Tag Archives: systemd

systemd.mount replacing autofs

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I have been a very satisfied user of autofs for several years. Using a laptop in multiple location without reboot, could often cause annoying timeouts with hard mounted NFS shares.

So I found autofs, which did a great job, especially the ghost option is nice, making you able to browse the filesystem when it’s not mounted, and only seeing a small delay when the autofs mounts it for you at your wish.

I have now discovered that systemd has a mount option: https://www.freedesktop.org/software/systemd/man/systemd.mount.html
It can be used as systemd units, but also directly from /etc/fstab where I prefer to have my mount options.

To replicate the autofs functionality, add something like this to your mount options:

noauto,x-systemd.automount,x-systemd.idle-timeout=60,x-systemd.mount-timeout=30,_netdev

The above options will mount when you try to access the share, and it will unmount after 1 minute of idling, and the _netdev tells the system not to mount it before the network is ready.
More or less the same functionality as autofs, but no need to install additional software.


Postgresql not listening on docker interface after reboot

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/etc/postgresql/12/main/postgresql.conf is where you define the interfaces for postgresql to listen on. It’s done with the line “listen_interfaces =”
So, to get postgresql to listen on a docker interface, you have to add the IP address to the configuration:

listen_addresses = 'localhost,172.18.0.1'

This will make postgresql listen after connections from my docker container. Unfortunately when i rebooted the machine, postgresql was only listening on the localhost. That was strange.

After doing some fiddling around, I discovered that I might had a timing issue, and I even found a couple of articles covering the issue. The postgresql service needs to wait for the docker service to be started, or it cannot listen on the docker interface, that seems logical. I tried following some of the workarounds described, but I couldn’t get it to work. I then took a look on how the default systemd is build, and it seems that /etc/systemd/system/default.target.wants/ consist of symbolic links to /lib/systemd/system/whatever, so i did the same:

sudo ln -s /lib/systemd/system/postgresql@.service /etc/systemd/system/default.target.wants/

I then added this line to the unit block:

After=docker.service

This seems to have done the trick. After a reboot, postgresql is listening on my docker interface. You can always verify with:

sudo ss -nltp | grep postgres