Systemd programming, 30 months later []

Some time ago, we published a pair of articles about systemd programming that extolled the value of providing high-quality unit files in upstream packages. The hope was that all distributions would use them and that problems could be fixed centrally rather than each distribution fixing its own problems independently. Now, 30 months later, it seems like a good time to see how well that worked out for nfs-utils, the focus of much of that discussion. Did distributors benefit from upstream unit files, and what sort of problems were encountered?

Source: Systemd programming, 30 months later []

Google introduce a new TCP congestion control algorithm

This commit implements a new TCP congestion control algorithm: BBR (Bottleneck Bandwidth and RTT). A detailed description of BBR will be published in ACM Queue, Vol. 14 No. 5, September-October 2016, as “BBR: Congestion-Based Congestion Control”. BBR has significantly increased throughput and reduced latency for connections on Google’s internal backbone networks and and YouTube Web servers. BBR requires only changes on the sender side, not in the network or the receiver side. Thus it can be incrementally deployed on today’s Internet, or in datacenters.

Source: [net-next,14/14] tcp_bbr: add BBR congestion control – Patchwork

Dynamic DNS updating in python with ipify

I’ve used free Dynamic DNS services to give my home machine a “static” address in the past but they either start charging or have poor performance.

As I run my own external nameserver, why not use RFC 2136 to dynamically update the address based on the IP from ipify? So with some python scripting, that’s what I did:

Welcome, ip-freely

To use this you’ll have to create keys /configure zone files as in this tutorial.

Steam emails not arriving

I run my own email server and never have any trouble with email delivery – however recently some steam emails failed to arrive.

I checked I wasn’t in any blacklists with senderbase, then dug further.

Turns out I had SSL enabled on my MTA but using my old cert which was SHA1 & revoked (with a SHA-256 replacement issued), replacing that fixed mail deliveries.

Normally MTAs don’t care about the validity of MTA certs (a lot of them are self-signed) so I hadn’t bothered replacing the cert there – only on website, but it seems Steam does.

Upgrading my old ML115 server box

I’ve upgraded my old ML115 ESX box to Ubuntu 16.04, using OpenNebula as the virtualization platform. ON is available in the system repos, but this is an old version (4.1) so I’d advise using the ON repos. OpenNebula provides an EC2-compatible API, which allows the use of libcloud and there is also Docker integration.

Ubuntu 16.04 also allows me to investigate ZFS and SystemD (systemd-networkd makes configuring the bridging interface required for OpenNebula very easy).