Occasional blog posts from a random systems engineer

Blog - MattBits

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Background I maintain a handful of open sources projects - most of which are of no interest to anyone. There are one or two, however, that have a small handful of users - and also a small number of contributors. Because of this, I spent a very inconsistent amount of time on each of these, occasionally fixing bugs and occasionally spending an hour or two each for a week to get a feature done.

AWS offers a broad variety of services - some of which are essential and unavoidable when using Amazon as a cloud provider. Others, on the other hand, provide solutions that, whilst on the surface are great as a quick start, do not scale. By scale, I don’t mean in the usual compute-power way, I mean in cost. If you use a service that provides scalability with a steady and predictable workload, then you are paying for flexibility that you aren’t using - and you do pay for this.

Goals I started off with a basic goal - host a small python website, which uses a MySQL-like database on a highly available cluster. After recently moving from a rack in a datacenter (and fortunately saving ~£250/month), I started looking at hosting some web applications on VPSs from a couple of providers. Of course, this means: Every instance costs money - I can no longer spin up 10 extra VMs because the hardware is already running… each instance costs.

Tinc - Mesh VPN

Tinc appears to be one of the few open source mesh VPNs and, in my expierience, once working, performs incredible well. That said, the configuration of tinc is a little clunky and repetitive, nor does their documentation give much of a clue as to what is required for a minimal setup. Example The following example will connect 4 machines in a tinc mesh network; one machine has a direct internet connection (and have public IP addresses); two are behind a NAT gateway, with tinc ports being fowarded to one of the nodes; one machine is behind a different NAT gateway, again, unable to forward ports.