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nvme_metrics: refactor metrics to better fit the verbose / nested JSON output of nvme-cli #228

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nvme_metrics: refactor metrics to better fit the verbose / nested JSON output of nvme-cli #228

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e016bbb
nvme_metrics: change nvmecli metric type to Info
dswarbrick Nov 19, 2024
4e2c7e1
nvme_metrics: refactor device_info metric as controller_info
dswarbrick Nov 19, 2024
da956a5
nvme_metrics: fetch device global SMART log once per controller
dswarbrick Nov 21, 2024
895fbb1
nvme_metrics: introduce nvme_namespace_info metric
dswarbrick Nov 21, 2024
75f33a7
nvme_metrics: use device label in namespace_info metric
dswarbrick Nov 21, 2024
6df15e5
nvme_metrics: adjust wording of comments
dswarbrick Nov 21, 2024
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197 changes: 101 additions & 96 deletions nvme_metrics.py
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Original file line number Diff line number Diff line change
Expand Up @@ -24,102 +24,109 @@

metrics = {
# fmt: off
"nvmecli": Info(
"nvmecli",
"nvme-cli tool information",
["version"], namespace=namespace, registry=registry,
),

# Controller-specific (e.g. "nvme0") metrics
"avail_spare": Gauge(
"available_spare_ratio",
"Device available spare ratio",
["device"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"controller_busy_time": Counter(
"controller_busy_time_seconds",
"Device controller busy time in seconds",
["device"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"controller_info": Info(
"controller",
"Controller information",
["controller", "model", "firmware", "serial", "transport"], namespace=namespace,
registry=registry,
),
"critical_warning": Gauge(
"critical_warning",
"Device critical warning bitmap field",
["device"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"data_units_read": Counter(
"data_units_read_total",
"Number of 512-byte data units read by host, reported in thousands",
["device"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"data_units_written": Counter(
"data_units_written_total",
"Number of 512-byte data units written by host, reported in thousands",
["device"], namespace=namespace, registry=registry,
),
"device_info": Info(
"device",
"Device information",
["device", "model", "firmware", "serial"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"host_read_commands": Counter(
"host_read_commands_total",
"Device read commands from host",
["device"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"host_write_commands": Counter(
"host_write_commands_total",
"Device write commands from host",
["device"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"media_errors": Counter(
"media_errors_total",
"Device media errors total",
["device"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"num_err_log_entries": Counter(
"num_err_log_entries_total",
"Device error log entry count",
["device"], namespace=namespace, registry=registry,
),
# FIXME: The "nvmecli" metric ought to be an Info type, not a Gauge. However, making this change
# will result in the metric having a "_info" suffix automatically appended, which is arguably
# a breaking change.
"nvmecli": Gauge(
"nvmecli",
"nvme-cli tool information",
["version"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"percent_used": Gauge(
"percentage_used_ratio",
"Device percentage used ratio",
["device"], namespace=namespace, registry=registry,
),
"physical_size": Gauge(
"physical_size_bytes",
"Device size in bytes",
["device"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"power_cycles": Counter(
"power_cycles_total",
"Device number of power cycles",
["device"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"power_on_hours": Counter(
"power_on_hours_total",
"Device power-on hours",
["device"], namespace=namespace, registry=registry,
),
"sector_size": Gauge(
"sector_size_bytes",
"Device sector size in bytes",
["device"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"spare_thresh": Gauge(
"available_spare_threshold_ratio",
"Device available spare threshold ratio",
["device"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"temperature": Gauge(
"temperature_celsius",
"Device temperature in degrees Celsius",
["device"], namespace=namespace, registry=registry,
["controller"], namespace=namespace, registry=registry,
),
"unsafe_shutdowns": Counter(
"unsafe_shutdowns_total",
"Device number of unsafe shutdowns",
["controller"], namespace=namespace, registry=registry,
),

# Namespace-specific (e.g. "nvme0n1") metrics
"namespace_info": Info(
"namespace",
"Namespace information",
["device", "nsid", "controller"], namespace=namespace, registry=registry,
),
"physical_size": Gauge(
"physical_size_bytes",
"Device size in bytes",
["device"], namespace=namespace, registry=registry,
),
"sector_size": Gauge(
"sector_size_bytes",
"Device sector size in bytes",
["device"], namespace=namespace, registry=registry,
),
"used_bytes": Gauge(
Expand Down Expand Up @@ -159,75 +166,73 @@ def main():
cli_version = match.group(1)
else:
cli_version = "unknown"
metrics["nvmecli"].labels(cli_version).set(1)
metrics["nvmecli"].labels(cli_version)

device_list = exec_nvme_json("list")

for device in device_list["Devices"]:
for subsys in device["Subsystems"]:
for ctrl in subsys["Controllers"]:
ctrl_dev = ctrl["Controller"]

metrics["controller_info"].labels(
ctrl_dev,
ctrl["ModelNumber"],
ctrl["Firmware"],
ctrl["SerialNumber"].strip(),
ctrl["Transport"],
)

for ns in ctrl["Namespaces"]:
device_name = ns["NameSpace"]

# FIXME: This metric ought to be refactored into a "controller_info" metric,
# since it contains information that is not unique to the namespace. However,
# previous versions of this collector erroneously referred to namespaces, e.g.
# "nvme0n1", as devices, so preserve the former behaviour for now.
metrics["device_info"].labels(
device_name,
ctrl["ModelNumber"],
ctrl["Firmware"],
ctrl["SerialNumber"].strip(),
)
ns_dev = ns["NameSpace"]

metrics["sector_size"].labels(device_name).set(ns["SectorSize"])
metrics["physical_size"].labels(device_name).set(ns["PhysicalSize"])
metrics["used_bytes"].labels(device_name).set(ns["UsedBytes"])

# FIXME: The smart-log should only need to be fetched once per controller, not
# per namespace. However, in order to preserve legacy metric labels, fetch it
# per namespace anyway. Most consumer grade SSDs will only have one namespace.
smart_log = exec_nvme_json("smart-log", os.path.join("/dev", device_name))

# Various counters in the NVMe specification are 128-bit, which would have to
# discard resolution if converted to a JSON number (i.e., float64_t). Instead,
# nvme-cli marshals them as strings. As such, they need to be explicitly cast
# to int or float when using them in Counter metrics.
metrics["data_units_read"].labels(device_name).inc(
int(smart_log["data_units_read"])
)
metrics["data_units_written"].labels(device_name).inc(
int(smart_log["data_units_written"])
)
metrics["host_read_commands"].labels(device_name).inc(
int(smart_log["host_read_commands"])
)
metrics["host_write_commands"].labels(device_name).inc(
int(smart_log["host_write_commands"])
)
metrics["avail_spare"].labels(device_name).set(smart_log["avail_spare"] / 100)
metrics["spare_thresh"].labels(device_name).set(smart_log["spare_thresh"] / 100)
metrics["percent_used"].labels(device_name).set(smart_log["percent_used"] / 100)
metrics["critical_warning"].labels(device_name).set(
smart_log["critical_warning"]["value"]
)
metrics["media_errors"].labels(device_name).inc(int(smart_log["media_errors"]))
metrics["num_err_log_entries"].labels(device_name).inc(
int(smart_log["num_err_log_entries"])
)
metrics["power_cycles"].labels(device_name).inc(int(smart_log["power_cycles"]))
metrics["power_on_hours"].labels(device_name).inc(
int(smart_log["power_on_hours"])
)
metrics["controller_busy_time"].labels(device_name).inc(
int(smart_log["controller_busy_time"])
)
metrics["unsafe_shutdowns"].labels(device_name).inc(
int(smart_log["unsafe_shutdowns"])
metrics["namespace_info"].labels(
ns_dev,
ns["NSID"],
ctrl_dev,
)

# NVMe reports temperature in kelvins; convert it to degrees Celsius.
metrics["temperature"].labels(device_name).set(smart_log["temperature"] - 273)
metrics["sector_size"].labels(ns_dev).set(ns["SectorSize"])
metrics["physical_size"].labels(ns_dev).set(ns["PhysicalSize"])
metrics["used_bytes"].labels(ns_dev).set(ns["UsedBytes"])

# Most SSDs (perhaps _all_ consumer grade SSDs) only contain a single namespace.
# Fetch the device global SMART log by omitting any --namespace-id flag.
smart_log = exec_nvme_json("smart-log", os.path.join("/dev", ctrl["Controller"]))

# Various counters in the NVMe specification are 128-bit, which would have to
# discard resolution if converted to a JSON number (i.e., float64_t). Instead,
# nvme-cli marshals them as strings. As such, they need to be explicitly cast to int
# or float when using them in Counter metrics.
metrics["data_units_read"].labels(ctrl_dev).inc(int(smart_log["data_units_read"]))
metrics["data_units_written"].labels(ctrl_dev).inc(
int(smart_log["data_units_written"])
)
metrics["host_read_commands"].labels(ctrl_dev).inc(
int(smart_log["host_read_commands"])
)
metrics["host_write_commands"].labels(ctrl_dev).inc(
int(smart_log["host_write_commands"])
)
metrics["avail_spare"].labels(ctrl_dev).set(smart_log["avail_spare"] / 100)
metrics["spare_thresh"].labels(ctrl_dev).set(smart_log["spare_thresh"] / 100)
metrics["percent_used"].labels(ctrl_dev).set(smart_log["percent_used"] / 100)
metrics["critical_warning"].labels(ctrl_dev).set(
smart_log["critical_warning"]["value"]
)
metrics["media_errors"].labels(ctrl_dev).inc(int(smart_log["media_errors"]))
metrics["num_err_log_entries"].labels(ctrl_dev).inc(
int(smart_log["num_err_log_entries"])
)
metrics["power_cycles"].labels(ctrl_dev).inc(int(smart_log["power_cycles"]))
metrics["power_on_hours"].labels(ctrl_dev).inc(int(smart_log["power_on_hours"]))
metrics["controller_busy_time"].labels(ctrl_dev).inc(
int(smart_log["controller_busy_time"])
)
metrics["unsafe_shutdowns"].labels(ctrl_dev).inc(int(smart_log["unsafe_shutdowns"]))

# NVMe reports temperature in kelvins; convert it to degrees Celsius.
metrics["temperature"].labels(ctrl_dev).set(smart_log["temperature"] - 273)


if __name__ == "__main__":
Expand Down