Hello,
I've been trying to figure out how the same specifier, particularly %H, is
resolved in Environment= and ExecStart=. For that I use a VM with Centos 7 that
has systemd v219 (from systemd-219-78.el7_9.2.x86_64 rpm), and a
consul-template binary, that starts as systemd service.
The system unit of the latter is quite simple:
...
[Service]
...
Environment=HOSTNAME=%H
ExecStart=/usr/bin/env HOSTNAME=%H /usr/bin/consul-template $CMD_OPTS
...
After the VM has booted that process has the following:
$ hostname
vm-0005
$ sudo systemctl show consul-template | grep -E 'Environment|ExecStart'
ExecStart={ path=/usr/bin/env ; argv[]=/usr/bin/env HOSTNAME=%H
/usr/bin/consul-template $CMD_OPTS ; ignore_errors=no ; start_time=[Wed
2021-02-03 21:43:37 UTC] ; stop_time=[n/a] ; pid=1198 ; code=(null) ;
status=0/0 }
Environment=HOSTNAME=vm-0004
EnvironmentFile=/etc/sysconfig/consul-template (ignore_errors=no)
$ sudo grep -aoE 'HOSTNAME=[-a-z0-9]+' /proc/$(pidof consul-template)/environ
HOSTNAME=vm-0005
HOSTNAME=vm-0004 was set on a previous VM, that was used to create an image for
vm-0005.
>From all of that I have guess that expansion of the same specifier happens at
>different point in time for Environment= and for ExecStart=. Unfortunately, I
>could not find any references about that in the documentation. If I edit that
>system unit or reload systemd, Environment= will have HOSTNAME=vm-0005 value.
Could you please explain how the same specifier is resolved in different
directives?
Thank you.
--
Kind regards,
R
_______________________________________________
systemd-devel mailing list
systemd-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/systemd-devel
