netconsole.txt 2.2 KB

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