Just getting up to speed on Elixir 1.9 deployments. I’m super excited about not relying on Distillery and eDeliver and even Docker containers (since I’m currently just tackling a smaller personal project), but I’m still getting caught up with how to properly do a release that runs in the background, via systemd.

I added GitHub - cogini/mix_systemd: Library of mix tasks to generate a systemd unit file for an Elixir project · GitHub to my deps and generated my systmd unit file and placed it in /etc/systemd/system and did some tests, but can’t get my app to show up at mysite:4000. Keep in mind, I originally just tested the build executable and was able to successfully see my app at that URL so I know the problem is somewhere with how I’m doing my systemd.

Here’s a copy of my systemd unit file:

[Unit]
Description=dayoff service
After=local-fs.target network.target

[Service]
Type=simple
User=deploy
Group=deploy
WorkingDirectory=/home/deploy/build/dayoff_1.9/_build/prod/rel/dayoff
ExecStart=/home/deploy/build/dayoff_1.9/_build/prod/rel/dayoff/bin/dayoff start
ExecStop=/home/deploy/build/dayoff_1.9/_build/prod/rel/dayoff/bin/dayoff stop
Environment=LANG=en_US.utf8
Environment=MIX_ENV=prod

Environment=PORT=4000
LimitNOFILE=65535
UMask=0027
SyslogIdentifier=dayoff
Restart=always

[Install]
WantedBy=multi-user.target

If i run a status check on the systemd service I see that it is active, however it seems to be starting and stopping every couple seconds.

● dayoff.service - dayoff service
   Loaded: loaded (/etc/systemd/system/dayoff.service; disabled;
   Active: active (running) since Sun 2020-02-23 10:24:49 EST; 7
  Process: 20886 ExecStop=/home/deploy/build/dayoff_1.9/_build/p
 Main PID: 20944 (beam.smp)
    Tasks: 5
   Memory: 6.4M
      CPU: 48ms
   CGroup: /system.slice/dayoff.service
           ├─20944 /home/deploy/build/dayoff_1.9/_build/prod/rel
           └─20986 erl_child_setup 65535

Feb 23 10:24:49 seojeek systemd[1]: dayoff.service: Service hold
Feb 23 10:24:49 seojeek systemd[1]: Stopped dayoff service.
Feb 23 10:24:49 seojeek systemd[1]: Started dayoff service.

Another area of potential confusion is where exactly I place my env vars. I was able to build my release successfully using the vars stored on the server in ~/.profile which I think seems to be a fine solution.

However, in my prod.exs I have some config vars for mix_systemd:

config :mix_systemd,
  app_user: "deploy",
  app_group: "deploy",
  base_dir: "/home/deploy/build/dayoff_1.9/_build/prod/rel",
  current_dir: "/home/deploy/build/dayoff_1.9/_build/prod/rel",
  env_vars: [
    "PORT=4000",
  ]

So I’m not sure if I should replace my ~/.profile and place them in my systemd config?

So yeah, any help is appreciated. Again, if I take the ExecStart command from my systemd file it runs so I just want to set it and forget it but can’t get it to stay on.

Thanks.