The parentheses prevent the `continue` line from working by running the
enclosed in a subshell -- I noticed that ZFS would start asking me for
my password to encrypted child datasets, even though they were not
specified in `requestEncryptionCredentials`. The following logs would
also be present in the import unit's journal:
Oct 31 22:13:17 host systemd[1]: Starting Import ZFS pool "pool"...
Oct 31 22:13:44 host zfs-import-pool-start[3711]: importing ZFS pool "pool"...
Oct 31 22:13:44 host zfs-import-pool-start[4017]:pool/nix/store/39zij3xcxn4w38v6x8f88bx8y91nv0rm-unit-script-zfs-import-pool-start/bin/zfs-import-pool-start: line 31: continue: only meaningful in a `for', `while', or `until' loop
Oct 31 22:13:44 host zfs-import-pool-start[4020]:pool/nix/store/39zij3xcxn4w38v6x8f88bx8y91nv0rm-unit-script-zfs-import-pool-start/bin/zfs-import-pool-start: line 31: continue: only meaningful in a `for', `while', or `until' loop
Oct 31 22:15:14 host zfs-import-pool-start[4023]: Failed to query password: Timer expired
Oct 31 22:15:14 host zfs-import-pool-start[4024]: Key load error: encryption failure
Oct 31 22:15:14 host systemd[1]: zfs-import-pool.service: Main process exited, code=exited, status=255/EXCEPTION
Oct 31 22:15:14 host systemd[1]: zfs-import-pool.service: Failed with result 'exit-code'.
Oct 31 22:15:14 host systemd[1]: Failed to start Import ZFS pool "pool".
Details on https://github.com/NixOS/nixops/issues/1063#issuecomment-453253666.
`partOf` makes that if `smokeping.service` is stopped, `thttpd.service` will
be stopped as well.
(But not that `thttpd` will be started when `smokeping` is started).
Once `thttpd.service` is stopped that way, `Restart = always` will not apply.
When the smokeping config options are changed, NixOS's `switch-configuration.pl`
will stop `smokeping` (whit shuts down thttpd due to `partOf`), and then restart
smokeping; but this does not start thttpd.
As a result, thttpd will be off after changing the config, which isn't desired.
This commit fixes it by removing the `partOf`, which makes `Restart` work
as expected.
This avoids a common problem:
Until now, port forwarding to multiple hosts running smokeping did not work;
they all show the data of the first smokeping instance.
That ws because the image URLs generated by smokeping are absolute
(`imgurl` setting).
Consequently, if you ran
ssh node-1 -L 8081:localhost:8081
ssh node-2 -L 8081:localhost:8082
ssh node-3 -L 8081:localhost:8083
and try to open http://localhost:8081, http://localhost:8082 and
http://localhost:8083, they all would show the images of node-1!
Using a relative `imgurl` fixes that.
As per smokeping docs on `imgurl`:
> Either an absolute URL to the `imgcache` directory or one relative to the
> directory where you keep the SmokePing cgi.
