bCC PMDA (BCC PMDA)
Имя (Name)
pmdabcc - BCC PMDA
Описание (Description)
pmdabcc is a Performance Co-Pilot (PCP) Performance Metrics
Domain Agent (PMDA) which extracts live performance data from
extended BPF (Berkeley Packet Filter) in-kernel programs by using
BCC (BPF Compiler Collection) Python frontend.
pmdabcc loads and acts as a bridge for any number of configured,
separate PCP BCC PMDA Python modules running BPF programs.
Existing BCC Python tools and programs should be possible to be
utilized with PCP BCC PMDA modules with reasonable effort.
See the BPF and BCC documentation for detailed description of
both.
Конфигурация (Configuration)
pmdabcc reads a mandatory ini-style configuration file:
$PCP_PMDAS_DIR/bcc/bcc.conf
This file must contain a [pmda] section. The following PMDA
options are available (their default values are shown in
parenthesis), options marked with asterisk (*) can be overridden
in module-specific configuration sections:
modules (unset)
The pmdabcc PMDA reads module-specific configuration for
each module listed in the comma-separated list of modules
(mandatory).
prefix (bcc.) *
By default, all metrics from the modules will appear under
the bcc Performance Metrics Name Space (PMNS) tree, prefix
(optional) can be used to change this generic prefix.
process_refresh (0)
See below.
module_failure_fatal (True)
A boolean value for module_failure_fatal (optional)
controls whether a module failing to compile should cause
the whole PMDA to abort (this is the default) or to start
up with possibly remaining functional modules. Module
configuration errors and internal errors (such as failing
to register the provided PMNS metrics, see PMNS(5)) will
always cause the PMDA to fail.
Of particular note, the process option accepted by some modules
evalutes the given PIDs and process names at PMDA/module
initialization time and apply filtering for only those processes
found at that stage. This is due to fact that the in-kernel BPF
program is compiled at module initialization time and, even more
importantly, they are often running at performance critical areas
where it is not acceptable to do process name lookups each time a
request is processed by the BPF program. To allow modules to
monitor named processes (say, process = java) even if they
restart the process_refresh should be set to a non-negative
integer N to dynamically refresh monitored processes every N
seconds. In case new processes matching the process filter have
appeared, the currently running BPF is detached and a new BPF
program with updated PID information is installed (and if no PIDs
matching the filter are anymore present, the BPF program will be
detach to avoid any needless overhead).
For each module listed in modules a corresponding [module]
section must be defined containing at least the following
options:
module Defines the actual Python module file name to be loaded
during PMDA startup under the modules subdirectory of the
PCP BCC PMDA installation.
cluster
Specifies the unique cluster ID (see PMNS(5)) for the
metrics provided by the module under the PMNS path.
All modules accept but not necessarily use the boolean debug
option.
Modules may also support additional module-specific configuration
options, refer to the default configuration file for their
supported options.
Установка (Installation)
To install, the following must be done as root:
# cd $PCP_PMDAS_DIR/bcc
# ./Install
To uninstall, the following must be done as root:
# cd $PCP_PMDAS_DIR/bcc
# ./Remove
pmdabcc is launched by pmcd(1) and should never be executed
directly. The Install and Remove scripts notify pmcd(1) when the
agent is installed or removed.
In case module_failure_fatal is set to False, the PMDA
installation will be considered successful even if some or even
all configured modules fail to load, in such cases metric values
provided by the failing modules will not be available. The
pmdabcc agent log file (see below) will contain detailed
information about activation of each module.
Some modules will start providing values only after having
collected data from related system activity. For instance, the
tcpperpid module will not provide any values unless there are
processes generating TCP traffic on the system.
Файлы (Files)
$PCP_PMDAS_DIR/bcc/bcc.conf
configuration file for the pmdabcc agent
$PCP_PMDAS_DIR/bcc/modules/*.{py,python}
PCP BCC PMDA Python modules available for the pmdabcc agent
$PCP_PMDAS_DIR/bcc/Install
installation script for the pmdabcc agent
$PCP_PMDAS_DIR/bcc/Remove
undo installation script for the pmdabcc agent
$PCP_LOG_DIR/pmcd/bcc.log
default log file for messages from the pmdabcc agent
Note that the usual/default value for $PCP_PMDAS_DIR is
/var/lib/pcp/pmdas and the default for $PCP_LOG_DIR is
/var/log/pcp but these settings are platform dependent.
Окружение PCP (PCP environment)
Environment variables with the prefix PCP_ are used to
parameterize the file and directory names used by PCP. On each
installation, the file /etc/pcp.conf contains the local values
for these variables. The $PCP_CONF variable may be used to
specify an alternative configuration file, as described in
pcp.conf(5).
Смотри также (See also)
PCPIntro(1), bcc(1), bpf(1) and pmcd(1).
