systemd/journal should be configured manually.
Interpreting PPID 1 as systemd unit is wrong,
especially when embedded etcd runs under Docker
container. For such case, every single log write
will error and fall back to stderr, which is
inefficient.
Instead, add "systemd/journal" log output option
and returns error if systemd/journal socket cannot
be found.
"--logger=zap --log-outputs=default" will only error
for v3.4, since zap logger is still experimental.
v3.5 deprecates capnslog and changes "--log-outputs"
default value to "--log-outputs=stderr".
Signed-off-by: Gyuho Lee <gyuhox@gmail.com>
nolouch