3:44 a.m.
Before getting into more discussion on the URI issue, I'll copy the
"Architecture & Notes" section here so that everyone can actually read
it first.
/* Architecture and notes:
*
* virConnectOpen ("remote:....") invokes this driver. Depending
* on the exact contents of the ellipsis "...." in the name string
* we will try some method to connect to a libvirtd daemon, running
* on a remote machine (or sometimes running on the local machine).
*
* All other vir* calls made on this connection are forwarded
* to the libvirtd daemon which carries out the requested action.
* So for example if you call virDomainCreateLinux, then the
* domain gets created on the remote machine, and virConnectListDomains
* lists domains running on the remote machine.
*
* Connections can be authenticated and encrypted -- it depends
* on the transport selected by the name string.
*
* The current implementation uses SunRPC layered over one of:
* - GnuTLS (an SSL/TLS library providing enterprise-level
* authentication and encryption)
* - a local Unix domain socket
* - ssh or another external program such as rsh
* - a plain TCP socket (unencrypted, not recommended for production)
*
* See http://et.redhat.com/~rjones/secure_rpc for an insight into
* the thinking that went into the selection of SunRPC. In
* the future we may use a different RPC system - for example
* XML-RPC would be a logical choice - so for now you should regard
* the protocol used as private and subject to change in future
* versions of libvirt without notice.
*
* The name string selects the transport to use and the type of
* virtualisation at the remote end. The general format is:
*
* "remote:<protocol>:<path> var=value var=value ..."
*
* Some examples:
*
* "remote:unix:/var/run/libvirtd/socket"
* "remote:tls:myxenserver"
* "remote:ssh:myserver name=qemud"
* "remote:ssh:myserver command=/opt/openssh/bin/ssh"
*
* The <protocol> is one of: tls, unix, ssh, ext or tcp.
* The <path> is protocol specific:
*
* Protocol Path-format
* -----------------------------------------
* tls hostname[:port]
* unix Path to local socket
* ssh hostname[:port]
* ext Name or path of external program
* tcp hostname[:port]
*
* For tls, the default port is 16514. For tcp, the default port is
* 16509 (but note that tcp is almost never enabled because it is
* insecure - it's only there for testing).
*
* For ssh: The default port for ssh is 22. You should configure ssh
* so that it doesn't ask for a password (eg. using ssh-agent). The
* remote server should have a recent version of the the netcat program
* installed as 'nc', and the remote libvirtd must be configured to
* listen on a Unix domain socket. The following full command is run:
* ssh -p $port $hostname nc -U /var/run/libvirtd/socket
*
* For ext: Only the command you specify is run. It is up to you to
* write this command so that it somehow makes a connection to a
* remote libvirtd, and passes input and output over its stdin/stdout.
*
* The var=value pairs provide optional extra information:
*
* Variable Protocols Meaning
* -----------------------------------------
* name (all) Name used in remote virConnectOpen
* (default is NULL).
* command ssh Name or path of external program (instead
* of "ssh").
*
* The value is %-escaped (just like URL encoding), so if you want it
* to contain a literal space use "%20" or "+", if you want it to
have
* a literal + character use "%2b", and for a literal % character use
"%25".
*
* To provide some forwards compatibility, variables which are not
* understood are ignored (but a warning is printed on stderr).
*
* Several shorthand syntaxes are available:
*
* "remote:/var/run/libvirtd/socket" connect to Unix domain socket
* "remote://server" connect to TLS socket on server
* "remote://server:9000" connect to TLS server port 9000
*
* For the details of the implementation of SunRPC over GnuTLS, etc.
* please see http://et.redhat.com/~rjones/secure_rpc which contains
* simple code samples which will allow you to understand what's
* going on here.
*/
--
Emerging Technologies, Red Hat http://et.redhat.com/~rjones/
64 Baker Street, London, W1U 7DF Mobile: +44 7866 314 421
"[Negative numbers] darken the very whole doctrines of the equations
and make dark of the things which are in their nature excessively
obvious and simple" (Francis Maseres FRS, mathematician, 1759)