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Werk #10041: Reduce apache memory usage + Change check parameters API

Component WATO
Title Reduce apache memory usage + Change check parameters API
Date Sep 13, 2019
Checkmk Editon Checkmk Raw (CRE)
Checkmk Version 2.0.0i1 1.6.0b10
Level Prominent Change
Class Bug Fix
Compatibility Incompatible - Manual interaction might be required

We recognized that the 1.6 check parameter (ruleset) plugin mechanism (which was based on classes and using the python abc module) consumed a lot more memory than the previous plugin API.

The apache processes were ~50% bigger than in previous Checkmk releases which a too large growth. The problem is that the apache processes are part of a dynamic process pool which can scale from 5 to 64 processes (in the default config). When your apache processes use 130 MB of memory, this means that you would need to have ~8 GB of memory available to be able to handle high usage peaks. In such a situation a single process growth of 50% is relevant and should be avoided if possible.

If you have already ported your WATO check parameter plugins to 1.6 you will now have to port it to the new mechanism.

The new plugin API for registering check parameters is similar to the 1.5 API, but more explicit to make it easier to understand. For example the 'logins' check parameter declaration looks like this:

C:+ from cmk.gui.i18n import _ from cmk.gui.valuespec import ( Integer, Tuple, )

from cmk.gui.plugins.wato import ( CheckParameterRulespecWithoutItem, rulespec_registry, RulespecGroupCheckParametersOperatingSystem, )

def _parameter_valuespec_logins(): return Tuple( help=_("This rule defines upper limits for the number of logins on a system."), elements=[ Integer(title=_("Warning at"), unit=_("users"), default_value=20), Integer(title=_("Critical at"), unit=_("users"), default_value=30) ], )

rulespec_registry.register( CheckParameterRulespecWithoutItem( check_group_name="logins", group=RulespecGroupCheckParametersOperatingSystem, parameter_valuespec=_parameter_valuespec_logins, title=lambda: _("Number of Logins on System"), ))

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