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Measures reported by StormTopSumTest
Spouts and bolts are connected together and they form a topology. Real-time application logic is specified inside Storm topology. In simple words, a topology is a directed graph where vertices are computation and edges are stream of data.
A simple topology starts with spouts. Spout emits the data to one or more bolts. Bolt represents a node in the topology having the smallest processing logic and the output of a bolt can be emitted into another bolt as input. Storm keeps the topology always running, until you kill the topology. Apache Storm’s main job is to run the topology and will run any number of topology at a given time.
This test reports the number of workers, executors and the tasks completed in the topology of the target Apache Storm. Using this test, administrators would be able to identify the status on whether/not the topology is active. Any abnormal condition of the topology will alert the administrators to take preventive action against the abnormal condition.
This test included in the eG agent also monitors the uptime of topology before users start complaining.
Outputs of the test: One set of results for each Topology in the target Apache Storm.
Descriptor: Topology
The measures made by this test are as follows:
| Measurement |
Description |
Measurement Unit |
Interpretation |
| status |
Indicates the status of the topology in the target Apache Storm. |
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The values reported by this measure and its numeric equivalents are mentioned in the table below:
| Measure Value |
Numeric Value |
| Killed |
70 |
| Rebalancing |
80 |
| Inactive |
90 |
| Active |
100 |
Note:
By default, this measure reports the Measure Values listed in the table above to indicate the status of the topology in the target Apache Storm.
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| workersTotal |
Indicates the total number of workers in Storm topology. |
Number |
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| executorsTotal |
Indicates the total number of executors in Storm topology. |
Number |
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| tasksTotal |
Indicates the total number of tasks in Storm topology. |
Number |
A very high value is required for this measure.
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| replicationCount |
Indicates the number of nimbus hosts on which this topology code is replicated. |
Number |
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| requestedTotalMem |
Indicates the size of requested memory for Storm topology. |
MB |
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| assignedTotalMem |
Indicates the size of assigned total memory for Storm topology. |
MB |
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| requestedMemOnHeap |
Indicates the size of requested heap memory for Storm topology. |
MB |
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| assignedMemOnHeap |
Indicates the size of assigned heap memory for Storm topology. |
MB |
As a rule of thumb, there should be enough heap memory to address data processing. If the heap memory is high, then it leads to garbage collection.
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| requestedMemOffHeap |
Indicates the size of requested memory off-heap for Storm topology. |
MB |
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| assignedMemOffHeap |
Indicates the size of assigned memory off-heap for Storm topology. |
MB |
If there is no off-heap memory, then you will be unable to perform the data processing. To avoid this, it would be good practice to allocate adequate off-heap memory.
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| requestedCpu |
Indicates the number of requested CPU core for Storm topology. |
Number |
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| assignedCpu |
Indicates the number of assigned CPU core for Storm topology. |
Number |
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| uptime |
Indicates the time period that the topology has been up since the last time this test ran. |
Hrs/Mins/Secs |
The accuracy of this metric is dependent on the measurement period - the smaller the measurement period, greater the accuracy.
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