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diff --git a/docs/HOWTOs/Console-HOWTO b/docs/HOWTOs/Console-HOWTO new file mode 100644 index 0000000000..4abdf52921 --- /dev/null +++ b/docs/HOWTOs/Console-HOWTO @@ -0,0 +1,85 @@ + New console I/O infrastructure in Xen 1.3 + ========================================= + + Keir Fraser, University of Cambridge, 3rd June 2004 + + I thought I'd write a quick note about using the new console I/O + infrastructure in Xen 1.3. Significant new features compared with 1.2, + and with older revisions of 1.3, include: + - bi-directional console access + - log in to a Xenolinux guest OS via its virtual console + - a new terminal client (replaces the use of telnet in character mode) + - proper handling of terminal emulation + +Accessing the virtual console from within the guest OS +------------------------------------------------------ + Every Xenolinux instance owns a bidirectional 'virtual console'. + The device node to which this console is attached can be configured + by specifying 'xencons=' on the OS command line: + 'xencons=off' --> disable virtual console + 'xencons=tty' --> attach console to /dev/tty1 (tty0 at boot-time) + 'xencons=ttyS' --> attach console to /dev/ttyS0 + The default is to attach to /dev/tty1, and also to create dummy + devices for /dev/tty2-63 to avoid warnings from many standard distro + startup scripts. The exception is domain 0, which by default attaches + to /dev/ttyS0. + +Domain 0 virtual console +------------------------ + The virtual console for domain 0 is shared with Xen's console. For + example, if you specify 'console=com1' as a boot parameter to Xen, + then domain 0 will have bi-directional access to the primary serial + line. Boot-time messages can be directed to the virtual console by + specifying 'console=ttyS0' as a boot parameter to Xenolinux. + +Connecting to the virtual console +--------------------------------- + Domain 0 console may be accessed using the supplied 'miniterm' program + if raw serial access is desired. If the Xen machine is connected to a + serial-port server, then the supplied 'xencons' program may be used to + connect to the appropriate TCP port on the server: + # xencons <server host> <server port> + +Logging in via virtual console +------------------------------ + It is possible to log in to a guest OS via its virtual console if a + 'getty' is running. In most domains the virtual console is named tty1 + so standard startup scripts and /etc/inittab should work + fine. Furthermore, tty2-63 are created as dummy console devices to + suppress warnings from standard startup scripts. If the OS has + attached the virtual console to /dev/ttyS0 then you will need to + start a 'mingetty' on that device node. + +Virtual console for other domains +--------------------------------- + Every guest OS has a virtual console that is accessible via + 'console=tty0' at boot time (or 'console=xencons0' for domain 0), and + mingetty running on /dev/tty1 (or /dev/xen/cons for domain 0). + However, domains other than domain 0 do not have access to the + physical serial line. Instead, their console data is sent to and from + a control daemon running in domain 0. When properly installed, this + daemon can be started from the init scripts (e.g., rc.local): + # /usr/sbin/xend start + + Alternatively, Redhat- and LSB-compatible Linux installations can use + the provided init.d script. To integrate startup and shutdown of xend + in such a system, you will need to run a few configuration commands: + # chkconfig --add xend + # chkconfig --level 35 xend on + # chkconfig --level 01246 xend off + This will avoid the need to run xend manually from rc.local, for example. + + Note that, when a domain is created using xc_dom_create.py, xend MUST + be running. If everything is set up correctly then xc_dom_create will + print the local TCP port to which you should connect to perform + console I/O. A suitable console client is provided by the Python + module xenctl.console_client: running this module from the command + line with <host> and <port> parameters will start a terminal + session. This module is also installed as /usr/bin/xencons, from a + copy in tools/misc/xencons. For example: + # xencons localhost 9600 + + An alternative to manually running a terminal client is to specify + '-c' to xc_dom_create.py, or add 'auto_console=True' to the defaults + file. This will cause xc_dom_create.py to automatically become the + console terminal after starting the domain. |