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diff --git a/chroot-dev.html b/chroot-dev.html deleted file mode 100644 index e05cc47..0000000 --- a/chroot-dev.html +++ /dev/null @@ -1,119 +0,0 @@ -<!DOCTYPE html> -<html lang="en"> -<head> - <meta charset="UTF-8" /> - <title>Using chroots as simple "containers"</title> - <link rel="stylesheet" href="./style.css" /> - <link rel="icon" href="./favicon.ico" sizes="any" /> - <!--link rel="icon" href="./icon.svg" type="image/svg+xml" / --> - <meta name="viewport" content="width=device-width, initial-scale=1.0" /> - <meta name="theme-color" content="#241504" /> - <meta name="color-scheme" content="light dark"> - <style> -pre { - border: 1px solid; - border-radius: 0.5rem; - padding: 0.5rem; -} - </style> -</head> -<body> -<header> - <h1>Using chroots as simple "containers"</h1> -</header> - -<article> - <p style="display: block; border: 1px solid; border-radius: 0.5rem; padding: 0.5rem;"> - Please note that what I am about to do isn't actually containerization or isolation. It merely separates <em>trusted</em> code such that it would generally not pollute the host system. Chroot is generally not a security measure; for example, processes inside the chroot could easily escape with <code>/proc/<i>x</i>/root</code> for a PID <i>x</i> that runs outside the chroot. - </p> - <p> - Often times I want to install a program that is not available in my current distribution (e.g. the Soju IRC bouncer is not available on Debian Bookworm, but I want to use a distribution-packaged version instead of running <code>go build</code> myself because I want to receive updates), or perhaps I want to run something like <code>rustup</code> without the fear of polluting my system. But I don't want to use Docker or LXC because they feel too complicated. - </p> - <p> - I ended up creating <a href="https://alpinelinux.org">Alpine Linux</a> chroots. Specifically, Alpine Linux Edge, because the <code>edge/testing</code> repository is huge and frequently updated. There's an article called <a href="https://wiki.alpinelinux.org/wiki/Alpine_Linux_in_a_chroot">Alpine Linux in a chroot</a> on the Alpine Linux wiki that provided the steps that I use in my scripts. (The official <a href="https://github.com/alpinelinux/alpine-chroot-install/">alpine-chroot-install</a> scripts exist but haven't been updated for quite a while.) - </p> - <h2><a href="https://git.sr.ht/~runxiyu/rxchroot">The rxchroot scripts</a></h2> - <p> - Check the Git repository linked above for the complete set of scripts; here is a short explanation from excerpts of the script. - </p> - <p> - The first step, of course, is to create the chroot. Basically: - </p> - <pre>umask 022 # or something else that ensures unprivileged users could access the chroot -curl -LO "https://dl-cdn.alpinelinux.org/alpine/edge/main/${arch}/APKINDEX.tar.gz" -tar xvf APKINDEX.tar.gz -curl -LO "https://dl-cdn.alpinelinux.org/alpine/edge/main/${arch}/apk-tools-static-$(sed -n '/P:apk-tools-static/{n;p;}' APKINDEX | cut -d ':' -f 2).apk" -tar -xzf apk-tools-static-*.apk -./sbin/apk.static -X https://dl-cdn.alpinelinux.org/alpine/edge/main -U --allow-untrusted -p "${chroot_dir}" --initdb add alpine-base -cp -L /etc/resolv.conf ${chroot_dir}/etc/ -mkdir -p "${chroot_dir}"/etc/apk -echo "https://dl-cdn.alpinelinux.org/alpine/edge/main" > "${chroot_dir}"/etc/apk/repositories -echo "https://dl-cdn.alpinelinux.org/alpine/edge/community" >> "${chroot_dir}"/etc/apk/repositories -echo "https://dl-cdn.alpinelinux.org/alpine/edge/testing" >> "${chroot_dir}"/etc/apk/repositories</pre> - <p> - Every time the chroot needs to be used, some special directories must be mounted. Don't double-mount though as that often causes issues. - </p> - <pre>mount -o bind /dev "${chroot_dir}/dev" -mount -t proc none "${chroot_dir}/proc" -mount -o bind /sys "${chroot_dir}/sys"</pre> - <p> - Then just enter the chroot: - </p> - <pre>chroot "${chroot_dir}" /bin/ash -l</pre> - <p> - And perhaps install stuff: - </p> - <pre>apk add build-base soju vim</pre> - <p> - I'm running on a Debian host, and perhaps I want to start services in the Alpine chroot with systemd: - </p> - <pre># alpine.service ############################################### - -[Unit] -Description=Alpine chroot mounts -Wants=network-online.target -After=network-online.target - -[Service] -Type=oneshot -RemainAfterExit=true -User=root -Group=root -RuntimeDirectory=/alpine -ExecStart=/root/rxchroot/alpine-chroot-activate /alpine -ExecReload=/root/rxchroot/alpine-chroot-activate /alpine -ExecStop=/root/rxchroot/alpine-chroot-deactivate /alpine - -[Install] -WantedBy=multi-user.target - -# soju.service ################################################# - -[Unit] -Description=soju in an Alpine chroot -Requires=alpine.service -After=alpine.service - -[Service] -Type=simple -User=root -Group=root -# Fix the userspec to match the Alpine UID/GUID -ExecStart=/sbin/chroot --userspec=101:102 /alpine /usr/bin/soju -ExecReload=/bin/kill -HUP $MAINPID -Restart=on-failure - -[Install] -WantedBy=multi-user.target</pre> - <p>Since a chroot doesn't have its own kernel and all system calls pass through the host kernel, network services open ports as if they just run in the host system.</p> -</article> - -<footer> - <ul role="list"> - <li><a href="./">Home</a></li> - <li>Runxi Yu</li> - <li><a rel="license" href="./pubdom.html">Public Domain</a></li> - </ul> -</footer> -</body> -</html> |