Envoy proxy: 503 Service Unavailable

Question

State of Servies:

Client ( nuxt ) is up on http://localhost:3000 and the client sends requests to http://localhost:8080 .

Server ( django ) is running on 0.0.0.0:50051 .

Also docker is up

78496fef541f   5f9773709483      "/docker-entrypoint.…"   29 minutes
 ago   Up 29 minutes   0.0.0.0:8080->8080/tcp, :::8080-8080/tcp,
 10000/tcp   envoy

---

envoy.yaml Configurations:

I configured the envoy.yaml file as follows:

static_resources:
  listeners:
    - name: listener_0
      address:
        socket_address: { address: 0.0.0.0, port_value: 8080 }
      filter_chains:
        - filters:
            - name: envoy.filters.network.http_connection_manager
              typed_config:
                "@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
                codec_type: auto
                stat_prefix: ingress_http
                route_config:
                  name: local_route
                  virtual_hosts:
                    - name: local_service
                      domains: ["*"]
                      routes:
                        - match: { prefix: "/" }
                          route:
                            cluster: greeter_service
                            max_stream_duration:
                              grpc_timeout_header_max: 0s
                      cors:
                        allow_origin_string_match:
                          - prefix: "*"
                        allow_methods: GET, PUT, DELETE, POST, OPTIONS
                        allow_headers: keep-alive,user-agent,cache-control,content-type,content-transfer-encoding,custom-header-1,x-accept-content-transfer-encoding,x-accept-response-streaming,x-user-agent,x-grpc-web,grpc-timeout
                        max_age: "1728000"
                        expose_headers: custom-header-1,grpc-status,grpc-message
                http_filters:
                  - name: envoy.filters.http.grpc_web
                  - name: envoy.filters.http.cors
                  - name: envoy.filters.http.router
  clusters:
    - name: greeter_service
      connect_timeout: 0.25s
      type: logical_dns
      http2_protocol_options: {}
      lb_policy: round_robin
      load_assignment:
        cluster_name: cluster_0
        endpoints:
          - lb_endpoints:
              - endpoint:
                  address:
                    socket_address:
                      address: 0.0.0.0
                      port_value: 50051

---

Error:

But the following error occurs and, as it seems, the requests do not reach the Django 0.0.0.0:50051 server.

503 Service Unavailable

grpc-message: upstream connect error or disconnect/reset before headers. reset reason: connection failure, transport failure reason: delayed connect error: 111

Answer 1

Please see my long answer here . I resolved this issue.

---

> Short Answer:

I needed a proxy to receive requests from the server. So I used envoy proxy . In this way, nginx received the request from the browser and then sent it to a port (for example 5000). On the other hand, envoy listens to port 5000 and then sends the request to the server running on port 50051.

This is how I designed the tracking of a gRPC connection.

Answer 2

I have encountered the same error. Here are my condition:

• Envoy: running on docker with listener at port 8080 and redirect to port 9090
• Next JS Web client: request to envoy proxy at port 8080
• Node Grpc Server: listen on port 9090

Im starting all on local environment.

Based on this example about configuring the envoy proxy that refer to this issue , I change the address on envoy proxy to host.docker.internal on envoy.yaml.

Just refer to this section, if you want to try:

clusters:
  - name: backend_service
    connect_timeout: 0.25s
    type: logical_dns
    http2_protocol_options: {}
    lb_policy: round_robin
    load_assignment:
      cluster_name: cluster_0
      endpoints:
        - lb_endpoints:
            - endpoint:
                address:
                  socket_address:
                    address: host.docker.internal // i change it, before was 0.0.0.0
                    port_value: 9090