Anaconda/Logging

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Revision as of 13:02, 25 January 2010 by Akozumpl (Talk | contribs)

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Contents

Introduction

Anaconda tracks all of its activities in logs. This includes:

  • changing installation steps (that roughly correspond to different screens in the graphical installer)
  • storage devices detection and manipulation
  • installation media detection
  • network initialization
  • kernel messages
  • calls to critical methods within anaconda
  • calls to external programs

Logging on the installed system

During the installation the logs are stored in the /tmp directory:

  • /tmp/anaconda.log, the general installation information, particularly the step changes.
  • /tmp/storage.log, storage devices scan and manipulation (hard drives, partitions, LVM, RAID), partitioning
  • /tmp/program.log, calls to external programs, their output
  • /tmp/messages.log, messages from kernel and external programs (Network Manager)
  • /tmp/yum.log, yum's internal log

Certain log messages are also written to the terminals.

  • /dev/tty3, messages from anaconda.log, storage.log and yum.log.
  • /dev/tty4, same as messages.log
  • /dev/tty5, stdout and stderr from external programs

tty3 and tty4 reflect certain log files. Log files always contain messages from all the loglevels, including debug, but the minimal loglevel on the terminals can be controlled with the loglevel command line option.

There are two other log files created on the target filesystem, in the /root directory, also accessible at /mnt/sysimage/root during the installation:

  • /mnt/sysimage/root/install.log, log of the package installation process.
  • /mnt/sysimage/root/install.log.syslog, messages from installation chroot logged through the system's syslog. Mostly information about users and groups created during yum's package installation.

Log format

In files the format of the log messages is as follows:

H:M:S,ms LOGLEVEL facility:message

where:

  • H:M:S is the message timestamp
  • ms is the millisecond part of timestamp. Note that this will usually become zero on a remote syslog.
  • LOGLEVEL is the message loglevel. In theory, because kernel messages are part of anaconda logs, all loglevels that are defined in rsyslog can appear in the logfiles. Anaconda itself will however log only at the following loglevels:
    1. DEBUG
    2. INFO
    3. WARN
    4. ERR
    5. CRITICAL
  • facility is the program or component that created the message. Could be for instance kernel<code>, <code>anaconda, storage or similar.
  • message is the log message itself.

For the logs running in terminals, the format simply is:

LOGLEVEL facility:message

Remote logging

Anaconda supports remote logging handled through the rsyslog daemon running on the installed system. It can be configured to forward its logs through TCP to an arbitrary machine in network that is also running a syslog daemon. This is controlled with the syslog command line option.

It's up to you how the remote logging daemon is configured, the following is an example that logs the messages into the same files as they are logged on the installed system:

#rsyslog v3 config file

#### MODULES ####

$ModLoad imuxsock.so	# provides support for local system logging (e.g. via logger command)
$SystemLogSocketName /home/akozumpl/projects/syslog/socket

# Provides UDP syslog reception
# $ModLoad imudp.so
# $UDPServerRun 6080

# Provides TCP syslog reception
$ModLoad imtcp.so  
$InputTCPServerRun 6080

#### GLOBAL DIRECTIVES ####

# Use default timestamp format
$ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat

# File syncing capability is disabled by default. This feature is usually not required, 
# not useful and an extreme performance hit
#$ActionFileEnableSync on


#### RULES ####

$template anaconda_tty4, "%timestamp:8:$:date-rfc3164%,%timestamp:1:3:date-subseconds% %syslogseverity-text:::uppercase% %programname%:%msg%\n"
$template anaconda_debug, "%syslogfacility-text%|%hostname%|%syslogseverity-text%|%syslogtag%|%msg%\n"
$template anaconda_syslog, "%timestamp:8:$:date-rfc3164%,%timestamp:1:3:date-subseconds% %syslogseverity-text:::uppercase% %programname%:%msg%\n"

*.*                                                  /home/akozumpl/projects/syslog/out_all_debug.log;anaconda_debug

kern.*;\
daemon.*                                             /home/akozumpl/projects/syslog/messages.log;anaconda_syslog

:programname, contains, "anaconda"                   /home/akozumpl/projects/syslog/anaconda.log;anaconda_syslog
:programname, contains, "program"                    /home/akozumpl/projects/syslog/program.log;anaconda_syslog
:programname, contains, "storage"                    /home/akozumpl/projects/syslog/storage.log;anaconda_syslog
:hostname, contains, "sysimage"                       /home/akozumpl/projects/syslog/install.log.syslog;anaconda_syslog

# discard those that we logged
:programname, contains, "rsyslogd"                   ~
:programname, contains, "anaconda"                   ~
:programname, contains, "program"                    ~
:programname, contains, "storage"                    ~
:hostname, contains, "sysimage"                      ~
kern.*                                               ~
daemon.*                                             ~
# dump the rest
*.*                                                  /home/akozumpl/projects/syslog/unknown_source.log;anaconda_debug

The remote syslog configuration exploits several log message characteristics to be able to sort them into the correct files:

  • anaconda.log, storage.log and program.log have the name embedded in them as programname.
  • messages.log are coming in from kernel and daemon facilities, just like they do on the installed system
  • install.log.syslog made during package installation is logged as a special sysimage hostname.

The sample configuration uses the same message format for remote logging as anaconda does, but note that the remote host can specify its own.

To do

The current list of logging requirements and tasks is maintained in bugzilla 524980.