Ubuntu Manpage: nsca-ng.cfg - NSCA-ng server configuration file

NAME

       nsca-ng.cfg - NSCA-ng server configuration file

SYNOPSIS

       /etc/nsca-ng.cfg

DESCRIPTION

The nsca-ng(8) process reads configuration data from the file specified with -c on the command line or
from /etc/nsca-ng.cfg.

File Format
Zero or more global settings and one or more authorizations must be defined in the configuration file
(see the Global Settings subsection and the Authorizations subsection, respectively). They may appear in
arbitrary order. An authorization is specified using the authorize keyword followed by a (possibly
quoted) client identity string and a brace-enclosed block of corresponding authorization settings.
However, an authorization setting may also be specified as a global setting outside of these authorize
sections. In this case, it serves as a global fallback for authorization sections that don't define the
setting in question.

Global settings and authorization settings are defined by specifying a variable name followed by an
equals sign (“=”) and a value (or possibly a list of values). Values can be strings, integers, or
floating-point numbers. Strings have to be enclosed in single or double quotes if they contain
whitespace characters, hash mark characters, or literal quotation marks. Otherwise, quoting is optional.
To specify a literal single or double quote in a string, either escape it by preceding it with a
backslash (“\”) or quote the string using the other quote character. A literal backslash must be
preceded with a second backslash if the string is enclosed in double quotes.

A variable can be set to the value of an environment variable by specifying ${FOO}, where FOO is the name
of the environment variable. The same can be done by specifying ${FOO:-bar}, except that in this case,
the value bar will be assigned when the environment variable FOO is not set.

Any whitespace surrounding tokens is ignored. Empty lines and comments are also ignored. Comments are
introduced with a hash mark character (“#”) and span to the end of the line. If the last character of a
line is a backslash (“\”), the subsequent line is treated as a continuation of the current line (and the
backslash is otherwise ignored).

The special directive include("file") tells nsca-ng(8) to treat the contents of the specified file as if
those contents had appeared at the point where this directive appears. If a directory is specified
instead of a file, all files with a .cfg or .conf extension in this directory and all subdirectories will
be included. Symbolic links are followed.

In the following subsections, the type of each value is denoted after an equals sign in angle brackets.

Global Settings
The nsca-ng(8) server recognizes the following global variables.

chroot = <string>
On startup, perform a chroot(2) operation to the specified directory. By default, nsca-ng(8) does
not call chroot(2). If this directive is used, the command_file, pid_file, and temp_directory
must be specified relative to this directory.

command_file = <string>
Submit monitoring commands to the specified path name. This should be the named pipe (FIFO) that
Nagios (or a compatible monitoring solution) checks for external commands to process. The default
is /var/nagios/rw/nagios.cmd. The specified value will be overridden if nsca-ng(8) is called with
the -C option.

listen = <string>
Bind to the specified IP address or host name. The default setting is “*”, which tells nsca-ng(8)
to listen on all available interfaces. A colon (“:”) followed by a service name or port number
may be appended to override the default port (5668) used by the nsca-ng(8) server. The specified
value will be ignored if nsca-ng(8) is called with the -b option, of if it is socket activated by
systemd(1).

log_level = <integer>
Use the specified log level, which must be an integer value between 0 and 5 inclusive. A value of
0 tells nsca-ng(8) to generate only fatal error messages, 1 adds non-fatal error messages, 2 adds
warnings, 3 additionally spits out every submitted command (plus startup and shutdown notices), 4
also logs each message sent or received at the protocol level, and 5 generates additional debug
output. The default log level is 3. The specified value will be overridden if nsca-ng(8) is
called with the -l option.

max_command_size = <integer>
Refuse monitoring commands (including check result submissions) which are longer than the
specified number of bytes. Setting this variable to 0 tells nsca-ng(8) to accept commands of
arbitrary length. The default value is 16384.

max_queue_size = <integer>
Don't queue more than the specified number of megabytes worth of monitoring commands while Nagios
isn't running (or not reading the command file). When the amount of available data exceeds this
threshold, the queued data is thrown away. If this variable is set to 0, nsca-ng(8) queues an
unlimited amount of data (until it exits due to running out of memory). The default value is 1024
(i.e., 1 gigabyte).

pid_file = <string>
During startup, try to create and lock the specified file and write the process ID of the
nsca-ng(8) daemon into it. Bail out if another process holds a lock on that file. By default, no
such PID file is written. The specified value will be overridden if nsca-ng(8) is called with the
-p option.

temp_directory = <string>
Write temporary files to the specified directory. Temporary files are only written if clients
submit very large commands (which cannot be written to the named pipe atomically). It is
recommended to specify a directory which resides on a memory file system. By default, /tmp is
used.

timeout = <floating-point>
Close the connection if a client didn't show any activity for the specified number of seconds. If
this value is set to 0.0, nsca-ng(8) won't enforce connection timeouts. The default setting is
60.0 seconds.

tls_ciphers = <string>
Limit the acceptable TLS-PSK cipher suites to the specified list of ciphers. The format of the
string is described in the ciphers(1) manual. By default, the ciphers in the list PSK-AES256-CBC-
SHA:PSK-AES128-CBC-SHA:PSK-3DES-EDE-CBC-SHA:PSK-RC4-SHA will be accepted.

user = <string>
Switch to the specified user, and to the groups the user belongs to. This is done early on
startup: after the configuration file has been read, but before the listening socket and
(possibly) the PID file are created. By default, nsca-ng(8) runs with the privileges of the
invoking user.

Authorizations
As mentioned above, an authorization section is introduced with the authorize keyword and a client
identity field followed by a brace-delimited block of one or more authorization settings. A client
provides its identity during the connection handshake. The server uses the provided identity string for
looking up the authorize section applicable to the client. The corresponding section, if any, defines
the authentication and authorization settings for the client in question. If no section explicitly
defined for this client identity is found, but a section for the special client identity "*" (including
the quotes) is defined, this section is used as a fallback. Note that no other wildcard characters are
available, and that the “*” character has no special meaning in the client identity field except when
specified exactly as described.

Within the brace-delimited block of an authorization section, values may be assigned to the variables
listed below. The pattern strings assigned to the commands, hosts, and services variables are POSIX
“extended” regular expressions, but with an implicit “^” at the beginning and “$” at the end of the
patterns. Multiple patterns can be specified as a brace-enclosed, comma-separated list; check results
and commands will then be accepted if they match any of the specified patterns. Commands and check
results will be rejected unless these settings authorize the client to submit them.

commands = <(list of) string(s)>
Match the specified regular expression(s) against submitted monitoring commands and accept
commands that match any of these expressions. The patterns are matched against the full command
string supplied by the client, except for the leading bracketed timestamp and any whitespace
following that timestamp.

hosts = <(list of) string(s)>
Match the specified regular expression(s) against the “host name” field of client-supplied
PROCESS_HOST_CHECK_RESULT commands and accept such commands if they match any of these
expressions.

password = <string>
Reject connections from clients that don't use the specified password. This setting is mandatory.

services = <(list of) string(s)>
Match the specified regular expression(s) against the “service description” field of client-
supplied PROCESS_SERVICE_CHECK_RESULT commands and accept such commands if they match any of these
expressions. If a specified string includes one or more at signs (“@”), only the part preceding
the last of these at signs is matched against the “service description” field. The part following
this at sign is used as a separate pattern which is matched against the “host name” field of the
same command. A service check result is then accepted only if both matches succeed for a given
command.

EXAMPLES

       The /etc/nsca-ng.cfg file might look similar to the following example.

              user = "nagios"
              chroot = "/var/nagios" # Other paths are relative to this one!
              command_file = "/rw/nagios.cmd"
              pid_file = "/run/nsca-ng.pid"
              temp_directory = "/dev/shm"
              listen = "monitoring.example.com:5668"
              tls_ciphers = "PSK-AES256-CBC-SHA"
              log_level = 3
              max_command_size = 65536
              max_queue_size = 128
              timeout = 15.0

              #
              # Authenticated "root" clients may submit arbitrary check
              # results and any other monitoring commands (see:
              # <http://nagios.org/developerinfo/externalcommands/>).
              #
              authorize "root" {
                  password = "g3m25sMCUAO4NecZGld1H4xcJ9uDWvhH"
                  commands = ".*"
              }

              #
              # Authenticated "checker" clients may submit arbitrary check
              # results, but no other commands.
              #
              authorize "checker" {
                  password = "ilzNanlE9XjMLdjrMkXnk09XBCTFQrj5"
                  hosts = ".*"
                  services = ".*"
              }

              #
              # Authenticated "web-checker" clients may submit check results
              # for arbitrary services on hosts whose names begin with "www".
              #
              authorize "web-checker" {
                  password = "m2uaIWwiq3AIqN55m3QdjwptkU1Q4Oov"
                  services = ".+@www.*"
              }

              #
              # Authenticated "nsca-checker" clients may talk to the NSCA-ng
              # server, but may not submit anything to Nagios.
              #
              authorize "nsca-checker" {
                  password = "ceOKwxpz14lKXroC4yUjJZbov6VAyKuT"
              }

              #
              # Other authenticated clients may submit check results for the
              # "disk", "swap", and "load" services on arbitrary hosts.
              #
              authorize "*" {
                  password = "awHW5vxr3DcA9EvcUC9T3a90QfEexsWd"
                  services = {
                      "disk",
                      "swap",
                      "load"
                  }
              }

CAVEATS

       Please  set  the  permissions  appropriately  to  make  sure  that  only  authorized users can access the
       /etc/nsca-ng.cfg file.

AUTHOR