My Envoy gateway tcp proxy max connections too low，what's the problem?

[chunhanRyan]

When the Envoy is started in static configuration mode, the maximum number of connections can only reach about 1024.
Envoy version is :1.25.11, The configuration like:

admin:
  address:
    socket_address: { address: 0.0.0.0, port_value: 9902 }
static_resources:
  listeners:
  - name: listener_0
    address:
      socket_address: { address: 0.0.0.0, port_value: 20000 }
    filter_chains:
    - filters:
      - name: envoy.filters.network.tcp_proxy
        typed_config:
          "@type": type.googleapis.com/envoy.extensions.filters.network.tcp_proxy.v3.TcpProxy
          stat_prefix: tcp_local_service
          cluster: some_service
  clusters:
  - name: some_service
    connect_timeout: 0.25s
    type: STATIC
    lb_policy: ROUND_ROBIN
    load_assignment:
      cluster_name: some_service
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address:
                address: 66.66.10.196
                port_value: 80
        - endpoint:
            address:
              socket_address:
                address: 66.66.10.195
                port_value: 80
layered_runtime:
  layers:
  - name: static_layer_0
    static_layer:
      envoy:
        resource_limits:
          listener:
            listener_0:
              connection_limit: 200000
      overload:
        global_downstream_max_connections: 200000

I use a client to test envoy supported max keepalived connections with 2000 connection (i changed the linux process max open file，and local port ....), but i can only reach max 1024 active connection with envoy admin stats interface,

Instead, the max connctions can be 100k+ or more when use envoy.filters.network.http_connection_manager. Is there any key different reason?

[pxpnetworks]

please check if you are hitting the some_service cluster's circuit breaker defaults

[wbpcode]

An upstream connection is holded by one downstream connection in the TCP proxy. (HCM use a shared connection pool).
So, the circuit breaker configuration (default allow 1024 max connections) of upstream cluster will limit the max connection of downstream listener.

[chunhanRyan]

@pxpnetworks @wbpcode thx, I changed the configuration with high circuit breaker limit,it works.

[derekargueta]

close issue?

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This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or "no stalebot" or other activity occurs. Thank you for your contributions.

[github-actions]

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