Introduction

Welcome to Day 2 of Convoy's Launch week! Over the months we have been working on a bunch of quality of life improvements and guides which would make it easy for you to deploy Convoy to your production environments faster. In this article, we will delve into how you can deploy Convoy with our updated helm charts to Kubernetes and how can you configure Convoy with a forward proxy for added security benefits.

Forward proxies

A forward proxy or a proxy server is an intermediary server that sits between clients and servers, forwarding requests on behalf of clients and providing additional services such as caching, security and anonymity. At times, webhook consumers require API providers to send webhooks from predefined IP addresses. A forward proxy can provide you with privacy and anonymity for your servers running convoy by masking their IP addresses. This ensures you can now route webhooks traffic through a dedicated egress.

We'll be exploring how you can configure Stripe's SmokeScreen and Nginx to work as a forward proxy with Convoy.

Configuring SmokeScreen

Stripe's Smokescreen is a powerful tool that can be used as a forward proxy for Convoy, it can be used to achieve Static IPs for your outbound webhook events.

To configure Smokescreen as a forward proxy for Convoy, follow the steps here to install smokescreen on your server.

Start smokescreen by running:

smokescreen --listen-port <your-desired-proxy-port>

You can configure your proxy URL with Convoy using the HTTP_PROXY environment variable or within your convoy.json file:

"server": {
  "http": {
    "proxy": "<smokescreen-url>",
    "ssl": false,
    "ssl_cert_file": "",
    "ssl_key_file": "",
    "port": 5005
  }
},

Access Control Lists (ACLs)

Smokescreen allows you to specify access control lists, these help prevent IP spoofing attacks.

---
version: v1
services:
    - name: enforce-dummy-srv
      project: usersec
      action: enforce
      allowed_domains:
          - example1.com
          - example2.com
          - deny1.com # overrides global deny list

    - name: report-dummy-srv
      project: security
      action: report
      allowed_domains:
          - example3.com

global_allow_list:
    - goodexample1.com
    - goodexample2.com
    - goodexample3.com
    - conflictingexample.com

global_deny_list:
    - deny1.com
    - deny2.com
    - conflictingexample.com

The enforce action makes smokescreen strictly follow the defined rule, as opposed to report which allows the rule to be broken with a warning. For more extensive documentation of Smokescreen's configuration see here.

Configuring Nginx

Nginx is a fast HTTP Proxy Server. It is usually used as a reverse proxy, but it can also serve as a forward proxy.

Nginx can be configured as a forward proxy, however the default configuration doesn't work very well with HTTPS connections. A solution for this, is to build and compile Nginx with the ngx_http_proxy_connect_module. The module allows the forward proxying work well with SSL connnections.

Using Docker, here's how you can build a custom Nginx image with the ngx_http_proxy_connect_module installed

Define your Dockerfile file:

FROM nginx:1.25.1-alpine

ENV NGINX_VERSION 1.25.1

# Download sources
# For latest build deps, see https://github.com/nginxinc/docker-nginx/blob/master/mainline/alpine/Dockerfile
RUN apk update && apk upgrade && \
    apk add --no-cache --virtual .build-deps \
    gcc \
    libc-dev \
    make \
    openssl-dev \
    pcre-dev \
    zlib-dev \
    linux-headers \
    curl \
    gnupg \
    libxslt-dev \
    gd-dev \
    geoip-dev \
    patch \
    bash \
    git \
    openssh

RUN wget "http://nginx.org/download/nginx-${NGINX_VERSION}.tar.gz" -O nginx.tar.gz
RUN git clone "https://github.com/chobits/ngx_http_proxy_connect_module"

RUN tar -zxC / -f nginx.tar.gz && \
    cd /nginx-$NGINX_VERSION && \
    patch -p1 < /ngx_http_proxy_connect_module/patch/proxy_connect_rewrite_102101.patch && \
    ./configure \
    --prefix=/etc/nginx \
    --sbin-path=/usr/sbin/nginx \
    --modules-path=/usr/lib/nginx/modules \
    --conf-path=/etc/nginx/nginx.conf \
    --error-log-path=/var/log/nginx/error.log \
    --http-log-path=/var/log/nginx/access.log \
    --pid-path=/var/run/nginx.pid \
    --lock-path=/var/run/nginx.lock \
    --http-client-body-temp-path=/var/cache/nginx/client_temp \
    --http-proxy-temp-path=/var/cache/nginx/proxy_temp \
    --http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp \
    --http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp \
    --http-scgi-temp-path=/var/cache/nginx/scgi_temp \
    --with-perl_modules_path=/usr/lib/perl5/vendor_perl \
    --user=nginx \
    --group=nginx \
    --with-compat \
    --with-file-aio \
    --with-threads \
    --with-http_addition_module \
    --with-http_auth_request_module \
    --with-http_dav_module \
    --with-http_flv_module \
    --with-http_gunzip_module \
    --with-http_gzip_static_module \
    --with-http_mp4_module \
    --with-http_random_index_module \
    --with-http_realip_module \
    --with-http_secure_link_module \
    --with-http_slice_module \
    --with-http_ssl_module \
    --with-http_stub_status_module \
    --with-http_sub_module \
    --with-http_v2_module \
    --with-mail \
    --with-mail_ssl_module \
    --with-stream \
    --with-stream_realip_module \
    --with-stream_ssl_module \
    --with-stream_ssl_preread_module \
    --add-dynamic-module=/ngx_http_proxy_connect_module && \
    make && make install

COPY nginx.conf /etc/nginx/nginx.conf

EXPOSE 8080

# Start Nginx
CMD ["nginx", "-g", "daemon off;"]

Add the nginx.conf file with the forward proxy configuration

load_module /usr/lib/nginx/modules/ngx_http_proxy_connect_module.so;

worker_processes  auto;

events {}

http {
    server {
        listen                         8080;

        # dns resolver used by forward proxying
        resolver                       8.8.8.8;

        # forward proxy for CONNECT requests
        proxy_connect;
        proxy_connect_connect_timeout  10s;
        proxy_connect_data_timeout     10s;

        # defined by yourself for non-CONNECT requests
        # Example: reverse proxy for non-CONNECT requests
        location / {
            proxy_pass http://$host;
            proxy_set_header Host $host;
        }
    }
}

Once you've built the image and have it running in a container, you can now update your convoy.json with the proxy URL.

"server": {
  "http": {
    "proxy": "http://localhost:8080",
    "ssl": false,
    "ssl_cert_file": "",
    "ssl_key_file": "",
    "port": 5005
  }
}

Kubernetes Deployment

Ease of Installation

We recently released v1 of our helm charts on Artifact Hub in which we refactored the charts based on industry standards. They are now very easy to install and configure making product evaluation and maintenance a breeze.

Documentation

Prior to v1, we had no documentation about how to tweak the configuration inside our chart; any developer could install it, but most times, we developers love to tune something to our specific needs, and we have rolled out our documentation which should enable more folks to run Convoy on Kubernetes.

Security

We all know how dangerous it can be to expose secrets without encrypting them; we used config maps for handling configurations, and they revealed specific credentials in plain text. In v1, We now use Kubernetes secrets, and yes, we know Kubernetes secrets are encoded, but you can use any of your favorite tools like Sops or External secrets for much better security. We got rid of convoy.json.

External Databases

Before v1, we only supported database creation from the helm chart; You could not necessarily use managed DB or bring your Database. Now With the externalDatabase and externalRedis attributes. You can use your own DB and not rely on the helm chart. Check the docs for more.

Deployments

Before Convoy can be up and running, it needs to do run db migrations if any exist. Before now, when the chart is deployed, other components go into a crash loop since the migrate component wasn't complete. Part of the benefit of using Kubernetes is that it has a reconciliation phase where it will retry the pods again. After several seconds and minutes, other components will start. So we had to fix that.

Introducing InitContainers, initContainers allows Kubernetes to run pre-containers before the actual container, which can also be helpful when dealing with migrations. Our new config was updated to this:

initContainers:
- name: wait-for-migrate
  image: bitnami/kubectl:1.24.4
  command:
    - /bin/sh
    - -c
    - |
      until kubectl wait --for=condition=complete --timeout=600s job/migrate; do
        echo "Waiting for migrate job to complete..."
        sleep 10
      done

The config above will check the migration job constantly every 10 seconds to ensure it is complete before other components will run.

Auto Scaling based on CPU and Memory Utilization

We also added Horizontal Pod Autoscaling (HPA) which allows specific components to scale based on CPU or memory utilization. All you need to do is enable them in the component and those pods will be scaled when they hit the limits.

autoscaling:
  enabled: true
  minReplicas: 2
  maxReplicas: 10
  targetCPUUtilizationPercentage: 80
  targetMemoryUtilizationPercentage: 80

What’s Next?

We plan on adding more support for other platforms you can configure to work as a forward proxy with Convoy such as Envoy, OpenResty etc. We'll also keep improving

You can stay up to date with the docs here to keep track of when the documentation is added.

Forward Proxies and Kubernetes Deployment

Written by

Dotun Jolaoso

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