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NAME | SYNOPSIS | DESCRIPTION | COMMANDS | CLASS POLICY FILE | DIAGNOSTICS | PCP ENVIRONMENT | SEE ALSO | COLOPHON |
PMLOGCTL(1) General Commands Manual PMLOGCTL(1)
pmlogctl - manage and control Performance Co-Pilot archive loggers
pmlogctl [-afNV?] [-c classname] [-i ident] [-p policyfile] command
[host ...]
pmlogctl may be used to manage non-primary instances of the
Performance Co-Pilot (PCP) archiver pmlogger(1). This would be most
relevant in a PCP archive logger ``farm'' where many pmlogger(1)
instances would be creating archives of performance data collected
from pmcd(1) on many remote hosts.
The primary pmlogger(1) instance is closely linked to the local
pmcd(1) process and as a consequence shares the same control
infrastructure, namely systemd(1) or the PCP init(1) ``rc scripts''.
This is why the primary pmlogger(1) instance cannot be managed with
pmlogctl.
For brevity in the description below, the term ``instance'' means a
pmlogger(1) instance.
All instances managed by pmlogctl, pmlogger_check(1) and
pmlogger_daily(1) abide by the following rules:
1. Each instance is fetching performance data from a single pmcd(1)
(i.e. one host), but each pmcd(1) may be providing performance
data to zero, one or more pmlogger(1) processes running on one or
more hosts.
2. On the local host, each pmlogger(1) instance must be specified
once in a pmlogger_check(1) control file and pmlogger(1) creates
archives in a unique directory, named in the 4th parameter of the
associated control file entry (see the CONFIGURATION section of
pmlogger_check(1)).
3. Each instance belongs to exactly one class, optionally named using
a $class=... assignment in the associated control file. The
special default class is reserved for all instances that do not
have an associated $class=... assignment. For reporting purposes
(refer to the summary command below), the primary pmlogger(1)
instance is automatically assigned to the special primary class.
Each pmlogctl execution manages one or more instances updating the
associated control files and then running pmlogger_check(1) to effect
the desired change.
The host arguments are usually valid host names. For all commands
except create and cond-create (described below) the host arguments
may also be egrep(1) regular expressions that match the whole of a
valid host name, so the pattern used is actually ^host$. For example
foo.* (matches all host names beginning with ``foo'') or .*foo
(matches all host names ending with ``foo'') or .*[fF][oO][oO].*
(matches all host names containing ``foo'' in upper, lower or mixed
case).
The combination of a classname from the optional -c option (or
default) and the host arguments to each command identifies a target
of set instances to which the command operation should be applied.
The -N option runs pmlogctl in ``show me'' mode where the intent of
the command is shown, but no changes are made.
The -i option may be used with the create or cond-create commands to
over-ride the instance identity that is specified in the ident
section of the class policy file (see the CLASS POLICY FILE section
below). Since the identifier must be unique across all instances and
all classes, it only makes sense to use this option when there is a
single host argument.
The -V option generally increases the verbosity of the output. A
second -V makes pmlogctl very chatty.
Given the tasks that pmlogctl is undertaking it usually must be run a
``root'', the exceptions being the status command or when the -N
option is specified.
command is one of the following:
create
Create new instances in the class classname (default by default)
for the host hosts. The name of the class is used to identify a
class policy file (see the CLASS POLICY FILE section below) which
provides a template for each new control file with %h replaced by
host and %i replaced by the instance's (unique) identifier from
the ident section of the class policy file or ident from the -i
option.
The -p option may be used to identify a class policy file other
than the one found in the standard place, i.e.
$PCP_ETC_DIR/pcp/pmlogger/class.d/classname.
At least one host must be specified for the create command.
cond-create
Similar to create but the instance will only be created if one of
the conditions in the create section of associated class policy
file(s) evaluates to true.
If a -c option is specified, then only the class classname will
be considered, otherwise all classes will be considered. In the
latter case, if none of the conditions in any of the classes
evaluates to true, the the special pmfind class is used (this is
the ``default'' class for the cond-create command when all else
fails).
If more than one class evalutes to true then a composite
pmlogger(1) configuration file is created and the instance is
also assigned to the special pmfind class. The composite
configuration file may contain a mix of explicit configuration
clauses and the more general conditional configuration clauses as
understood by the pmlogconf(1) tool.
start
Start the target set of instances.
If the target set intentionally contains more than one instance,
then the -a option should be used (this is designed to reduce the
risk of accidentally starting a potentially large number of
pmlogger(1) processes).
If an instance in the target set is already started, no change is
made (see the restart command to force new instances to be
launched).
stop
Stop the target set of instances.
If the target set intentionally contains more than one instance,
then the -a option should be used (this is designed to reduce the
risk of accidentally stopping a potentially large number of
pmlogger(1) processes).
If an instance in the target set is already stopped, no change is
made but a warning is issued.
restart
Stop and then start the target set of instances.
If the target set intentionally contains more than one instance,
then the -a option should be used (this is designed to reduce the
risk of accidentally stopping and starting a potentially large
number of pmlogger(1) processes).
If an instance in the target set is already stopped, a warning is
issued before the instance is started.
status
Report the status of the target set of instances. If there is no
-c option specified and no host arguments, i.e. the target set is
empty, then all instances will be reported.
destroy
Destroy the target set of instances. At the end of this
operation the associated pmlogger(1) processes will have been
stopped and the relevant control file information removed.
If the target set intentionally contains more than one instance,
then the -a option should be used (this is designed to reduce the
risk of accidentally terminating a potentially large number of
pmlogger(1) processes and removing their pmlogger_check(1)
configurations).
The policy file linked to the class of an instance to be
destroyed may contain a destroy section that may influence if and
how the destroy operation should be performed. This may require
a -p option to find the associated class policy file.
The class policy checking can be by-passed using the -f (force)
command line option.
A class policy file contains a number of sections, each section
begins with a line that simply starts with the name of the section
followed enclosed by ``['' and ``]''.
Lines beginning with a hash (#) are treated as comments and ignored.
Blank or empty lines are also ignored.
The typical location of the policy file for the class foo is
$PCP_ETC_DIR/pcp/pmlogger/class.d/foo.
[class]
The optional class name section names the class. If it is
missing, the name of the policy file (stripped of any directory
prefix) is used as the name of the class.
[ident]
The ident section specifies the template to be used for the
instance identifier to be given to each member of the class.
This identifier needs to be unique across all instances and all
classes, and it needs to be a valid file name in the local
filesystem, so would normally contain the class name and the
macro %h, e.g. foo-%h. The macro is replaced by the host when
each instance is created.
[control]
The control section consists of one or more lines of template
text that will be used to create the control file for each
instance. This must at least include the pmlogger_check(1)
control line to specify how to start the associated pmlogger(1)
process; this line contains fields separated by white space as
follows:
1. the hostname, usually the macro %h
2. n to indicate this is a non-primary instance
3. the ``socks'' flag, typically n
4. the directory in which the pmlogger(1) archives will be
created; this needs to be unique and is usually specified
using the pmlogger_check(1) macro PCP_ARCHIVE_DIR as the
start of the path, followed by the instance identifier,
usually the macro %i, e.g. PCP_ARCHIVE_DIR/%i
5. additional parameters to pmlogger(1) which probably include
at least a -c option to provide a configuration file that
describes which metrics should be logged for instances of
this class, which may be the same for all instances in this
class, or it may include the %i macro to use a different
configuration file for each instance. Note that if this
configuration file does not exist, it will be created using
pmlogconf(1) the first time pmlogger_check(1) is run.
Before the control line there should be a line that defines the
version of the control line that follows, i.e.
$version=1.1
If this is missing, pmlogctl will assume the version is 1.1 and
insert the line when the instance is created.
pmlogctl will also add the class name during creation. e.g.
$class=foo
[create]
The create section defines the conditions that must be met before
an instance will be created with the cond-create command. The
intent is to allow different decisions to be made when a new host
running pmcd(1) is discovered, e.g. by pmfind(1).
Each non-blank line in the create section is a condition of the
form function(arg), where function is one of the following:
exists
arg is the name of a performance metric and exits evaluates
to true if that metric exists in the Performance Metrics Name
Space (PMNS) on the remote host
values
arg is the name of a performance metric in the remote PMNS
and values evaluates to true if some instance of that metric
has a value on the remote host
condition
arg is a derived metric expression in the format supported by
pmRegisterDerived(3), and condition evaluates to true if the
value of that expression on the remote host is greater than
zero
hostname
arg is a regular expression in the style of egrep(1) and
hostname evaluates to true if the remote host name matches
arg
[destroy]
The destroy section defines the policy to be applied when an
instance is destroyed.
The intent is to allow different decisions to be made when
discovery service, e.g. pmfind(1), notices that a host
associated with an instance is no longer present. But in the
current version this is not implemented and the destroy section
syntax and semantics is not yet defined.
A sample class policy file is as follows:
# policy file for the foo class
[class]
foo
[ident]
foo-%h
[control]
$version=1.1
%h n n PCP_ARCHIVE_DIR/%i -c foo-metrics.config
[create]
# matches all hosts
hostname(.*)
[destroy]
# still to be defined
Most error or warning messages are self-explanatory.
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).
egrep(1), init(1), PCPIntro(1), pmcd(1), pmlc(1), pmlogconf(1),
pmlogger(1), pmlogger_check(1), pmlogger_daily(1), systemd(1),
PMAPI(3), pmDerivedRegister(3) and pcp.conf(5).
This page is part of the PCP (Performance Co-Pilot) project.
Information about the project can be found at ⟨http://www.pcp.io/⟩.
If you have a bug report for this manual page, send it to
pcp@groups.io. This page was obtained from the project's upstream
Git repository ⟨https://github.com/performancecopilot/pcp.git⟩ on
2020-08-13. (At that time, the date of the most recent commit that
was found in the repository was 2020-08-11.) If you discover any
rendering problems in this HTML version of the page, or you believe
there is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
Performance Co-Pilot PCP PMLOGCTL(1)
Pages that refer to this page: pmlogger_check(1) , pmlogger_daily(1)