DNS Defense and Architectural Evolution

In this episode of Running in Production, Anthony Eden covers building a domain management service with Rails, Go and Erlang. It’s hosted on a combination of 70+ bare metal servers, AWS and Heroku. It’s been been up and running since 2010.

Anthony talks about handling millions of API queries per day, ~5 billion monthly DNS queries, spikes of up to 10,000 requests per second, sticking with a Rails monolith for the web dashboard, scaling PostgreSQL, building multiple data centers, feature flags and tons more.

Topics Include

• 3:58 – Millions of API queries per day and 2-5 billion DNS queries per month
• 6:40 – How Rails, Go and Erlang are being used along with why they were chosen
• 12:54 – How DNS lookups happen and the importance of DDoS protection
• 16:40 – The Erlang service has ~10k LOC and was written before Elixir existed
• 21:23 – Go is responsible for a lot of glue services
• 24:50 – A monolithic Rails app (server rendered templates) powers the web dashboard
• 28:08 – Sidekiq (Enterprise), Redis, PostgreSQL and all services run on Ubuntu LTS
• 29:41 – For cloud hosted services they end up on AWS or Heroku depending on what it is
• 31:45 – There’s 2 PostgreSQL instances and only the Rails app writes to it
• 34:55 – nginx is sitting in front of the Rails app
• 35:43 – Topping out at 5-10k requests per second through the Erlang service
• 42:44 – You can spin things up locally with or without Docker
• 47:15 – Datadog is used to help view metrics and logs to detect potential issues
• 50:10 – What exactly is Anycast?
• 52:07 – Picking out hardware for their data centers (roughly 70 physical servers)
• 59:29 – Chef is being used to configure all of the servers
• 1:02:23 – What the process is like to develop something and then deploy it to production
• 1:07:59 – Toggling feature flags, managing database migrations at scale and API versioning
• 1:16:15 – How developers add new features through pull requests and then deploy code
• 1:21:53 – Stripe handles all of the payments for each subscription tier
• 1:24:26 – Handling database backups with snapshots and streaming the data offsite
• 1:26:45 – Bugsnag is used for error handling and logs get written to Datadog as well
• 1:29:16 – Everyone’s been working remotely from day 1 and there is no centralized office
• 1:31:39 – Best tips? Have good processes in place as you grow in size
• 1:34:07 – Check out https://dnsimple.com/ and you can find Anthony on Twitter

Links

📄 References

• https://en.wikipedia.org/wiki/Anycast
• https://www.cloudflare.com/learning/ddos/dns-amplification-ddos-attack/
• https://miro.com/

⚙️ Tech Stack

• rails →
• ruby →
• erlang →
• golang →
• vue →
• aws →
• bugsnag →
• chef →
• cloudflare →
• datadog →
• docker →
• env-key →
• heroku →
• lets-encrypt →
• memcached →
• nginx →
• pingdom →
• postgres →
• redis →
• slack →
• statuspage →
• stripe →
• ubuntu →
• webpack →

🛠 Libraries Used

• https://github.com/hanami/hanami
• https://github.com/dnsimple/erldns
• https://github.com/dnsimple/dns_erlang
• https://github.com/wal-e/wal-e

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