Category: sysadmin

  • bash – escaping variables for use within commands

    Escaping quotes within variables is always painful in bash (somehow) – e.g. foo”bar and it’s not obvious that you’d need to write e.g. “foo”\””bar” (at least to me). Thankfully a bash built in magical thing can be used to do the escaping for you. In my case, I need to pass a ‘PASSWORD’ variable through…

  • Resizing a VM’s disk within Azure

    random notes on disk resizing with an Azure VM

  • systemd-resolve (DNS is always to blame)

    Random unscientific finding; perhaps systemd-resolve isn’t quite ready for prime time yet?

  • faster rsync (ssh cipher choice)

    Perhaps the bottleneck isn’t always bandwidth – but does changing ssh cipher make any difference? Using a derivative of : In unscientific tests, it looks like ssh parameters might do something when copying a 4GiB file between two random virtual machines in different data centres, but both in London. SSH Variant Speed -e “ssh” ~45MB/s…

  • (re)building varnish modules

    Automated rebuilding of varnish modules using docker …

  • Time to update to Varnish 6?

    Random config dump for varnish 6 + hitch on Debian Linux. (includes http2 support)

  • AWS vs Azure … round 1, fight!

    So, for whatever reason, I need to move some virtual machines and things from AWS (EC2, RDS), to an Azure. I have a few years experience with AWS, but until recently I’ve not really used Azure …. Here are some initial notes…… AWS tooling feels more mature (with the ‘stock’ ansible that ships with Ubuntu…

  • docker proxy image download

    Docker doesn’t like me for some reason, and I often get really bad download speeds from my home IP address. One crude fix, is use an external server I can access as a SOCKS proxy. To do so, edit / create /etc/systemd/system/docker.service.d/http-proxy.conf and put in it : [Service] Environment=”HTTP_PROXY=socks5://localhost:8888″ Then, restart/reload systemd ( systemctl daemon-reload…

  • rsyslog filtering (with loggly)

    Filtering rsyslog output being sent to loggly (e.g. from an apache imfile input)

  • Using hitch with varnish on Debian Jessie

    I ended up needing to install hitch on a server recently, so the https:// traffic could be routed through Varnish (along with the existing ‘http’ stuff) for performance reasons. The server only runs WordPress sites, so there are WordPress specific things in the Varnish configuration (vcl) file below. Versions: Varnish 5.2, Hitch 1.4.4, Apache 2.4 and…