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On Sun, 26 May 2013 11:20:25 +0200 |
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Michał Górny <mgorny@g.o> wrote: |
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> It is *easy*. |
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> |
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> ln -s /sbin/newinit /sbin/init.new |
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> mv /sbin/init.new /sbin/init |
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> |
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> Easy and atomic. The inconsistency potential is similar to one given |
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> by init upgrades. Yet we don't do anything magical to defer init |
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> upgrade until reboot, and that's why the upgrades go smoothly. |
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Easy isn't always good. It's not atomic since you can't reboot and |
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because of that I wouldn't call it smooth either. |
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> > I think that safest way not using wrapper is to stop all services |
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> > and keep only mounted /, than change things (symlinks,configuration |
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> > update) and reboot. |
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> |
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> This can be done two ways. |
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> |
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> One is hacking into init (RC) reboot procedure. It's fragile, it needs |
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> to be fit into the right moment and I'm not sure if all inits will |
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> handle this without actually needing to patch the code. And in the |
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> end, the init gets replaced before init stops working anyway. |
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You're making things way more complex than a wrapper would do. I'm not |
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a fan of using the words "hacking", "fragile" and "not sure" for |
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selling an approach; so, why were you suggesting the symlink approach? |
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> The other is going beside init and directly into the reboot. This |
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> either requires kernel hacking (please don't!) |
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Yes, please don't, it's against our general objectives. |
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http://www.gentoo.org/proj/en/kernel/maintenance.xml#doc_chap3 |
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Furthermore, even if you would consider this then you can't be |
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guaranteed that everyone uses genpatches; and I don't think we would |
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want this in the eclass either, its users will very likely object. |
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> or hacking the reboot procedure in init code. And of course |
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> remounting R/W, then writing, remounting back... |
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I don't think patching them is a reliable approach; it steps away from |
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being loosely coupled and therefore makes it harder to understand, you |
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are changing multiple things at once and introduce a maintenance burden. |
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With a wrapper, you don't have a problem with any of those... |
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Loose coupling, high cohesion. |
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-- |
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With kind regards, |
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Tom Wijsman (TomWij) |
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Gentoo Developer |
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E-mail address : TomWij@g.o |
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GPG Public Key : 6D34E57D |
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GPG Fingerprint : C165 AF18 AB4C 400B C3D2 ABF0 95B2 1FCD 6D34 E57D |
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