Setting hostname on boot doesn't affect avahi

[StefanScherer]

I have added a /boot/device-init.yaml file on a running RPi2 with

hostname: "new"

Then I rebooted with sudo reboot.

After rebooting I couldn't ssh into the renamed machine with ssh pirate@new.local, but still with ssh pirate@black-pearl.local.

Investigating the /var/log/syslog after the reboot with sudo grep 'avahi\|device-init' /var/log/syslog shows that the device-init rename is too late:

Feb 11 18:21:59 black-pearl avahi-daemon[195]: Found user 'avahi' (UID 105) and group 'avahi' (GID 111).
Feb 11 18:21:59 black-pearl avahi-daemon[195]: Successfully dropped root privileges.
Feb 11 18:21:59 black-pearl avahi-daemon[195]: avahi-daemon 0.6.31 starting up.
Feb 11 18:21:59 black-pearl avahi-daemon[195]: WARNING: No NSS support for mDNS detected, consider installing nss-mdns!
Feb 11 18:21:59 black-pearl avahi-daemon[195]: Successfully called chroot().
Feb 11 18:21:59 black-pearl avahi-daemon[195]: Successfully dropped remaining capabilities.
Feb 11 18:21:59 black-pearl avahi-daemon[204]: chroot.c: open() failed: No such file or directory
Feb 11 18:21:59 black-pearl avahi-daemon[195]: Failed to open /etc/resolv.conf: Invalid argument
Feb 11 18:21:59 black-pearl avahi-daemon[195]: No service file found in /etc/avahi/services.
Feb 11 18:21:59 black-pearl avahi-daemon[195]: Network interface enumeration completed.
Feb 11 18:21:59 black-pearl avahi-daemon[195]: Registering HINFO record with values 'ARMV7L'/'LINUX'.
Feb 11 18:21:59 black-pearl avahi-daemon[195]: Server startup complete. Host name is black-pearl.local. Local service cookie is 1581608388.
Feb 11 18:21:59 black-pearl systemd[1]: Starting device-init...
Feb 11 18:22:00 black-pearl device-init[224]: Using config file: /boot/device-init.yaml
Feb 11 18:22:00 black-pearl device-init[224]: Set hostname: new
Feb 11 18:22:00 black-pearl systemd[1]: Started device-init.
Feb 11 18:22:00 black-pearl avahi-daemon[195]: Joining mDNS multicast group on interface eth0.IPv4 with address 192.168.1.203.
Feb 11 18:22:00 black-pearl avahi-daemon[195]: New relevant interface eth0.IPv4 for mDNS.
Feb 11 18:22:00 black-pearl avahi-daemon[195]: Registering new address record for 192.168.1.203 on eth0.IPv4.
Feb 11 18:22:02 black-pearl avahi-daemon[195]: Joining mDNS multicast group on interface eth0.IPv6 with address fe80::ba27:ebff:feed:7480.
Feb 11 18:22:02 black-pearl avahi-daemon[195]: New relevant interface eth0.IPv6 for mDNS.
Feb 11 18:22:02 black-pearl avahi-daemon[195]: Registering new address record for fe80::ba27:ebff:feed:7480 on eth0.*.
Feb 11 18:22:02 black-pearl avahi-daemon[195]: Joining mDNS multicast group on interface docker0.IPv4 with address 172.17.0.1.
Feb 11 18:22:02 black-pearl avahi-daemon[195]: New relevant interface docker0.IPv4 for mDNS.
Feb 11 18:22:02 black-pearl avahi-daemon[195]: Registering new address record for 172.17.0.1 on docker0.IPv4.

So we have to change service dependencies to change boot order.

[StefanScherer]

This is what occi did: https://github.com/adafruit/Adafruit-Occi/blob/master/usr/bin/occi#L188-L194

if hostname changed and avahi-daemon installed then restart avahi-daemon

[Govinda-Fichtner]

@StefanScherer I know what occi did. I looked at it while I implemented device-init. I left out the avahi part intentionally as I was not sure if we would need it.

We would only need it if we have a running avahi daemon and are changing the hostname.
As I understand it this is not related to the boot order of device-init, is it?

[Govinda-Fichtner]

Fixed with fda11e9.