Invalid characters on MibObj's alias prevent their usage on thresholds expressions
Description
Suppose that you want to create a low threshold expression based on ns-dskPercent, to retrieve the available space on a file system, in order to generate an alarm when the value is lower than X, we should use an expression like the following:
100 - ns-dskPercent
This expression will be parsed like this:
100 - ns - dskPercent
The problem is that the variables "ns" and "dskPercent" don't exist and the threshold won't be processed.
The character minus confuses the expression parser and should be avoided on any mibObj. Searching the current content of datacollection-config, I found the following list of invalid mibObjects:
The solution is just rename the alias but that means all people that are currently using those mibObjects will lose their historical data. One idea to deal with this problem is to adapt Ben's conversion tool to remediate the ds-names in existing rrd files.
Acceptance / Success Criteria
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Alejandro Galue December 6, 2011 at 8:18 AM
I found a better solution for this problems in order to avoid changes on datacollection-config.xml.
For variables with invalid characters from the point of view of Apache JEXL, all the required variables are also accessible through a map called "datasources", so in order to define correctly the following expression:
you should write:
Fixed on revision ea9e44bd9954fc4d5123d7d2c19aeab34f073fd8 for 1.10.
Suppose that you want to create a low threshold expression based on ns-dskPercent, to retrieve the available space on a file system, in order to generate an alarm when the value is lower than X, we should use an expression like the following:
100 - ns-dskPercent
This expression will be parsed like this:
100 - ns - dskPercent
The problem is that the variables "ns" and "dskPercent" don't exist and the threshold won't be processed.
The character minus confuses the expression parser and should be avoided on any mibObj. Searching the current content of datacollection-config, I found the following list of invalid mibObjects:
netBotz-temp
netBotz-humidity
netBotz-airflow
netBotz-temp-min
netBotz-temp-max
netBotz-humid-min
netBotz-humid-max
netBotz-air-min
ns-dskPath
ns-dskTotal
ns-dskAvail
ns-dskUsed
ns-dskPercent
ns-dskDevice
ns-dskPercentNode
ns-dskTotalLow
ns-dskTotalHigh
ns-dskAvailLow
ns-dskAvailHigh
ns-dskUsedLow
ns-dskUsedHigh
The solution is just rename the alias but that means all people that are currently using those mibObjects will lose their historical data. One idea to deal with this problem is to adapt Ben's conversion tool to remediate the ds-names in existing rrd files.