rabbitmq service fails to start on system boot

rabbitmq-server does not start automatically during system boot:

eq-os1:~$ systemctl status snap.microstack.rabbitmq-server
● snap.microstack.rabbitmq-server.service - Service for snap application microstack.rabbitmq-server
   Loaded: loaded (/etc/systemd/system/snap.microstack.rabbitmq-server.service; enabled; vendor preset: enable
   Active: failed (Result: exit-code) since Sun 2022-06-19 14:37:39 CST; 21h ago
  Process: 9923 ExecStart=/usr/bin/snap run microstack.rabbitmq-server (code=exited, status=1/FAILURE)
 Main PID: 9923 (code=exited, status=1/FAILURE)

6月 19 14:37:39 eq-os1 systemd[1]: snap.microstack.rabbitmq-server.service: Service hold-off time over, schedu
6月 19 14:37:39 eq-os1 systemd[1]: snap.microstack.rabbitmq-server.service: Scheduled restart job, restart cou
6月 19 14:37:39 eq-os1 systemd[1]: Stopped Service for snap application microstack.rabbitmq-server.
6月 19 14:37:39 eq-os1 systemd[1]: snap.microstack.rabbitmq-server.service: Start request repeated too quickly
6月 19 14:37:39 eq-os1 systemd[1]: snap.microstack.rabbitmq-server.service: Failed with result 'exit-code'.
6月 19 14:37:39 eq-os1 systemd[1]: Failed to start Service for snap application microstack.rabbitmq-server.
eq-os1:~$ sudo cat /var/snap/microstack/common/log/rabbitmq/startup_log
ERROR: epmd error for host eq-os1: address (cannot connect to host/port)
eq-os1:~$

This happens because it tries to connect to epmd via hostname which points to IP address of eno1 interface (via /etc/hosts):

eq-os1:~$ grep eq-os1 /etc/hosts
10.30.0.11 eq-os1
eq-os1:~$ ip addr show dev eno1
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 78:2b:cb:3b:50:89 brd ff:ff:ff:ff:ff:ff
    inet 10.30.0.11/22 brd 10.30.3.255 scope global eno1
       valid_lft forever preferred_lft forever
    inet6 fe80::7a2b:cbff:fe3b:5089/64 scope link
       valid_lft forever preferred_lft forever
eq-os1:~$

The workaround is to add a missing dependency on network-online.target for snap.microstack.rabbitmq-server.service:

eq-os1:~$ cat /etc/systemd/system/snap.microstack.rabbitmq-server.service.d/deps.conf
[Unit]
Wants=network-online.target
eq-os1:~$

System information:

eq-os1:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.6 LTS
Release: 18.04
Codename: bionic
dell@eq-os1:~$ snap list microstack
Name Version Rev Tracking Publisher Notes
microstack ussuri 245 latest/beta canonical✓ -
eq-os1:~$