Ubuntu Server Guide

Merge lp:~louis/serverguide/remote-kdump-update into lp:serverguide/trunk

  1. remote-kdump-update
  2. Merge into trunk
Proposed by Louis Bouchard
Status: Merged
Approved by: Doug Smythies
Approved revision: 282
Merged at revision: 282
Proposed branch: lp:~louis/serverguide/remote-kdump-update
Merge into: lp:serverguide/trunk
Diff against target: 169 lines (+137/-9)
1 file modified
serverguide/C/installation.xml (+137/-9)
To merge this branch: bzr merge lp:~louis/serverguide/remote-kdump-update
Reviewer Review Type Date Requested Status
Doug Smythies Approve
Review via email: mp+291252@code.launchpad.net

Description of the change

Added configuration details for the remote kernel crash dump functionality now included in Xenial

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Revision history for this message
Doug Smythies (dsmythies) wrote :

I get the following warnings while compiling the PDF:

[INFO] FOUserAgent - Rendered page #17.
[WARN] FOUserAgent - Glyph "┌" (0x250c, SF010000) not available in font "Courier".
[WARN] FOUserAgent - Glyph "─" (0x2500, SF100000) not available in font "Courier".
[WARN] FOUserAgent - Glyph "┤" (0x2524, SF090000) not available in font "Courier".
[WARN] FOUserAgent - Glyph "├" (0x251c, SF080000) not available in font "Courier".
[WARN] FOUserAgent - Glyph "┐" (0x2510, SF030000) not available in font "Courier".
[WARN] FOUserAgent - Glyph "│" (0x2502, SF110000) not available in font "Courier".
[WARN] FOUserAgent - Glyph "└" (0x2514, SF020000) not available in font "Courier".
[WARN] FOUserAgent - Glyph "┘" (0x2518, SF040000) not available in font "Courier".
[INFO] FOUserAgent - Rendered page #18.

And when I check for non-ascii characters in the master English source, I get a bunch of hits (including one that snuck in there with Serge's MP).

See also:
https://wiki.ubuntu.com/DocumentationTeam/SystemDocumentation/Repository/Members-Serverguide#ASCII_Policy

review: Needs Fixing
Revision history for this message
Simon Quigley (tsimonq2) wrote :

Lines 16-26 of the diff are the culprit, and in the LXD guide, Stephane Graber's name is the culprit of that warning. It's a really simple fix, and I have a fix that you could do the following with:

============================================================

bzr merge lp:~tsimonq2/serverguide/fix-remote-kdump-update

bzr commit -m "Merged Simon's fix"

bzr push lp:~louis-bouchard/serverguide/remote-kdump-update

============================================================

Link to my fix: https://code.launchpad.net/~tsimonq2/serverguide/fix-remote-kdump-update

Revision history for this message
Doug Smythies (dsmythies) wrote :

Simon, thanks. Yes, I knew what the problem was, just didn't have time to fix it myself.

Revision history for this message
Doug Smythies (dsmythies) wrote :

O.K. I did the same edits as Simon proposed and will push this into trunk.

review: Approve

Preview Diff

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=== modified file 'serverguide/C/installation.xml'
--- serverguide/C/installation.xml 2016-04-07 00:08:38 +0000
+++ serverguide/C/installation.xml 2016-04-07 13:43:00 +0000
@@ -1402,21 +1402,131 @@
1402<command>sudo apt install linux-crashdump</command>1402<command>sudo apt install linux-crashdump</command>
1403</screen>1403</screen>
14041404
1405 </sect2>1405
1406 <note>
1407 <para>Starting with 16.04, the kernel crash dump mechanism is enabled by default. During the installation, you will be prompted with the following dialog. Unless chosen otherwise, the kdump mechanism will be enabled.
1408 </para>
1409 </note>
1410
1411 <screen>
1412 ┌────────────────────────┤ Configuring kdump-tools ├────────────────────────┐
1413 │ │
1414 │ If you choose this option, the kdump-tools mechanism will be enabled. A │
1415 │ reboot is still required in order to enable the crashkernel kernel │
1416 │ parameter. │
1417 │ │
1418 │ Should kdump-tools be enabled by default? │
1419 │ │
1420 │ <emphasis role="bold">&lt;Yes&gt;</emphasis> &lt;No&gt; │
1421 │ │
1422 └───────────────────────────────────────────────────────────────────────────┘
1423 </screen>
1424 <para>
1425 If you ever need to manually enable the functionality, you can use the <command>dpkg-reconfigure kdump-tools</command> command and answer Yes to the question. You can also edit <filename>/etc/default/kdump-tools</filename> by including the following line:
1426<programlisting>
1427USE_KDUMP=1
1428</programlisting>
1429 </para>
1430
1431 <para>
1432 If a reboot has not been done since installation of the linux-crashdump package, a reboot will be required in order to activate the crashkernel= boot parameter. Upon reboot, kdump-tools will be enabled and active.
1433 </para>
1434 <para>
1435 If you enable kdump-tools after a reboot, you will only need to issue the <command>kdump-config load</command> command to activate the kdump mechanism.
1436 </para>
1437 </sect2>
1406 <sect2 id="kernel-dump-configuration" status="review">1438 <sect2 id="kernel-dump-configuration" status="review">
1407 <title>Configuration</title>1439 <title>Configuration</title>
14081440
1409 <para>1441 <para>
1410 Edit <filename>/etc/default/kdump-tools</filename> by including the following line:1442 In addition to local dump, it is now possible to use the remote dump functionality to send the kernel crash dump to a remote server, using either the <emphasis>SSH</emphasis> or <emphasis>NFS</emphasis> protocols.
1411<programlisting>
1412USE_KDUMP=1
1413</programlisting>
1414 </para>1443 </para>
14151444 <sect3 id="local-dump" status="review">
1445 <title>Local Kernel Crash Dumps</title>
1446 <para>
1447 Local dumps are configured automatically and will remain in use unless a remote protocol is chosen. Many configuration options exist and are thoroughly documented in the <filename>/etc/default/kdump-tools</filename> file.
1448 </para>
1449 </sect3>
1450
1451 <sect3 id="ssh-dump" status="review">
1452 <title>Remote Kernel Crash Dumps using the SSH protocol</title>
1453 <para>
1454 To enable remote dumps using the <emphasis>SSH</emphasis> protocol, the <filename>/etc/default/kdump-tools</filename> must be modified in the following manner :</para>
1455 <programlisting>
1456# ---------------------------------------------------------------------------
1457# Remote dump facilities:
1458# SSH - username and hostname of the remote server that will receive the dump
1459# and dmesg files.
1460# SSH_KEY - Full path of the ssh private key to be used to login to the remote
1461# server. use kdump-config propagate to send the public key to the
1462# remote server
1463# HOSTTAG - Select if hostname of IP address will be used as a prefix to the
1464# timestamped directory when sending files to the remote server.
1465# 'ip' is the default.
1466<emphasis role="bold">SSH="ubuntu@kdump-netcrash"</emphasis>
1467 </programlisting>
1468 <para>The only mandatory variable to define is SSH. It must contain the username and hostname of the remote server using the format {username}@{remote server}.</para>
1469
1470 <para>SSH_KEY may be used to provide an existing private key to be used. Otherwise, the <command>kdump-config propagate</command> command will create a new keypair. The HOSTTAG variable may be used to use the hostname of the system as a prefix to the remote directory to be created instead of the IP address. </para>
1471
1472 <para>The following example shows how <command>kdump-config propagate</command> is used to create and propagate a new keypair to the remote server :
1473 <screen>
1474<command>sudo kdump-config propagate</command>
1475Need to generate a new ssh key...
1476The authenticity of host 'kdump-netcrash (192.168.1.74)' can't be established.
1477ECDSA key fingerprint is SHA256:iMp+5Y28qhbd+tevFCWrEXykDd4dI3yN4OVlu3CBBQ4.
1478Are you sure you want to continue connecting (yes/no)? yes
1479ubuntu@kdump-netcrash's password:
1480propagated ssh key /root/.ssh/kdump_id_rsa to server ubuntu@kdump-netcrash
1481 </screen>
1482 The password of the account used on the remote server will be required in order to successfully send the public key to the server</para>
1483 <para>
1484 The <command>kdump-config show</command> command can be used to confirm that kdump is correctly configured to use the SSH protocol :
1485 <screen>
1486<command>kdump-config show</command>
1487DUMP_MODE: kdump
1488USE_KDUMP: 1
1489KDUMP_SYSCTL: kernel.panic_on_oops=1
1490KDUMP_COREDIR: /var/crash
1491crashkernel addr: 0x2c000000
1492 /var/lib/kdump/vmlinuz: symbolic link to /boot/vmlinuz-4.4.0-10-generic
1493kdump initrd:
1494 /var/lib/kdump/initrd.img: symbolic link to /var/lib/kdump/initrd.img-4.4.0-10-generic
1495<emphasis role="bold">SSH: ubuntu@kdump-netcrash
1496SSH_KEY: /root/.ssh/kdump_id_rsa
1497HOSTTAG: ip
1498current state: ready to kdump</emphasis>
1499 </screen></para>
1500 </sect3>
1501
1502 <sect3 id="nfs-dump" status="review">
1503 <title>Remote Kernel Crash Dumps using the NFS protocol</title>
1416 <para>1504 <para>
1417 A reboot is then needed.1505 To enable remote dumps using the <emphasis>NFS</emphasis> protocol, the <filename>/etc/default/kdump-tools</filename> must be modified in the following manner :</para>
1418 </para>1506 <programlisting>
14191507# NFS - Hostname and mount point of the NFS server configured to receive
1508# the crash dump. The syntax must be {HOSTNAME}:{MOUNTPOINT}
1509# (e.g. remote:/var/crash)
1510#
1511<emphasis role="bold">NFS="kdump-netcrash:/var/crash"</emphasis>
1512 </programlisting>
1513 <para>As with the SSH protocol, the HOSTTAG variable can be used to replace the IP address by the hostname as the prefix of the remote directory.</para>
1514 <para>The <command>kdump-config show</command> command can be used to confirm that kdump is correctly configured to use the NFS protocol :
1515 <screen>
1516<command>kdump-config show</command>
1517DUMP_MODE: kdump
1518USE_KDUMP: 1
1519KDUMP_SYSCTL: kernel.panic_on_oops=1
1520KDUMP_COREDIR: /var/crash
1521crashkernel addr: 0x2c000000
1522 /var/lib/kdump/vmlinuz: symbolic link to /boot/vmlinuz-4.4.0-10-generic
1523kdump initrd:
1524 /var/lib/kdump/initrd.img: symbolic link to /var/lib/kdump/initrd.img-4.4.0-10-generic
1525<emphasis role="bold">NFS: kdump-netcrash:/var/crash
1526HOSTTAG: hostname
1527current state: ready to kdump</emphasis>
1528 </screen></para>
1529 </sect3>
1420 </sect2>1530 </sect2>
14211531
1422 <sect2 id="verification" status="review">1532 <sect2 id="verification" status="review">
@@ -1471,6 +1581,24 @@
1471</computeroutput>1581</computeroutput>
1472</screen>1582</screen>
14731583
1584 <para>
1585 Finally, as seen previously, the <command>kdump-config show</command> command displays the current status of the kdump-tools configuration :
1586 <screen>
1587 <command>kdump-config show
1588</command>DUMP_MODE: kdump
1589USE_KDUMP: 1
1590KDUMP_SYSCTL: kernel.panic_on_oops=1
1591KDUMP_COREDIR: /var/crash
1592crashkernel addr: 0x2c000000
1593 /var/lib/kdump/vmlinuz: symbolic link to /boot/vmlinuz-4.4.0-10-generic
1594kdump initrd:
1595 /var/lib/kdump/initrd.img: symbolic link to /var/lib/kdump/initrd.img-4.4.0-10-generic
1596current state: ready to kdump
1597
1598kexec command:
1599 /sbin/kexec -p --command-line="BOOT_IMAGE=/vmlinuz-4.4.0-10-generic root=/dev/mapper/VividS--vg-root ro debug break=init console=ttyS0,115200 irqpoll maxcpus=1 nousb systemd.unit=kdump-tools.service" --initrd=/var/lib/kdump/initrd.img /var/lib/kdump/vmlinuz
1600 </screen>
1601 </para>
1474 </sect2>1602 </sect2>
14751603
1476 <sect2 id="kdump-testing" status="review">1604 <sect2 id="kdump-testing" status="review">

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