From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 28068 invoked from network); 29 Jan 2021 14:33:45 -0000 Received: from alyss.skarnet.org (95.142.172.232) by inbox.vuxu.org with ESMTPUTF8; 29 Jan 2021 14:33:45 -0000 Received: (qmail 1459 invoked by uid 89); 29 Jan 2021 14:34:10 -0000 Mailing-List: contact supervision-help@list.skarnet.org; run by ezmlm Sender: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Received: (qmail 1452 invoked from network); 29 Jan 2021 14:34:10 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:subject:message-id:mail-followup-to:references :mime-version:content-disposition:in-reply-to; bh=mj7En1pddtyR90zh8ykJm7bAtZUv9FmzkdsPPyAOtuo=; b=jBjQnY5mWvMU9BV/R8Mj2Nr/rHGaFj2I7xeP6XjuBQ+PIv0g/aXfp9mFXDQdJGjXfO 8h7dopYEzNmE8uplYzoc/qz0cfm34XLQAfd4YDMRMI2emUWP02I3OuhX5lzf1Yrz+7eG btLfXJH3nwM7DselWk+5dMF5CwEHEzqS8/hu2v58rRHoNINQGos5hZv9LXdZVR3dX5fM GbIU+IFZjqoKu5f7QRgf3Tt4S8ThLdn2/0q9EnMrvRTT+a1qTtHcwKti6kw4GgDks9LQ 297sANACvOos5AFwPaIu2bWKPvky/VRajbPx8kEuKDveb2xznxCSX2uwUuQynBNIvUSV sf+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:subject:message-id:mail-followup-to :references:mime-version:content-disposition:in-reply-to; bh=mj7En1pddtyR90zh8ykJm7bAtZUv9FmzkdsPPyAOtuo=; b=TlJiC6rVb+Gc0XNLaE8A5xwjQWxWprX38gMar5S2PDf23Tr/bUWbBrzb7kMeA36C+D oLNIdFxfAsz5f3C8+HF7KD/fnxvchJdn2CMprcIPevPgKriasgSWsOdPBf+4T+e3M+gm HXHk7eWK2QLz04L8cVqhFOCC5tV5q1GpZ/JQAh2XpOSRigslKDS5Kk4QEX9Yquk32MIa 709sEKVpQ0qyxXvxSOlJxE0pPWaCsB1H7o2PB9Ukq1MvV8d6hsp14W56pg489fbMBnGK zJbpUAENFxYUotxLE3oZKpB1ChiSEBz0LSXpZ9dr8rub6+NNguekqK9xuPs7H/25HCVO 0KsA== X-Gm-Message-State: AOAM533XjPoBKjcHUaVFLJW3R7uMEjqVSitM9v0ax9EywPWQ+AbmFpH+ +Q1l8kX1TVPJOUwcnSKG7jcHqFpejMw= X-Google-Smtp-Source: ABdhPJwY3ytWT8u4EjQeA1m+eK85p8XRlMIh2h+aW1PWJzHLM+uEPg9oLDMsW7G7NYiG7I7gmSu8sw== X-Received: by 2002:aa7:d39a:: with SMTP id x26mr5234558edq.51.1611930823222; Fri, 29 Jan 2021 06:33:43 -0800 (PST) From: "Casper Ti. Vector" X-Google-Original-From: "Casper Ti. Vector" Date: Fri, 29 Jan 2021 22:33:36 +0800 To: supervision@list.skarnet.org Subject: Re: Some suggestions on old-fashioned usage with s6 2.10.x Message-ID: Mail-Followup-To: supervision@list.skarnet.org References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Fri, Jan 29, 2021 at 09:57:43AM +0000, Laurent Bercot wrote: > It may cost more *to you*, but there is real and significant value > in following existing interfaces that people are familiar with. Being > able to just use "reboot" instead of the, uh, slightly less intuitive > "s6-svscanctl -6 /run/service" to reboot your machine, is one fewer > obstacle on the way to mainstream s6 adoption. But even `s6-reboot' from older s6-linux-init, or `busybox reboot' with slew can already do that... > Additionally, and maybe more to your liking, there are also technical > benefits to never killing s6-svscan. Being able to assume that a > supervision tree will be operational at all times, including during > shutdown (and even in stage 4!), is really comfortable, it cuts down > on a lot of specialcasing, it makes shutdown procedures recoverable, > integration into various configurations easier (I'm thinking > containers with or without a catch-all logger, for instance), and There is some non-trivial trade-off: in short, the existence of the supervision tree after stage 2 is by itself a kind of "special case" (eg. search for "careful handling" in [1]). I am also thinking about an application scenario, where a supervision tree with a new s6 version replaces the active tree with an old version. This is somewhat silly: it can be a little useful in case of major version bump, but is probably better solved by complete reboot to completely get rid of all old things (s6 or not, updated together) in the memory. [1] . > all-in-all has just less of a "screwdriver and duct tape" feel than > a bunch of execline (or rc ;)) scripts. I am very sorry, but I do feel a strong smell of systemd mindset here :( -- My current OpenPGP key: RSA4096/0x227E8CAAB7AA186C (expires: 2022.09.20) 7077 7781 B859 5166 AE07 0286 227E 8CAA B7AA 186C