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<p>Hello,<br>
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I am working on a feature to add system health metrics to HA. With this information, HA could failover nodes away from hardware that might have problems. The initial proposal briefly started on the linux-HA mailing list, but it has been moved to the pacemaker mailing list.<br>
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The following is a short description of what we want this new feature to do.<br>
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Feature Name: Health monitoring support<br>
Purpose: Allow pacemaker to schedule resources in a way that's sensitive to a variety of server-related health metrics<br>
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Description:<br>
Add support in pacemaker for a class of attributes which would be specially treated. Under this proposal, all attributes defined for a node whose name matches the regular expression /^#health-.*$/ would be automatically added into the score for each resource being considered for scheduling on that node.<br>
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The purpose of this is to allow multiple independent health monitors to each set their own health status and have that taken into account when scheduling resources. For example, IBM might define one called #health-ibmserver. Someone using smarttools (disk health monitors) might define one called #health-smarttools. Someone else using IPMI might define one called #health-ipmi. This means that this feature is not specific to any vendor, and various health monitor providers can develop health metrics for their hardware and not have to coordinate with each other in their development process.<br>
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Typical usage of these variables is expected to be something like this:<br>
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Health Attribute-value Meaning<br>
green 1000 server is happy, capable of running any resource<br>
yellow 0 server is marginal - it is desirable to schedule resources somewhere else if you can<br>
red -INFINITY server is unreliable (but still up) and should not be used<br>
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Note that all of the values given would be configuration-specific. These attributes would be set via attrd_updater.<br>
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Should the translation of health scores (colors) into specific valuse be done outside the core system?<br>
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There should be an API for health monitoring agents.<br>
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This would be similar to cluster-wide default set by symmetric-cluster true (0) or false (-INFINITY).<br>
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Special Note:<br>
IBM is already in the process of developing such a health monitoring tool for IBM X (intel-class) servers.<br>
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So, what do you all think of this proposed functionality? Does it sound reasonable? Comments are appreciated.<br>
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Mark</body></html>