2.6 port and netpoll api by Matt Mackall <mpm@selenic.com>, Sep 9 2003
Please send bug reports to Matt Mackall <mpm@selenic.com>
+and Satyam Sharma <satyam.sharma@gmail.com>
+
+Introduction:
+=============
This module logs kernel printk messages over UDP allowing debugging of
problem where disk logging fails and serial consoles are impractical.
capture of early kernel panics, it does capture most of the boot
process.
+Sender and receiver configuration:
+==================================
+
It takes a string configuration parameter "netconsole" in the
following format:
insmod netconsole netconsole=@/,@10.0.0.2/
+It also supports logging to multiple remote agents by specifying
+parameters for the multiple agents separated by semicolons and the
+complete string enclosed in "quotes", thusly:
+
+ modprobe netconsole netconsole="@/,@10.0.0.2/;@/eth1,6892@10.0.0.3/"
+
Built-in netconsole starts immediately after the TCP stack is
initialized and attempts to bring up the supplied dev at the supplied
address.
The remote host can run either 'netcat -u -l -p <port>' or syslogd.
+Dynamic reconfiguration:
+========================
+
+Dynamic reconfigurability is a useful addition to netconsole that enables
+remote logging targets to be dynamically added, removed, or have their
+parameters reconfigured at runtime from a configfs-based userspace interface.
+[ Note that the parameters of netconsole targets that were specified/created
+from the boot/module option are not exposed via this interface, and hence
+cannot be modified dynamically. ]
+
+To include this feature, select CONFIG_NETCONSOLE_DYNAMIC when building the
+netconsole module (or kernel, if netconsole is built-in).
+
+Some examples follow (where configfs is mounted at the /sys/kernel/config
+mountpoint).
+
+To add a remote logging target (target names can be arbitrary):
+
+ cd /sys/kernel/config/netconsole/
+ mkdir target1
+
+Note that newly created targets have default parameter values (as mentioned
+above) and are disabled by default -- they must first be enabled by writing
+"1" to the "enabled" attribute (usually after setting parameters accordingly)
+as described below.
+
+To remove a target:
+
+ rmdir /sys/kernel/config/netconsole/othertarget/
+
+The interface exposes these parameters of a netconsole target to userspace:
+
+ enabled Is this target currently enabled? (read-write)
+ dev_name Local network interface name (read-write)
+ local_port Source UDP port to use (read-write)
+ remote_port Remote agent's UDP port (read-write)
+ local_ip Source IP address to use (read-write)
+ remote_ip Remote agent's IP address (read-write)
+ local_mac Local interface's MAC address (read-only)
+ remote_mac Remote agent's MAC address (read-write)
+
+The "enabled" attribute is also used to control whether the parameters of
+a target can be updated or not -- you can modify the parameters of only
+disabled targets (i.e. if "enabled" is 0).
+
+To update a target's parameters:
+
+ cat enabled # check if enabled is 1
+ echo 0 > enabled # disable the target (if required)
+ echo eth2 > dev_name # set local interface
+ echo 10.0.0.4 > remote_ip # update some parameter
+ echo cb:a9:87:65:43:21 > remote_mac # update more parameters
+ echo 1 > enabled # enable target again
+
+You can also update the local interface dynamically. This is especially
+useful if you want to use interfaces that have newly come up (and may not
+have existed when netconsole was loaded / initialized).
+
+Miscellaneous notes:
+====================
+
WARNING: the default target ethernet setting uses the broadcast
ethernet address to send packets, which can cause increased load on
other systems on the same ethernet segment.
git.openpandora.org / pandora-kernel.git / blobdiff