projects / mirror_ubuntu-zesty-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | |
| 2 | started by Ingo Molnar <mingo@redhat.com>, 2001.09.17 | |
| 3 | 2.6 port and netpoll api by Matt Mackall <mpm@selenic.com>, Sep 9 2003 | |
| 4 | ||
| 5 | Please send bug reports to Matt Mackall <mpm@selenic.com> | |
| 6 | ||
| 7 | This module logs kernel printk messages over UDP allowing debugging of | |
| 8 | problem where disk logging fails and serial consoles are impractical. | |
| 9 | ||
| 10 | It can be used either built-in or as a module. As a built-in, | |
| 11 | netconsole initializes immediately after NIC cards and will bring up | |
| 12 | the specified interface as soon as possible. While this doesn't allow | |
| 13 | capture of early kernel panics, it does capture most of the boot | |
| 14 | process. | |
| 15 | ||
| 16 | It takes a string configuration parameter "netconsole" in the | |
| 17 | following format: | |
| 18 | ||
| 19 | netconsole=[src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr] | |
| 20 | ||
| 21 | where | |
| 22 | src-port source for UDP packets (defaults to 6665) | |
| 23 | src-ip source IP to use (interface address) | |
| 24 | dev network interface (eth0) | |
| 25 | tgt-port port for logging agent (6666) | |
| 26 | tgt-ip IP address for logging agent | |
| 27 | tgt-macaddr ethernet MAC address for logging agent (broadcast) | |
| 28 | ||
| 29 | Examples: | |
| 30 | ||
| 31 | linux netconsole=4444@10.0.0.1/eth1,9353@10.0.0.2/12:34:56:78:9a:bc | |
| 32 | ||
| 33 | or | |
| 34 | ||
| 35 | insmod netconsole netconsole=@/,@10.0.0.2/ | |
| 36 | ||
| 37 | Built-in netconsole starts immediately after the TCP stack is | |
| 38 | initialized and attempts to bring up the supplied dev at the supplied | |
| 39 | address. | |
| 40 | ||
| 41 | The remote host can run either 'netcat -u -l -p <port>' or syslogd. | |
| 42 | ||
| 43 | WARNING: the default target ethernet setting uses the broadcast | |
| 44 | ethernet address to send packets, which can cause increased load on | |
| 45 | other systems on the same ethernet segment. | |
| 46 | ||
| 47 | NOTE: the network device (eth1 in the above case) can run any kind | |
| 48 | of other network traffic, netconsole is not intrusive. Netconsole | |
| 49 | might cause slight delays in other traffic if the volume of kernel | |
| 50 | messages is high, but should have no other impact. | |
| 51 | ||
| 52 | Netconsole was designed to be as instantaneous as possible, to | |
| 53 | enable the logging of even the most critical kernel bugs. It works | |
| 54 | from IRQ contexts as well, and does not enable interrupts while | |
| 55 | sending packets. Due to these unique needs, configuration can not | |
| 56 | be more automatic, and some fundamental limitations will remain: | |
| 57 | only IP networks, UDP packets and ethernet devices are supported. |