nonroot: systemctl --user enable scylla-server.service failed on Ubuntu 18

[syuu1228]

Seems like systemctl --user enable scylla-server.service failed because of symbolic link:

Do you want the Scylla server service to automatically start when the Scylla node boots?
Yes - Scylla server service automatically starts on Scylla node boot. No - skips this step. Note you will have to start the Scylla Server service manually.
[YES/no]
Failed to execute operation: Too many levels of symbolic links
Traceback (most recent call last):
  File "/home/vagrant/scylladb/scripts/libexec/scylla_setup", line 364, in <module>
    systemd_unit('scylla-server.service').enable()
  File "/home/vagrant/scylladb/scripts/scylla_util.py", line 765, in enable
    return run('systemctl {} enable {}'.format(self.ctlparam, self._unit))
  File "/home/vagrant/scylladb/scripts/scylla_util.py", line 504, in run
    return subprocess.run(cmd, stdout=stdout, stderr=stderr, shell=shell, check=exception, env=scylla_env).returncode
  File "/home/vagrant/scylladb/python3/lib64/python3.8/subprocess.py", line 512, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['systemctl', '--user', 'enable', 'scylla-server.service']' returned non-zero exit status 1.

Even though, symlink seems working:

vagrant@ubuntu1604:~/scylladb$ ls -l ~/.config/systemd/user/
total 12
lrwxrwxrwx 1 vagrant vagrant   51 Sep 27 09:35 node-exporter.service -> ../../../scylladb/etc/systemd/node-exporter.service
drwxrwxr-x 2 vagrant vagrant 4096 Sep 27 09:35 node-exporter.service.d
lrwxrwxrwx 1 vagrant vagrant   48 Sep 27 09:35 scylla-jmx.service -> ../../../scylladb/etc/systemd/scylla-jmx.service
drwxrwxr-x 2 vagrant vagrant 4096 Sep 27 09:35 scylla-jmx.service.d
lrwxrwxrwx 1 vagrant vagrant   51 Sep 27 09:35 scylla-server.service -> ../../../scylladb/etc/systemd/scylla-server.service
drwxrwxr-x 2 vagrant vagrant 4096 Sep 27 09:35 scylla-server.service.d
vagrant@ubuntu1604:~/scylladb$ systemctl --user cat scylla-server.service
# /home/vagrant/.config/systemd/user/../../../scylladb/etc/systemd/scylla-server.service
[Unit]
Description=Scylla Server
Wants=scylla-jmx.service
Wants=scylla-housekeeping-restart.timer
Wants=scylla-housekeeping-daily.timer

[Service]
PermissionsStartOnly=true
Type=notify
LimitMEMLOCK=infinity
LimitNOFILE=800000
LimitAS=infinity
LimitNPROC=8096
EnvironmentFile=/etc/sysconfig/scylla-server
EnvironmentFile=/etc/scylla.d/*.conf
ExecStartPre=/opt/scylladb/scripts/scylla_prepare
ExecStart=/usr/bin/scylla $SCYLLA_ARGS $SEASTAR_IO $DEV_MODE $CPUSET $MEM_CONF
ExecStopPost=/opt/scylladb/scripts/scylla_stop
TimeoutStartSec=1y
TimeoutStopSec=900
KillMode=process
Restart=on-abnormal
User=scylla
OOMScoreAdjust=-950
StandardOutput=syslog
StandardError=syslog
SyslogLevelPrefix=false
Slice=scylla-server.slice

[Install]
WantedBy=multi-user.target

# /home/vagrant/.config/systemd/user/scylla-server.service.d/nonroot.conf
[Service]
EnvironmentFile=
EnvironmentFile=/home/vagrant/scylladb//etc/sysconfig/scylla-server
EnvironmentFile=/home/vagrant/scylladb/etc/scylla.d/*.conf
ExecStartPre=
ExecStart=
ExecStart=/home/vagrant/scylladb/bin/scylla $SCYLLA_ARGS $SEASTAR_IO $DEV_MODE $CPUSET
ExecStopPost=
User=

Maybe we should stop using symlink for this, we can just copy these unit files.

[avikivity]

This is for systemd user mode. Already on 4.3, not backporting further.