March 2021 Summaries

The article discusses the process of setting up an Anycast network, which involves announcing a single IP block from multiple locations to connect users to the nearest server. To do this, one needs to acquire IPs and then "announce" them using Border Gateway Protocol (BGP). The author suggests registering with a Regional Internet Registry (RIR) such as RIPE NCC or ARIN, which charge an annual membership fee. Acquiring IPv4 addresses can be challenging due to limited availability, so one might need to buy or lease them from a broker. It's also important to ensure the purchased IPs are not on abuse lists and are compatible with your RIR. To announce your own blocks, you need at least an IPv4 /24 or an IPv6 /48. The article also mentions obtaining an Autonomous System number (ASN) for grouping IPs together, which is free from RIPE and relatively easy to set up.

The text discusses the concept of building a Content Delivery Network (CDN) using web applications and NGINX, a popular open-source web server. It explains that a CDN functions as a distributed caching proxy, hoovering up files from a central repository and storing copies close to users. The author suggests using existing work done by others rather than building from scratch, and provides examples of tools like Varnish, Apache Traffic Server, and NGINX. The text also covers traffic direction methods such as Anycast and DNS load balancing, and emphasizes the importance of redundancy in case a server fails. It mentions monitoring options for detecting issues with servers or the Internet, including Datadog, updown.io, and Honeycomb. The author then discusses caching strategies like cache sharding and onion layers to increase cache ratios and improve performance. The text concludes by highlighting the advantages of using CDNs for improving cache ratios and avoiding bad Internet connections. It also touches upon advanced features that can be added to a CDN, such as image optimization, WAF, API rate limiting, and bot detection.

Fly.io has introduced an SSH feature for its platform, which enables users to pop a shell on their applications hosted on the provider. The new feature is built using 6PN and Hallpass, with authentication handled by SSH client certificates. Additionally, user-mode TCP/IP WireGuard has been implemented to allow SSH into instances without installing WireGuard. This development aims to provide users with more flexibility and control over their applications hosted on Fly.io.