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,MAILING_LIST_MULTI,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 6418 invoked from network); 19 Nov 2023 00:32:02 -0000 Received: from alyss.skarnet.org (95.142.172.232) by inbox.vuxu.org with ESMTPUTF8; 19 Nov 2023 00:32:02 -0000 Received: (qmail 47681 invoked by uid 89); 19 Nov 2023 00:32:26 -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 47670 invoked from network); 19 Nov 2023 00:32:25 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=telent.net; s=mail; t=1700353917; bh=cknvHLldxKkOoFucCLc46X77SraNR1UfOiMVRsTnTcI=; h=From:To:Subject:In-Reply-To:References:Date; b=X0Xz9tQHiadQuqGjWr0lfLX0GaUV9bM1MszfEwSYhmPvJXy3dI1iAWGfJzelUNmCK j1rKxFaTPqqQprJCdnVFyvGnh2xePjpoCipj0s58sW+9wftT/B48EB9tBZkrXtK9nr vNF0r6teQtM6eR0VZjnbM9Dzfk5bKXkhJF7CBkwM= From: Daniel Barlow To: Laurent Bercot , supervision@list.skarnet.org Subject: Re: restarting s6-svscan (as pid 1) In-Reply-To: References: <871qco81jj.fsf@telent.net> Date: Sun, 19 Nov 2023 00:31:43 +0000 Message-ID: <87wmue7fdc.fsf@telent.net> MIME-Version: 1.0 Content-Type: text/plain "Laurent Bercot" writes: > That said, I'm not sure your goal is as valuable as you think it is. > If you have a running system, by definition, it's running. It has > booted, > and you have access to its rootfs and all the tools on it; there is > nothing to gain by doing something fragile such as exec'ing into > another pid 1 and pivot_rooting. Unless I've missed something, the > amount of space you'll need for your maintenance system will be the > exact same whether you switch to it from your production system or from > cold booting. I would agree with you generally, but in this case the running system has a readonly squashfs filesystem which can't be updated except by flashing a complete new filesystem image on top of it. (I have tried doing this on the running system just to see what would happen, but the result was as about terminal as you might imagine it would be.) I believe (have not yet tested) that I can relatively simply create the maintenance system on the fly by copying a subset of the root fs into a ramdisk, so it doesn't take any space until it's needed. -dan