Internal telemetry
You can monitor the health of any OpenTelemetry Collector instance by checking its own internal telemetry. Read on to learn about this telemetry and how to configure it to help you troubleshoot Collector issues.
Activate internal telemetry in the Collector
By default, the Collector exposes its own telemetry in two ways:
- Internal metrics are exposed using a Prometheus
interface which defaults to port
8888
. - Logs are emitted to
stderr
by default.
Configure internal metrics
You can configure how internal metrics are generated and exposed by the
Collector. By default, the Collector generates basic metrics about itself and
exposes them for scraping at http://127.0.0.1:8888/metrics
. You can expose the
endpoint to one specific or all network interfaces when needed. For
containerized environments, you might want to expose this port on a public
interface.
Set the address in the config service::telemetry::metrics
:
service:
telemetry:
metrics:
address: 0.0.0.0:8888
You can adjust the verbosity of the Collector metrics output by setting the
level
field to one of the following values:
none
: no telemetry is collected.basic
: essential service telemetry.normal
: the default level, adds standard indicators on top of basic.detailed
: the most verbose level, includes dimensions and views.
Each verbosity level represents a threshold at which certain metrics are emitted. For the complete list of metrics, with a breakdown by level, see Lists of internal metrics.
The default level for metrics output is normal
. To use another level, set
service::telemetry::metrics::level
:
service:
telemetry:
metrics:
level: detailed
The Collector can also be configured to scrape its own metrics using a Prometheus receiver and send them through configured pipelines. For example:
receivers:
prometheus:
config:
scrape_configs:
- job_name: 'otelcol'
scrape_interval: 10s
static_configs:
- targets: ['0.0.0.0:8888']
metric_relabel_configs:
- source_labels: [__name__]
regex: '.*grpc_io.*'
action: drop
exporters:
debug:
service:
pipelines:
metrics:
receivers: [prometheus]
exporters: [debug]
Caution
When self-monitoring, the Collector collects its own telemetry and sends it to the desired backend for analysis. This can be a risky practice. If the Collector is underperforming, its self-monitoring capability could be impacted. As a result, the self-monitored telemetry might not reach the backend in time for critical analysis.Configure internal logs
Log output is found in stderr
. You can configure logs in the config
service::telemetry::logs
. The configuration
options are:
Field name | Default value | Description |
---|---|---|
level | INFO | Sets the minimum enabled logging level. Other possible values are DEBUG , WARN , and ERROR . |
development | false | Puts the logger in development mode. |
encoding | console | Sets the logger’s encoding. The other possible value is json . |
disable_caller | false | Stops annotating logs with the calling function’s file name and line number. By default, all logs are annotated. |
disable_stacktrace | false | Disables automatic stacktrace capturing. Stacktraces are captured for logs at WARN level and above in development and at ERROR level and above in production. |
sampling::enabled | true | Sets a sampling policy. |
sampling::tick | 10s | The interval in seconds that the logger applies to each sampling. |
sampling::initial | 10 | The number of messages logged at the start of each sampling::tick . |
sampling::thereafter | 100 | Sets the sampling policy for subsequent messages after sampling::initial messages are logged. When sampling::thereafter is set to N , every Nth message is logged and all others are dropped. If N is zero, the logger drops all messages after sampling::initial messages are logged. |
output_paths | ["stderr"] | A list of URLs or file paths to write logging output to. |
error_output_paths | ["stderr"] | A list of URLs or file paths to write logger errors to. |
initial_fields | A collection of static key-value pairs added to all log entries to enrich logging context. By default, there is no initial field. |
You can also see logs for the Collector on a Linux systemd system using
journalctl
:
journalctl | grep otelcol
journalctl | grep otelcol | grep Error
Types of internal observability
The OpenTelemetry Collector aims to be a model of observable service by clearly exposing its own operational metrics. Additionally, it collects host resource metrics that can help you understand if problems are caused by a different process on the same host. Specific components of the Collector can also emit their own custom telemetry. In this section, you will learn about the different types of observability emitted by the Collector itself.
Values observable with internal metrics
The Collector emits internal metrics for the following current values:
- Resource consumption, including CPU, memory, and I/O.
- Data reception rate, broken down by receiver.
- Data export rate, broken down by exporters.
- Data drop rate due to throttling, broken down by data type.
- Data drop rate due to invalid data received, broken down by data type.
- Throttling state, including Not Throttled, Throttled by Downstream, and Internally Saturated.
- Incoming connection count, broken down by receiver.
- Incoming connection rate showing new connections per second, broken down by receiver.
- In-memory queue size in bytes and in units.
- Persistent queue size.
- End-to-end latency from receiver input to exporter output.
- Latency broken down by pipeline elements, including exporter network roundtrip latency for request/response protocols.
Rate values are averages over 10 second periods, measured in bytes/sec or units/sec (for example, spans/sec).
Caution
Byte measurements can be expensive to compute.The Collector also emits internal metrics for these cumulative values:
- Total received data, broken down by receivers.
- Total exported data, broken down by exporters.
- Total dropped data due to throttling, broken down by data type.
- Total dropped data due to invalid data received, broken down by data type.
- Total incoming connection count, broken down by receiver.
- Uptime since start.
Lists of internal metrics
The following tables group each internal metric by level of verbosity: basic
,
normal
, and detailed
. Each metric is identified by name and description and
categorized by instrumentation type.
basic
-level metrics
Metric name | Description | Type |
---|---|---|
otelcol_exporter_enqueue_failed_ log_records | Number of spans that exporter(s) failed to enqueue. | Counter |
otelcol_exporter_enqueue_failed_ metric_points | Number of metric points that exporter(s) failed to enqueue. | Counter |
otelcol_exporter_enqueue_failed_ spans | Number of spans that exporter(s) failed to enqueue. | Counter |
otelcol_exporter_queue_capacity | Fixed capacity of the retry queue, in batches. | Gauge |
otelcol_exporter_queue_size | Current size of the retry queue, in batches. | Gauge |
otelcol_exporter_send_failed_ log_records | Number of logs that exporter(s) failed to send to destination. | Counter |
otelcol_exporter_send_failed_ metric_points | Number of metric points that exporter(s) failed to send to destination. | Counter |
otelcol_exporter_send_failed_ spans | Number of spans that exporter(s) failed to send to destination. | Counter |
otelcol_exporter_sent_log_records | Number of logs successfully sent to destination. | Counter |
otelcol_exporter_sent_metric_points | Number of metric points successfully sent to destination. | Counter |
otelcol_exporter_sent_spans | Number of spans successfully sent to destination. | Counter |
otelcol_process_cpu_seconds | Total CPU user and system time in seconds. | Counter |
otelcol_process_memory_rss | Total physical memory (resident set size). | Gauge |
otelcol_process_runtime_heap_ alloc_bytes | Bytes of allocated heap objects (see ‘go doc runtime.MemStats.HeapAlloc’). | Gauge |
otelcol_process_runtime_total_ alloc_bytes | Cumulative bytes allocated for heap objects (see ‘go doc runtime.MemStats.TotalAlloc’). | Counter |
otelcol_process_runtime_total_ sys_memory_bytes | Total bytes of memory obtained from the OS (see ‘go doc runtime.MemStats.Sys’). | Gauge |
otelcol_process_uptime | Uptime of the process. | Counter |
otelcol_processor_accepted_ log_records | Number of logs successfully pushed into the next component in the pipeline. | Counter |
otelcol_processor_accepted_ metric_points | Number of metric points successfully pushed into the next component in the pipeline. | Counter |
otelcol_processor_accepted_spans | Number of spans successfully pushed into the next component in the pipeline. | Counter |
otelcol_processor_batch_batch_ send_size_bytes | Number of bytes in the batch that was sent. | Histogram |
otelcol_processor_dropped_ log_records | Number of logs dropped by the processor. | Counter |
otelcol_processor_dropped_ metric_points | Number of metric points dropped by the processor. | Counter |
otelcol_processor_dropped_spans | Number of spans dropped by the processor. | Counter |
otelcol_receiver_accepted_ log_records | Number of logs successfully ingested and pushed into the pipeline. | Counter |
otelcol_receiver_accepted_ metric_points | Number of metric points successfully ingested and pushed into the pipeline. | Counter |
otelcol_receiver_accepted_spans | Number of spans successfully ingested and pushed into the pipeline. | Counter |
otelcol_receiver_refused_ log_records | Number of logs that could not be pushed into the pipeline. | Counter |
otelcol_receiver_refused_ metric_points | Number of metric points that could not be pushed into the pipeline. | Counter |
otelcol_receiver_refused_spans | Number of spans that could not be pushed into the pipeline. | Counter |
otelcol_scraper_errored_ metric_points | Number of metric points the Collector failed to scrape. | Counter |
otelcol_scraper_scraped_ metric_points | Number of metric points scraped by the Collector. | Counter |
Additional normal
-level metrics
Metric name | Description | Type |
---|---|---|
otelcol_processor_batch_batch_ send_size | Number of units in the batch. | Histogram |
otelcol_processor_batch_batch_ size_trigger_send | Number of times the batch was sent due to a size trigger. | Counter |
otelcol_processor_batch_metadata_ cardinality | Number of distinct metadata value combinations being processed. | Counter |
otelcol_processor_batch_timeout_ trigger_send | Number of times the batch was sent due to a timeout trigger. | Counter |
Additional detailed
-level metrics
Metric name | Description | Type |
---|---|---|
http_client_active_requests | Number of active HTTP client requests. | Counter |
http_client_connection_duration | Measures the duration of the successfully established outbound HTTP connections. | Histogram |
http_client_open_connections | Number of outbound HTTP connections that are active or idle on the client. | Counter |
http_client_request_body_size | Measures the size of HTTP client request bodies. | Histogram |
http_client_request_duration | Measures the duration of HTTP client requests. | Histogram |
http_client_response_body_size | Measures the size of HTTP client response bodies. | Histogram |
http_server_active_requests | Number of active HTTP server requests. | Counter |
http_server_request_body_size | Measures the size of HTTP server request bodies. | Histogram |
http_server_request_duration | Measures the duration of HTTP server requests. | Histogram |
http_server_response_body_size | Measures the size of HTTP server response bodies. | Histogram |
rpc_client_duration | Measures the duration of outbound RPC. | Histogram |
rpc_client_request_size | Measures the size of RPC request messages (uncompressed). | Histogram |
rpc_client_requests_per_rpc | Measures the number of messages received per RPC. Should be 1 for all non-streaming RPCs. | Histogram |
rpc_client_response_size | Measures the size of RPC response messages (uncompressed). | Histogram |
rpc_client_responses_per_rpc | Measures the number of messages sent per RPC. Should be 1 for all non-streaming RPCs. | Histogram |
rpc_server_duration | Measures the duration of inbound RPC. | Histogram |
rpc_server_request_size | Measures the size of RPC request messages (uncompressed). | Histogram |
rpc_server_requests_per_rpc | Measures the number of messages received per RPC. Should be 1 for all non-streaming RPCs. | Histogram |
rpc_server_response_size | Measures the size of RPC response messages (uncompressed). | Histogram |
rpc_server_responses_per_rpc | Measures the number of messages sent per RPC. Should be 1 for all non-streaming RPCs. | Histogram |
Events observable with internal logs
The Collector logs the following internal events:
- A Collector instance starts or stops.
- Data dropping begins due to throttling for a specified reason, such as local saturation, downstream saturation, downstream unavailable, etc.
- Data dropping due to throttling stops.
- Data dropping begins due to invalid data. A sample of the invalid data is included.
- Data dropping due to invalid data stops.
- A crash is detected, differentiated from a clean stop. Crash data is included if available.