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Sending logs with Promtail

In this guide we show how to configure a Promtail instance to securely send logs to your Opstrace cluster.


  • An Opstrace cluster.
  • A decision: for which Opstrace tenant would you like to send data?
  • An Opstrace tenant authentication token file (for the tenant of your choice). Also see concepts.

@type loki output configuration block: the basics

Promtail can be instructed to send logs to an Opstrace cluster using the following basic configuration structure:

url: <string>
bearer_token_file: <filename>
insecure_skip_verify: <boolean>

Choosing url

This is the tenant-specific data API endpoint of an Opstrace cluster for ingesting metrics. The endpoint URL is constructed using the tenant name and the cluster name:

url: https://loki.${TENANT_NAME}.${CLUSTER_NAME}.opstrace.io/loki/api/v1/push


url: https://loki.default.testcluster.opstrace.io/loki/api/v1/push

Choosing bearer_token_file

Your Opstrace cluster exposes the logs ingestion API securely. For authenticating the client towards the Opstrace cluster, the client has to present a tenant-specific data API authentication token with every request.

To achieve that, we use the bearer_token_file parameter:


bearer_token_file: /var/run/default-tenant/tenant-api-token-default

Choosing insecure_tls

TLS is used for establishing a secure, private transport between the Promtail instance and the Opstrace cluster. By default, FluentD attempts to verify the certificate exposed by the Opstrace cluster against its trust store, for establishing authenticity of the Opstrace cluster towards Promtail. Depending on the cert_issuer cluster configuration option (see cluster configuration) you may want to disable server certificate verification for testing purposes.

This can be achieved via

insecure_skip_verify: true

This is required for example when using letsencrypt-staging as cert_issuer.