Windows based Front proxy

To get a flavor of what Envoy has to offer on Windows, we are releasing a docker compose sandbox that deploys a front Envoy and a couple of services (simple Flask apps) colocated with a running service Envoy.

The three containers will be deployed inside a virtual network called envoymesh.

Below you can see a graphic showing the docker compose deployment:

All incoming requests are routed via the front Envoy, which is acting as a reverse proxy sitting on the edge of the envoymesh network. Port 8080, 8443, and 8001 are exposed by docker compose (see docker-compose.yaml) to handle HTTP, HTTPS calls to the services and requests to /admin respectively.

Moreover, notice that all traffic routed by the front Envoy to the service containers is actually routed to the service Envoys (routes setup in front-envoy.yaml).

In turn the service Envoys route the request to the Flask app via the loopback address (routes setup in service-envoy.yaml). This setup illustrates the advantage of running service Envoys collocated with your services: all requests are handled by the service Envoy, and efficiently routed to your services.

Step 1: Start all of our containers

Change to the examples/front-proxy directory.

PS> $PWD
D:\envoy\examples\win32-front-proxy
PS> docker-compose build --pull
PS> docker-compose up -d
PS> docker-compose ps
    Name                            Command               State                                         Ports
------------------------------------------------------------------------------------------------------------------------------------------------------------
envoy-front-proxy_front-envoy_1   powershell.exe ./start_env ... Up      10000/tcp, 0.0.0.0:8003->8003/tcp, 0.0.0.0:8080->8080/tcp, 0.0.0.0:8443->8443/tcp
envoy-front-proxy_service1_1      powershell.exe ./start_ser ... Up      10000/tcp
envoy-front-proxy_service2_1      powershell.exe ./start_ser ... Up      10000/tcp

Step 2: Test Envoy’s routing capabilities

You can now send a request to both services via the front-envoy.

For service1:

PS> curl -v localhost:8080/service/1
*   Trying ::1...
* TCP_NODELAY set
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /service/1 HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.55.1
> Accept: */*
>
< HTTP/1.1 200 OK
< content-type: text/html; charset=utf-8
< content-length: 92
< server: envoy
< date: Wed, 05 May 2021 05:55:55 GMT
< x-envoy-upstream-service-time: 18
<
Hello from behind Envoy (service 1)! hostname: 8a45bba91d83 resolvedhostname: 172.30.97.237
* Connection #0 to host localhost left intact

For service2:

PS> curl -v localhost:8080/service/2
*   Trying ::1...
* TCP_NODELAY set
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /service/2 HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.55.1
> Accept: */*
>
< HTTP/1.1 200 OK
< content-type: text/html; charset=utf-8
< content-length: 93
< server: envoy
< date: Wed, 05 May 2021 05:57:03 GMT
< x-envoy-upstream-service-time: 14
<
Hello from behind Envoy (service 2)! hostname: 51e28eb3c8b8 resolvedhostname: 172.30.109.113
* Connection #0 to host localhost left intact

Notice that each request, while sent to the front Envoy, was correctly routed to the respective application.

We can also use HTTPS to call services behind the front Envoy. For example, calling service1:

PS> curl https://localhost:8443/service/1 -k -v
*   Trying ::1...
* TCP_NODELAY set
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8443 (#0)
* schannel: SSL/TLS connection with localhost port 8443 (step 1/3)
* schannel: disabled server certificate revocation checks
* schannel: verifyhost setting prevents Schannel from comparing the supplied target name with the subject names in server certificates.
* schannel: sending initial handshake data: sending 171 bytes...
* schannel: sent initial handshake data: sent 171 bytes
* schannel: SSL/TLS connection with localhost port 8443 (step 2/3)
* schannel: failed to receive handshake, need more data
* schannel: SSL/TLS connection with localhost port 8443 (step 2/3)
* schannel: encrypted data got 1081
* schannel: encrypted data buffer: offset 1081 length 4096
* schannel: sending next handshake data: sending 93 bytes...
* schannel: SSL/TLS connection with localhost port 8443 (step 2/3)
* schannel: encrypted data got 258
* schannel: encrypted data buffer: offset 258 length 4096
* schannel: SSL/TLS handshake complete
* schannel: SSL/TLS connection with localhost port 8443 (step 3/3)
* schannel: stored credential handle in session cache
> GET /service/1 HTTP/1.1
> Host: localhost:8443
> User-Agent: curl/7.55.1
> Accept: */*
>
* schannel: client wants to read 102400 bytes
* schannel: encdata_buffer resized 103424
* schannel: encrypted data buffer: offset 0 length 103424
* schannel: encrypted data got 286
* schannel: encrypted data buffer: offset 286 length 103424
* schannel: decrypted data length: 257
* schannel: decrypted data added: 257
* schannel: decrypted data cached: offset 257 length 102400
* schannel: encrypted data buffer: offset 0 length 103424
* schannel: decrypted data buffer: offset 257 length 102400
* schannel: schannel_recv cleanup
* schannel: decrypted data returned 257
* schannel: decrypted data buffer: offset 0 length 102400
< HTTP/1.1 200 OK
< content-type: text/html; charset=utf-8
< content-length: 92
< server: envoy
< date: Wed, 05 May 2021 05:57:45 GMT
< x-envoy-upstream-service-time: 3
<
Hello from behind Envoy (service 1)! hostname: 8a45bba91d83 resolvedhostname: 172.30.97.237
* Connection #0 to host localhost left intact

Step 3: Test Envoy’s load balancing capabilities

Now let’s scale up our service1 nodes to demonstrate the load balancing abilities of Envoy:

PS> docker-compose scale service1=3
Creating and starting example_service1_2 ... done
Creating and starting example_service1_3 ... done

Now if we send a request to service1 multiple times, the front Envoy will load balance the requests by doing a round robin of the three service1 machines:

PS> curl -v localhost:8080/service/1
*   Trying ::1...
* TCP_NODELAY set
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /service/1 HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.55.1
> Accept: */*
>
< HTTP/1.1 200 OK
< content-type: text/html; charset=utf-8
< content-length: 93
< server: envoy
< date: Wed, 05 May 2021 05:58:40 GMT
< x-envoy-upstream-service-time: 22
<
Hello from behind Envoy (service 1)! hostname: 8d2359ee21a8 resolvedhostname: 172.30.101.143
* Connection #0 to host localhost left intact
PS> curl -v localhost:8080/service/1
*   Trying ::1...
* TCP_NODELAY set
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /service/1 HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.55.1
> Accept: */*
>
< HTTP/1.1 200 OK
< content-type: text/html; charset=utf-8
< content-length: 91
< server: envoy
< date: Wed, 05 May 2021 05:58:43 GMT
< x-envoy-upstream-service-time: 11
<
Hello from behind Envoy (service 1)! hostname: 41e1141eebf4 resolvedhostname: 172.30.96.11
* Connection #0 to host localhost left intact
PS> curl -v localhost:8080/service/1
*   Trying ::1...
* TCP_NODELAY set
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /service/1 HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.55.1
> Accept: */*
>
< HTTP/1.1 200 OK
< content-type: text/html; charset=utf-8
< content-length: 92
< server: envoy
< date: Wed, 05 May 2021 05:58:44 GMT
< x-envoy-upstream-service-time: 7
<
Hello from behind Envoy (service 1)! hostname: 8a45bba91d83 resolvedhostname: 172.30.97.237
* Connection #0 to host localhost left intact

Step 4: Enter containers and curl services

In addition of using curl from your host machine, you can also enter the containers themselves and curl from inside them. To enter a container you can use docker-compose exec <container_name> /bin/bash. For example we can enter the front-envoy container, and curl for services locally:

PS> docker-compose exec front-envoy powershell
PS C:\> (curl -UseBasicParsing http://localhost:8080/service/1).Content
Hello from behind Envoy (service 1)! hostname: 41e1141eebf4 resolvedhostname: 172.30.96.11

PS C:\> (curl -UseBasicParsing http://localhost:8080/service/1).Content
Hello from behind Envoy (service 1)! hostname: 8a45bba91d83 resolvedhostname: 172.30.97.237

PS C:\> (curl -UseBasicParsing http://localhost:8080/service/1).Content
Hello from behind Envoy (service 1)! hostname: 8d2359ee21a8 resolvedhostname: 172.30.101.143

Step 5: Enter container and curl admin interface

When Envoy runs it also attaches an admin to your desired port.

In the example configs the admin listener is bound to port 8001.

We can curl it to gain useful information:

/server_info provides information about the Envoy version you are running.
/stats provides statistics about the Envoy server.

In the example we can enter the front-envoy container to query admin:

PS> docker-compose exec front-envoy powershell
PS C:\> (curl http://localhost:8003/server_info -UseBasicParsing).Content

{
  "version": "093e2ffe046313242144d0431f1bb5cf18d82544/1.15.0-dev/Clean/RELEASE/BoringSSL",
  "state": "LIVE",
  "hot_restart_version": "11.104",
  "command_line_options": {
    "base_id": "0",
    "use_dynamic_base_id": false,
    "base_id_path": "",
    "concurrency": 8,
    "config_path": "/etc/front-envoy.yaml",
    "config_yaml": "",
    "allow_unknown_static_fields": false,
    "reject_unknown_dynamic_fields": false,
    "ignore_unknown_dynamic_fields": false,
    "admin_address_path": "",
    "local_address_ip_version": "v4",
    "log_level": "info",
    "component_log_level": "",
    "log_format": "[%Y-%m-%d %T.%e][%t][%l][%n] [%g:%#] %v",
    "log_format_escaped": false,
    "log_path": "",
    "service_cluster": "front-proxy",
    "service_node": "",
    "service_zone": "",
    "drain_strategy": "Gradual",
    "mode": "Serve",
    "disable_hot_restart": false,
    "enable_mutex_tracing": false,
    "restart_epoch": 0,
    "cpuset_threads": false,
    "disabled_extensions": [],
    "bootstrap_version": 0,
    "hidden_envoy_deprecated_max_stats": "0",
    "hidden_envoy_deprecated_max_obj_name_len": "0",
    "file_flush_interval": "10s",
    "drain_time": "600s",
    "parent_shutdown_time": "900s"
  },
  "uptime_current_epoch": "188s",
  "uptime_all_epochs": "188s"
}

PS C:\> (curl http://localhost:8003/stats -UseBasicParsing).Content
cluster.service1.external.upstream_rq_200: 7
...
cluster.service1.membership_change: 2
cluster.service1.membership_total: 3
...
cluster.service1.upstream_cx_http2_total: 3
...
cluster.service1.upstream_rq_total: 7
...
cluster.service2.external.upstream_rq_200: 2
...
cluster.service2.membership_change: 1
cluster.service2.membership_total: 1
...
cluster.service2.upstream_cx_http2_total: 1
...
cluster.service2.upstream_rq_total: 2
...

Notice that we can get the number of members of upstream clusters, number of requests fulfilled by them, information about http ingress, and a plethora of other useful stats.