elasticsearch sink

Batches `log` events to Elasticsearch via the `_bulk` API endpoint.

The elasticsearch sink is in beta. Please see the current enhancements and bugs for known issues. We kindly ask that you add any missing issues as it will help shape the roadmap of this component.

The elasticsearch sink batches log events to Elasticsearch via the _bulk API endpoint.

Config File

vector.toml (example)
vector.toml (schema)
vector.toml (specification)
# REQUIRED - General
type = "elasticsearch" # must be: "elasticsearch"
inputs = ["my-source-id"]
host = ""
# OPTIONAL - General
doc_type = "_doc" # default
healthcheck = true # default
index = "vector-%Y-%m-%d"
# OPTIONAL - Batching
batch_size = 10490000 # default, bytes
batch_timeout = 1 # default, seconds
# OPTIONAL - Requests
rate_limit_duration = 1 # default, seconds
rate_limit_num = 5 # default
request_in_flight_limit = 5 # default
request_timeout_secs = 60 # default, seconds
retry_attempts = 5 # default
retry_backoff_secs = 5 # default, seconds
# OPTIONAL - Basic auth
password = "password"
user = "username"
# OPTIONAL - Buffer
type = "memory" # default, enum: "memory" or "disk"
when_full = "block" # default, enum: "block" or "drop_newest"
max_size = 104900000 # no default, bytes, relevant when type = "disk"
num_items = 500 # default, events, relevant when type = "memory"
# OPTIONAL - Headers
X-Powered-By = "Vector"
# OPTIONAL - Query
X-Powered-By = "Vector"





REQUIRED - General



The component type required must be: "elasticsearch"



A list of upstream source or transform IDs. See Config Composition for more info. required example: ["my-source-id"]



The host of your Elasticsearch cluster. This should be the full URL as shown in the example. required example: ""

OPTIONAL - General



The doc_type for your index data. This is only relevant for Elasticsearch <= 6.X. If you are using >= 7.0 you do not need to set this option since Elasticsearch has removed it. default: "_doc"



Enables/disables the sink healthcheck upon start. See Health Checks for more info. default: true



Index name to write events to.This option supports dynamic values via Vector's template syntax. See Template Syntax for more info. default: "vector-%F"

OPTIONAL - Batching



The maximum size of a batch before it is flushed. See Buffers & Batches for more info. default: 10490000 unit: bytes



The maximum age of a batch before it is flushed. See Buffers & Batches for more info. default: 1 unit: seconds

OPTIONAL - Requests



The window used for the request_rate_limit_num option See Rate Limits for more info. default: 1 unit: seconds



The maximum number of requests allowed within the rate_limit_duration window. See Rate Limits for more info. default: 5



The maximum number of in-flight requests allowed at any given time. See Rate Limits for more info. default: 5



The maximum time a request can take before being aborted. See Timeouts for more info. default: 60 unit: seconds



The maximum number of retries to make for failed requests. See Retry Policy for more info. default: 5



The amount of time to wait before attempting a failed request again. See Retry Policy for more info. default: 5 unit: seconds

OPTIONAL - Basic auth



The basic authentication password. required example: "password"



The basic authentication user name. required example: "username"




The buffer's type / location. disk buffers are persistent and will be retained between restarts. default: "memory" enum: "memory" or "disk"



The behavior when the buffer becomes full. default: "block" enum: "block" or "drop_newest"



The maximum size of the buffer on the disk. Only relevant when type = "disk" no default example: 104900000 unit: bytes



The maximum number of events allowed in the buffer. Only relevant when type = "memory" default: 500 unit: events

OPTIONAL - Headers



A custom header to be added to each outgoing Elasticsearch request. required example: (see above)




A custom parameter to be added to each Elasticsearch request. required example: (see above)


The elasticsearch sink batches log up to the batch_size or batch_timeout options. When flushed, Vector will write to Elasticsearch via the _bulk API endpoint. The encoding is dictated by the encoding option. For example:

POST <host>/_bulk HTTP/1.1
Host: <host>
Content-Type: application/x-ndjson
Content-Length: 654
{ "index" : { "_index" : "<index>" } }
{"timestamp": 1557932537, "message": "GET /roi/evolve/embrace/transparent", "host": "Stracke8362", "process_id": 914, "remote_addr": "", "response_code": 504, "bytes": 29763}
{ "index" : { "_index" : "<index>" } }
{"timestamp": 1557933548, "message": "PUT /value-added/b2b", "host": "Wiza2458", "process_id": 775, "remote_addr": "", "response_code": 503, "bytes": 9468}
{ "index" : { "_index" : "<index>" } }
{"timestamp": 1557933742, "message": "DELETE /reinvent/interfaces", "host": "Herman3087", "process_id": 775, "remote_addr": "", "response_code": 503, "bytes": 9700}

How It Works

Buffers & Batches

The elasticsearch sink 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.

Buffers types

The buffer.type option allows you to control buffer resource usage:




Pros: Fast. Cons: Not persisted across restarts. Possible data loss in the event of a crash. Uses more memory.


Pros: Persisted across restarts, durable. Uses much less memory. Cons: Slower, see below.

Buffer overflow

The buffer.when_full option allows you to control the behavior when the buffer overflows:




Applies back pressure until the buffer makes room. This will help to prevent data loss but will cause data to pile up on the edge.


Drops new data as it's received. This data is lost. This should be used when performance is the highest priority.

Batch flushing

Batches are flushed when 1 of 2 conditions are met:

  1. The batch age meets or exceeds the configured batch_timeout (default: 1 seconds).

  2. The batch size meets or exceeds the configured batch_size (default: 10490000 bytes).

Delivery Guarantee

Due to the nature of this component, it offers a best effort delivery guarantee.

Environment Variables

Environment variables are supported through all of Vector's configuration. Simply add ${MY_ENV_VAR} in your Vector configuration file and the variable will be replaced before being evaluated.

You can learn more in the Environment Variables section.

Health Checks

Health checks ensure that the downstream service is accessible and ready to accept data. This check is performed upon sink initialization.

If the health check fails an error will be logged and Vector will proceed to start. If you'd like to exit immediately upon health check failure, you can pass the --require-healthy flag:

vector --config /etc/vector/vector.toml --require-healthy

And finally, if you'd like to disable health checks entirely for this sink you can set the healthcheck option to false.

Nested Documents

Vector will explode events into nested documents before writing them to Elasticsearch. Vector assumes keys with a . delimit nested fields. You can read more about how Vector handles nested documents in the Data Model document.

Rate Limits

Vector offers a few levers to control the rate and volume of requests to the downstream service. Start with the rate_limit_duration and rate_limit_num options to ensure Vector does not exceed the specified number of requests in the specified window. You can further control the pace at which this window is saturated with the request_in_flight_limit option, which will guarantee no more than the specified number of requests are in-flight at any given time.

Please note, Vector's defaults are carefully chosen and it should be rare that you need to adjust these. If you found a good reason to do so please share it with the Vector team by opening an issie.

Retry Policy

Vector will retry failed requests (status == 429, >= 500, and != 501). Other responses will not be retried. You can control the number of retry attempts and backoff rate with the retry_attempts and retry_backoff_secs options.

Template Syntax

The index options support Vector's template syntax, enabling dynamic values derived from the event's data. This syntax accepts strftime specifiers as well as the {{ field_name }} syntax for accessing event fields. For example:

# ...
index = "vector-%Y-%m-%d"
index = "application-{{ application_id }}-%Y-%m-%d"
# ...

You can read more about the complete syntax in the template syntax section.


To ensure the pipeline does not halt when a service fails to respond Vector will abort requests after 60 seconds. This can be adjsuted with the request_timeout_secs option.

It is highly recommended that you do not lower value below the service's internal timeout, as this could create orphaned requests, pile on retries, and result in deuplicate data downstream.


The best place to start with troubleshooting is to check the Vector logs. This is typically located at /var/log/vector.log, then proceed to follow the Troubleshooting Guide.

If the Troubleshooting Guide does not resolve your issue, please:

  1. If encountered a bug, please file a bug report.

  2. If encountered a missing feature, please file a feature request.

  3. If you need help, join our chat/forum community. You can post a question and search previous questions.