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author | Euan Kemp <euank@euank.com> | 2020-03-22 22:26:38 -0700 |
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committer | Frederik Rietdijk <freddyrietdijk@fridh.nl> | 2020-04-05 15:34:18 +0200 |
commit | e370711ad0e07519a0d675ecf2ec0587f07d75e0 (patch) | |
tree | ff84a120c786c7f174286dd9d1a23719e3919da6 /pkgs/applications/networking/cluster/k3s/default.nix | |
parent | d6a8d0ca5b03dbdb84070b47021b2b852429348e (diff) | |
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k3s: init at 1.17.3+k3s1
This packages k3s as a single self-contained binary (as upstream k3s does), but without having to download any impure already-built binaries. The upstream packaging scripts are used. Due to k3s's rather complicated packaging arrangement, this ends up being a rather long derivation.
Diffstat (limited to 'pkgs/applications/networking/cluster/k3s/default.nix')
-rw-r--r-- | pkgs/applications/networking/cluster/k3s/default.nix | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/pkgs/applications/networking/cluster/k3s/default.nix b/pkgs/applications/networking/cluster/k3s/default.nix new file mode 100644 index 00000000000..a032a3c12ad --- /dev/null +++ b/pkgs/applications/networking/cluster/k3s/default.nix @@ -0,0 +1,233 @@ +with import <nixpkgs> {}; + +{ stdenv, lib, makeWrapper, fetchFromGitHub, fetchurl, fetchzip }: + +with lib; + +# k3s is a kinda weird derivation. One of the main points of k3s is the +# simplicity of it being one binary that can perform several tasks. +# However, when you have a good package manager (like nix), that doesn't +# actually make much of a difference; you don't really care if it's one binary +# or 10 since with a good package manager, installing and running it is +# identical. +# Since upstream k3s packages itself as one large binary with several +# "personalities" (in the form of subcommands like 'k3s agent' and 'k3s +# kubectl'), it ends up being easiest to mostly mimic upstream packaging, with +# some exceptions. +# K3s also carries patches to some packages (such as containerd and cni +# plugins), so we intentionally use the k3s versions of those binaries for k3s, +# even if the upstream version of those binaries exist in nixpkgs already. In +# the end, that means we have a thick k3s binary that behaves like the upstream +# one for the most part. +# However, k3s also bundles several pieces of unpatched software, from the +# strongswan vpn software, to iptables, to socat, conntrack, busybox, etc. +# Those pieces of software we entirely ignore upstream's handling of, and just +# make sure they're in the path if desired. +let + k3sVersion = "1.17.3+k3s1"; # k3s git tag + traefikChartVersion = "1.81.0"; # taken from ./scripts/version.sh at the above k3s tag + k3sRootVersion = "0.3.0"; # taken from .s/cripts/version.sh at the above k3s tag + # bundled into the k3s binary + traefikChart = fetchurl { + url = "https://kubernetes-charts.storage.googleapis.com/traefik-${traefikChartVersion}.tgz"; + sha256 = "1aqpzgjlvqhil0g3angz94zd4xbl4iq0qmpjcy5aq1xv9qciwdi9"; + }; + # so, k3s is a complicated thing to package + # This derivation attempts to avoid including any random binaries from the + # internet. k3s-root is _mostly_ binaries built to be bundled in k3s (which + # we don't care about doing, we can add those as build or runtime + # dependencies using a real package manager). + # In addition to those binaries, it's also configuration though (right now + # mostly strongswan configuration), and k3s does use those files. + # As such, we download it in order to grab 'etc' and bundle it into the final + # k3s binary. + k3sRoot = fetchzip { + # Note: marked as apache 2.0 license + url = "https://github.com/rancher/k3s-root/releases/download/v${k3sRootVersion}/k3s-root-amd64.tar"; + sha256 = "12xafn5jivl8lqdcs25b28xrc4mf7yf1xif5np169nvvxgvmpdxp"; + stripRoot=false; + }; + k3sPlugins = buildGoPackage rec { + name = "k3s-cni-plugins"; + version = "0.7.6-k3s1"; # from ./scripts/version.sh 'VERSION_CNIPLUGINS'; update when k3s's repo is updated. + + goPackagePath = "github.com/containernetworking/plugins"; + subPackages = [ "." ]; + + src = fetchFromGitHub { + owner = "rancher"; + repo = "plugins"; + rev = "v${version}"; + sha256 = "0ax72z1ziann352bp6khfds8vlf3bbkqckrkpx4l4jxgqks45izs"; + }; + + meta = { + description = "k3s-cni-plugins"; + license = licenses.asl20; + homepage = https://k3s.io; + maintainers = []; + platforms = platforms.linux; + }; + }; + # Grab this separately from a build because it's used by both stages of the + # k3s build. + k3sRepo = fetchgit { + url = "https://github.com/rancher/k3s"; + rev = "v${k3sVersion}"; + leaveDotGit = true; # for version / build date below + sha256 = "0qahyc0mf9glxj49va6d20mcncqg4svfic2iz8b1lqid5c4g68mm"; + }; + # Stage 1 of the k3s build: + # Let's talk about how k3s is structured. + # One of the ideas of k3s is that there's the single "k3s" binary which can + # do everything you need, from running a k3s server, to being a worker node, + # to running kubectl. + # The way that actually works is that k3s is a single go binary that contains + # a bunch of bindata that it unpacks at runtime into directories (either the + # user's home directory or /var/lib/rancher if run as root). + # This bindata includes both binaries and configuration. + # In order to let nixpkgs do all its autostripping/patching/etc, we split this into two derivations. + # First, we build all the binaries that get packed into the thick k3s binary + # (and output them from one derivation so they'll all be suitably patched up). + # Then, we bundle those binaries into our thick k3s binary and use that as + # the final single output. + # This approach was chosen because it ensures the bundled binaries all are + # correctly built to run with nix (we can lean on the existing buildGoPackage + # stuff), and we can again lean on that tooling for the final k3s binary too. + # Other alternatives would be to manually run the + # strip/patchelf/remove-references step ourselves in the installPhase of the + # derivation when we've built all the binaries, but haven't bundled them in + # with generated bindata yet. + k3sBuildStage1 = buildGoPackage rec { + name = "k3s-build-1"; + version = "${k3sVersion}"; + + goPackagePath = "github.com/rancher/k3s"; + + src = k3sRepo; + + patches = [ ./patches/00-k3s.patch ]; + + nativeBuildInputs = [ pkgconfig autoPatchelfHook breakpointHook ]; + buildInputs = [ git runc libseccomp ]; + + buildPhase = '' + pushd go/src/${goPackagePath} + + patchShebangs ./scripts/build ./scripts/version.sh + mkdir -p bin + ./scripts/build + + popd + ''; + + installPhase = '' + pushd go/src/${goPackagePath} + + mkdir -p "$bin/bin" + install -m 0755 -t "$bin/bin" ./bin/* + + popd + ''; + + meta = { + description = "The various binaries that get packaged into the final k3s binary."; + license = licenses.asl20; + homepage = https://k3s.io; + maintainers = []; + platforms = platforms.linux; + }; + }; + k3sBuild = buildGoPackage rec { + name = "k3s-build"; + version = "${k3sVersion}"; + + goPackagePath = "github.com/rancher/k3s"; + + src = k3sRepo; + + patches = [ ./patches/00-k3s.patch ]; + + nativeBuildInputs = [ pkgconfig autoPatchelfHook breakpointHook ]; + buildInputs = [ git k3sBuildStage1 ]; + + # In order to build the thick k3s binary (which is what + # ./scripts/package-cli does), we need to get all the binaries that script + # expects in place. + buildPhase = '' + pushd go/src/${goPackagePath} + + patchShebangs ./scripts/build ./scripts/version.sh ./scripts/package-cli + + mkdir -p bin + + install -m 0755 -t ./bin ${k3sBuildStage1}/bin/* + install -m 0755 -T "${k3sPlugins}/bin/plugins" ./bin/cni + # Note: use the already-nixpkgs-bundled k3s rather than the one bundled + # in k3s because the k3s one is completely unmodified from upstream + # (unlike containerd, cni, etc) + install -m 0755 -T "${runc}/bin/runc" ./bin/runc + cp -R "${k3sRoot}/etc" ./etc + mkdir -p "build/static/charts" + cp "${traefikChart}" "build/static/charts/traefik-${traefikChartVersion}.tgz" + + ./scripts/package-cli + + popd + ''; + + installPhase = '' + pushd go/src/${goPackagePath} + + mkdir -p "$bin/bin" + install -m 0755 -t "$bin/bin" ./dist/artifacts/k3s + + popd + ''; + + meta = { + description = "The k3s go binary which is used by the final wrapped output below."; + license = licenses.asl20; + homepage = https://k3s.io; + maintainers = []; + platforms = platforms.linux; + }; + }; +in +stdenv.mkDerivation rec { + name = "k3s"; + + # Important utilities used by the kubelet, see + # https://github.com/kubernetes/kubernetes/issues/26093#issuecomment-237202494 + # Note the list in that issue is stale and some aren't relevant for k3s. + k3sRuntimeDeps = [ + socat iptables iproute bridge-utils ethtool utillinux ipset conntrack-tools + ]; + + buildInputs = [ + k3sBuild makeWrapper + ] ++ k3sRuntimeDeps; + + unpackPhase = "true"; + + # And, one final derivation (you thought the last one was it, right?) + # We got the binary we wanted above, but it doesn't have all the runtime + # dependencies k8s wants, including mount utilities for kubelet, networking + # tools for cni/kubelet stuff, etc + # Use a wrapper script to reference all the binaries that k3s tries to + # execute, but that we didn't bundle with it. + installPhase = '' + mkdir -p "$out/bin" + makeWrapper ${k3sBuild}/bin/k3s "$out/bin/k3s" \ + --prefix PATH : ${lib.makeBinPath k3sRuntimeDeps} \ + --prefix PATH : "$out/bin" + ''; + + meta = { + description = "A lightweight Kubernetes distribution."; + license = licenses.asl20; + homepage = https://k3s.io; + maintainers = with maintainers; [ euank ]; + platforms = platforms.linux; + }; +} |