Loki
Deliver log event data to the Loki aggregation system
Configuration
Example configurations
{
"sinks": {
"my_sink_id": {
"type": "loki",
"inputs": [
"my-source-or-transform-id"
],
"endpoint": "http://localhost:3100",
"labels": {
"forwarder": "vector",
"event": "{{ event_field }}",
"key": "value",
"\"{{ event_field }}\"": "{{ another_event_field }}",
"pod_labels_*": "{{ kubernetes.pod_labels }}"
},
"acknowledgements": null,
"compression": "none",
"encoding": {
"codec": "json"
},
"healthcheck": null
}
}
}
[sinks.my_sink_id]
type = "loki"
inputs = [ "my-source-or-transform-id" ]
endpoint = "http://localhost:3100"
compression = "none"
[sinks.my_sink_id.labels]
forwarder = "vector"
event = "{{ event_field }}"
key = "value"
"\"{{ event_field }}\"" = "{{ another_event_field }}"
"pod_labels_*" = "{{ kubernetes.pod_labels }}"
[sinks.my_sink_id.encoding]
codec = "json"
---
sinks:
my_sink_id:
type: loki
inputs:
- my-source-or-transform-id
endpoint: http://localhost:3100
labels:
forwarder: vector
event: "{{ event_field }}"
key: value
"\"{{ event_field }}\"": "{{ another_event_field }}"
pod_labels_*: "{{ kubernetes.pod_labels }}"
acknowledgements: null
compression: none
encoding:
codec: json
healthcheck: null
{
"sinks": {
"my_sink_id": {
"type": "loki",
"inputs": [
"my-source-or-transform-id"
],
"endpoint": "http://localhost:3100",
"auth": null,
"labels": {
"forwarder": "vector",
"event": "{{ event_field }}",
"key": "value",
"\"{{ event_field }}\"": "{{ another_event_field }}",
"pod_labels_*": "{{ kubernetes.pod_labels }}"
},
"out_of_order_action": "drop",
"remove_label_fields": null,
"remove_timestamp": true,
"buffer": null,
"acknowledgements": null,
"batch": null,
"compression": "none",
"encoding": {
"codec": "json"
},
"healthcheck": null,
"request": null,
"tls": null,
"proxy": null,
"tenant_id": "some_tenant_id"
}
}
}
[sinks.my_sink_id]
type = "loki"
inputs = [ "my-source-or-transform-id" ]
endpoint = "http://localhost:3100"
out_of_order_action = "drop"
remove_timestamp = true
compression = "none"
tenant_id = "some_tenant_id"
[sinks.my_sink_id.labels]
forwarder = "vector"
event = "{{ event_field }}"
key = "value"
"\"{{ event_field }}\"" = "{{ another_event_field }}"
"pod_labels_*" = "{{ kubernetes.pod_labels }}"
[sinks.my_sink_id.encoding]
codec = "json"
---
sinks:
my_sink_id:
type: loki
inputs:
- my-source-or-transform-id
endpoint: http://localhost:3100
auth: null
labels:
forwarder: vector
event: "{{ event_field }}"
key: value
"\"{{ event_field }}\"": "{{ another_event_field }}"
pod_labels_*: "{{ kubernetes.pod_labels }}"
out_of_order_action: drop
remove_label_fields: null
remove_timestamp: true
buffer: null
acknowledgements: null
batch: null
compression: none
encoding:
codec: json
healthcheck: null
request: null
tls: null
proxy: null
tenant_id: some_tenant_id
acknowledgements
common optional objectacknowledgement
settings.acknowledgements.enabled
optional boolfalse
auth
optional objectauth.password
optional string literalauth.strategy
optional string literal enumOption | Description |
---|---|
basic | The basic authentication strategy. |
bearer | The bearer token authentication strategy. |
auth.token
optional string literalauth.user
optional string literalbatch
optional objectbatch.max_bytes
optional uintbatch.max_events
optional uintbatch.timeout_secs
optional float1
(seconds)buffer
optional objectbuffer.max_events
optional uinttype = "memory"
500
(events)buffer.type
optional string literal enumOption | Description |
---|---|
disk | Stores the sink’s buffer on disk. This is less performant, but durable. Data will not be lost between restarts. Will also hold data in memory to enhance performance. WARNING: This may stall the sink if disk performance isn’t on par with the throughput. For comparison, AWS gp2 volumes are usually too slow for common cases. |
memory | Stores the sink’s buffer in memory. This is more performant, but less durable. Data will be lost if Vector is restarted forcefully. |
memory
buffer.when_full
optional string literal enumOption | Description |
---|---|
block | Applies back pressure when the buffer is full. This prevents data loss, but will cause data to pile up on the edge. |
drop_newest | Drops new data as it’s received. This data is lost. This should be used when performance is the highest priority. |
block
compression
common optional string literal enumThe compression strategy used to compress the encoded event data before transmission.
Some cloud storage API clients and browsers will handle decompression transparently, so files may not always appear to be compressed depending how they are accessed.
Option | Description |
---|---|
gzip | Gzip standard DEFLATE compression. |
none | No compression. |
none
encoding
required objectConfigures the encoding specific sink behavior.
Note: When data in encoding
is malformed, currently only a very generic error “data did not match any variant of untagged enum EncodingConfig” is reported. Follow this issue to track progress on improving these error messages.
encoding.codec
optional string literal enumOption | Description |
---|---|
json | JSON encoded event. |
logfmt | logfmt encoded event. |
text | The message field from the event. |
encoding.except_fields
optional [string]encoding.only_fields
optional [string]encoding.timestamp_format
optional string literal enumOption | Description |
---|---|
rfc3339 | Formats as a RFC3339 string |
unix | Formats as a unix timestamp |
rfc3339
endpoint
required string literal/loki/api/v1/push
to this.inputs
required [string]A list of upstream source or transform
IDs. Wildcards (*
) are supported.
See configuration for more info.
labels
required objectA set of labels that are attached to each batch of events. Both keys and values are templatable, which enables you to attach dynamic labels to events. Labels can be suffixed with a “*” to allow the expansion of objects into multiple labels, see “How it works” for more information.
Note: If the set of labels has high cardinality, this can cause drastic performance issues with Loki. To prevent this from happening, reduce the number of unique label keys and values.
labels.*
optional string templateout_of_order_action
optional string literal enumOption | Description |
---|---|
accept | Don’t do anything, send events into Loki normally (needs Loki 2.4.0 and newer) |
drop | Drop the event. |
rewrite_timestamp | Rewrite timestamp of the event to the latest timestamp that was pushed. |
drop
proxy
optional objectproxy.http
optional string literalproxy.https
optional string literalproxy.no_proxy
optional [string]A list of hosts to avoid proxying. Allowed patterns here include:
Pattern | Example match |
---|---|
Domain names | example.com matches requests to example.com |
Wildcard domains | .example.com matches requests to example.com and its subdomains |
IP addresses | 127.0.0.1 matches requests to 127.0.0.1 |
CIDR blocks | 192.168.0.0./16 matches requests to any IP addresses in this range |
Splat | * matches all hosts |
remove_label_fields
optional booltrue
then when labels are collected from events those fields will also get removed from the event.false
remove_timestamp
optional booltrue
then the timestamp will be removed from the event payload. Note the event timestamp will still be sent as metadata to Loki for indexing.true
request
optional objectrequest.adaptive_concurrency
optional objectrequest.adaptive_concurrency.decrease_ratio
optional float0.9
request.adaptive_concurrency.ewma_alpha
optional float0.7
request.adaptive_concurrency.rtt_deviation_scale
optional float2
request.concurrency
optional uintrequest.rate_limit_duration_secs
optional uintrate_limit_num
option.1
(seconds)request.rate_limit_num
optional uintrate_limit_duration_secs
time window.9.223372036854776e+18
request.retry_attempts
optional uint1.8446744073709552e+19
request.retry_initial_backoff_secs
optional uint1
(seconds)request.retry_max_duration_secs
optional uint3600
(seconds)request.timeout_secs
optional uint60
(seconds)tenant_id
optional string templateThe tenant id that’s sent with every request, by default this is not required since a proxy should set this header. When running Loki locally a tenant id is not required either.
You can read more about tenant id’s here.
tls
optional objecttls.ca_file
optional string literaltls.crt_file
optional string literalkey_file
must also be set.tls.key_file
optional string literalcrt_file
must also be set.tls.key_pass
optional string literalkey_file
is set.tls.verify_certificate
optional booltrue
(the default), Vector will validate the TLS certificate of the remote host.true
tls.verify_hostname
optional booltrue
(the default), Vector will validate the configured remote host name against the remote host’s TLS certificate. Do NOT set this to false
unless you understand the risks of not verifying the remote hostname.true
Telemetry
Metrics
linkbuffer_byte_size
gaugecomponent_id
instead. The value is the same as component_id
.buffer_discarded_events_total
countercomponent_id
instead. The value is the same as component_id
.buffer_events
gaugecomponent_id
instead. The value is the same as component_id
.buffer_received_event_bytes_total
countercomponent_id
instead. The value is the same as component_id
.buffer_received_events_total
countercomponent_id
instead. The value is the same as component_id
.buffer_sent_event_bytes_total
countercomponent_id
instead. The value is the same as component_id
.buffer_sent_events_total
countercomponent_id
instead. The value is the same as component_id
.component_received_event_bytes_total
countercomponent_id
instead. The value is the same as component_id
.component_received_events_count
histogramcomponent_id
instead. The value is the same as component_id
.component_received_events_total
countercomponent_id
instead. The value is the same as component_id
.component_sent_bytes_total
countercomponent_id
instead. The value is the same as component_id
.component_sent_event_bytes_total
countercomponent_id
instead. The value is the same as component_id
.component_sent_events_total
countercomponent_id
instead. The value is the same as component_id
.events_discarded_total
counterevents_in_total
countercomponent_received_events_total
instead.component_id
instead. The value is the same as component_id
.events_out_total
countercomponent_sent_events_total
instead.component_id
instead. The value is the same as component_id
.processed_bytes_total
countercomponent_id
instead. The value is the same as component_id
.processing_errors_total
countercomponent_id
instead. The value is the same as component_id
.streams_total
countercomponent_id
instead. The value is the same as component_id
.utilization
gaugecomponent_id
instead. The value is the same as component_id
.How it works
Buffers and batches
This component buffers & batches data as shown in the diagram above. You’ll notice that Vector treats these concepts differently, instead of treating them as global concepts, Vector treats them as sink specific concepts. This isolates sinks, ensuring services disruptions are contained and delivery guarantees are honored.
Batches are flushed when 1 of 2 conditions are met:
- The batch age meets or exceeds the configured
timeout_secs
. - The batch size meets or exceeds the configured
max_bytes
ormax_events
.
Buffers are controlled via the buffer.*
options.
Decentralized Deployments
Event Ordering
loki
sink will ensure that all logs are sorted via
their timestamp
. This is to ensure that logs will be
accepted by Loki. If no timestamp is supplied with events
then the Loki sink will supply its own monotonically
increasing timestamp.Health checks
Require health checks
If you’d like to exit immediately upon a health check failure, you can pass the
--require-healthy
flag:
vector --config /etc/vector/vector.toml --require-healthy
Disable health checks
healthcheck
option to
false
.Label Expansion
The labels
option can be passed keys suffixed with “*” to
allow for setting multiple keys based on the contents of an
object. For example, with an object:
{"kubernetes":{"pod_labels":{"app":"web-server","name":"unicorn"}}}
and a configuration:
[sinks.my_sink_id.labels]
pod_labels_*: "{{ kubernetes.pod_labels }}"
This would expand into two labels:
pod_labels_app: web-server
pod_labels_name: unicorn
Partitioning
Vector supports dynamic configuration values through a simple template syntax. If an option supports templating, it will be noted with a badge and you can use event fields to create dynamic values. For example:
[sinks.my-sink]
dynamic_option = "application={{ application_id }}"
In the above example, the application_id
for each event will be
used to partition outgoing data.
Rate limits & adaptive concurrency
Adaptive Request Concurrency (ARC)
Adaptive Request Concurrency is a feature of Vector that does away with static concurrency limits and automatically optimizes HTTP concurrency based on downstream service responses. The underlying mechanism is a feedback loop inspired by TCP congestion control algorithms. Checkout the announcement blog post,
We highly recommend enabling this feature as it improves performance and reliability of Vector and the systems it communicates with. As such, we have made it the default, and no further configuration is required.
Static concurrency
If Adaptive Request Concurrency is not for you, you can manually set static concurrency
limits by specifying an integer for request.concurrency
:
[sinks.my-sink]
request.concurrency = 10
Rate limits
In addition to limiting request concurrency, you can also limit the overall request
throughput via the request.rate_limit_duration_secs
and request.rate_limit_num
options.
[sinks.my-sink]
request.rate_limit_duration_secs = 1
request.rate_limit_num = 10
These will apply to both adaptive
and fixed request.concurrency
values.