logging
Statement
logging {
[ channel channel_name {
( file path_name
[ versions ( number | unlimited ) ]
[ size size_spec ]
| syslog ( kern | user | mail | daemon | auth | syslog | lpr |
news | uucp | cron | authpriv | ftp |
local0 | local1 | local2 | local3 |
local4 | local5 | local6 | local7 )
| null );
[ severity ( critical | error | warning | notice |
info | debug [ level ] | dynamic ); ]
[ print-category yes_or_no; ]
[ print-severity yes_or_no; ]
[ print-time yes_or_no; ]
}; ]
[ category category_name {
channel_name; [ channel_name; ... ]
}; ]
...
};
The logging statement configures a wide variety of
logging options for the nameserver. Its channel phrase
associates output methods, format options and severity levels with a
name that can then be used with the category phrase to
select how various classes of messages are logged.
Only one logging statement is used to define as many
channels and categories as are wanted. If there are multiple logging
statements in a configuration, the first defined statement determines
the logging, and warnings are issued for the others. If there is no
logging statement, the logging configuration is as follows:
logging {
category default { default_syslog; default_debug; };
category panic { default_syslog; default_stderr; };
category packet { default_debug; };
category eventlib { default_debug; };
};
The logging configuration is established as soon as the
logging statement is parsed. If you want to redirect
messages about processing of the entire configuration file, the
logging statement must appear first. Even if you do not
redirect configuration file parsing messages, it is recommended that
you put the logging statement first so that this rule
need not be consciously recalled if you ever do need want the
parser's messages relocated.
channel phraseAll log output goes to one or more channels; you can make as many of them as you want.
Every channel definition must include a clause that specifies
whether messages selected for the channel go to a file, to a
particular syslog facility, or are discarded. It can
optionally also limit the message severity level that will be
accepted by the channel (default is info), and whether
to include a timestamp generated by named, the category
name, or severity level. The default is not to include any.
The word null as the destination option for the
channel will cause all messages sent to it to be discarded; other
options for the channel are meaningless.
The file clause can include limitations both on how
large the file is allowed to become, and how many versions of the
file will be saved each time the file is opened.
The size option for files is simply a hard ceiling on
log growth. If the file ever exceeds the size, named
will just not write anything more to it until the file is reopened;
exceeding the size does not automatically trigger a reopen. The
default behavior is to not limit the size of the file.
If you use the version option, named
will retain that many backup versions of the file by renaming them
when opening. For example, if you choose to keep 3 old versions of
the file lamers.log then just before it is opened
lamers.log.1 is renamed to lamers.log.2,
lamers.log.0 is renamed to lamers.log.1,
and lamers.log is renamed to lamers.log.0.
No rolled versions are kept by default; any existing log file is
simply appended. The unlimited keyword is synonymous
with 99 in current BIND releases.
Example usage of the size and versions options:
channel an_example_level {
file "lamers.log" versions 3 size 20m;
print-time yes;
print-category yes;
};
The argument for the syslog clause is a syslog
facility as described in the syslog reference page. How
syslogd will handle messages sent to this facility is
described in the syslog.conf reference page. If you have
a system which uses a very old version of syslog that
only uses two arguments to the openlog() function, this
clause is silently ignored.
The severity clause works like syslog's
priorities, except that they can also be used if you are writing
straight to a file rather than using syslog. Messages
which are not at least of the severity level given are not selected
for the channel; messages of higher severity levels are accepted.
If you are using syslog, the syslog.conf
priorities also determine what eventually passes through. For
example, defining a channel facility and severity as
daemon and debug but only logging
daemon.warning via syslog.conf will cause
messages of severity info and notice to be
dropped. If the situation were reversed, with named
writing messages of only warning or higher,
syslogd would print all messages it received from the
channel.
The server can supply extensive debugging information when it is
in debugging mode. If the server's global debug level is greater than
zero, debugging mode will be active. The global debug level is set
either by starting the named server with the
-d flag followed by a positive integer, or by sending
the running server the SIGUSR1 signal (for example, by using
ndc trace). The global debug level can be set to zero,
and debugging mode turned off, by sending the server the SIGUSR2
signal (ndc notrace). All debugging messages in the
server have a debug level, and higher debug levels give more more
detailed output. Channels that specify a specific debug severity will
get debugging output of level 3 or less any time the sever is in
debugging mode, regardless of the global debugging level. For
example:
channel specific_debug_level {
file "foo";
severity debug 3;
};
Channels with dynamic severity use the server's
global level to determine what messages to print.
If print-time has been turned on, the date and time
will be logged. The print-time option may be specified
for a syslog channel, but is usually meaningless because
syslog also prints the date and time. If
print-category is requested, then the category of the
message will be logged as well. Finally, if
print-severity is on, the severity level of the message
will be logged. The print- options may be used in any
combination, and will always be printed in the following order: time,
category, severity. Here is an example where all three
print- options are on:
28-Apr-1997 15:05:32.863 default: notice: Ready to answer queries.
The following four predefined channels are used for
named's default logging. See the category
phrase section for a description on how to use them.
channel default_syslog {
syslog daemon; # send to syslog's daemon facility
severity info; # only send priority info and higher
};
channel default_debug {
file "named.run"; # write to named.run in the working directory
# Note: stderr is used instead of "named.run"
# if the server is started with the "-f" option.
severity dynamic; # log at the server's current debug level
};
channel default_stderr { # writes to stderr
file "<stderr>"; # this is illustrative only; there's currently
# no way of specifying an internal file
# descriptor in the configuration language.
severity info; # only send priority info and higher
};
channel null {
null; # toss anything sent to this channel
};
Once a channel is defined, it cannot be redefined. Thus you cannot alter the built-in channels directly, but you can modify the default logging by pointing categories at channels you have defined.
category phraseThere are many categories, so you can send the logs you want to
see wherever you want, without seeing logs you do not want. If you do
not specify a list of channels for a category, log messages in that
category will be sent to the default category instead.
If you do not specify a default category, the following is used:
category default { default_syslog; default_debug; };
As an example, if you want to log security events to a file, but you also want keep the default logging behavior, you would specify the following:
channel my_security_channel {
file "my_security_file";
severity info;
};
category security { my_security_channel; default_syslog; default_debug; };
To discard all messages in a category, specify the
null channel, as follows:
category lame-servers { null; };
category cname { null; };
The following categories are available:
cnameconfigdbdefault
category default { default_syslog; default_debug; };eventlibcategory eventlib { default_debug; };insistlame-serversloadmaintenancencache
notifyospacketcategory packet { default_debug; };paniccategory panic { default_syslog; default_stderr; };parserqueriesresponse-checkssecuritystatisticsupdatexfer-inxfer-out