全部博文（55）
分类： LINUX
2011-03-17 10:15:08
对于linux 的系统安全来说，日志文件是极其重要的工具。
系统管理员可以使用logrotate 程序用来管理系统中的最新的事件。logrotate 还可以用来备份日志文件，本篇将通过以下几部分来介绍
日志文件的管理：
1、logrotate 配置
2、缺省配置 logrotate
3、使用include 选项读取其他配置文件
4、使用include 选项覆盖缺省配置
5、为指定的文件配置转储参数
一、logrotate 配置
logrotate 程序是一个日志文件管理工具。用来把旧的日志文件删除，并创建新的日志文件，我们把它叫做“转储”。我们可以根据日志文件的大小，也可以根据其天数来转储，这个过程一般通过 cron 程序来执行。
logrotate 程序还可以用于压缩日志文件，以及发送日志到指定的E-mail 。
logrotate 的配置文件是 /etc/logrotate.conf。主要参数如下表：
参数 功能
compress 通过gzip 压缩转储以后的日志
nocompress 不需要压缩时，用这个参数
copytruncate 用于还在打开中的日志文件，把当前日志备份并截断
nocopytruncate 备份日志文件但是不截断
create mode owner group 转储文件，使用指定的文件模式创建新的日志文件
nocreate 不建立新的日志文件
delaycompress 和 compress 一起使用时，转储的日志文件到下一次转储时才压缩
nodelaycompress 覆盖 delaycompress 选项，转储同时压缩。
errors address 专储时的错误信息发送到指定的Email 地址
ifempty 即使是空文件也转储，这个是 logrotate 的缺省选项。
notifempty 如果是空文件的话，不转储
mail address 把转储的日志文件发送到指定的E-mail 地址
nomail 转储时不发送日志文件
olddir directory 转储后的日志文件放入指定的目录，必须和当前日志文件在同一个文件系统
noolddir 转储后的日志文件和当前日志文件放在同一个目录下
prerotate/endscript 在转储以前需要执行的命令可以放入这个对，这两个关键字必须单独成行
postrotate/endscript 在转储以后需要执行的命令可以放入这个对，这两个关键字必须单独成行
daily 指定转储周期为每天
weekly 指定转储周期为每周
monthly 指定转储周期为每月
rotate count 指定日志文件删除之前转储的次数，0 指没有备份，5 指保留5 个备份
tabootext [+] list 让logrotate 不转储指定扩展名的文件，缺省的扩展名是：.rpm-orig, .rpmsave, v, 和 ~
size size 当日志文件到达指定的大小时才转储，Size 可以指定 bytes (缺省)以及KB (sizek)或者MB (sizem).
二、缺省配置 logrotate
logrotate 缺省的配置募??/etc/logrotate.conf。
Red Hat linux 缺省安装的文件内容是：
缺省的配置一般放在logrotate.conf 文件的最开始处，影响整个系统。在本例中就是前面12行。
第三行weekly 指定所有的日志文件每周转储一次。
第五行 rotate 4 指定转储文件的保留 4份。
第七行 errors root 指定错误信息发送给root。
第九行create 指定 logrotate 自动建立新的日志文件，新的日志文件具有和
原来的文件一样的权限。
第11行 #compress 指定不压缩转储文件，如果需要压缩，去掉注释就可以了。
三、使用include 选项读取其他配置文件
include 选项允许系统管理员把分散到几个文件的转储信息，集中到一个
主要的配置文件。当 logrotate 从logrotate.conf 读到include 选项时，会从指定文件读入配置信息，就好像他们已经在/etc/logrotate.conf 中一样。
第13行 include /etc/logrotate.d 告诉 logrotate 读入存放在/etc/logrotate.d 目录中的日志转储参数，当系统中安装了RPM 软件包时，使用include 选项十分有用。RPM 软件包的日志转储参数一般存放在/etc/logrotate.d 目录。
include 选项十分重要，一些应用把日志转储参数存放在 /etc/logrotate.d 。
典型的应用有：apache, linuxconf, samba, cron 以及syslog。
这样，系统管理员只要管理一个 /etc/logrotate.conf 文件就可以了。
四、使用include 选项覆盖缺省配置
当 /etc/logrotate.conf 读入文件时，include 指定的文件中的转储参数将覆盖缺省的参数，如下例：
# linuxconf 的参数
在这个例子中，当 /etc/logrotate.d/linuxconf 文件被读入时，下面的参数将覆盖/etc/logrotate.conf中缺省的参数。
Notifempty
errors jim
五、为指定的文件配置转储参数
经常需要为指定文件配置参数，一个常见的例子就是每月转储/var/log/wtmp。为特定文件而使用的参数格式是：
下面的例子就是每月转储 /var/log/wtmp 一次：
六、其他需要注意的问题
1、尽管花括号的开头可以和其他文本放在同一行上，但是结尾的花括号必须单独成行。
2、使用 prerotate 和 postrotate 选项
下面的例子是典型的脚本 /etc/logrotate.d/syslog，这个脚本只是对
/var/log/messages 有效。
第一行指定脚本对 /var/log messages 有效
花ê哦阅诓康慕疟驹诵杏? /var/log/messages
prerotate 命令指定转储以前的动作/usr/bin/chattr -a 去掉/var/log/messages文件的“只追加”属性 endscript 结束 prerotate 部分的脚本postrotate 指定转储后的动作
/usr/bin/killall -HUP syslogd
用来重新初始化系统日志守护程序 syslogd
/usr/bin/chattr +a /var/log/messages
重新为 /var/log/messages 文件指定“只追加”属性，这样防治程序员或用户覆盖此文件。
最后的 endscript 用于结束 postrotate 部分的脚本
3、logrotate 的运行分为三步：
判断系统的日志文件，建立转储计划以及参数，通过cron daemon 运行下面的代码是 Red Hat linux 缺省的crontab 来每天运行logrotate。
#/etc/cron.daily/logrotate
#! /bin/sh
/usr/sbin/logrotate /etc/logrotate.conf
4、/var/log/messages 不能产生的原因：
这种情况很少见，但是如果你把/etc/services 中的 514/UDP 端口关掉的话，这个文件就不能产生了。
小结：本文通过对Red Hat 系统上典型的logrotate 配置例子的介绍，详细说明了logrotate 程序的应用方法。希望对所有linux 系统管理员有所帮助。管理好，分析好日志文件是系统安全的第一步，在以后的文章里FreeLAMP还会介绍另外一个检查日志的好东东 logcheck。
[root@test001 ~]# man logrotateLOGROTATE(8) System Administrator's Manual LOGROTATE(8)
NAME
logrotate - rotates, compresses, and mails system logs
SYNOPSIS
logrotate [-dv] [-f|--force] [-s|--state file] config_file+
DESCRIPTION
logrotate is designed to ease administration of systems that generate
large numbers of log files. It allows automatic rotation, compression,
removal, and mailing of log files. Each log file may be handled daily,
weekly, monthly, or when it grows too large.
Normally, logrotate is run as a daily cron job. It will not modify a
log multiple times in one day unless the criterium for that log is
based on the log's size and logrotate is being run multiple times each
day, or unless the -f or -force option is used.
Any number of config files may be given on the command line. Later con-
fig files may override the options given in earlier files, so the order
in which the logrotate config files are listed in is important. Nor-
mally, a single config file which includes any other config files which
are needed should be used. See below for more information on how to
use the include directive to accomplish this. If a directory is given
on the command line, every file in that directory is used as a config
file.
If no command line arguments are given, logrotate will print version
and copyright information, along with a short usage summary. If any
errors occur while rotating logs, logrotate will exit with non-zero
status.
OPTIONS
-v Turn on verbose mode.
-d Turns on debug mode and implies -v. In debug mode, no changes
will be made to the logs or to the logrotate state file.
-f, --force
Tells logrotate to force the rotation, even if it doesn't think
this is necessary. Sometimes this is useful after adding new
entries to logrotate, or if old log files have been removed by
hand, as the new files will be created, and logging will con-
tinue correctly.
-m, --mail
Tells logrotate which command to use when mailing logs. This
command should accept two arguments: 1) the subject of the mes-
sage, and 2) the recipient. The command must then read a message
on standard input and mail it to the recipient. The default mail
command is /bin/mail -s.
-s, --state
Tells logrotate to use an alternate state file. This is useful
if logrotate is being run as a different user for various sets
of log files. The default state file is /var/lib/logrotate.sta-
tus.
--usage
Prints a short usage message.
CONFIGURATION FILE
logrotate reads everything about the log files it should be handling
from the series of configuration files specified on the command line.
Each configuration file can set global options (local definitions over-
ride global ones, and later definitions override earlier ones) and
specify logfiles to rotate. A simple configuration file looks like
this:
# sample logrotate configuration file
compress
/var/log/messages {
rotate 5
weekly
postrotate
/sbin/killall -HUP syslogd
endscript
}
"/var/log/httpd/access.log" /var/log/httpd/error.log {
rotate 5
mail
size 100k
sharedscripts
postrotate
/sbin/killall -HUP httpd
endscript
}
/var/log/news/* {
monthly
rotate 2
olddir /var/log/news/old
missingok
postrotate
kill -HUP `cat /var/run/inn.pid`
endscript
nocompress
}
The first few lines set global options; in the example, logs are com-
pressed after they are rotated. Note that comments may appear anywhere
in the config file as long as the first non-whitespace character on the
line is a #.
The next section of the config files defined how to handle the log file
/var/log/messages. The log will go through five weekly rotations before
being removed. After the log file has been rotated (but before the old
version of the log has been compressed), the command /sbin/killall -HUP
syslogd will be executed.
The next section defines the parameters for both
/var/log/httpd/access.log and /var/log/httpd/error.log. They are
rotated whenever it grows over 100k in size, and the old logs files are
mailed (uncompressed) to after going through 5 rotations,
rather then being removed. The sharedscripts means that the postrotate
script will only be run once, not once for each log which is rotated.
Note that the double quotes around the first filename at the beginning
of this section allows logrotate to rotate logs with spaces in the
name. Normal shell quoting rules apply, with ', ", and \ characters
supported.
The last section defines the parameters for all of the files in
/var/log/news. Each file is rotated on a monthly basis. This is con-
sidered a single rotation directive and if errors occur for more then
one file, the log files are not compressed.
Please use wildcards with caution. If you specify *, logrotate will
rotate all files, including previously rotated ones. A way around this
is to use the olddir directive or a more exact wildcard (such as
*.log).
Here is more information on the directives which may be included in a
logrotate configuration file:
compress
Old versions of log files are compressed with gzip by default.
See also nocompress.
compresscmd
Specifies which command to use to compress log files. The
default is gzip. See also compress.
uncompresscmd
Specifies which command to use to uncompress log files. The
default is gunzip.
compres***t
Specifies which extension to use on compressed logfiles, if com-
pression is enabled. The default follows that of the configured
compression command.
compressoptions
Command line options may be passed to the compression program,
if one is in use. The default, for gzip, is "-9" (maximum com-
pression).
copy Make a copy of the log file, but don't change the original at
all. This option can be used, for instance, to make a snapshot
of the current log file, or when some other utility needs to
truncate or pare the file. When this option is used, the create
option will have no effect, as the old log file stays in place.
copytruncate
Truncate the original log file in place after creating a copy,
instead of moving the old log file and optionally creating a new
one, It can be used when some program can not be told to close
its logfile and thus might continue writing (appending) to the
previous log file forever. Note that there is a very small time
slice between copying the file and truncating it, so some log-
ging data might be lost. When this option is used, the create
option will have no effect, as the old log file stays in place.
create mode owner group
Immediately after rotation (before the postrotate script is run)
the log file is created (with the same name as the log file just
rotated). mode specifies the mode for the log file in octal
(the same as chmod(2)), owner specifies the user name who will
own the log file, and group specifies the group the log file
will belong to. Any of the log file attributes may be omitted,
in which case those attributes for the new file will use the
same values as the original log file for the omitted attributes.
This option can be disabled using the nocreate option.
daily Log files are rotated every day.
dateext
Archive old versions of log files adding a daily extension like
YYYYMMDD instead of simply adding a number.
delaycompress
Postpone compression of the previous log file to the next rota-
tion cycle. This has only effect when used in combination with
compress. It can be used when some program can not be told to
close its logfile and thus might continue writing to the previ-
ous log file for some time.
extension ext
Log files with ext extension can keep it after the rotation. If
compression is used, the compression extension (normally .gz)
appears after ext. For example you have a logfile named
mylog.foo and want to rotate it to mylog.1.foo.gz instead of
mylog.foo.1.gz.
ifempty
Rotate the log file even if it is empty, overiding the
notifempty option (ifempty is the default).
include file_or_directory
Reads the file given as an argument as if it was included inline
where the include directive appears. If a directory is given,
most of the files in that directory are read in alphabetic order
before processing of the including file continues. The only
files which are ignored are files which are not regular files
(such as directories and named pipes) and files whose names end
with one of the taboo extensions, as specified by the tabooext
directive. The include directive may not appear inside of a log
file definition.
mail address
When a log is rotated out-of-existence, it is mailed to address.
If no mail should be generated by a particular log, the nomail
directive may be used.
mailfirst
When using the mail command, mail the just-rotated file, instead
of the about-to-expire file.
maillast
When using the mail command, mail the about-to-expire file,
instead of the just-rotated file (this is the default).
maxage count
Remove rotated logs older than
checked if the logfile is to be rotated. The files are mailed to
the configured address if maillast and mail are configured.
minsize size
Log files are rotated when they grow bigger then size bytes, but
not before the additionally specified time interval (daily,
weekly, monthly, or yearly). The related size option is similar
except that it is mutually exclusive with the time interval
options, and it causes log files to be rotated without regard
for the last rotation time. When minsize is used, both the size
and timestamp of a log file are considered.
missingok
If the log file is missing, go on to the next one without issu-
ing an error message. See also nomissingok.
monthly
Log files are rotated the first time logrotate is run in a month
(this is normally on the first day of the month).
nocompress
Old versions of log files are not compressed with gzip. See also
compress.
nocopy Do not copy the original log file and leave it in place. (this
overrides the copy option).
nocopytruncate
Do not truncate the original log file in place after creating a
copy (this overrides the copytruncate option).
nocreate
New log files are not created (this overrides the create
option).
nodelaycompress
Do not postpone compression of the previous log file to the next
rotation cycle (this overrides the delaycompress option).
nodateext
Do not archive old versions of log files with date extension
(this overrides the dateext option).
nomail Don't mail old log files to any address.
nomissingok
If a log file does not exist, issue an error. This is the
default.
noolddir
Logs are rotated in the same directory the log normally resides
in (this overrides the olddir option).
nosharedscripts
Run prerotate and postrotate scripts for every log file which is
rotated (this is the default, and overrides the sharedscripts
option).
notifempty
Do not rotate the log if it is empty (this overrides the ifempty
option).
olddir directory
Logs are moved into directory for rotation. The directory must
be on the same physical device as the log file being rotated,
and is assumed to be relative to the directory holding the log
file unless an absolute path name is specified. When this option
is used all old versions of the log end up in directory. This
option may be overriden by the noolddir option.
postrotate/endscript
The lines between postrotate and endscript (both of which must
appear on lines by themselves) are executed after the log file
is rotated. These directives may only appear inside of a log
file definition. See prerotate as well.
prerotate/endscript
The lines between prerotate and endscript (both of which must
appear on lines by themselves) are executed before the log file
is rotated and only if the log will actually be rotated. These
directives may only appear inside of a log file definition. See
postrotate as well.
firstaction/endscript
The lines between firstaction and endscript (both of which must
appear on lines by themselves) are executed once before all log
files that match the wildcarded pattern are rotated, before pre-
rotate script is run and only if at least one log will actually
be rotated. These directives may only appear inside of a log
file definition. See lastaction as well.
lastaction/endscript
The lines between lastaction and endscript (both of which must
appear on lines by themselves) are executed once after all log
files that match the wildcarded pattern are rotated, after
postrotate script is run and only if at least one log is
rotated. These directives may only appear inside of a log file
definition. See firstaction as well.
rotate count
Log files are rotated
mailed to the address specified in a mail directive. If count is
0, old versions are removed rather then rotated.
size size
Log files are rotated when they grow bigger then size bytes. If
size is followed by M, the size if assumed to be in megabytes.
If the k is used, the size is in kilobytes. So size 100, size
100k, and size 100M are all valid.
sharedscripts
Normally, prescript and postscript scripts are run for each log
which is rotated, meaning that a single script may be run multi-
ple times for log file entries which match multiple files (such
as the /var/log/news/* example). If sharedscript is specified,
the scripts are only run once, no matter how many logs match the
wildcarded pattern. However, if none of the logs in the pattern
require rotating, the scripts will not be run at all. This
option overrides the nosharedscripts option and implies create
option.
start count
This is the number to use as the base for rotation. For example,
if you specify 0, the logs will be created with a .0 extension
as they are rotated from the original log files. If you specify
9, log files will be created with a .9, skipping 0-8. Files
will still be rotated the number of times specified with the
count directive.
tabooext [+] list
The current taboo extension list is changed (see the include
directive for information on the taboo extensions). If a + pre-
cedes the list of extensions, the current taboo extension list
is augmented, otherwise it is replaced. At startup, the taboo
extension list contains .rpmorig, .rpmsave, ,v, .swp, .rpmnew,
and ~.
weekly Log files are rotated if the current weekday is less then the
weekday of the last rotation or if more then a week has passed
since the last rotation. This is normally the same as rotating
logs on the first day of the week, but it works better if logro-
tate is not run every night.
yearly Log files are rotated if the current year is not the same as the
last rotation.
FILES
/var/lib/logrotate.status Default state file.
/etc/logrotate.conf Configuration options.
SEE ALSO
gzip(1)
AUTHORS
Erik Troan <>
Preston Brown <>
Red Hat Linux Wed Nov 5 2002 LOGROTATE(8)
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