amazon S3 or Ceph as
       disk images.

       This plugin uses the Python Amazon Web Services SDK called Boto3.

EXAMPLES

        nbdkit S3 endpoint-url=https://ceph.example.com \
                  bucket=MY-BUCKET key=disk.img

       Provides read only block device holding the data contained in the "disk.img" object.

        nbdkit S3 endpoint-url=https://ceph.example.com \
                  size=50G object-size=128k \
                  bucket=MY-BUCKET key=disk

       Provides a read-write block device with size 50G, whose contents are stored multiple in objects of size
       128k, prefixed with disk/

PARAMETERS

       access-key=ACCESS_KEY
       secret-key=SECRET_KEY
       session-token=SESSION_TOKEN
           The AWS credentials may be specified on the command line using these parameters, but it is more
           secure to pass them using files (see "CREDENTIALS" below).

       endpoint-url=ENDPOINT
           If accessing Ceph or another compatible S3 service, provide the endpoint URL through this parameter.

       bucket=BUCKET
           The bucket containing the object(s).  This parameter is required.

       key=STRING
           The object name (if "size" is not specified) or object prefix (if "size" is specified) to use within
           the bucket.  This parameter is required.

       size=SIZE
       object-size=SIZE
           These two parameters must always be specified together. If set, data will be split into blocks of
           "object-size" and stored as separate objects. The block device will report a total size of "size" and
           be writeable and trim-able.

           Object names will have the form key/%16x, where %16x is the 16-digit hexadecimal block number. If
           there are existing objects under such name that do not have the expected size, the plugin will crash.

PERFORMANCE CONSIDERATIONS

       It is highly recommended that clients do their utmost to issue requests that exactly match the object
       size: Smaller write requests will incur a performance penalty due to the need for read-modify-write
       cycles (thus also incurring latency from two network round-trips). Larger read and write requests will
       incur a performance penalty because of sequential execution.

       The nbdkit-blocksize-filter(1) can be used to alleviate the impact of requests larger than the object
       size, but does not help if the client issues requests smaller than the block size.

       The nbdkit-stats-filter(1) can be used to investigate what block sizes and alignments are used by the
       client.

       When connecting through the Linux kernel's NBD module, consider setting
       "/sys/block/nbd<X>/queue/max_sectors_kb" to match the object size.

CREDENTIALS

       Although AWS credentials can be passed to nbdkit on the command line, this is not secure since a user on
       the same machine could read them using ps(1).

       A better way is to pass the credentials through the ~/.aws/credentials file.  This takes the form:

        [default]
        aws_access_key_id = XXX
        aws_secret_access_key = YYY

        [profile]
        aws_access_key_id = XXX
        aws_secret_access_key = YYY

       Different profiles from the file can be selected by setting the "AWS_PROFILE" environment variable.

       There is much more information about credentials in the Boto3 documentation.

COMPARISON TO S3FS-FUSE AND S3BACKER

       s3fs-fuse (https://github.com/s3fs-fuse/s3fs-fuse) and s3backer (https://github.com/archiecobbs/s3backer)
       provide similar functionality but are based on FUSE (rather than NBD). They provide a regular file
       (backed by S3) which can then be loopback-mounted to provide a block device. s3backer also supports to
       optionally encrypt and compress objects.

       In theory, NBD should provide better performance than FUSE, because:

       •   The kernel no longer serializes write and read requests but issues them concurrently.

       •   Read and write request size can exceed 128 kB

       •   The system can still be reliably hibernated (a running FUSE daemon may prevent this)

       •   Requests pass through the VFS only once, not twice

       •   Data is present in the page cache only once, not twice

       However, for high-bandwith network connections s3backer and s3fs-fuse may be faster because they are
       written in C rather than Python.

FILES

       $plugindir/nbdkit-S3-plugin
           The plugin.

           Use "nbdkit --dump-config" to find the location of $plugindir.

       $HOME/.aws/credentials
           AWS credentials can be passed to boto3 using this file.

ENVIRONMENT VARIABLES

       "AWS_*"
           Boto3 reads some credential information from "AWS_*" environment variables.

VERSION

       "nbdkit-S3-plugin" first appeared in nbdkit 1.24.

SEE ALSO

       nbdkit(1), nbdkit-plugin(3), nbdkit-python-plugin(3), https://pypi.org/project/boto3/,
       https://boto3.amazonaws.com/v1/documentation/api/latest/index.html,
       https://boto3.amazonaws.com/v1/documentation/api/latest/guide/credentials.html.

AUTHORS

       Richard W.M. Jones

       Nikolaus Rath

COPYRIGHT

       Copyright Red Hat

LICENSE

       Redistribution and use in source and binary forms, with or without modification, are permitted provided
       that the following conditions are met:

       •   Redistributions of source code must retain the above copyright notice, this list of conditions and
           the following disclaimer.

       •   Redistributions in binary form must reproduce the above copyright notice, this list of conditions and
           the following disclaimer in the documentation and/or other materials provided with the distribution.

       •   Neither the name of Red Hat nor the names of its contributors may be used to endorse or promote
           products derived from this software without specific prior written permission.

       THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
       INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
       PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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