From 0a12ec87a513b31eb3b6e035d30649e483322270 Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" Date: Tue, 9 Apr 2013 15:30:53 +0100 Subject: block: Add support for Secure Shell (ssh) block device. qemu-system-x86_64 -drive file=ssh://hostname/some/image QEMU will ssh into 'hostname' and open '/some/image' which is made available as a standard block device. You can specify a username (ssh://user@host/...) and/or a port number (ssh://host:port/...). You can also use an alternate syntax using properties (file.user, file.host, file.port, file.path). Current limitations: - Authentication must be done without passwords or passphrases, using ssh-agent. Other authentication methods are not supported. - Uses a single connection, instead of concurrent AIO with multiple SSH connections. This is implemented using libssh2 on the client side. The server just requires a regular ssh daemon with sftp-server support. Most ssh daemons on Unix/Linux systems will work out of the box. Signed-off-by: Richard W.M. Jones Cc: Stefan Hajnoczi Cc: Kevin Wolf Signed-off-by: Stefan Hajnoczi --- qemu-doc.texi | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) (limited to 'qemu-doc.texi') diff --git a/qemu-doc.texi b/qemu-doc.texi index af84bef0e9..5b36004873 100644 --- a/qemu-doc.texi +++ b/qemu-doc.texi @@ -423,6 +423,7 @@ snapshots. * disk_images_sheepdog:: Sheepdog disk images * disk_images_iscsi:: iSCSI LUNs * disk_images_gluster:: GlusterFS disk images +* disk_images_ssh:: Secure Shell (ssh) disk images @end menu @node disk_images_quickstart @@ -1038,6 +1039,54 @@ qemu-system-x86_64 -drive file=gluster+unix:///testvol/dir/a.img?socket=/tmp/glu qemu-system-x86_64 -drive file=gluster+rdma://1.2.3.4:24007/testvol/a.img @end example +@node disk_images_ssh +@subsection Secure Shell (ssh) disk images + +You can access disk images located on a remote ssh server +by using the ssh protocol: + +@example +qemu-system-x86_64 -drive file=ssh://[@var{user}@@]@var{server}[:@var{port}]/@var{path}[?host_key_check=@var{host_key_check}] +@end example + +Alternative syntax using properties: + +@example +qemu-system-x86_64 -drive file.driver=ssh[,file.user=@var{user}],file.host=@var{server}[,file.port=@var{port}],file.path=@var{path}[,file.host_key_check=@var{host_key_check}] +@end example + +@var{ssh} is the protocol. + +@var{user} is the remote user. If not specified, then the local +username is tried. + +@var{server} specifies the remote ssh server. Any ssh server can be +used, but it must implement the sftp-server protocol. Most Unix/Linux +systems should work without requiring any extra configuration. + +@var{port} is the port number on which sshd is listening. By default +the standard ssh port (22) is used. + +@var{path} is the path to the disk image. + +The optional @var{host_key_check} parameter controls how the remote +host's key is checked. The default is @code{yes} which means to use +the local @file{.ssh/known_hosts} file. Setting this to @code{no} +turns off known-hosts checking. Or you can check that the host key +matches a specific fingerprint: +@code{host_key_check=md5:78:45:8e:14:57:4f:d5:45:83:0a:0e:f3:49:82:c9:c8} +(@code{sha1:} can also be used as a prefix, but note that OpenSSH +tools only use MD5 to print fingerprints). + +Currently authentication must be done using ssh-agent. Other +authentication methods may be supported in future. + +Note: The ssh driver does not obey disk flush requests (ie. to commit +data to the backing disk when the guest requests it). This is because +the underlying protocol (SFTP) does not support this. Thus there is a +risk of guest disk corruption if the remote server or network goes +down during writes. + @node pcsys_network @section Network emulation -- cgit v1.2.1