nixpkgs/nixos/modules/services/cluster/kubernetes/kubelet.nix
Tristan Gosselin-Hane 5a03aa5a45 nixos/kubernetes: add extraConfig to kubelet config
Every now and then, kubernetes adds new configuration parameters to the
kubelet configuration. Since this is defined using a nix attrset which
is then converted to json/yaml, it would be nice to have an escape hatch
similar to the extraOpts one that exists for additional CLI arguments.
The typical use case would be to configure new settings before they are
officially supported in the nixos module.
2024-08-30 22:12:40 -04:00

408 lines
12 KiB
Nix

{ config, lib, options, pkgs, ... }:
with lib;
let
top = config.services.kubernetes;
otop = options.services.kubernetes;
cfg = top.kubelet;
cniConfig =
if cfg.cni.config != [] && cfg.cni.configDir != null then
throw "Verbatim CNI-config and CNI configDir cannot both be set."
else if cfg.cni.configDir != null then
cfg.cni.configDir
else
(pkgs.buildEnv {
name = "kubernetes-cni-config";
paths = imap (i: entry:
pkgs.writeTextDir "${toString (10+i)}-${entry.type}.conf" (builtins.toJSON entry)
) cfg.cni.config;
});
infraContainer = pkgs.dockerTools.buildImage {
name = "pause";
tag = "latest";
copyToRoot = pkgs.buildEnv {
name = "image-root";
pathsToLink = [ "/bin" ];
paths = [ top.package.pause ];
};
config.Cmd = ["/bin/pause"];
};
kubeconfig = top.lib.mkKubeConfig "kubelet" cfg.kubeconfig;
# Flag based settings are deprecated, use the `--config` flag with a
# `KubeletConfiguration` struct.
# https://kubernetes.io/docs/tasks/administer-cluster/kubelet-config-file/
#
# NOTE: registerWithTaints requires a []core/v1.Taint, therefore requires
# additional work to be put in config format.
#
kubeletConfig = pkgs.writeText "kubelet-config" (builtins.toJSON ({
apiVersion = "kubelet.config.k8s.io/v1beta1";
kind = "KubeletConfiguration";
address = cfg.address;
port = cfg.port;
authentication = {
x509 = lib.optionalAttrs (cfg.clientCaFile != null) { clientCAFile = cfg.clientCaFile; };
webhook = {
enabled = true;
cacheTTL = "10s";
};
};
authorization = {
mode = "Webhook";
};
cgroupDriver = "systemd";
hairpinMode = "hairpin-veth";
registerNode = cfg.registerNode;
containerRuntimeEndpoint = cfg.containerRuntimeEndpoint;
healthzPort = cfg.healthz.port;
healthzBindAddress = cfg.healthz.bind;
} // lib.optionalAttrs (cfg.tlsCertFile != null) { tlsCertFile = cfg.tlsCertFile; }
// lib.optionalAttrs (cfg.tlsKeyFile != null) { tlsPrivateKeyFile = cfg.tlsKeyFile; }
// lib.optionalAttrs (cfg.clusterDomain != "") { clusterDomain = cfg.clusterDomain; }
// lib.optionalAttrs (cfg.clusterDns != "") { clusterDNS = [ cfg.clusterDns ] ; }
// lib.optionalAttrs (cfg.featureGates != {}) { featureGates = cfg.featureGates; }
// lib.optionalAttrs (cfg.extraConfig != {}) cfg.extraConfig
));
manifestPath = "kubernetes/manifests";
taintOptions = with lib.types; { name, ... }: {
options = {
key = mkOption {
description = "Key of taint.";
default = name;
defaultText = literalMD "Name of this submodule.";
type = str;
};
value = mkOption {
description = "Value of taint.";
type = str;
};
effect = mkOption {
description = "Effect of taint.";
example = "NoSchedule";
type = enum ["NoSchedule" "PreferNoSchedule" "NoExecute"];
};
};
};
taints = concatMapStringsSep "," (v: "${v.key}=${v.value}:${v.effect}") (mapAttrsToList (n: v: v) cfg.taints);
in
{
imports = [
(mkRemovedOptionModule [ "services" "kubernetes" "kubelet" "applyManifests" ] "")
(mkRemovedOptionModule [ "services" "kubernetes" "kubelet" "cadvisorPort" ] "")
(mkRemovedOptionModule [ "services" "kubernetes" "kubelet" "allowPrivileged" ] "")
(mkRemovedOptionModule [ "services" "kubernetes" "kubelet" "networkPlugin" ] "")
(mkRemovedOptionModule [ "services" "kubernetes" "kubelet" "containerRuntime" ] "")
];
###### interface
options.services.kubernetes.kubelet = with lib.types; {
address = mkOption {
description = "Kubernetes kubelet info server listening address.";
default = "0.0.0.0";
type = str;
};
clusterDns = mkOption {
description = "Use alternative DNS.";
default = "10.1.0.1";
type = str;
};
clusterDomain = mkOption {
description = "Use alternative domain.";
default = config.services.kubernetes.addons.dns.clusterDomain;
defaultText = literalExpression "config.${options.services.kubernetes.addons.dns.clusterDomain}";
type = str;
};
clientCaFile = mkOption {
description = "Kubernetes apiserver CA file for client authentication.";
default = top.caFile;
defaultText = literalExpression "config.${otop.caFile}";
type = nullOr path;
};
cni = {
packages = mkOption {
description = "List of network plugin packages to install.";
type = listOf package;
default = [];
};
config = mkOption {
description = "Kubernetes CNI configuration.";
type = listOf attrs;
default = [];
example = literalExpression ''
[{
"cniVersion": "0.3.1",
"name": "mynet",
"type": "bridge",
"bridge": "cni0",
"isGateway": true,
"ipMasq": true,
"ipam": {
"type": "host-local",
"subnet": "10.22.0.0/16",
"routes": [
{ "dst": "0.0.0.0/0" }
]
}
} {
"cniVersion": "0.3.1",
"type": "loopback"
}]
'';
};
configDir = mkOption {
description = "Path to Kubernetes CNI configuration directory.";
type = nullOr path;
default = null;
};
};
containerRuntimeEndpoint = mkOption {
description = "Endpoint at which to find the container runtime api interface/socket";
type = str;
default = "unix:///run/containerd/containerd.sock";
};
enable = mkEnableOption "Kubernetes kubelet";
extraOpts = mkOption {
description = "Kubernetes kubelet extra command line options.";
default = "";
type = separatedString " ";
};
extraConfig = mkOption {
description = "Kubernetes kubelet extra configuration file entries.";
default = {};
type = attrsOf attrs;
};
featureGates = mkOption {
description = "Attribute set of feature gate";
default = top.featureGates;
defaultText = literalExpression "config.${otop.featureGates}";
type = attrsOf bool;
};
healthz = {
bind = mkOption {
description = "Kubernetes kubelet healthz listening address.";
default = "127.0.0.1";
type = str;
};
port = mkOption {
description = "Kubernetes kubelet healthz port.";
default = 10248;
type = port;
};
};
hostname = mkOption {
description = "Kubernetes kubelet hostname override.";
defaultText = literalExpression "config.networking.fqdnOrHostName";
type = str;
};
kubeconfig = top.lib.mkKubeConfigOptions "Kubelet";
manifests = mkOption {
description = "List of manifests to bootstrap with kubelet (only pods can be created as manifest entry)";
type = attrsOf attrs;
default = {};
};
nodeIp = mkOption {
description = "IP address of the node. If set, kubelet will use this IP address for the node.";
default = null;
type = nullOr str;
};
registerNode = mkOption {
description = "Whether to auto register kubelet with API server.";
default = true;
type = bool;
};
port = mkOption {
description = "Kubernetes kubelet info server listening port.";
default = 10250;
type = port;
};
seedDockerImages = mkOption {
description = "List of docker images to preload on system";
default = [];
type = listOf package;
};
taints = mkOption {
description = "Node taints (https://kubernetes.io/docs/concepts/configuration/assign-pod-node/).";
default = {};
type = attrsOf (submodule [ taintOptions ]);
};
tlsCertFile = mkOption {
description = "File containing x509 Certificate for HTTPS.";
default = null;
type = nullOr path;
};
tlsKeyFile = mkOption {
description = "File containing x509 private key matching tlsCertFile.";
default = null;
type = nullOr path;
};
unschedulable = mkOption {
description = "Whether to set node taint to unschedulable=true as it is the case of node that has only master role.";
default = false;
type = bool;
};
verbosity = mkOption {
description = ''
Optional glog verbosity level for logging statements. See
<https://github.com/kubernetes/community/blob/master/contributors/devel/logging.md>
'';
default = null;
type = nullOr int;
};
};
###### implementation
config = mkMerge [
(mkIf cfg.enable {
environment.etc."cni/net.d".source = cniConfig;
services.kubernetes.kubelet.seedDockerImages = [infraContainer];
boot.kernel.sysctl = {
"net.bridge.bridge-nf-call-iptables" = 1;
"net.ipv4.ip_forward" = 1;
"net.bridge.bridge-nf-call-ip6tables" = 1;
};
systemd.services.kubelet = {
description = "Kubernetes Kubelet Service";
wantedBy = [ "kubernetes.target" ];
after = [ "containerd.service" "network.target" "kube-apiserver.service" ];
path = with pkgs; [
gitMinimal
openssh
util-linux
iproute2
ethtool
thin-provisioning-tools
iptables
socat
] ++ lib.optional config.boot.zfs.enabled config.boot.zfs.package ++ top.path;
preStart = ''
${concatMapStrings (img: ''
echo "Seeding container image: ${img}"
${if (lib.hasSuffix "gz" img) then
''${pkgs.gzip}/bin/zcat "${img}" | ${pkgs.containerd}/bin/ctr -n k8s.io image import --all-platforms -''
else
''${pkgs.coreutils}/bin/cat "${img}" | ${pkgs.containerd}/bin/ctr -n k8s.io image import --all-platforms -''
}
'') cfg.seedDockerImages}
rm /opt/cni/bin/* || true
${concatMapStrings (package: ''
echo "Linking cni package: ${package}"
ln -fs ${package}/bin/* /opt/cni/bin
'') cfg.cni.packages}
'';
serviceConfig = {
Slice = "kubernetes.slice";
CPUAccounting = true;
MemoryAccounting = true;
Restart = "on-failure";
RestartSec = "1000ms";
ExecStart = ''${top.package}/bin/kubelet \
--config=${kubeletConfig} \
--hostname-override=${cfg.hostname} \
--kubeconfig=${kubeconfig} \
${optionalString (cfg.nodeIp != null)
"--node-ip=${cfg.nodeIp}"} \
--pod-infra-container-image=pause \
${optionalString (cfg.manifests != {})
"--pod-manifest-path=/etc/${manifestPath}"} \
${optionalString (taints != "")
"--register-with-taints=${taints}"} \
--root-dir=${top.dataDir} \
${optionalString (cfg.verbosity != null) "--v=${toString cfg.verbosity}"} \
${cfg.extraOpts}
'';
WorkingDirectory = top.dataDir;
};
unitConfig = {
StartLimitIntervalSec = 0;
};
};
# Always include cni plugins
services.kubernetes.kubelet.cni.packages = [pkgs.cni-plugins pkgs.cni-plugin-flannel];
boot.kernelModules = ["br_netfilter" "overlay"];
services.kubernetes.kubelet.hostname =
mkDefault (lib.toLower config.networking.fqdnOrHostName);
services.kubernetes.pki.certs = with top.lib; {
kubelet = mkCert {
name = "kubelet";
CN = top.kubelet.hostname;
action = "systemctl restart kubelet.service";
};
kubeletClient = mkCert {
name = "kubelet-client";
CN = "system:node:${top.kubelet.hostname}";
fields = {
O = "system:nodes";
};
action = "systemctl restart kubelet.service";
};
};
services.kubernetes.kubelet.kubeconfig.server = mkDefault top.apiserverAddress;
})
(mkIf (cfg.enable && cfg.manifests != {}) {
environment.etc = mapAttrs' (name: manifest:
nameValuePair "${manifestPath}/${name}.json" {
text = builtins.toJSON manifest;
mode = "0755";
}
) cfg.manifests;
})
(mkIf (cfg.unschedulable && cfg.enable) {
services.kubernetes.kubelet.taints.unschedulable = {
value = "true";
effect = "NoSchedule";
};
})
];
meta.buildDocsInSandbox = false;
}