I had to figure out a way to remove specific hosts that had generated new host keys from the SSH known hosts file on the AWX system. What I came up with is the following playbook:

- hosts: all
  gather_facts: false
  tasks:
  - name: Remove host key from known_hosts
    command:
      cmd: ssh-keygen -R {{ inventory_hostname }}
    delegate_to: "localhost"

I just run this playbook with the limit set to the host or hosts I want to clear and have setup a template that just asks me for that limit.

I known that there is a module known_hosts, but it has a shortcoming in my opinion: It points to ~/.ssh/known\_hosts by default instead of parsing the ~/.ssh/config file to determine the default location.

#ansible #awx

#PHP #Webapplications in #NixOS are a bit special, as they commonly violate the split between configuration, data and application. Sometimes it's all in the same directory but more commonly it's a subdirectory that contains the data. Packaging the sources can be easy or complicated, depending on wether there is some build process. For Shaarli I just use their full.tar.gz and don't have to worry about that.

Got a message from a #freifunk colleague that users are unable to change their password on our mailserver. They just get bounced back into the login form of our PostfixAdmin after submitting it. Quick check: Yes, I have the same problem. Even the admin login is broken. No idea when it broke. #NixOS allows me to quickly activate an old configuration and software by executing a script (/nix/var/nix/profiles/system-476-link/bin/switch-to-configuration test), so I went back 15 days. That old generation worked. First success.

mbuffer reads data from an input and writes it to one or more outputs. The more important thing though is the buffering, as you can just tell it to use X amount of memory as a buffer, the default is usually 2 MBytes.

direnv manages shell environments.

direnv is one of these tools that you basically setup once and after that forget that it's there. You just notice it when it does the job you set it up for and are happy it saves you a lot of hassle.