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in_mem_metrics: initial documentation. #1170

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in_mem_metrics: initial documentation.
pwhelan Jul 26, 2023
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Update pipeline/inputs/mem-metrics.md
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# Memory metrics

The _mem_metrics_, or memory metrics plugin, generates metrics for memory statistics for processes using the `smaps_rollup` file for each process in /proc. This plugin works exclusively on Linux.

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[FluentBit.Spelling] Spelling check: 'mem_metrics'?

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{"message": "[FluentBit.Spelling] Spelling check: 'mem_metrics'?", "location": {"path": "pipeline/inputs/mem-metrics.md", "range": {"start": {"line": 3, "column": 6}}}, "severity": "INFO"}

# Configuration parameters
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[markdownlint] reported by reviewdog 🐶
MD025/single-title/single-h1 Multiple top-level headings in the same document [Context: "# Configuration parameters"]


| **Key*** | Description | Default |
| :------------ | :------------------------------------------------- | :----------- |
| `proc_path` | The path of the proc pseudo filesystem. | `/proc` |
| `filter_exec` | Filter for a single executable by path. | **inactive** |
| `filter_cmd` | Filter by command line. | **inactive** |
| `filter_pid` | Filter by comma delimited list of PIDs. | **inactive** |

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{"message": "[FluentBit.Spelling] Spelling check: 'PIDs'?", "location": {"path": "pipeline/inputs/mem-metrics.md", "range": {"start": {"line": 12, "column": 55}}}, "severity": "INFO"}
| `interval_sec` | Set the interval seconds between events generation. | `5` |
| `interval_nsec` | Set the nanoseconds interval (sub seconds). | `0` |

The `filter_pid` can include or be set to either `0` or `self` to refer to the fluent-bit process itself.

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{"message": "[FluentBit.FluentBitCasing] Use the proper noun 'Fluent Bit' with correct casing and spacing.", "location": {"path": "pipeline/inputs/mem-metrics.md", "range": {"start": {"line": 16, "column": 80}}}, "severity": "WARNING"}

## Getting Started

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[FluentBit.Headings] 'Getting Started' should use sentence-style capitalization.

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{"message": "[FluentBit.Headings] 'Getting Started' should use sentence-style capitalization.", "location": {"path": "pipeline/inputs/mem-metrics.md", "range": {"start": {"line": 18, "column": 4}}}, "severity": "INFO"}

You can run the plugin from the command line or through a configuration file. By default metrics will be generated for all processes the current user can analyze.

### Command Line

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[FluentBit.Headings] 'Command Line' should use sentence-style capitalization.

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{"message": "[FluentBit.Headings] 'Command Line' should use sentence-style capitalization.", "location": {"path": "pipeline/inputs/mem-metrics.md", "range": {"start": {"line": 22, "column": 5}}}, "severity": "INFO"}

```bash
$ fluent-bit -i mem_metrics -o stdout
Fluent Bit v2.1.8
* Copyright (C) 2015-2022 The Fluent Bit Authors
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

2023-07-26T14:37:49.919778443Z node_smaps_rollup_rss{pid="4540"} = 21064
2023-07-26T14:37:49.919778443Z node_smaps_rollup_pss{pid="4540",type="clean"} = 9598
2023-07-26T14:37:49.919778443Z node_smaps_rollup_pss{pid="4540",type="dirty"} = 5998
2023-07-26T14:37:49.919778443Z node_smaps_rollup_pss{pid="4540",type="anon"} = 5996
2023-07-26T14:37:49.919778443Z node_smaps_rollup_pss{pid="4540",type="file"} = 3602
2023-07-26T14:37:49.919778443Z node_smaps_rollup_pss{pid="4540",type="shmem"} = 0
2023-07-26T14:37:49.919778443Z node_smaps_rollup_shared{pid="4540",type="clean"} = 15008
2023-07-26T14:37:49.919778443Z node_smaps_rollup_shared{pid="4540",type="dirty"} = 4
2023-07-26T14:37:49.919778443Z node_smaps_rollup_private{pid="4540",type="clean"} = 56
2023-07-26T14:37:49.919778443Z node_smaps_rollup_private{pid="4540",type="dirty"} = 5996
2023-07-26T14:37:49.919778443Z node_smaps_rollup_referenced{pid="4540"} = 21064
2023-07-26T14:37:49.919778443Z node_smaps_rollup_anonymous{pid="4540"} = 5996
2023-07-26T14:37:49.919778443Z node_smaps_rollup_lazy_free{pid="4540"} = 0
2023-07-26T14:37:49.919778443Z node_smaps_rollup_anon_huge_pages{pid="4540"} = 0
2023-07-26T14:37:49.919778443Z node_smaps_rollup_shmem_pmd_mapped{pid="4540"} = 0
2023-07-26T14:37:49.919778443Z node_smaps_rollup_file_pmd_mapped{pid="4540"} = 0
2023-07-26T14:37:49.919778443Z node_smaps_rollup_shared_hugetlb{pid="4540"} = 0
2023-07-26T14:37:49.919778443Z node_smaps_rollup_private_hugetlb{pid="4540"} = 0
2023-07-26T14:37:49.919778443Z node_smaps_rollup_swap{pid="4540"} = 0
2023-07-26T14:37:49.919778443Z node_smaps_rollup_swap_pss{pid="4540"} = 0
2023-07-26T14:37:49.919778443Z node_smaps_rollup_locked{pid="4540"} = 0
```

### Configuration File

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{"message": "[FluentBit.Headings] 'Configuration File' should use sentence-style capitalization.", "location": {"path": "pipeline/inputs/mem-metrics.md", "range": {"start": {"line": 54, "column": 5}}}, "severity": "INFO"}

Minimal pipeline for logging memory metrics to the console:

```ini
[INPUT]
Name mem_metrics
Tag mem

[OUTPUT]
Name stdout
Match mem
```

Log all instances of fluent-bit to prometheus:

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{"message": "[FluentBit.Spelling] Spelling check: 'prometheus'?", "location": {"path": "pipeline/inputs/mem-metrics.md", "range": {"start": {"line": 68, "column": 36}}}, "severity": "INFO"}

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[FluentBit.FluentBitCasing] Use the proper noun 'Fluent Bit' with correct casing and spacing.

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{"message": "[FluentBit.FluentBitCasing] Use the proper noun 'Fluent Bit' with correct casing and spacing.", "location": {"path": "pipeline/inputs/mem-metrics.md", "range": {"start": {"line": 68, "column": 22}}}, "severity": "WARNING"}

```ini
[INPUT]
Name mem_metrics
Filter_cmd fluent-bit
Tag mem

[OUTPUT]
Name prometheus_remote_write
Match mem
Host localhost
Port 9090
Uri /prometheus/v1/write?prometheus_server=mem
```

### Exposed Metrics

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{"message": "[FluentBit.Headings] 'Exposed Metrics' should use sentence-style capitalization.", "location": {"path": "pipeline/inputs/mem-metrics.md", "range": {"start": {"line": 84, "column": 5}}}, "severity": "INFO"}

All metrics are logged as gauges since they can both increase and decrease. Currenrtly supported gauges are:

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* node_smaps_rollup_rss
* node_smaps_rollup_pss
* type=clean
* type=dirty
* type=anon
* type=file
* type=shmem
* node_smaps_rollup_shared
* type=clean
* type=dirty
* node_smaps_rollup_private
* type=dirty
* type=clean
* node_smaps_rollup_referenced
* node_smaps_rollup_anonymous
* node_smaps_rollup_lazy_free
* node_smaps_rollup_anon_huge_pages
* node_smaps_rollup_shmem_pmd_mapped
* node_smaps_rollup_file_pmd_mapped
* node_smaps_rollup_shared_hugetlb
* node_smaps_rollup_private_hugetlb
* node_smaps_rollup_swap
* node_smaps_rollup_swap_pss
* node_smaps_rollup_locked
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