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.. _logging:
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*******
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Logging
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*******
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Logging Configuration
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=====================
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During its operation Kea may produce many messages. They differ in
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severity (some are more important than others) and source (different
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components, like hooks, produce different messages). It is useful to
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understand which log messages are critical and which are not, and to
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configure logging appropriately. For example, debug-level messages
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can be safely ignored in a typical deployment. They are, however, very
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useful when debugging a problem.
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The logging system in Kea is configured through the loggers entry in the
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server section of your configuration file. In previous Kea releases this
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entry was in an independent Logging section; this is still supported for
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backward compatibility.
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Loggers
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-------
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Within Kea, a message is logged through an entity called a "logger."
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Different components log messages through different loggers, and each
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logger can be configured independently of the others. Some components,
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in particular the DHCP server processes, may use multiple loggers to log
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messages pertaining to different logical functions of the component. For
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example, the DHCPv4 server uses one logger for messages about packet
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reception and transmission, another logger for messages related to lease
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allocation, and so on. Some of the libraries used by the Kea server,
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such as libdhcpsrv, use their own loggers.
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Users implementing hooks libraries (code attached to the server at
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runtime) are responsible for creating the loggers used by those
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libraries. Such loggers should have unique names, different from the
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logger names used by Kea. In this way the messages produced by the hooks
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library can be distinguished from messages issued by the core Kea code.
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Unique names also allow the loggers to be configured independently of
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loggers used by Kea. Whenever it makes sense, a hooks library can use
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multiple loggers to log messages pertaining to different logical parts
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of the library.
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In the server section of a configuration file the
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configuration for zero or more loggers (including loggers used by the
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proprietary hooks libraries) can be specified. If there are no loggers specified, the
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code will use default values; these cause Kea to log messages of INFO
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severity or greater to standard output. There is a small time window
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after Kea has been started but before it has read its configuration;
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logging in this short period can be controlled using environment
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variables. For details, see :ref:`logging-during-startup`.
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The three main elements of a logger configuration are: ``name`` (the
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component that is generating the messages), ``severity`` (what to log),
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and ``output_commands`` (where to log). There is also a ``debuglevel``
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element, which is only relevant if debug-level logging has been
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selected.
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The name (string) Logger
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~~~~~~~~~~~~~~~~~~~~~~~~
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Each logger in the system has a name: that of the component binary file
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using it to log messages. For instance, to configure logging
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for the DHCPv4 server, add an entry for a logger named “kea-dhcp4”.
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This configuration will then be used by the loggers in the DHCPv4
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server and all the libraries used by it, unless a library defines its
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own logger and there is a specific logger configuration that applies to
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that logger.
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When tracking down an issue with the server's operation, use of DEBUG
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logging is required to obtain the verbose output needed for problem
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diagnosis. However, the high verbosity is likely to overwhelm the
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logging system in cases where the server is processing high-volume
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traffic. To mitigate this problem, Kea can use multiple loggers, for
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different functional parts of the server, that can each be configured
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independently. If the user is reasonably confident that a problem
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originates in a specific function of the server, or that the problem is
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related to a specific type of operation, they may enable high verbosity
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only for the relevant logger, thereby limiting the debug messages to the
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required minimum.
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The loggers are associated with a particular library or binary of Kea.
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However, each library or binary may (and usually does) include multiple
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loggers. For example, the DHCPv4 server binary contains separate loggers
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for packet parsing, dropped packets, callouts, etc.
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The loggers form a hierarchy. For each program in Kea, there is a "root"
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logger, named after the program (e.g. the root logger for kea-dhcp, the
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DHCPv4 server) is named kea-dhcp4. All other loggers are children of
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this logger and are named accordingly, e.g. the allocation engine in the
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DHCPv4 server logs messages using a logger called
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kea-dhcp4.alloc-engine.
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This relationship is important, as each child logger derives its default
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configuration from its parent root logger. In the typical case, the root
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logger configuration is the only logging configuration specified in the
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configuration file and so applies to all loggers. If an entry is made
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for a given logger, any attributes specified override those of the root
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logger, whereas any not specified are inherited from it.
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To illustrate this, suppose we are using the DHCPv4 server with the
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root logger “kea-dhcp4” logging at the INFO level. In order to enable
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DEBUG verbosity for DHCPv4 packet drops, we must create a configuration
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entry for the logger called “kea-dhcp4.bad-packets” and specify severity
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DEBUG for this logger. All other configuration parameters may be omitted
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for this logger if the logger should use the default values specified in
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the root logger's configuration.
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If there are multiple logger specifications in the configuration that
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might match a particular logger, the specification with the more
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specific logger name takes precedence. For example, if there are entries
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for both “kea-dhcp4” and “kea-dhcp4.dhcpsrv”, the main DHCPv4 server
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program — and all libraries it uses other than the dhcpsrv library
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(libdhcpsrv) — will log messages according to the configuration in the
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first entry (“kea-dhcp4”). Messages generated by the dhcpsrv library
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will be logged according to the configuration set by the second entry.
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Currently defined loggers are defined in the following table. The
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"Software Package" column of this table specifies whether the particular
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loggers belong to the core Kea code (open source Kea binaries and
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libraries), or hooks libraries (open source or premium).
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.. table:: List of Loggers Supported by Kea Servers and Hooks Libraries Shipped With Kea and Premium Packages
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+----------------------------------+------------------------+--------------------------------+
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| Logger Name | Software Package | Description |
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+==================================+========================+================================+
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| ``kea-ctrl-agent`` | core | The root logger for |
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| | | the Control Agent |
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| | | exposing the RESTful |
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| | | control API. All |
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| | | components used by |
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| | | the Control Agent |
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| | | inherit the settings |
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| | | from this logger. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-ctrl-agent.http`` | core | A logger which |
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| | | outputs log messages |
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| | | related to receiving, |
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| | | parsing, and sending |
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| | | HTTP messages. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4`` | core | The root logger for |
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| | | the DHCPv4 server. |
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| | | All components used |
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| | | by the DHCPv4 server |
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| | | inherit the settings |
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| | | from this logger. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp6`` | core | The root logger for |
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| | | the DHCPv6 server. |
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| | | All components used |
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| | | by the DHCPv6 server |
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| | | inherit the settings |
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| | | from this logger. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.alloc-engine``, | core | Used by the lease |
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| ``kea-dhcp6.alloc-engine`` | | allocation engine, |
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| | | which is responsible |
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| | | for managing leases |
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| | | in the lease |
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| | | database, i.e. |
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| | | creating, modifying, |
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| | | and removing DHCP |
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| | | leases as a result of |
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| | | processing messages |
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| | | from clients. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.bad-packets``, | core | Used by the DHCP |
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| ``kea-dhcp6.bad-packets`` | | servers for logging |
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| | | inbound client |
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| | | packets that were |
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| | | dropped or to which |
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| | | the server responded |
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| | | with a DHCPNAK. It |
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| | | allows administrators |
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| | | to configure a |
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| | | separate log output |
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| | | that contains only |
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| | | packet drop and |
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| | | reject entries. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.callouts``, | core | Used to log messages |
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| ``kea-dhcp6.callouts`` | | pertaining to the |
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| | | callouts registration |
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| | | and execution for the |
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| | | particular hook |
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| | | point. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.commands``, | core | Used to log messages |
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| ``kea-dhcp6.commands`` | | relating to the |
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| | | handling of commands |
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| | | received by the DHCP |
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| | | server over the |
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| | | command channel. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.database``, | core | Used to log messages |
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| ``kea-dhcp6.database`` | | relating to general |
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| | | operations on the |
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| | | relational databases |
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| | | and Cassandra. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.ddns``, | core | Used by the DHCP |
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| ``kea-dhcp6.ddns`` | | server to log |
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| | | messages related to |
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| | | Client FQDN and |
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| | | Hostname option |
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| | | processing. It also |
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| | | includes log messages |
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| | | related to the |
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| | | relevant DNS updates. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.dhcp4`` | core | Used by the DHCPv4 |
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| | | server daemon to log |
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| | | basic operations. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.dhcpsrv``, | core | The base loggers for |
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| ``kea-dhcp6.dhcpsrv`` | | the libkea-dhcpsrv |
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| | | library. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.eval``, | core | Used to log messages |
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| ``kea-dhcp6.eval`` | | relating to the |
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| | | client classification |
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| | | expression evaluation |
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| | | code. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.host-cache-hooks``, | libdhcp_host_cache | This logger is used |
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| ``kea-dhcp6.host-cache-hooks`` | premium hook library | to log messages |
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| | | related to the |
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| | | operation of the Host |
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| | | Cache hooks library. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.flex-id-hooks``, | libdhcp_flex_id | This logger is used |
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| ``kea-dhcp6.flex-id-hooks`` | premium hook library | to log messages |
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| | | related to the |
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| | | operation of the |
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| | | Flexible Identifiers |
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| | | hooks library. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.ha-hooks``, | libdhcp_ha hook | This logger is used |
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| ``kea-dhcp6.ha-hooks`` | library | to log messages |
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| | | related to the |
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| | | operation of the High |
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| | | Availability hooks |
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| | | library. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.hooks``, | core | Used to log messages |
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| ``kea-dhcp6.hooks`` | | related to the |
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| | | management of hooks |
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| | | libraries, e.g. |
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| | | registration and |
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| | | deregistration of the |
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| | | libraries, and to the |
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| | | initialization of the |
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| | | callouts execution |
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| | | for various hook |
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| | | points within the |
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| | | DHCP server. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.host-cmds-hooks``, | libdhcp_host_cmds | This logger is used |
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| ``kea-dhcp6.host-cmds-hooks`` | premium hook library | to log messages |
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| | | related to the |
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| | | operation of the Host |
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| | | Commands hooks |
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| | | library. In general, |
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| | | these will pertain to |
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| | | the loading and |
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| | | unloading of the |
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| | | library and the |
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| | | execution of commands |
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| | | by the library. |
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+----------------------------------+------------------------+--------------------------------+
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| ``kea-dhcp4.hosts``, | core | Used within the |
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| ``kea-dhcp6.hosts`` | | libdhcpsrv, it logs |
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| | | messages related to |
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| | | the management of |
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| | | DHCP host |
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| | | reservations, i.e. |
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| | | retrieving |
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| | | reservations and |
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| | | adding new |
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| | | reservations. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp4.lease-cmds-hooks``, | libdhcp_lease_cmds | This logger is used |
|
|
|
|
|
| ``kea-dhcp6.lease-cmds-hooks`` | hook library | to log messages |
|
|
|
|
|
| | | related to the |
|
|
|
|
|
| | | operation of the |
|
|
|
|
|
| | | Lease Commands hooks |
|
|
|
|
|
| | | library. In general, |
|
|
|
|
|
| | | these will pertain to |
|
|
|
|
|
| | | the loading and |
|
|
|
|
|
| | | unloading of the |
|
|
|
|
|
| | | library and the |
|
|
|
|
|
| | | execution of commands |
|
|
|
|
|
| | | by the library. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp4.leases``, | core | Used by the DHCP |
|
|
|
|
|
| ``kea-dhcp6.leases`` | | server to log |
|
|
|
|
|
| | | messages related to |
|
|
|
|
|
| | | lease allocation. The |
|
|
|
|
|
| | | messages include |
|
|
|
|
|
| | | detailed information |
|
|
|
|
|
| | | about the allocated |
|
|
|
|
|
| | | or offered leases, |
|
|
|
|
|
| | | errors during the |
|
|
|
|
|
| | | lease allocation, |
|
|
|
|
|
| | | etc. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp4.legal-log-hooks``, | libdhcp_legal_log | This logger is used |
|
|
|
|
|
| ``kea-dhcp6.legal-log-hooks`` | premium hook library | to log messages |
|
|
|
|
|
| | | related to the |
|
|
|
|
|
| | | operation of the |
|
|
|
|
|
| | | Forensic Logging |
|
|
|
|
|
| | | hooks library. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp4.options``, | core | Used by the DHCP |
|
|
|
|
|
| ``kea-dhcp4.options`` | | server to log |
|
|
|
|
|
| | | messages related to |
|
|
|
|
|
| | | the processing of |
|
|
|
|
|
| | | options in the DHCP |
|
|
|
|
|
| | | messages, i.e. |
|
|
|
|
|
| | | parsing options, |
|
|
|
|
|
| | | encoding options into |
|
|
|
|
|
| | | on-wire format, and |
|
|
|
|
|
| | | packet classification |
|
|
|
|
|
| | | using options |
|
|
|
|
|
| | | contained in the |
|
|
|
|
|
| | | received packets. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp4.packets``, | core | This logger is mostly |
|
|
|
|
|
| ``kea-dhcp6.packets`` | | used to log messages |
|
|
|
|
|
| | | related to |
|
|
|
|
|
| | | transmission of the |
|
|
|
|
|
| | | DHCP packets, i.e. |
|
|
|
|
|
| | | packet reception and |
|
|
|
|
|
| | | the sending of a |
|
|
|
|
|
| | | response. Such |
|
|
|
|
|
| | | messages include |
|
|
|
|
|
| | | information about the |
|
|
|
|
|
| | | source and |
|
|
|
|
|
| | | destination IP |
|
|
|
|
|
| | | addresses and |
|
|
|
|
|
| | | interfaces used to |
|
|
|
|
|
| | | transmit packets. The |
|
|
|
|
|
| | | logger is also used |
|
|
|
|
|
| | | to log messages |
|
|
|
|
|
| | | related to subnet |
|
|
|
|
|
| | | selection, as this |
|
|
|
|
|
| | | selection is usually |
|
|
|
|
|
| | | based on the IP |
|
|
|
|
|
| | | addresses, relay |
|
|
|
|
|
| | | addresses, and/or |
|
|
|
|
|
| | | interface names, |
|
|
|
|
|
| | | which can be |
|
|
|
|
|
| | | retrieved from the |
|
|
|
|
|
| | | received packet even |
|
|
|
|
|
| | | before the DHCP |
|
|
|
|
|
| | | message carried in |
|
|
|
|
|
| | | the packet is parsed. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp4.radius-hooks``, | libdhcp_radius | This logger is used |
|
|
|
|
|
| ``kea-dhcp6.radius-hooks`` | premium hook library | to log messages |
|
|
|
|
|
| | | related to the |
|
|
|
|
|
| | | operation of the |
|
|
|
|
|
| | | RADIUS hooks library. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp4.stat-cmds-hooks``, | libdhcp_stat_cmds | This logger is used |
|
|
|
|
|
| ``kea-dhcp6.stat-cmds-hooks`` | hook library | to log messages |
|
|
|
|
|
| | | related to the |
|
|
|
|
|
| | | operation of the |
|
|
|
|
|
| | | Statistics Commands |
|
|
|
|
|
| | | hooks library. In |
|
|
|
|
|
| | | general, these will |
|
|
|
|
|
| | | pertain to loading |
|
|
|
|
|
| | | and unloading the |
|
|
|
|
|
| | | library and the |
|
|
|
|
|
| | | execution of commands |
|
|
|
|
|
| | | by the library. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp4.subnet-cmds-hooks``, | libdhcp_subnet_cmds | This logger is used |
|
|
|
|
|
| ``kea-dhcp6.subnet-cmds-hooks`` | hook library | to log messages |
|
|
|
|
|
| | | related to the |
|
|
|
|
|
| | | operation of the |
|
|
|
|
|
| | | Subnet Commands hooks |
|
|
|
|
|
| | | library. In general, |
|
|
|
|
|
| | | these will pertain to |
|
|
|
|
|
| | | loading and unloading |
|
|
|
|
|
| | | the library and the |
|
|
|
|
|
| | | execution of commands |
|
|
|
|
|
| | | by the library. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp4.mysql-cb-hooks``, | libdhcp_mysql_cb_hooks | This logger is used |
|
|
|
|
|
| ``kea-dhcp6.mysql-cb-hooks`` | hook library | to log messages |
|
|
|
|
|
| | | related to the |
|
|
|
|
|
| | | operation of the |
|
|
|
|
|
| | | MySQL Configuration |
|
|
|
|
|
| | | Backend hooks |
|
|
|
|
|
| | | library. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp-ddns`` | core | The root logger for |
|
|
|
|
|
| | | the kea-dhcp-ddns |
|
|
|
|
|
| | | daemon. All |
|
|
|
|
|
| | | components used by |
|
|
|
|
|
| | | this daemon inherit |
|
|
|
|
|
| | | the settings from |
|
|
|
|
|
| | | this logger unless |
|
|
|
|
|
| | | there are |
|
|
|
|
|
| | | configurations for |
|
|
|
|
|
| | | more specialized |
|
|
|
|
|
| | | loggers. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp-ddns.dctl`` | core | The logger used by |
|
|
|
|
|
| | | the kea-dhcp-ddns |
|
|
|
|
|
| | | daemon for logging |
|
|
|
|
|
| | | basic information |
|
|
|
|
|
| | | about the process, |
|
|
|
|
|
| | | received signals, and |
|
|
|
|
|
| | | triggered |
|
|
|
|
|
| | | reconfigurations. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp-ddns.dhcpddns`` | core | The logger used by |
|
|
|
|
|
| | | the kea-dhcp-ddns |
|
|
|
|
|
| | | daemon for logging |
|
|
|
|
|
| | | events related to |
|
|
|
|
|
| | | DDNS operations. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp-ddns.dhcp-to-d2`` | core | Used by the |
|
|
|
|
|
| | | kea-dhcp-ddns daemon |
|
|
|
|
|
| | | for logging |
|
|
|
|
|
| | | information about |
|
|
|
|
|
| | | events dealing with |
|
|
|
|
|
| | | receiving messages |
|
|
|
|
|
| | | from the DHCP servers |
|
|
|
|
|
| | | and adding them to |
|
|
|
|
|
| | | the queue for |
|
|
|
|
|
| | | processing. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-dhcp-ddns.d2-to-dns`` | core | Used by the |
|
|
|
|
|
| | | kea-dhcp-ddns daemon |
|
|
|
|
|
| | | for logging |
|
|
|
|
|
| | | information about |
|
|
|
|
|
| | | events dealing with |
|
|
|
|
|
| | | sending and receiving |
|
|
|
|
|
| | | messages to and from |
|
|
|
|
|
| | | the DNS servers. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
|
|
|
|
| ``kea-netconf`` | core | The root logger for |
|
|
|
|
|
| | | the NETCONF agent. |
|
|
|
|
|
| | | All components used |
|
|
|
|
|
| | | by NETCONF inherit |
|
|
|
|
|
| | | the settings from |
|
|
|
|
|
| | | this logger if there |
|
|
|
|
|
| | | is no specialized |
|
|
|
|
|
| | | logger provided. |
|
|
|
|
|
+----------------------------------+------------------------+--------------------------------+
|
2019-06-06 18:25:46 +02:00
|
|
|
|
|
|
|
|
Note that user-defined hook libraries should not use any of the loggers
|
|
|
|
|
mentioned above, but should instead define new loggers with names that
|
2019-06-28 17:57:37 -04:00
|
|
|
correspond to the libraries using them. Suppose that a user created
|
|
|
|
|
a library called “libdhcp-packet-capture” to dump packets received and
|
|
|
|
|
transmitted by the server to a file. An appropriate name for the
|
2019-06-06 18:25:46 +02:00
|
|
|
logger could be ``kea-dhcp4.packet-capture-hooks``. (Note that the hook
|
|
|
|
|
library implementer only specifies the second part of this name, i.e.
|
|
|
|
|
“packet-capture”. The first part is a root-logger name and is prepended
|
|
|
|
|
by the Kea logging system.) It is also important to note that since this
|
|
|
|
|
new logger is a child of a root logger, it inherits the configuration
|
|
|
|
|
from the root logger, something that can be overridden by an entry in
|
|
|
|
|
the configuration file.
|
|
|
|
|
|
|
|
|
|
The easiest way to find a logger name is to configure all logging to go
|
2019-06-28 17:57:37 -04:00
|
|
|
to a single destination and look there for specific logger names. See
|
|
|
|
|
:ref:`logging-message-format` for details.
|
2019-06-06 18:25:46 +02:00
|
|
|
|
2019-06-28 17:57:37 -04:00
|
|
|
The severity (string) Logger
|
|
|
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
2019-06-06 18:25:46 +02:00
|
|
|
|
|
|
|
|
This specifies the category of messages logged. Each message is logged
|
|
|
|
|
with an associated severity, which may be one of the following (in
|
|
|
|
|
descending order of severity):
|
|
|
|
|
|
|
|
|
|
- FATAL - associated with messages generated by a condition that is so
|
|
|
|
|
serious that the server cannot continue executing.
|
|
|
|
|
|
|
|
|
|
- ERROR - associated with messages generated by an error condition. The
|
|
|
|
|
server will continue executing, but the results may not be as
|
|
|
|
|
expected.
|
|
|
|
|
|
|
|
|
|
- WARN - indicates an out-of-the-ordinary condition. However, the
|
|
|
|
|
server will continue executing normally.
|
|
|
|
|
|
|
|
|
|
- INFO - an informational message marking some event.
|
|
|
|
|
|
|
|
|
|
- DEBUG - messages produced for debugging purposes.
|
|
|
|
|
|
|
|
|
|
When the severity of a logger is set to one of these values, it will
|
|
|
|
|
only log messages of that severity and above (e.g. setting the logging
|
|
|
|
|
severity to INFO will log INFO, WARN, ERROR, and FATAL messages). The
|
|
|
|
|
severity may also be set to NONE, in which case all messages from that
|
|
|
|
|
logger are inhibited.
|
|
|
|
|
|
2019-07-01 14:20:05 -04:00
|
|
|
.. note::
|
2019-06-06 18:25:46 +02:00
|
|
|
|
2019-06-28 17:57:37 -04:00
|
|
|
The ``keactrl`` tool, described in :ref:`keactrl`, can be configured
|
2019-06-06 18:25:46 +02:00
|
|
|
to start the servers in verbose mode. If this is the case, the
|
|
|
|
|
settings of the logging severity in the configuration file will have
|
2019-06-28 17:57:37 -04:00
|
|
|
no effect; the servers will use a logging severity of DEBUG
|
2019-06-06 18:25:46 +02:00
|
|
|
regardless of the logging settings specified in the configuration
|
2019-06-28 17:57:37 -04:00
|
|
|
file. To control severity via the configuration file,
|
2019-06-06 18:25:46 +02:00
|
|
|
please make sure that the ``kea_verbose`` value is set to "no" within
|
2019-06-28 17:57:37 -04:00
|
|
|
the ``keactrl`` configuration.
|
2019-06-06 18:25:46 +02:00
|
|
|
|
2019-06-28 17:57:37 -04:00
|
|
|
The debuglevel (integer) Logger
|
|
|
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
2019-06-06 18:25:46 +02:00
|
|
|
|
|
|
|
|
When a logger's severity is set to DEBUG, this value specifies what
|
|
|
|
|
level of debug messages should be printed. It ranges from 0 (least
|
|
|
|
|
verbose) to 99 (most verbose). If severity for the logger is not DEBUG,
|
|
|
|
|
this value is ignored.
|
|
|
|
|
|
2019-06-28 17:57:37 -04:00
|
|
|
The output_options (list) Logger
|
|
|
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
2019-06-06 18:25:46 +02:00
|
|
|
|
|
|
|
|
Each logger can have zero or more ``output_options``. These specify
|
|
|
|
|
where log messages are sent and are explained in detail below.
|
|
|
|
|
|
2019-06-28 17:57:37 -04:00
|
|
|
The output (string) Option
|
|
|
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^
|
2019-06-06 18:25:46 +02:00
|
|
|
|
|
|
|
|
This value determines the type of output. There are several special
|
|
|
|
|
values allowed here: ``stdout`` (messages are printed on standard
|
|
|
|
|
output), ``stderr`` (messages are printed on stderr), ``syslog``
|
2019-06-28 17:57:37 -04:00
|
|
|
(messages are logged to syslog using the default name), ``syslog:name``
|
|
|
|
|
(messages are logged to syslog using a specified name). Any other value is
|
2019-06-06 18:25:46 +02:00
|
|
|
interpreted as a filename to which messages should be written.
|
|
|
|
|
|
2019-06-28 17:57:37 -04:00
|
|
|
The flush (true of false) Option
|
|
|
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
2019-06-06 18:25:46 +02:00
|
|
|
|
|
|
|
|
Flush buffers after each log message. Doing this will reduce performance
|
|
|
|
|
but will ensure that if the program terminates abnormally, all messages
|
|
|
|
|
up to the point of termination are output. The default is "true".
|
|
|
|
|
|
2019-06-28 17:57:37 -04:00
|
|
|
The maxsize (integer) Option
|
|
|
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
2019-06-06 18:25:46 +02:00
|
|
|
|
2019-06-28 17:57:37 -04:00
|
|
|
This option is only relevant when the destination is a file; this is the maximum size
|
2019-06-06 18:25:46 +02:00
|
|
|
in bytes that a log file may reach. When the maximum size is reached,
|
|
|
|
|
the file is renamed and a new file opened. For example, a ".1" is
|
2019-06-28 17:57:37 -04:00
|
|
|
appended to the name; if a ".1" file exists, it is renamed ".2", etc.
|
2019-06-06 18:25:46 +02:00
|
|
|
This is referred to as rotation.
|
|
|
|
|
|
2019-06-28 17:57:37 -04:00
|
|
|
The default value is 10240000 (10MB). The smallest value that can be
|
2019-06-06 18:25:46 +02:00
|
|
|
specified without disabling rotation is 204800. Any value less than
|
|
|
|
|
this, including 0, disables rotation.
|
|
|
|
|
|
2019-07-01 14:20:05 -04:00
|
|
|
.. note::
|
2019-06-06 18:25:46 +02:00
|
|
|
|
|
|
|
|
Due to a limitation of the underlying logging library (log4cplus),
|
|
|
|
|
rolling over the log files (from ".1" to ".2", etc) may show odd
|
2019-06-28 17:57:37 -04:00
|
|
|
results; there can be multiple small files at the timing of rollover.
|
|
|
|
|
This can happen when multiple processes try to roll over the
|
2019-06-06 18:25:46 +02:00
|
|
|
files simultaneously. Version 1.1.0 of log4cplus solved this problem,
|
|
|
|
|
so if this version or later of log4cplus is used to build Kea, the
|
|
|
|
|
issue should not occur. Even for older versions, it is normally
|
|
|
|
|
expected to happen rarely unless the log messages are produced very
|
|
|
|
|
frequently by multiple different processes.
|
|
|
|
|
|
2019-06-28 17:57:37 -04:00
|
|
|
The maxver (integer) Option
|
|
|
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
2019-06-06 18:25:46 +02:00
|
|
|
|
2019-06-28 17:57:37 -04:00
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This option is only relevant when the destination is a file and rotation is enabled
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(i.e. maxsize is large enough). This is the maximum number of rotated
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versions that will be kept. Once that number of files has been reached,
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the oldest file, "log-name.maxver", will be discarded each time the log
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rotates. In other words, at most there will be the active log file plus
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maxver rotated files. The minimum and default value is 1.
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Example Logger Configurations
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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In this example we want to set the server logging to write to the
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console using standard output.
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::
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"Server": {
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"loggers": [
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{
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"name": "kea-dhcp4",
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"output_options": [
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{
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"output": "stdout"
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}
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],
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"severity": "WARN"
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}
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]
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}
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In this second example, we want to store debug log messages in a file
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that is at most 2MB and keep up to eight copies of old logfiles. Once the
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logfile grows to 2MB, it will be renamed and a new file will be created.
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::
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"Server": {
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"loggers": [
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{
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"name": "kea-dhcp6",
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"output_options": [
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{
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"output": "/var/log/kea-debug.log",
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"maxver": 8,
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"maxsize": 204800,
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"flush": true
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}
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],
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"severity": "DEBUG",
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"debuglevel": 99
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}
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]
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}
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.. _logging-message-format:
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Logging Message Format
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----------------------
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Each message written to the configured logging destinations comprises a
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number of components that identify the origin of the message and, if the
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message indicates a problem, information about the problem that may be
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useful in fixing it.
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Consider the message below logged to a file:
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::
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2014-04-11 12:58:01.005 INFO [kea-dhcp4.dhcpsrv/27456]
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DHCPSRV_MEMFILE_DB opening memory file lease database: type=memfile universe=4
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Note: the layout of messages written to the system logging file (syslog)
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may be slightly different. This message has been split across two lines
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here for display reasons; in the logging file, it will appear on one
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line.
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The log message comprises a number of components:
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2014-04-11 12:58:01.005
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The date and time at which the message was generated.
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INFO
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The severity of the message.
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[kea-dhcp4.dhcpsrv/27456]
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The source of the message. This includes two elements: the Kea
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process generating the message (in this case, ``kea-dhcp4``) and the
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component within the program from which the message originated
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(``dhcpsrv``, which is the name of the common library used by DHCP
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server implementations). The number after the slash is a process ID
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(PID).
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DHCPSRV_MEMFILE_DB
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The message identification. Every message in Kea has a unique
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identification, which can be used as an index to the `Kea Messages
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|
Manual <https://jenkins.isc.org/job/Kea_doc/messages/kea-messages.html>`__,
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where more information can be obtained.
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opening memory file lease database: type=memfile universe=4
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A brief description. Within this text, information relating to the
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condition that caused the message to be logged will be included. In
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this example, the information is logged that the in-memory lease
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database backend will be used to store DHCP leases.
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.. _logging-during-startup:
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Logging During Kea Startup
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--------------------------
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The logging configuration is specified in the configuration file.
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However, when Kea starts, the configuration file is not read until partway into the
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initialization process. Prior to that, the logging settings are set to
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default values, although it is possible to modify some aspects of the
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settings by means of environment variables. Note that in the absence of
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any logging configuration in the configuration file, the settings of the
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(possibly modified) default configuration will persist while the program
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is running.
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The following environment variables can be used to control the behavior
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|
|
of logging during startup:
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|
KEA_LOCKFILE_DIR
|
|
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|
|
Specifies a directory where the logging system should create its lock
|
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|
|
file. If not specified, it is prefix/var/run/kea, where "prefix"
|
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|
|
defaults to /usr/local. This variable must not end with a slash.
|
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|
|
|
There is one special value: "none", which instructs Kea not to create
|
2019-06-06 18:25:46 +02:00
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|
|
a lock file at all. This may cause issues if several processes log to
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|
|
the same file.
|
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|
|
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|
|
KEA_LOGGER_DESTINATION
|
2019-06-28 17:57:37 -04:00
|
|
|
Specifies logging output. There are several special values:
|
2019-06-06 18:25:46 +02:00
|
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|
|
stdout
|
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|
|
Log to standard output.
|
|
|
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|
|
stderr
|
|
|
|
|
Log to standard error.
|
|
|
|
|
|
|
|
|
|
syslog[:fac]
|
|
|
|
|
Log via syslog. The optional fac (which is separated from the word
|
|
|
|
|
"syslog" by a colon) specifies the facility to be used for the log
|
|
|
|
|
messages. Unless specified, messages will be logged using the
|
|
|
|
|
facility "local0".
|
|
|
|
|
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|
|
Any other value is treated as a name of the output file. If not
|
|
|
|
|
specified otherwise, Kea will log to standard output.
|
