diff --git a/nix/cluster-configuration.nix b/nix/cluster-configuration.nix
new file mode 100644
index 0000000..18faca0
--- /dev/null
+++ b/nix/cluster-configuration.nix
@@ -0,0 +1,210 @@
+{ config, pkgs, lib, ... }:
+
+with ( import ./toplevel.nix );
+let
+  fqdn = config.networking.hostName + domain;
+  node = (builtins.head (builtins.filter (n: n.fqdn == fqdn) nodes));
+  otherNodes = (builtins.filter (n: n.fqdn != fqdn) nodes);
+
+in rec {
+  imports =
+    [ # Include the results of the hardware scan.
+      ./hardware-configuration.nix
+    ];
+
+  # Use the GRUB 2 boot loader.
+  boot.loader.grub.enable = true;
+  boot.loader.grub.version = 2;
+  boot.loader.grub.device = node.diskBoot;
+
+  time.timeZone = "Europe/Warsaw";
+
+  # List packages installed in system profile. To search, run:
+  # $ nix search wget
+  environment.systemPackages = with pkgs; [
+    wget vim htop tcpdump
+    rxvt_unicode.terminfo
+  ];
+
+  # Some programs need SUID wrappers, can be configured further or are
+  # started in user sessions.
+  programs.mtr.enable = true;
+
+  # List services that you want to enable:
+  virtualisation.docker.enable = true;
+  virtualisation.docker.extraOptions = "--iptables=false --ip-masq=false --ip-forward=true";
+
+  # Docker 1.13 sets iptables FORWARD to DROP. Unfuck this.
+  systemd.services."docker-iptables-unfuck" = {
+    enable = true;
+    wantedBy = [ "kubernetes.target" ];
+    description = "Docker iptable Unfuck";
+    after = [ "docker.service" ];
+    requires = [ "docker.service" ];
+    path = [ pkgs.iptables ];
+    script = ''
+      iptables -P FORWARD ACCEPT
+    '';
+    serviceConfig.Type = "oneshot";
+  };
+
+  # Enable the OpenSSH daemon.
+  services.openssh.enable = true;
+  users.users.root.openssh.authorizedKeys.keys = [
+    "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDD4VJXAXEHEXZk2dxNwehneuJcEGkfXG/U7z4fO79vDVIENdedtXQUyLyhZJc5RTEfHhQj66FwIqzl7mzBHd9x9PuDp6QAYXrkVNMj48s6JXqZqBvF6H/weRqFMf4a2TZv+hG8D0kpvmLheCwWAVRls7Jofnp/My+yDd57GMdsbG/yFEf6WPMiOnA7hxdSJSVihCsCSw2p8PD4GhBe8CVt7xIuinhutjm9zYBjV78NT8acjDUfJh0B1ODTjs7nuW1CC4jybSe2j/OU3Yczj4AxRxBNWuFxUq+jBo9BfpbKLh+Tt7re+zBkaicM77KM/oV6943JJxgHNBBOsv9scZE7 q3k@amnesia"
+    "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDQb3YQoiYFZLKwvHYKbu1bMqzNeDCAszQhAe1+QI5SLDOotclyY/vFmOReZOsmyMFl71G2d7d+FbYNusUnNNjTxRYQ021tVc+RkMdLJaORRURmQfEFEKbai6QSFTwErXzuoIzyEPK0lbsQuGgqT9WaVnRzHJ2Q/4+qQbxAS34PuR5NqEkmn4G6LMo3OyJ5mwPkCj9lsqz4BcxRaMWFO3mNcwGDfSW+sqgc3E8N6LKrTpZq3ke7xacpQmcG5DU9VO+2QVPdltl9jWbs3gXjmF92YRNOuKPVfAOZBBsp8JOznfx8s9wDgs7RwPmDpjIAJEyoABqW5hlXfqRbTnfnMvuR informatic@InformaticPC"
+    "ssh-rsa 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 patryk.jakuszew@gmail.com"
+    "ssh-rsa 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 bartek@IHM"
+  ];
+
+  networking.firewall.enable = false;
+
+  # Point k8s apiserver address at ourselves, as every node runs an apiserver with this cert name.
+  networking.extraHosts = ''
+    127.0.0.1 ${k8sapi}
+  '';
+
+  security.acme.certs = {
+    host = {
+      email = acmeEmail;
+      domain = fqdn;
+      webroot = services.nginx.virtualHosts.host.root;
+    };
+  };
+
+  services.nginx = {
+    enable = true;
+    virtualHosts.host = {
+      serverName = fqdn;
+      root = "/var/www/${fqdn}";
+    };
+  };
+
+  services.etcd = {
+    enable = true;
+    name = fqdn;
+    listenClientUrls = ["https://0.0.0.0:2379"];
+    advertiseClientUrls = ["https://${fqdn}:2379"];
+    listenPeerUrls = ["https://0.0.0.0:2380"];
+    initialAdvertisePeerUrls = ["https://${fqdn}:2380"];
+    initialCluster = (map (n: "${n.fqdn}=https://${n.fqdn}:2380") nodes);
+
+    clientCertAuth = true;
+    trustedCaFile = pki.etcd.server.ca;
+    certFile = pki.etcd.server.cert;
+    keyFile = pki.etcd.server.key;
+
+    peerClientCertAuth = true;
+    peerTrustedCaFile = pki.etcdPeer.ca;
+    peerCertFile = pki.etcdPeer.cert;
+    peerKeyFile = pki.etcdPeer.key;
+
+    extraConf = {
+      PEER_CLIENT_CERT_AUTH = "true";
+    };
+  };
+
+  services.kubernetes = {
+    roles = []; # We do not use any nixpkgs predefined roles for k8s. Instead,
+                # we enable k8s components manually.
+
+    caFile = pki.kube.apiserver.ca;
+    clusterCidr = "10.10.16.0/20";
+    verbose = false;
+
+    path = [ pkgs.e2fsprogs ]; # kubelet wants to mkfs.ext4 when mounting pvcs
+
+    addons.dns.enable = false;
+
+    etcd = {
+      servers = (map (n: "https://${n.fqdn}:2379") nodes);
+      caFile = pki.etcd.kube.ca;
+      keyFile = pki.etcd.kube.key;
+      certFile = pki.etcd.kube.cert;
+    };
+
+    apiserver = rec {
+      enable = true;
+      port = ports.k8sAPIServerPlain;
+      securePort = ports.k8sAPIServerSecure;
+      advertiseAddress = "${node.ipAddr}";
+
+      tlsCertFile = pki.kube.apiserver.cert;
+      tlsKeyFile = pki.kube.apiserver.key;
+
+      clientCaFile = pki.kube.apiserver.ca;
+
+      kubeletHttps = true;
+      kubeletClientCaFile = pki.kube.apiserver.ca;
+      kubeletClientCertFile = pki.kube.apiserver.cert;
+      kubeletClientKeyFile = pki.kube.apiserver.key;
+
+      serviceAccountKeyFile = pki.kube.serviceaccounts.key;
+
+      serviceClusterIpRange = "10.10.12.0/24";
+      runtimeConfig = "api/all,authentication.k8s.io/v1beta1";
+      authorizationMode = ["Node" "RBAC"];
+      enableAdmissionPlugins = ["Initializers" "NamespaceLifecycle" "NodeRestriction" "LimitRanger" "ServiceAccount" "DefaultStorageClass" "ResourceQuota"];
+      extraOpts = ''
+        --apiserver-count=3 \
+        --proxy-client-cert-file=${pki.kubeFront.apiserver.cert} \
+        --proxy-client-key-file=${pki.kubeFront.apiserver.key} \
+        --requestheader-allowed-names= \
+        --requestheader-client-ca-file=${pki.kubeFront.apiserver.ca} \
+        --requestheader-extra-headers-prefix=X-Remote-Extra- \
+        --requestheader-group-headers=X-Remote-Group  \
+        --requestheader-username-headers=X-Remote-User \
+        -v=5
+      '';
+    };
+
+    controllerManager = {
+      enable = true;
+      address = "0.0.0.0";
+      port = ports.k8sControllerManagerPlain;
+      leaderElect = true;
+      serviceAccountKeyFile = pki.kube.serviceaccounts.key;
+      rootCaFile = pki.kube.ca;
+      extraOpts = ''
+        --service-cluster-ip-range=10.10.12.0/24 \
+        --use-service-account-credentials=true \
+        --secure-port=${toString ports.k8sControllerManagerSecure}\
+      '';
+      kubeconfig = pki.kube.controllermanager.config;
+    };
+
+    scheduler = {
+      enable = true;
+      address = "0.0.0.0";
+      port = 0;
+      leaderElect = true;
+      kubeconfig = pki.kube.scheduler.config;
+    };
+
+    proxy = {
+      enable = true;
+      kubeconfig = pki.kube.proxy.config;
+      extraOpts = ''
+        --hostname-override=${fqdn}\
+        --proxy-mode=iptables
+      '';
+    };
+
+    kubelet = {
+      enable = true;
+      unschedulable = false;
+      hostname = fqdn;
+      tlsCertFile = pki.kube.kubelet.cert;
+      tlsKeyFile = pki.kube.kubelet.key;
+      clientCaFile = pki.kube.kubelet.ca;
+      nodeIp = node.ipAddr;
+      networkPlugin = "cni";
+      clusterDns = "10.10.12.254";
+      kubeconfig = pki.kube.kubelet.config;
+      extraOpts = ''
+        --cni-conf-dir=/opt/cni/conf \
+        --cni-bin-dir=/opt/cni/bin
+      '';
+    };
+  };
+}
diff --git a/nix/toplevel.nix b/nix/toplevel.nix
new file mode 100644
index 0000000..15b552a
--- /dev/null
+++ b/nix/toplevel.nix
@@ -0,0 +1,90 @@
+rec {
+  domain = ".hswaw.net";
+  k8sapi = "k0.hswaw.net";
+  acmeEmail = "q3k@hackerspace.pl";
+
+  nodes = [
+    {
+      fqdn = "bc01n01.hswaw.net";
+      ipAddr = "185.236.240.35";
+      podNet = "10.10.16.0/24";
+      diskBoot = "/dev/sdb";
+    }
+    {
+      fqdn = "bc01n02.hswaw.net";
+      ipAddr = "185.236.240.36";
+      podNet = "10.10.17.0/24";
+      diskBoot = "/dev/sdb";
+    }
+    {
+      fqdn = "bc01n03.hswaw.net";
+      ipAddr = "185.236.240.37";
+      podNet = "10.10.18.0/24";
+      diskBoot = "/dev/sdb";
+    }
+  ];
+
+  pki = rec {
+    root = /opt/hscloud;
+
+    make = (radix: name: rec {
+      ca = root + "/${radix}-ca.crt";
+      cert = root + "/${radix}-${name}.crt";
+      key = root + "/${radix}-${name}.key";
+
+      json = (builtins.toJSON {
+        ca = (builtins.toString ca);
+        cert = (builtins.toString cert);
+        key = (builtins.toString key);
+      });
+    });
+
+    etcdPeer = (make "etcdpeer" "server");
+
+    etcd = {
+        server = (make "etcd" "server");
+        kube = (make "etcd" "kube");
+    };
+
+    makeKube = (name: (make "kube" name) // {
+      config = {
+        server = "https://${k8sapi}:${toString ports.k8sAPIServerSecure}";
+        certFile = (make "kube" name).cert;
+        keyFile = (make "kube" name).key;
+      };
+    });
+
+    kube = rec {
+      ca = apiserver.ca;
+      
+      # Used to identify apiserver.
+      apiserver = (makeKube "apiserver");
+
+      # Used to identify controller-manager.
+      controllermanager = (makeKube "controller-manager");
+
+      # Used to identify scheduler.
+      scheduler = (makeKube "scheduler");
+
+      # Used to identify kube-proxy.
+      proxy = (makeKube "proxy");
+
+      # Used to identify kubelet.
+      kubelet = (makeKube "node");
+
+      # Used to encrypt service accounts.
+      serviceaccounts = (makeKube "serviceaccounts");
+    };
+
+    kubeFront = {
+      apiserver = (make "kubeFront" "apiserver");
+    };
+  };
+
+  ports = {
+    k8sAPIServerPlain = 4000;
+    k8sAPIServerSecure = 4001;
+    k8sControllerManagerPlain = 0; # 4002; do not serve plain http
+    k8sControllerManagerSecure = 4003;
+  };
+}