TL;DR
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Updates Sysctl collector and analyzer for virtual memory parameters
Details
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Adds supoort for virtual memory parameters to the Sysctl collector and
analyzers. I uncovered this writing a pre-flight for a Helm chart that
includes ECK as a subchart. Since ECK requires a specific minimum value
for `vm.max_map_count` I wanted to use the Sysctl analyzer to check for
the expected value, but wasn't able to because of the limited values it
collected. I also learned that Sonarqube expects the same parameter to
be increased, so it seemed like a general enough requirement to add it
in.
The code updates the collector to collect values under `/proc/sys/vm`
and adds tests to the analyzer to based on the ECK requirements. Making
the tests pass required adding operators to the when expression, since
the existing code only allowed for `=`, `==`, and `===`. The when
expression now supports `>`, `<`, `>=`, and `<=`.
All tests pass.