Updated transmission image

 Simple base image update to alpine 3.15.1, no other changes.

flexget and finance-quote

My recent patch fixing a crash (undefined var) on anilist plugin of flexget when yuna.moe is unreachable has been merged. It's included on flexget 3.3.1 and on my docker image grmontesino/flexget:3.3.1-i1

In similar news, the Tesouro Direto finance-quote module I've submited to finance-quote also have been merged and should be available on finance-quote 1.52 release planned to mid-year.

WSL tricks part 2: VPN and MTU Setting

The first time you try to ssh to a remote server from WSL over a VPN connection, there's a good chance the connection will hang as soon as you start using it. After a little testing you may notice that it happens when using any command with longer output.

It turns out that the interface for the HyperV VM used to run wsl2 doesn't set its MTU correctly, and the network packets get discarded somewhere along the way. To fix this (assuming we don't have control over the VPN configurations) we need to set the MTU manually.

To find out what MTU setting should be used, the "tracepath" command can be used. Just install the package if needed, run "tracepath <server reachable by VPN>" and check the lowest "pmtu" value shown, that should be set as interface MTU.

For the configuration itself, a quick search on the internet did wield a few alternatives, but the nicer ones unfortunately didn't work... Setting the MTU directly on the HyperV configuration didn't get persisted across reboots; WSL's ubuntu doesn't seem to read any interface configuration on startup by default (and I don't see any good reason to install a init system on WSL)... 

In the end I've resigned myself and adopted the ugly solution: put the command to set it directly on ~/.bashrc:

#MTU
sudo ip link set eth0 mtu 1350

To get it at least a little less ugly, we can make it so sudo doesn't ask for a password: run "sudo visudo -f /etc/sudoers.d/mtu" and create the file with the following content:

ALL    ALL = (root) NOPASSWD: /sbin/ip link set eth0 mtu 1350

That will fix the hanging SSH problem. It's ugly because the MTU should be set dynamically / automatically and It's ugly because bashrc isn't the proper place for this kind of configuration, but at least it works.

Docker Image: BURP BackUp and Restore Program

Just released my images for burp on github. This is a somewhat more complex stack with 4 images - base, server, client and web user interface - and a bit more of scripting on the entrypoints to support the configuration file schema used by burp.

With 4 images in one repository and a dependency relation on the base for the other three, I wasn't sure how it would be to build everything automatically through github actions, but it turned out to be pretty easy. Just build base first, the other three after in parallel. 

Github actions matrix strategy option for running similar jobs with a few parameters changes with no need to make various almost identical copies of the definition and/or having to make some more complex reusable job configuration turned out to be very handy.