Issue with ceilometer transformers

    - name: cpu_source
      interval: 600
      meters:
          - "cpu"
      sinks:
          - cpu_sink
          - cpu_delta_sink

    - name: memory_source
      interval: 600
      meters:
          - "memory.resident"
          - "memory.usage"
      sinks:
          - memory_sink

    - name: health_source
      interval: 600
      meters:
          - "cpu"
          - "memory.resident"
          - "memory.usage"
      sinks:
          - health_sink

/********************************************************//

    - name: cpu_sink
      transformers:
          - name: "rate_of_change"
            parameters:
                target:
                    name: "cpu_util"
                    unit: "%"
                    type: "gauge"
                    scale: "100.0 / (10**9 * (resource_metadata.cpu_number or 1))"
      publishers:
          - notifier://

    - name: memory_sink
      transformers:
          - name: "arithmetic"
            parameters:
                target:
                    name: "memory_util"
                    unit: "%"
                    type: "gauge"
                    expr: "100.0 * $(memory.usage) / $(memory.resident)"
      publishers:
          - notifier://

# This produces cpu_util & memory_util metric properly

    - name: cpu_memory_sink
      transformers:
          - name: "rate_of_change"
            parameters:
                source:
                    map_from:
                        name: cpu
                        unit: "cycles"
                target:
                    map_to:
                        name: "cpu_util_aux"
                        unit: "%"
                    type: "gauge"
                    scale: "100.0 / (10**9 * (resource_metadata.cpu_number or 1))"
          - name: "arithmetic"
            parameters:
                target:
                    name: "memory_util_aux"
                    unit: "%"
                    type: "gauge"
                    expr: "100.0 * $(memory.usage) / $(memory.resident)"
          - name: "arithmetic"
            parameters:
                target:
                    name: "health"
                    unit: "%"
                    type: "gauge"
                    expr: "($(memory_util_aux) + $(cpu_util_aux)) / 2"
      publishers:
          - notifier://


# But when we try to perform multiple transformers like this, the results are incorrect, cpu_util_aux returns similar values to cpu_util, but for memory_util_aux, in most of cases on the ceilometer-agent-compute.log we are seeing this:

# "2016-10-25 12:56:44.007 22075 DEBUG ceilometer.pipeline [-] Pipeline health_sink: Transform sample None from 2 transformer _publish_samples /usr/local/lib/python2.7/dist-packages/ceilometer/pipeline.py:401"

# And in the very few cases it shows some results the values are not the same than memory_util, even negative values are shown:

# 2016-10-25 12:56:44.012 22075 DEBUG ceilometer.pipeline [-] Pipeline health_sink: Transform sample <name: memory_util_aux, volume: -0.0 [..]
# 2016-10-25 12:46:44.179 22075 DEBUG ceilometer.pipeline [-] Pipeline health_sink: Transform sample <name: memory_util_aux, volume: -49.9165275459 [..]
# 2016-10-25 12:36:46.144 22075 DEBUG ceilometer.pipeline [-] Pipeline health_sink: Transform sample <name: memory_util_aux, volume: -550.0 [..]

# For the third transformer we dont get any results, since in most cases we are not getting a proper result in #2 calculating memory_util.

#In the collector we checked the logs, and we always get only the last transformer valid value, in this scenario cpu_util_aux and some memory_util_aux, not both, if 2nd transformer fails we get the 1st transformer, but even if all 3 would run fine only the last one will get in the collector so we are forced to get cpu_util and memory_util in separated sinks.