Provided by: pcp_5.3.7-1_amd64 
NAME
pmlogctl - manage and control Performance Co-Pilot archive loggers
SYNOPSIS
pmlogctl [-afmNV?] [-c class] [-i ident] [-p policy] command [host ...]
DESCRIPTION
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 class 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 -i option may be used with the create or cond-create commands to override 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.
Given the tasks that pmlogctl is undertaking it usually must be run as ``root'', the
exceptions being the status command or when the -N option is specified.
COMMANDS
command is one of the following:
check
Check the status of all currently configured pmlogger instances and restart any that
have failed. If the -m flag is given on systemd(1) platforms, also migrate matching
(and new) processes to the pmlogger_farm service.
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_SYSCONF_DIR/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.
CLASS POLICY FILE
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_SYSCONF_DIR/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
OPTIONS
The available command line options are:
-a, --all
Apply action to all matching instances. By default only one instance definition is
expected and acted upon.
-c class, --class=class
Set the name of the class for which pmlogger(1) instances belong to as class.
-f, --force
Force action if possible.
-i ident, --ident=ident
Override instance identifier with ident. This option applies only for the commands
create and cond-create.
-N, --showme
Runs pmlogctl in a ``show me'' or ``dry run'' mode where the intent of the command is
shown, but no changes are made.
-m, --migrate
When used with the create or check commands on systemd(1) platforms, also migrate new
or existing non-primary pmlogger processes to the pmlogger_farm service. This is
normally done automatically by the pmlogger_farm_check service, which is timer driven
(so there may be a few minutes delay before automatic migration is initiated).
-p policy, --policy=policy
Use policy as the class policy file. Defaults to
$PCP_SYSCONF_DIR/pmlogger/class.d/<class>.
-V, --verbose
Enable verbose mode. Using this option twice increases verbosity.
-?, --help
Display usage message and exit.
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).
SEE ALSO
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).