DCV gateway healtcheck not working, connection reset by peer

Question

I am deploying a DCV Gateway docker container in a Swarm cluster. I really need to have a healthcheck working for this container. In the case of DCV gateway, the healthcheck should be extremely easy to setup:

```
    [health-check]
    bind-addr = "0.0.0.0"
    port = 8989
```

The problem is that the healtcheck continuosly fail. I tried to call the healtcheck API with curl and wget, and I get the same error:

```
    curl: (56) Recv failure: Connection reset by peer

--2024-02-02 13:36:03--  http://localhost:8989/
    Resolving localhost (localhost)... 127.0.0.1, ::1
    Connecting to localhost (localhost)|127.0.0.1|:8989... connected.
    HTTP request sent, awaiting response... Read error (Connection reset by peer) in headers.
    Retrying.
```

What am I doing wrong?

```yaml
dcv-gateway:  
    image: dcv-gateway:1.0.0-stage
    hostname: "dcv-gateway-{{.Task.ID}}"
    networks:
      - public-stage
      - dcv-network-stage
    secrets:
      - source: tls_cert
        target: tls_cert
        uid: "999"
        gid: "999"
        mode: 0600
      - source: tls_cert_pkcs8_key
        target: tls_cert_key
        uid: "999"
        gid: "999"
        mode: 0600
    healthcheck:
      test: ["CMD", "wget", "--no-verbose", "--spider", "--tries=1", "http://localhost:8989/"]
      interval: 5s
      timeout: 5s
      retries: 5
      start_period: 5s
    deploy:
      mode: replicated
      replicas: 3
      placement:
        max_replicas_per_node: 1
      update_config:
        parallelism: 1
        delay: 10s
      restart_policy:
        condition: on-failure
        delay: 10s
        max_attempts: 3
        window: 120s
      resources:
        limits:
          cpus: '1.0'
          memory: 1024M
```

The `dcv-gateway` image is build using an Ubuntu image and installing dcv gateway in it, then running dcv gateway as the entry point. It is a pretty basic Dockerfile.

Answer

Hey there, thanks for the question! Can you modify the localhost health check to be `https` from `http`? I believe it is refusing the connection since it has a TLS certificate but is trying to not use it. Assuming this is a self-signed certificate, I would also add `--no-check-certificate` to your wget command so it doesn't attempt to validate the certificate.

DCV gateway healtcheck not working, connection reset by peer

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