nbdkit-curl-plugin man page
nbdkit-curl-plugin — nbdkit curl plugin (HTTP, FTP, SSH and other protocols)
nbdkit -r curl url=http://example.com/disk.img nbdkit -r curl url=sftp://firstname.lastname@example.org/~/disk.img
"nbdkit-curl-plugin" is a plugin for nbdkit(1) which turns content served over HTTP, FTP, SSH, and more, into a Network Block Device. It uses a library called libcurl (also known as cURL) to read data from URLs. The exact list of protocols that libcurl can handle depends on how it was compiled, but most versions will handle HTTP, HTTPS, FTP, FTPS and SFTP (see:
"curl -V"). For more information about libcurl, see <http://curl.haxx.se>.
Note: This plugin supports writes. However:
- For HTTP, you may not want nbdkit to issue PUT requests to the remote server (which probably doesn't understand them).
- SFTP helpfully truncates the target file when you open it for writing. Not useful!
To force nbdkit to use a readonly connection, pass the -r flag.
nbdkit -r curl url=http://example.com/disk.img
which serves the remote disk image as a NBD on TCP port 10809 (to control ports and protocols used to serve NBD see nbdkit(1)).
Accessing SSH servers
You can also access SSH servers. This uses the SFTP protocol which is built into most SSH servers:
nbdkit -r curl url=sftp://example.com/~/disk.img
You may need to specify a username and/or a password. In this example the password is read from stdin:
nbdkit -r curl url=sftp://example.com/~/disk.img username=fred password=-
Set the password to use when connecting to the remote server.
Note that passing this on the command line is not secure on shared machines.
Ask for the password (interactively) when nbdkit starts up.
Read the password from the named file. This is the most secure method to supply a password, as long as you set the permissions on the file appropriately.
Don't verify the SSL certificate of the remote host.
Set the timeout for requests.
Use the default libcurl timeout for requests.
The URL of the remote disk image. This is passed to libcurl directly via "CURLOPT_URL" in curl_easy_setopt(3).
This parameter is required.
Set the username to use when connecting to the remote server. This may also be set in the URL (eg.
curl(1), libcurl(3), nbdkit(1), nbdkit-plugin(3).
Richard W.M. Jones
Parts derived from Alexander Graf's "QEMU Block driver for CURL images".
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