From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yann E. MORIN <yann.morin.1998@free.fr>
Date: Wed, 8 Apr 2015 23:12:43 +0200
Subject: [Buildroot] [PATCH] help entries for Init system config menu
In-Reply-To: <20150324202302.GA4645@vostro>
References: <20150324202302.GA4645@vostro>
Message-ID: <20150408211243.GD4197@free.fr>
List-Id: <buildroot.busybox.net>
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To: buildroot@busybox.net

Alex, All,

On 2015-03-24 22:23 +0200, Alex Suykov spake thusly:
> Primary focus is on (auto-)respawning and runtime control.
> 
> Systemd entry describes current state, with several daemons
> configured as forking.

I think this is going a bit too far.

People buildign a system from scratch are expected to have at least some
knowledge about what ehy're doing, especially with regard to the init
system.

Sicne this will never be a complete description (especially the systemd
one as it gets more features), we'd be lagging behind quite fast.

So, I'm not too fond of this...

Regards,
Yann E. MORIN.

> Signed-off-by: Alex Suykov <alex.suykov@gmail.com>
> ---
> Patch split from the series since it does not depend on any
> of the changes there.
> 
>  system/Config.in | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 54 insertions(+)
> 
> diff --git a/system/Config.in b/system/Config.in
> index 9973cc2..59c759a 100644
> --- a/system/Config.in
> +++ b/system/Config.in
> @@ -75,15 +75,40 @@ config BR2_TARGET_GENERIC_PASSWD_METHOD
>  choice
>  	prompt "Init system"
>  	default BR2_INIT_BUSYBOX
> +	help
> +	  Upon bootup, kernel spawns init and init is expected
> +	  to spawn anything else.
> +
> +	  Buildroot supports several alternative init implementations
> +	  providing varying degrees of control over the spawned processes.
>  
>  config BR2_INIT_BUSYBOX
>  	bool "BusyBox"
>  	select BR2_PACKAGE_BUSYBOX
> +	help
> +	  Minimalistic init implementation from busybox
> +	  with systemV-style init scripts.
> +
> +	  Runlevels are not supported.
> +
> +	  Daemons are started in background using scripts
> +	  from /etc/init.d. Failed processes are not respawned.
> +	  Pid files provide some control over running processes.
>  
>  config BR2_INIT_SYSV
>  	bool "systemV"
>  	select BR2_PACKAGE_BUSYBOX_SHOW_OTHERS # sysvinit
>  	select BR2_PACKAGE_SYSVINIT
> +	help
> +	  System V init, probably the best-known init implementation
> +	  in Linux, with simplified SysV-style initscripts.
> +
> +	  Supports runlevels, but buildroot does not use them.
> +	  The system boots into the default runlevel and stays there.
> +
> +	  Daemons are started in background using scripts
> +	  from /etc/init.d. Failed processes are not respawned.
> +	  Pid files provide some control over running processes.
>  
>  config BR2_INIT_SYSTEMD
>  	bool "systemd"
> @@ -98,6 +123,29 @@ config BR2_INIT_SYSTEMD
>  	depends on !BR2_STATIC_LIBS
>  	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_7
>  	select BR2_PACKAGE_SYSTEMD
> +	help
> +	  systemd is more that just an init implementation.
> +	  It is a composite package handling most aspects
> +	  of system initialization and daemon supervision.
> +
> +	  Systemd uses arbitrary-named "targets" instead
> +	  of systemV-style runlevels. Daemons may be stopped
> +	  and restarted using systemctl command. If configured
> +	  so, failed processes are respawned.
> +
> +	  Whenever possible, package-supplied service files
> +	  are used. Some daemons are configured to run in
> +	  foreground and some run as background processes.
> +
> +	  Due its pervasiveness and extensive feature range,
> +	  choosing systemd shapes the rest of the system.
> +	  A systemd-based buildroot will differ little
> +	  from any major systemd-based Linux distribution
> +	  in pretty much any aspects of the boot process,
> +	  initialization, runtime configuration and process
> +	  supervision.
> +
> +	  Beware of its large size and numerous dependencies.
>  
>  comment 'systemd needs an (e)glibc toolchain, headers >= 3.7'
>  	depends on !(BR2_TOOLCHAIN_USES_GLIBC \
> @@ -105,6 +153,12 @@ comment 'systemd needs an (e)glibc toolchain, headers >= 3.7'
>  
>  config BR2_INIT_NONE
>  	bool "None"
> +	help
> +	  Do not install any kind of init system.
> +
> +	  Make sure your initrd and/or root fs skeleton provide
> +	  some executable for kernel to start, otherwise
> +	  the system will panic at boot.
>  
>  endchoice
>  
> -- 
> 2.0.3
> 
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot

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