The ideal way for applications running in a Kubernetes cluster to log to Seq is to use a native logging library and HTTP ingestion with the Seq instance's cluster internal DNS record, like
http://seq.logging.svc.cluster.local. Seq natively supports the OpenTelemetry logs protocol, so using it as a target is a broadly compatible option. See Ingestion with OpenTelemetry for details.
Another way to ingest logs in Kubernetes and other container orchestrators is to log directly to an output stream and let the ambient infrastructure collect the data and ship it off to the log server. There are many approaches to this and what you choose will depend on how you manage your Kubernetes cluster. The Seq Helm Chart has a sample that demonstrates a simple log pipeline using Fluent Bit.
Updated about 2 months ago