snmp - The SNMP Application
Please see following description for synopsis
Erlang Application Definition SNMP(7)
NAME
SNMP - The SNMP Application
DESCRIPTION
This chapter describes the snmp application in OTP. The SNMP applica-
tion provides the following services:
* a multilingual extensible SNMP agent
* a SNMP manager
* a MIB compiler
CONFIGURATION
The following configuration parameters are defined for the SNMP appli-
cation. Refer to application(3) for more information about configura-
tion parameters.
The snmp part of the config file specifying the configuration parame-
ters is basically the following tuple:
{snmp, snmp_components_config()}
A minimal config file for starting a node with both a manager and an
agent:
[{snmp,
[{agent, [{db_dir, "/tmp/snmp/agent/db"},
{config, [{dir, "/tmp/snmp/agent/conf"}]}]},
{manager, [{config, [{dir, "/tmp/snmp/manager/conf"},
{db_dir, "/tmp/snmp/manager/db"}]}]}]}
]
}
].
Each snmp component has its own set of configuration parameters, even
though some of the types are common to both components.
snmp_components_config() -> [snmp_component_config()]
snmp_component_config() -> {agent, agent_options()} | {manager, manager_options()}
agent_options() = [agent_option()]
agent_option() = {restart_type, restart_type()} |
{agent_type, agent_type()} |
{agent_verbosity, verbosity()} |
{discovery, agent_discovery()} |
{versions, versions()} |
{gb_max_vbs, gb_max_vbs()} |
{priority, priority()} |
{multi_threaded, multi_threaded()} |
{db_dir, db_dir()} |
{db_init_error, db_init_error()} |
{local_db, local_db()} |
{net_if, agent_net_if()} |
{mibs, mibs()} |
{mib_storage, mib_storage()} |
{mib_server, mib_server()} |
{audit_trail_log, audit_trail_log()} |
{error_report_mod, error_report_mod()} |
{note_store, note_store()} |
{symbolic_store, symbolic_store()} |
{target_cache, target_cache()} |
{config, agent_config()}
manager_options() = [manager_option()]
manager_option() = {restart_type, restart_type()} |
{net_if, manager_net_if()} |
{server, server()} |
{note_store, note_store()} |
{config, manager_config()} |
{inform_request_behaviour, manager_irb()} |
{mibs, manager_mibs()} |
{priority, priority()} |
{audit_trail_log, audit_trail_log()} |
{versions, versions()} |
{def_user_mod, def_user_module() |
{def_user_data, def_user_data()}
Agent specific config options and types:
agent_type() = master | sub <optional>:
If master, one master agent is started. Otherwise, no agents are
started.
Default is master.
agent_discovery() = [agent_discovery_opt()] <optional>:
agent_discovery_opt() = {terminating, agent_terminating_discov-
ery_opts()} | {originating, agent_originating_discovery_opts()}
The terminating options effects discovery initiated by a manager.
The originating options effects discovery initiated by this agent.
For defaults see the options in agent_discovery_opt().
agent_terminating_discovery_opts() = [agent_terminating_discov-
ery_opt()] <optional>:
agent_terminating_discovery_opt() = {enable, boolean()} | {stage2,
discovery | plain} | {trigger_username, string()}
These are options effecting discovery terminating in this agent
(i.e. initiated by a manager).
The default values for the terminating discovery options are:
* enable: true
* stage2: discovery
* trigger_username: ""
agent_originating_discovery_opts() = [agent_originating_discov-
ery_opt()] <optional>:
agent_originating_discovery_opt() = {enable, boolean()}
These are options effecting discovery originating in this agent.
The default values for the originating discovery options are:
* enable: true
multi_threaded() = bool() | extended <optional>:
If true (or extended), the agent is multi-threaded, with one thread
for each get request.
The value extended means that a special 'process' is also created
intended to handle all notifications.
* true - One worker dedicated to 'set-requests' and one (main)
worker for all other requests ('get-request' and notifications).
If the 'main' worker is busy, a temporary process is spawned to
handle that job ('get-request' or notification).
* extended - One worker dedicated to 'set-requests', one worker
dedicated to notifications and one (main) worker for all 'get-
requests'.
If the 'main' worker is busy, a temporary process is spawned to
handle that 'get-request'.
Note:
Even with multi-threaded set to extended there is still a risk for
'reorder' when sending inform-requsts, which require a response (and
may therefor require resending).
Also, there is of course no way to guarantee order once the package
is on the network.
Default is false.
db_dir() = string() <mandatory>:
Defines where the SNMP agent internal db files are stored.
gb_max_vbs() = pos_integer() | infinity <optional>:
Defines the maximum number of varbinds allowed in a Get-BULK
response.
Default is 1000.
local_db() = [local_db_opt()] <optional>:
local_db_opt() = {repair, agent_repair()} | {auto_save,
agent_auto_save()} | {verbosity, verbosity()}
Defines options specific for the SNMP agent local database.
For defaults see the options in local_db_opt().
agent_repair() = false | true | force <optional>:
When starting snmpa_local_db it always tries to open an existing
database. If false, and some errors occur, a new database is cre-
ated instead. If true, an existing file will be repaired. If force,
the table will be repaired even if it was properly closed.
Default is true.
agent_auto_save() = integer() | infinity <optional>:
The auto save interval. The table is flushed to disk whenever not
accessed for this amount of time.
Default is 5000.
agent_net_if() = [agent_net_if_opt()] <optional>:
agent_net_if_opt() = {module, agent_net_if_module()} | {verbosity,
verbosity()} | {options, agent_net_if_options()}
Defines options specific for the SNMP agent network interface
entity.
For defaults see the options in agent_net_if_opt().
agent_net_if_module() = atom() <optional>:
Module which handles the network interface part for the SNMP agent.
Must implement the snmpa_network_interface behaviour.
Default is snmpa_net_if.
agent_net_if_options() = [agent_net_if_option()] <optional>:
agent_net_if_option() = {bind_to, bind_to()} | {sndbuf, sndbuf()} |
{recbuf, recbuf()} | {no_reuse, no_reuse()} | {req_limit,
req_limit()} | {filter, agent_net_if_filter_options()} |
{extra_sock_opts, extra_socket_options()} | {inet_backend, inet |
socket}
These options are actually specific to the used module. The ones
shown here are applicable to the default agent_net_if_module().
Note:
If the user has configured transports with options then those will
take precedence over these options. See agent information for more
info.
For defaults see the options in agent_net_if_option().
req_limit() = integer() | infinity <optional>:
Max number of simultaneous requests handled by the agent.
Default is infinity.
agent_net_if_filter_options() = [agent_net_if_filter_option()]
<optional>:
agent_net_if_filter_option() = {module, agent_net_if_filter_mod-
ule()}
These options are actually specific to the used module. The ones
shown here are applicable to the default agent_net_if_filter_mod-
ule().
For defaults see the options in agent_net_if_filter_option().
agent_net_if_filter_module() = atom() <optional>:
Module which handles the network interface filter part for the SNMP
agent. Must implement the snmpa_network_interface_filter behaviour.
Default is snmpa_net_if_filter.
agent_mibs() = [string()] <optional>:
Specifies a list of MIBs (including path) that defines which MIBs
are initially loaded into the SNMP master agent.
Note that the following mibs will always be loaded:
* version v1: STANDARD-MIB
* version v2: SNMPv2
* version v3: SNMPv2, SNMP-FRAMEWORK-MIB and SNMP-MPD-MIB
Default is [].
mib_storage() = [mib_storage_opt()] <optional>:
mib_storage_opt() = {module, mib_storage_module()} | {options,
mib_storage_options()}
This option specifies how basic mib data is stored. This option is
used by two parts of the snmp agent: The mib-server and the sym-
bolic-store.
Default is [{module, snmpa_mib_storage_ets}].
mib_storage_module() = snmpa_mib_data_ets | snmpa_mib_data_dets |
snmpa_mib_data_mnesia | module():
Defines the mib storage module of the SNMP agent as defined by the
snmpa_mib_storage behaviour.
Several entities (mib-server via the its data module and the sym-
bolic-store) of the snmp agent uses this for storage of miscela-
neous mib related data retrieved while loading a mib.
There are several implementations provided with the agent:
snmpa_mib_storage_ets, snmpa_mib_storage_dets and snmpa_mib_stor-
age_mnesia.
Default module is snmpa_mib_storage_ets.
mib_storage_options() = list() <optional>:
This is implementattion depended. That is, it depends on the mod-
ule. For each module a specific set of options are valid. For the
module provided with the app, these options are supported:
* snmpa_mib_storage_ets: {dir, filename()} | {action, keep |
clear}, {checksum, boolean()}
* dir - If present, points to a directory where a file to which
all data in the ets table is "synced".
Also, when a table is opened this file is read, if it exists.
By default, this will not be used.
* action - Specifies the behaviour when a non-empty file is
found: Keep its content or clear it out.
Default is keep.
* checksum - Defines if the file is checksummed or not.
Default is false.
* snmpa_mib_storage_dets: {dir, filename()} | {action, keep |
clear}, {auto_save, default | pos_integer()} | {repair, force |
boolean()}
* dir - This mandatory option points to a directory where to
place the file of a dets table.
* action - Specifies the behaviour when a non-empty file is
found: Keep its content or clear it out.
Default is keep.
* auto_save - Defines the dets auto-save frequency.
Default is default.
* repair - Defines the dets repair behaviour.
Default is false.
* snmpa_mib_storage_mnesia: {action, keep | clear}, {nodes,
[node()]}
* action - Specifies the behaviour when a non-empty, already
existing, table: Keep its content or clear it out.
Default is keep.
* nodes - A list of node names (or an atom describing a list of
nodes) defining where to open the table. Its up to the user to
ensure that mnesia is actually running on the specified nodes.
The following distinct values are recognised:
* [] - Translated into a list of the own node: [node()]
* all - erlang:nodes()
* visible - erlang:nodes(visible)
* connected - erlang:nodes(connected)
* db_nodes - mnesia:system_info(db_nodes)
Default is the result of the call: erlang:nodes().
mib_server() = [mib_server_opt()] <optional>:
mib_server_opt() = {mibentry_override, mibentry_override()} |
{trapentry_override, trapentry_override()} | {verbosity, ver-
bosity()} | {cache, mibs_cache()} | {data_module,
mib_server_data_module()}
Defines options specific for the SNMP agent mib server.
For defaults see the options in mib_server_opt().
mibentry_override() = bool() <optional>:
If this value is false, then when loading a mib each mib- entry is
checked prior to installation of the mib. The purpose of the check
is to prevent that the same symbolic mibentry name is used for dif-
ferent oid's.
Default is false.
trapentry_override() = bool() <optional>:
If this value is false, then when loading a mib each trap is
checked prior to installation of the mib. The purpose of the check
is to prevent that the same symbolic trap name is used for differ-
ent trap's.
Default is false.
mib_server_data_module() = snmpa_mib_data_tttn | module() <optional>:
Defines the backend data module of the SNMP agent mib-server as
defined by the snmpa_mib_data behaviour.
At present only the default module is provided with the agent,
snmpa_mib_data_tttn.
Default module is snmpa_mib_data_tttn.
mibs_cache() = bool() | mibs_cache_opts() <optional>:
Shall the agent utilize the mib server lookup cache or not.
Default is true (in which case the mibs_cache_opts() default values
apply).
mibs_cache_opts() = [mibs_cache_opt()] <optional>:
mibs_cache_opt() = {autogc, mibs_cache_autogc()} | {gclimit,
mibs_cache_gclimit()} | {age, mibs_cache_age()}
Defines options specific for the SNMP agent mib server cache.
For defaults see the options in mibs_cache_opt().
mibs_cache_autogc() = bool() <optional>:
Defines if the mib server shall perform cache gc automatically or
leave it to the user (see gc_mibs_cache/0,1,2,3).
Default is true.
mibs_cache_age() = integer() > 0 <optional>:
Defines how old the entries in the cache will be allowed to become
before they are GC'ed (assuming GC is performed). Each entry in the
cache is "touched" whenever it is accessed.
The age is defined in milliseconds.
Default is 10 timutes.
mibs_cache_gclimit() = infinity | integer() > 0 <optional>:
When performing a GC, this is the max number of cache entries that
will be deleted from the cache.
The reason why its possible to set a limit, is that if the cache is
large, the GC can potentially take a long time, during which the
agent is "busy". But on a heavily loaded system, we also risk not
removing enough elements in the cache, instead causing it to grow
over time. This is the reason the default value is infinity, which
will ensure that all candidates are removed as soon as possible.
Default is infinity.
error_report_mod() = atom() <optional>:
Defines an error report module, implementing the snmpa_error_report
behaviour. Two modules are provided with the toolkit:
snmpa_error_logger and snmpa_error_io.
Default is snmpa_error_logger.
symbolic_store() = [symbolic_store_opt()]:
symbolic_store_opt() = {verbosity, verbosity()}
Defines options specific for the SNMP agent symbolic store.
For defaults see the options in symbolic_store_opt().
target_cache() = [target_cache_opt()]:
target_cache_opt() = {verbosity, verbosity()}
Defines options specific for the SNMP agent target cache.
For defaults see the options in target_cache_opt().
agent_config() = [agent_config_opt()] <mandatory>:
agent_config_opt() = {dir, agent_config_dir()} | {force_load,
force_load()} | {verbosity, verbosity()}
Defines specific config related options for the SNMP agent.
For defaults see the options in agent_config_opt().
agent_config_dir = dir() <mandatory>:
Defines where the SNMP agent configuration files are stored.
force_load() = bool() <optional>:
If true the configuration files are re-read during start-up, and
the contents of the configuration database ignored. Thus, if true,
changes to the configuration database are lost upon reboot of the
agent.
Default is false.
Manager specific config options and types:
server() = [server_opt()] <optional>:
server_opt() = {timeout, server_timeout()} | {verbosity, ver-
bosity()} | {cbproxy, server_cbproxy()} | {netif_sup, server_nis()}
Specifies the options for the manager server process.
Default is silence.
server_timeout() = integer() <optional>:
Asynchronous request cleanup time. For every requests, some info is
stored internally, in order to be able to deliver the reply (when
it arrives) to the proper destination. If the reply arrives, this
info will be deleted. But if there is no reply (in time), the info
has to be deleted after the best before time has been passed. This
cleanup will be performed at regular intervals, defined by the
server_timeout() time. The information will have an best before
time, defined by the Expire time given when calling the request
function (see async_get, async_get_next and async_set).
Time in milli-seconds.
Default is 30000.
server_cbproxy() = temporary (default) | permanent <optional>:
This option specifies how the server will handle callback calls.
temporary (default):
A temporary process will be created for each callback call.
permanent:
With this the server will create a permanent (named) process that
in effect serializes all callback calls.
Default is temporary.
server_nis() = none (default) | {PingTO, PongTO} <optional>:
This option specifies if the server should actively supervise the
net-if process. Note that this will only work if the used net-if
process actually supports the protocol. See snmpm_network_interface
behaviour for more info.
none (default):
No active supervision of the net-if process.
{PingTO :: pos_integer(), PongTO :: pos_integer()}:
The PingTO time specifies the between a successful ping (or
start) and the time when a ping message is to be sent to the net-
if process (basically the time between ping).
The PongTO time specifies how long time the net-if process has to
respond to a ping message, with a pong message. Its starts count-
ing when the ping message has been sent.
Both times are in milli seconds.
Default is none.
manager_config() = [manager_config_opt()] <mandatory>:
manager_config_opt() = {dir, manager_config_dir()} | {db_dir, man-
ager_db_dir()} | {db_init_error, db_init_error()} | {repair, man-
ager_repair()} | {auto_save, manager_auto_save()} | {verbosity,
verbosity()}
Defines specific config related options for the SNMP manager.
For defaults see the options in manager_config_opt().
manager_config_dir = dir() <mandatory>:
Defines where the SNMP manager configuration files are stored.
manager_db_dir = dir() <mandatory>:
Defines where the SNMP manager store persistent data.
manager_repair() = false | true | force <optional>:
Defines the repair option for the persistent database (if and how
the table is repaired when opened).
Default is true.
manager_auto_save() = integer() | infinity <optional>:
The auto save interval. The table is flushed to disk whenever not
accessed for this amount of time.
Default is 5000.
manager_irb() = auto | user | {user, integer()} <optional>:
This option defines how the manager will handle the sending of
response (acknowledgment) to received inform-requests.
* auto - The manager will autonomously send response (acknowledg-
ment> to inform-request messages.
* {user, integer()} - The manager will send response (acknowledg-
ment) to inform-request messages when the handle_inform function
completes. The integer is the time, in milli-seconds, that the
manager will consider the stored inform-request info valid.
* user - Same as {user, integer()}, except that the default time,
15 seconds (15000), is used.
See snmpm_network_interface, handle_inform and definition of the
manager net if for more info.
Default is auto.
manager_mibs() = [string()] <optional>:
Specifies a list of MIBs (including path) and defines which MIBs
are initially loaded into the SNMP manager.
Default is [].
manager_net_if() = [manager_net_if_opt()] <optional>:
manager_net_if_opt() = {module, manager_net_if_module()} | {ver-
bosity, verbosity()} | {options, manager_net_if_options()}
Defines options specific for the SNMP manager network interface
entity.
For defaults see the options in manager_net_if_opt().
manager_net_if_options() = [manager_net_if_option()] <optional>:
manager_net_if_option() = {bind_to, bind_to()} | {sndbuf, sndbuf()}
| {recbuf, recbuf()} | {no_reuse, no_reuse()} | {filter, man-
ager_net_if_filter_options()} | {extra_sock_opts,
extra_socket_options()} | {inet_backend, inet | socket}
These options are actually specific to the used module. The ones
shown here are applicable to the default manager_net_if_module().
For defaults see the options in manager_net_if_option().
manager_net_if_module() = atom() <optional>:
The module which handles the network interface part for the SNMP
manager. It must implement the snmpm_network_interface behaviour.
Default is snmpm_net_if.
manager_net_if_filter_options() = [manager_net_if_filter_option()]
<optional>:
manager_net_if_filter_option() = {module, manager_net_if_fil-
ter_module()}
These options are actually specific to the used module. The ones
shown here are applicable to the default manager_net_if_filter_mod-
ule().
For defaults see the options in manager_net_if_filter_option().
manager_net_if_filter_module() = atom() <optional>:
Module which handles the network interface filter part for the SNMP
manager. Must implement the snmpm_network_interface_filter behav-
iour.
Default is snmpm_net_if_filter.
def_user_module() = atom() <optional>:
The module implementing the default user. See the snmpm_user behav-
iour.
Default is snmpm_user_default.
def_user_data() = term() <optional>:
Data for the default user. Passed to the user module when calling
the callback functions.
Default is undefined.
Common config types:
restart_type() = permanent | transient | temporary:
See supervisor documentation for more info.
Default is permanent for the agent and transient for the manager.
db_init_error() = terminate | create | create_db_and_dir:
Defines what to do if the agent or manager is unable to open an
existing database file. terminate means that the agent/manager will
terminate and create means that the agent/manager will remove the
faulty file(s) and create new ones, and create_db_and_dir means
that the agent/manager will create the database file along with any
missing parent directories for the database file.
Default is terminate.
priority() = atom() <optional>:
Defines the Erlang priority for all SNMP processes.
Default is normal.
versions() = [version()] <optional>:
version() = v1 | v2 | v3
Which SNMP versions shall be accepted/used.
Default is [v1,v2,v3].
verbosity() = silence | info | log | debug | trace <optional>:
Verbosity for a SNMP process. This specifies now much debug info is
printed.
Default is silence.
bind_to() = bool() <optional>:
If true, net_if binds to the IP address. If false, net_if listens
on any IP address on the host where it is running.
Default is false.
no_reuse() = bool() <optional>:
If true, net_if does not specify that the IP and port address
should be reusable. If false, the address is set to reusable.
Default is false.
recbuf() = integer() <optional>:
Receive buffer size.
Default value is defined by gen_udp.
sndbuf() = integer() <optional>:
Send buffer size.
Default value is defined by gen_udp.
extra_socket_options() = list() <optional>:
A list of arbitrary socket options.
This list is not inspected by snmp (other then checking that its a
list). Its the users responsibility to ensure that these are valid
options and does not conflict with the "normal" options.
Default is [].
note_store() = [note_store_opt()] <optional>:
note_store_opt() = {timeout, note_store_timeout()} | {verbosity,
verbosity()}
Specifies the start-up verbosity for the SNMP note store.
For defaults see the options in note_store_opt().
note_store_timeout() = integer() <optional>:
Note cleanup time. When storing a note in the note store, each note
is given lifetime. Every timeout the note_store process performs a
GC to remove the expired note's. Time in milli-seconds.
Default is 30000.
audit_trail_log() = [audit_trail_log_opt()] <optional>:
audit_trail_log_opt() = {type, atl_type()} | {dir, atl_dir()} |
{size, atl_size()} | {repair, atl_repair()} | {seqno, atl_seqno()}
If present, this option specifies the options for the audit trail
logging. The disk_log module is used to maintain a wrap log. If
present, the dir and size options are mandatory.
If not present, audit trail logging is not used.
atl_type() = read | write | read_write <optional>:
Specifies what type of an audit trail log should be used. The
effect of the type is actually different for the the agent and the
manager.
For the agent:
* If write is specified, only set requests are logged.
* If read is specified, only get requests are logged.
* If read_write, all requests are logged.
For the manager:
* If write is specified, only sent messages are logged.
* If read is specified, only received messages are logged.
* If read_write, both outgoing and incoming messages are logged.
Default is read_write.
atl_dir = dir() <mandatory>:
Specifies where the audit trail log should be stored.
If audit_trail_log specifies that logging should take place, this
parameter must be defined.
atl_size() = {integer(), integer()} <mandatory>:
Specifies the size of the audit trail log. This parameter is sent
to disk_log.
If audit_trail_log specifies that logging should take place, this
parameter must be defined.
atl_repair() = true | false | truncate | snmp_repair <optional>:
Specifies if and how the audit trail log shall be repaired when
opened. Unless this parameter has the value snmp_repair it is sent
to disk_log. If, on the other hand, the value is snmp_repair, snmp
attempts to handle certain faults on its own. And even if it cannot
repair the file, it does not truncate it directly, but instead
moves it aside for later off-line analysis.
Default is true.
atl_seqno() = true | false <optional>:
Specifies if the audit trail log entries will be (sequence) num-
bered or not. The range of the sequence numbers are according to
RFC 5424, i.e. 1 through 2147483647.
Default is false.
SEE ALSO
application(3), disk_log(3)
Ericsson AB snmp 5.11 SNMP(7)