quit nicely with bitcoin-cli stop; use simple mode

[SmartLayer]

• stop bitcoind with bitcoin-cli stop
  (as I Googled around it seem to be the neater way to stop bitcoind)

• Put bitcoind to the foreground - Supervision services like systemd usually prefer daemons to be running in the foreground.

Tested on my production server, Debian 9.5.

[ch4ot1c]

I also had issues stopping/restarting with the prior version, so this is a welcome commit. Was on Debian as well (Raspbian Stretch Lite, Pi3).

Working better - restarted successfully!

[DrahtBot]

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Conflicts

Reviewers, this pull request conflicts with the following ones:

• #12255 (Update bitcoin.service to conform to init.md by dongcarl)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

[fanquake]

@dongcarl can you comment on how this overlaps with #12255

[dongcarl]

@fanquake It seems somewhat orthogonal to what I was doing in #12255, this commit seems to want to have systemd handle the daemonizing of bitcoind, whereas my change explicitly configures the pid file location such that systemd has a way to reach bitcoind. I am fine with either approach, and will rebase my commit sometime.

[promag]

Can't test ATM, what happens when you try to stop or restart if service is already stopped?

[dongcarl]

@promag I believe since systemd handles the daemonizing of bitcoind, if bitcoind is stopped directly (through bitcoin-cli or via a kill signal), the systemd service will also be stopped.

[dongcarl]

@colourful-land Upon re-looking at this PR, I'm not sure that we should be stopping the node with bitcoin-cli stop.

If you look at the Shutdown section of init.cpp here:

bitcoin/src/init.cpp

Lines 102 to 104 in e77a225

	// A clean exit happens when StartShutdown() or the SIGTERM
	// signal handler sets ShutdownRequested(), which makes main thread's
	// WaitForShutdown() interrupts the thread group.

It seems that SIGTERM is sufficient, and that is the default KillSignal according to systemd.kill. I would specify it explicitly, but that's not entirely necessary.

Not running bitcoind in daemon mode could be helpful, and I would explicitly add printtoconsole so that logs are available from journald.

[laanwj]

It should be unnecessary if SIGTERM is currently used, as SIGTERM does exactly the same as bitcoin-cli stop

[dongcarl]

For the "use simple mode" part of this PR, see here (#12255 (comment)) for why it's not a good idea.

[fanquake]

Closing for now, due to comments here as well as in #12255.