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

Provided by: nbdkit-plugin-python_1.40.4-1ubuntu1_amd64 bug

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
       access-key=+FILENAME
       access-key=-
       access-key=-FD
       secret-key=SECRET_KEY
       secret-key=+FILENAME
       secret-key=-
       secret-key=-FD
       session-token=SESSION_TOKEN
       session-token=+FILENAME
       session-token=-
       session-token=-FD
           Pass AWS credentials.  See "CREDENTIALS".

       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
       You can pass AWS credentials in several ways:

       In plaintext on the nbdkit command line
           For example:

            nbdkit S3 access-key=ABC secret-key=SECRET session-token=123

           This is not secure since a user on the same machine could read them using ps(1).

       Via files on the nbdkit command line
           (nbdkit ≥ 1.38)

           For example:

            nbdkit S3 access-key=+/tmp/access [...]

           Be careful with the permissions on these files to ensure that no one else can read the sensitive
           information.

       Interactively when nbdkit starts up
           (nbdkit ≥ 1.38)

           For example:

            nbdkit S3 access-key=- [...]

           nbdkit will ask for each key to be entered interactively.

       Inherited through a file descriptor
           (nbdkit ≥ 1.38)

           For example:

            nbdkit S3 access-key=-3 [...]

           The parent process must set up the file descriptor (FD 3 in the example) so that nbdkit can read the
           key from it.

       Using ~/.aws/credentials file
           This file 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.

       Through environment variables
           Use the environment variables "AWS_ACCESS_KEY_ID", "AWS_SECRET_ACCESS_KEY" and "AWS_SESSION_TOKEN".

       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-bandwidth 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), nbdkit-gcs-plugin(1),
       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 Red Hat


LICENSE
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