Issue with docs/ops/best-practices/observability/index.md

[ethernoy]

Hi, the aggregation rule of Istio TCP metrics in this document seems is not referring to the latest valid set of Istio TCP metrics.

- record: "workload:istio_tcp_sent_bytes_total_count"
    expr: |
      sum without(instance, namespace, pod) (istio_tcp_sent_bytes_total_count)

  - record: "workload:istio_tcp_sent_bytes_total_sum"
    expr: |
      sum without(instance, namespace, pod) (istio_tcp_sent_bytes_total_sum)

  - record: "workload:istio_tcp_sent_bytes_total_bucket"
    expr: |
      sum without(instance, namespace, pod) (istio_tcp_sent_bytes_total_bucket)

  - record: "workload:istio_tcp_received_bytes_total_count"
    expr: |
      sum without(instance, namespace, pod) (istio_tcp_received_bytes_total_count)

  - record: "workload:istio_tcp_received_bytes_total_sum"
    expr: |
      sum without(instance, namespace, pod) (istio_tcp_received_bytes_total_sum)

  - record: "workload:istio_tcp_received_bytes_total_bucket"
    expr: |
      sum without(instance, namespace, pod) (istio_tcp_received_bytes_total_bucket)

The available Istio TCP metrics of v1.9 contains:

• istio_tcp_connections_opened_total
• istio_tcp_connections_closed_total
• istio_tcp_received_bytes_total
• istio_tcp_sent_bytes_total

The last two metrics listed above are not included in the aggregation.

I wonder if this document is outdated and should be updated? If so I am glad to help.