From bfe0723728ae2d995b99f22fe9783a34889b1828 Mon Sep 17 00:00:00 2001
From: tv <tv@shackspace.de>
Date: Thu, 1 Oct 2015 01:48:15 +0200
Subject: move config scripts to krebs

---
 Makefile                                   |  15 +-
 default.nix                                |  31 ++-
 krebs/3modules/build.nix                   |  72 +++++++
 krebs/3modules/build/default.nix           | 304 -----------------------------
 krebs/3modules/build/infest/finalize.sh    |  65 ------
 krebs/3modules/build/infest/install-nix.sh |  57 ------
 krebs/3modules/build/infest/prepare.sh     |  74 -------
 krebs/3modules/default.nix                 |   2 +-
 krebs/4lib/infest/finalize.sh              |  65 ++++++
 krebs/4lib/infest/install-nix.sh           |  57 ++++++
 krebs/4lib/infest/prepare.sh               |  74 +++++++
 krebs/default.nix                          | 263 +++++++++++++++++++++++++
 12 files changed, 554 insertions(+), 525 deletions(-)
 create mode 100644 krebs/3modules/build.nix
 delete mode 100644 krebs/3modules/build/default.nix
 delete mode 100644 krebs/3modules/build/infest/finalize.sh
 delete mode 100644 krebs/3modules/build/infest/install-nix.sh
 delete mode 100644 krebs/3modules/build/infest/prepare.sh
 create mode 100644 krebs/4lib/infest/finalize.sh
 create mode 100644 krebs/4lib/infest/install-nix.sh
 create mode 100644 krebs/4lib/infest/prepare.sh
 create mode 100644 krebs/default.nix

diff --git a/Makefile b/Makefile
index 3727793e8..552e6e0fd 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,8 @@
 #
 # usage:
-#		make system=foo
-#		make systems='foo bar'
+#		make infest system=foo [target=bar]
+#		make [deploy] system=foo [target=bar]
+#		make [deploy] systems='foo bar'
 #		make eval get=tv.wu.config.time.timeZone [filter=json]
 #
 
@@ -11,6 +12,7 @@
 ifdef systems
 $(systems):
 	@
+	unset target
 	parallel \
 		--line-buffer \
 		-j0 \
@@ -20,7 +22,7 @@ $(systems):
 else ifdef system
 .PHONY: deploy infest
 deploy infest:;@
-	export get=$$LOGNAME.${system}.config.krebs.build.scripts.$@
+	export get=krebs.$@
 	export filter=json
 	make -s eval | sh
 
@@ -39,8 +41,11 @@ endif
 		--eval \
 		-A "$$get" \
 		'<stockholm>' \
-		--argstr user-name "$$LOGNAME" \
-		--argstr host-name "$$HOSTNAME" \
+		--argstr current-date "$$(date -Is)" \
+		--argstr current-host-name "$$HOSTNAME" \
+		--argstr current-user-name "$$LOGNAME" \
+		$${system+--argstr system "$$system"} \
+		$${target+--argstr target "$$target"} \
 		| filter
 else
 $(error unbound variable: system[s])
diff --git a/default.nix b/default.nix
index 1c3341ba7..7f3f621b8 100644
--- a/default.nix
+++ b/default.nix
@@ -1,36 +1,29 @@
-{ user-name, host-name }:
+{ current-date
+, current-host-name
+, current-user-name
+}:
 
 let
   lib = import <nixpkgs/lib>;
 
   krebs-modules-path = ./krebs/3modules;
   krebs-pkgs-path = ./krebs/5pkgs;
-  user-modules-path = ./. + "/${user-name}/3modules";
-  user-pkgs-path = ./. + "/${user-name}/5pkgs";
+  user-modules-path = ./. + "/${current-user-name}/3modules";
+  user-pkgs-path = ./. + "/${current-user-name}/5pkgs";
 
   out =
-    (lib.mapAttrs (k: v: mk-namespace (./. + "/${k}"))
+    (lib.mapAttrs
+      (k: v:
+        if builtins.pathExists (./. + "/${k}/1systems")
+          then mk-namespace (./. + "/${k}")
+          else import (./. + "/${k}"))
       (lib.filterAttrs
-        (k: v: !lib.hasPrefix "." k && v == "directory" &&
-          builtins.pathExists (./. + "/${k}/1systems"))
+        (k: v: !lib.hasPrefix "." k && v == "directory")
         (builtins.readDir ./.)));
 
   eval = path: import <nixpkgs/nixos/lib/eval-config.nix> {
     system = builtins.currentSystem;
     modules = [
-      ({ config, ... }:
-        with import ./krebs/4lib { inherit lib; };
-        {
-          options.krebs.exec.host = mkOption {
-            type = types.host;
-            default = config.krebs.hosts.${host-name};
-          };
-          options.krebs.exec.user = mkOption {
-            type = types.user;
-            default = config.krebs.users.${user-name};
-          };
-        }
-      )
       path
       krebs-modules-path
       user-modules-path
diff --git a/krebs/3modules/build.nix b/krebs/3modules/build.nix
new file mode 100644
index 000000000..57495ea69
--- /dev/null
+++ b/krebs/3modules/build.nix
@@ -0,0 +1,72 @@
+{ config, lib, ... }:
+
+with import ../4lib { inherit lib; };
+
+let
+  target = config.krebs.build // { user.name = "root"; };
+
+  out = {
+    # TODO deprecate krebs.build.host
+    options.krebs.build.host = mkOption {
+      type = types.host;
+    };
+
+    # TODO make krebs.build.profile shell safe
+    options.krebs.build.profile = mkOption {
+      type = types.str;
+      default = "/nix/var/nix/profiles/system";
+    };
+
+    # TODO make krebs.build.target.host :: host
+    options.krebs.build.target = mkOption {
+      type = with types; nullOr str;
+      default = null;
+    };
+
+    # TODO deprecate krebs.build.user
+    options.krebs.build.user = mkOption {
+      type = types.user;
+    };
+
+    options.krebs.build.source.dir = mkOption {
+      type = types.attrsOf (types.submodule ({ config, ... }: {
+        options = {
+          host = mkOption {
+            type = types.host;
+          };
+          path = mkOption {
+            type = types.str;
+          };
+          target-path = mkOption {
+            type = types.str;
+            default = "/root/${config._module.args.name}";
+          };
+          url = mkOption {
+            type = types.str;
+            default = "file://${config.host.name}${config.path}";
+          };
+        };
+      }));
+      default = {};
+    };
+
+    options.krebs.build.source.git = mkOption {
+      type = with types; attrsOf (submodule ({ config, ... }: {
+        options = {
+          url = mkOption {
+            type = types.str; # TODO must be shell safe
+          };
+          rev = mkOption {
+            type = types.str;
+          };
+          target-path = mkOption {
+            type = types.str;
+            default = "/root/${config._module.args.name}";
+          };
+        };
+      }));
+      default = {};
+    };
+  };
+
+in out
diff --git a/krebs/3modules/build/default.nix b/krebs/3modules/build/default.nix
deleted file mode 100644
index 23bd8c8fd..000000000
--- a/krebs/3modules/build/default.nix
+++ /dev/null
@@ -1,304 +0,0 @@
-{ config, lib, ... }:
-
-with import ../../4lib { inherit lib; };
-
-let
-  target = config.krebs.build // { user.name = "root"; };
-
-  out = {
-    # TODO deprecate krebs.build.host
-    options.krebs.build.host = mkOption {
-      type = types.host;
-    };
-
-    # TODO make krebs.build.profile shell safe
-    options.krebs.build.profile = mkOption {
-      type = types.str;
-      default = "/nix/var/nix/profiles/system";
-    };
-
-    # TODO make krebs.build.target.host :: host
-    options.krebs.build.target = mkOption {
-      type = with types; nullOr str;
-      default = null;
-    };
-
-    # TODO deprecate krebs.build.user
-    options.krebs.build.user = mkOption {
-      type = types.user;
-    };
-
-    options.krebs.build.scripts.init = lib.mkOption {
-      type = lib.types.str;
-      default =
-        let
-          inherit (config.krebs.build) host;
-        in
-        ''
-          #! /bin/sh
-          set -efu
-
-          hostname=${host.name}
-          secrets_dir=${config.krebs.build.source.dir.secrets.path}
-          key_type=ed25519
-          key_file=$secrets_dir/ssh.id_$key_type
-          key_comment=$hostname
-
-          if test -e "$key_file"; then
-            echo "Warning: privkey already exists: $key_file" >&2
-          else
-            ssh-keygen \
-                -C "$key_comment" \
-                -t "$key_type" \
-                -f "$key_file" \
-                -N ""
-            rm "$key_file.pub"
-          fi
-
-          pubkey=$(ssh-keygen -y -f "$key_file")
-
-          cat<<EOF
-          # put following into config.krebs.hosts.$hostname:
-          ssh.pubkey = $(echo $pubkey | jq -R .);
-          EOF
-        '';
-    };
-
-    options.krebs.build.scripts.deploy = lib.mkOption {
-      type = lib.types.str;
-      default = ''
-        set -efu
-        (${config.krebs.build.scripts._source})
-        ${ssh-target ''
-          ${config.krebs.build.scripts._nix-env}
-          ${config.krebs.build.profile}/bin/switch-to-configuration switch
-        ''}
-        echo OK
-      '';
-    };
-
-    options.krebs.build.scripts.infest = lib.mkOption {
-      type = lib.types.str;
-      default = ''
-        set -efu
-
-        export RSYNC_RSH; RSYNC_RSH="$(type -p ssh) \
-          -o 'HostName ${target.host.infest.addr}' \
-          -o 'Port ${toString target.host.infest.port}' \
-        "
-        ssh() {
-          eval "$RSYNC_RSH \"\$@\""
-        }
-
-        ${ssh-target ''
-          ${readFile ./infest/prepare.sh}
-          ${readFile ./infest/install-nix.sh}
-        ''}
-
-        (${config.krebs.build.scripts._source})
-
-        ${ssh-target ''
-          export PATH; PATH=/root/.nix-profile/bin:$PATH
-
-          src=$(type -p nixos-install)
-          cat_src() {
-            sed < "$src" "$(
-              { sed < "$src" -n '
-                    /^if ! test -e "\$mountPoint\/\$NIXOS_CONFIG/,/^fi$/=
-                    /^nixpkgs=/=
-                    /^NIX_PATH=/,/^$/{/./=}
-
-                    # Disable: Copy the NixOS/Nixpkgs sources to the target as
-                    # the initial contents of the NixOS channel.
-                    /^srcs=/,/^ln -sfn /=
-                  '
-              } | sed 's:$:s/^/#krebs#/:'
-            )"
-          }
-
-          # Location to insert config.krebs.build.scripts._nix-env
-          i=$(sed -n '/^echo "building the system configuration/=' "$src")
-
-          {
-            cat_src | sed -n "1,$i{p}"
-            cat ${doc config.krebs.build.scripts._nix-env}
-            cat_src | sed -n "$i,\''${$i!p}"
-          } > nixos-install
-          chmod +x nixos-install
-
-          # Wrap inserted config.krebs.build.scripts._nix-env into chroot.
-          nix_env=$(cat_src | sed -n '
-            s:.*\(/nix/store/[a-z0-9]*-nix-[0-9.]\+/bin/nix-env\).*:\1:p;T;q
-          ')
-          echo nix-env is $nix_env
-          sed -i '
-            s:^nix-env:chroot $mountPoint '"$nix_env"':
-          ' nixos-install
-
-          ./nixos-install
-
-          ${readFile ./infest/finalize.sh}
-        ''}
-      '';
-    };
-
-    options.krebs.build.scripts._nix-env = lib.mkOption {
-      type = lib.types.str;
-      default = ''
-        set -efu
-        NIX_PATH=${config.krebs.build.source.NIX_PATH} \
-        nix-env \
-          -f '<stockholm>' \
-          -Q \
-          --argstr user-name ${config.krebs.exec.user.name} \
-          --argstr host-name ${target.host.name} \
-          --profile ${config.krebs.build.profile} \
-          --set \
-          -A ${lib.escapeShellArg (lib.concatStringsSep "." [
-                config.krebs.build.user.name
-                config.krebs.build.host.name
-                "system"
-              ])}
-      '';
-    };
-
-    options.krebs.build.scripts._source = lib.mkOption {
-      type = lib.types.str;
-      default = ''
-        set -efu
-        ${
-          lib.concatStringsSep "\n"
-            (lib.mapAttrsToList
-              (name: { scripts, url, ... }: "(${scripts._source})")
-              (config.krebs.build.source.dir //
-               config.krebs.build.source.git))
-        }
-      '';
-    };
-
-    options.krebs.build.source.NIX_PATH = mkOption {
-      type = types.str;
-      default =
-        lib.concatStringsSep ":"
-          (lib.mapAttrsToList (name: _: "${name}=/root/${name}")
-            (config.krebs.build.source.dir //
-             config.krebs.build.source.git));
-    };
-
-    options.krebs.build.source.dir = mkOption {
-      type =
-        let
-          exec = config.krebs.exec;
-        in
-        types.attrsOf (types.submodule ({ config, ... }:
-          let
-            url = "file://${config.host.name}${config.path}";
-
-            can-link = config.host.name == target.host.name;
-            can-push = config.host.name == exec.host.name;
-
-            push-method = ''
-              rsync \
-                --exclude .git \
-                --exclude .graveyard \
-                --exclude old \
-                --exclude tmp \
-                --rsync-path='mkdir -p ${config.target-path} && rsync' \
-                --delete-excluded \
-                -vrLptgoD \
-                ${config.path}/ \
-                ${target.user.name}@${target.host.name}:${config.target-path}
-            '';
-          in
-          {
-            options = {
-              host = mkOption {
-                type = types.host;
-              };
-              path = mkOption {
-                type = types.str;
-              };
-              scripts._source = mkOption {
-                type = types.str;
-                default =
-                  #if can-link then link-method else
-                  if can-push then push-method else
-                  throw "cannot source ${url}";
-              };
-              target-path = mkOption {
-                type = types.str;
-                default = "/root/${config._module.args.name}";
-              };
-              url = mkOption {
-                type = types.str;
-                default = "file://${config.host.name}${config.path}";
-              };
-            };
-          }
-        ));
-      default = {};
-    };
-
-    options.krebs.build.source.git = mkOption {
-      type =
-        let
-          target = config.krebs.build // { user.name = "root"; };
-        in
-        with types; attrsOf (submodule ({ config, ... }:
-          {
-            options = {
-              url = mkOption {
-                type = types.str; # TODO must be shell safe
-              };
-              rev = mkOption {
-                type = types.str;
-              };
-              scripts._source = mkOption {
-                type = types.str;
-                default = ssh-target ''
-                  mkdir -p ${config.target-path}
-                  cd ${config.target-path}
-                  if ! test -e .git; then
-                    git init
-                  fi
-                  if ! cur_url=$(git config remote.origin.url 2>/dev/null); then
-                    git remote add origin ${config.url}
-                  elif test "$cur_url" != ${config.url}; then
-                    git remote set-url origin ${config.url}
-                  fi
-                  if test "$(git rev-parse --verify HEAD 2>/dev/null)" != ${config.rev}; then
-                    git fetch origin
-                    git checkout ${config.rev} -- .
-                    git checkout -q ${config.rev}
-                    git submodule init
-                    git submodule update
-                  fi
-                  git clean -dxf
-                '';
-              };
-              target-path = mkOption {
-                type = types.str;
-                default = "/root/${config._module.args.name}";
-              };
-            };
-          }
-      ));
-      default = {};
-    };
-  };
-
-  doc = s:
-    let b = "EOF${hashString "sha256" s}"; in
-    ''
-    <<\${b}
-    ${s}
-    ${b}
-    '';
-
-  ssh-target = script:
-    "ssh root@${target.host.name} -T ${doc ''
-      set -efu
-      ${script}
-    ''}";
-
-in out
diff --git a/krebs/3modules/build/infest/finalize.sh b/krebs/3modules/build/infest/finalize.sh
deleted file mode 100644
index ced5a4d4d..000000000
--- a/krebs/3modules/build/infest/finalize.sh
+++ /dev/null
@@ -1,65 +0,0 @@
-#! /bin/sh
-set -eux
-{
-  umount /mnt/nix || [ $? -eq 32 ]
-  umount /mnt/boot || [ $? -eq 32 ]
-  umount /mnt/root || [ $? -eq 32 ]
-  umount /mnt || [ $? -eq 32 ]
-  umount /boot || [ $? -eq 32 ]
-
-  PATH=$(set +f; for i in /nix/store/*coreutils*/bin; do :; done; echo $i)
-  export PATH
-
-  mkdir /oldshit
-
-  mv /bin /oldshit/
-  mv /newshit/bin /
-
-  # TODO ensure /boot is empty
-  rmdir /newshit/boot
-
-  # skip /dev
-  rmdir /newshit/dev
-
-  mv /etc /oldshit/
-  mv /newshit/etc /
-
-  # skip /nix (it's already there)
-  rmdir /newshit/nix
-
-  # skip /proc
-  rmdir /newshit/proc
-
-  # skip /run
-  rmdir /newshit/run
-
-  # skip /sys
-  rmdir /newshit/sys
-
-  # skip /root
-  rmdir /newshit/root
-
-  # skip /tmp
-  # TODO rmdir /newshit/tmp
-
-  mv /home /oldshit/
-  mv /newshit/home /
-
-  mv /usr /oldshit/
-  mv /newshit/usr /
-
-  mv /var /oldshit/
-  mv /newshit/var /
-
-  mv /lib /oldshit/
-  mv /lib64 /oldshit/
-  mv /sbin /oldshit/
-  mv /srv /oldshit/
-  mv /opt /oldshit/
-
-
-  mv /newshit /root/  # TODO this one shoult be empty
-  mv /oldshit /root/
-
-  sync
-}
diff --git a/krebs/3modules/build/infest/install-nix.sh b/krebs/3modules/build/infest/install-nix.sh
deleted file mode 100644
index 88c8c3e1e..000000000
--- a/krebs/3modules/build/infest/install-nix.sh
+++ /dev/null
@@ -1,57 +0,0 @@
-#! /bin/sh
-set -efu
-
-nix_url=https://nixos.org/releases/nix/nix-1.10/nix-1.10-x86_64-linux.tar.bz2
-nix_sha256=504f7a3a85fceffb8766ae5e1005de9e02e489742f5a63cc3e7552120b138bf4
-
-install_nix() {(
-
-  # install nix on host (cf. https://nixos.org/nix/install)
-  if ! test -e /root/.nix-profile/etc/profile.d/nix.sh; then
-    (
-      verify() {
-        printf '%s  %s\n' $nix_sha256  $(basename $nix_url) | sha256sum -c
-      }
-      if ! verify; then
-        curl -C - -O "$nix_url"
-        verify
-      fi
-    )
-    nix_src_dir=$(basename $nix_url .tar.bz2)
-    tar jxf $nix_src_dir.tar.bz2
-    mkdir -v -m 0755 -p /nix
-    $nix_src_dir/install
-  fi
-
-  #TODO: make this general or move to prepare
-  if ! mount | grep -Fq '/dev/mapper/centos-root on /mnt/nix type xfs'; then
-    mkdir -p /mnt/nix
-    mount --bind /nix /mnt/nix
-  fi
-
-  . /root/.nix-profile/etc/profile.d/nix.sh
-
-  for i in \
-    bash \
-    coreutils \
-    # This line intentionally left blank.
-  do
-    if ! nix-env -q $i | grep -q .; then
-      nix-env -iA nixpkgs.pkgs.$i
-    fi
-  done
-
-  # install nixos-install
-  if ! type nixos-install 2>/dev/null; then
-    nixpkgs_expr='import <nixpkgs> { system = builtins.currentSystem; }'
-    nixpkgs_path=$(find /nix/store -mindepth 1 -maxdepth 1 -name *-nixpkgs-* -type d)
-    nix-env \
-      --arg config "{ nix.package = ($nixpkgs_expr).nix; }" \
-      --arg pkgs "$nixpkgs_expr" \
-      --arg modulesPath 'throw "no modulesPath"' \
-      -f $nixpkgs_path/nixpkgs/nixos/modules/installer/tools/tools.nix \
-      -iA config.system.build.nixos-install
-  fi
-)}
-
-install_nix "$@"
diff --git a/krebs/3modules/build/infest/prepare.sh b/krebs/3modules/build/infest/prepare.sh
deleted file mode 100644
index 07c00c3a5..000000000
--- a/krebs/3modules/build/infest/prepare.sh
+++ /dev/null
@@ -1,74 +0,0 @@
-#! /bin/sh
-set -efu
-
-prepare() {(
-  if test -e /etc/os-release; then
-    . /etc/os-release
-    case $ID in
-      centos)
-        case $VERSION_ID in
-          7)
-            prepare_centos7 "$@"
-            exit
-            ;;
-        esac
-        ;;
-    esac
-  fi
-  echo "$0 prepare: unknown OS" >&2
-  exit -1
-)}
-
-prepare_centos7() {
-  type bzip2 2>/dev/null || yum install -y bzip2
-  type git   2>/dev/null || yum install -y git
-  type rsync 2>/dev/null || yum install -y rsync
-  if ! getent group nixbld >/dev/null; then
-    groupadd -g 30000 -r nixbld
-  fi
-  for i in `seq 1 10`; do
-    if ! getent passwd nixbld$i 2>/dev/null; then
-      useradd \
-        -c "CentOS Nix build user $i" \
-        -d /var/empty \
-        -g 30000 \
-        -G 30000 \
-        -l \
-        -M \
-        -s /sbin/nologin \
-        -u $(expr 30000 + $i) \
-        nixbld$i
-      rm -f /var/spool/mail/nixbld$i
-    fi
-  done
-
-  #
-  # mount install directory
-  #
-
-  if ! mount | grep -Fq '/dev/mapper/centos-root on /mnt type xfs'; then
-    mkdir -p /newshit
-    mount --bind /newshit /mnt
-  fi
-
-  if ! mount | grep -Fq '/dev/sda1 on /mnt/boot type xfs'; then
-    mkdir -p /mnt/boot
-    mount /dev/sda1 /mnt/boot
-  fi
-
-  mount | grep 'on /mnt\>' >&2
-
-  #
-  # prepare install directory
-  #
-
-  mkdir -p /mnt/etc/nixos
-  mkdir -m 0555 -p /mnt/var/empty
-
-  if ! mount | grep -Fq '/dev/mapper/centos-root on /mnt/root type xfs'; then
-    mkdir -p /mnt/root
-    mount --bind /root /mnt/root
-  fi
-}
-
-prepare "$@"
diff --git a/krebs/3modules/default.nix b/krebs/3modules/default.nix
index 2b4a13c42..d3481505b 100644
--- a/krebs/3modules/default.nix
+++ b/krebs/3modules/default.nix
@@ -6,7 +6,7 @@ let
 
   out = {
     imports = [
-      ./build
+      ./build.nix
       ./exim-retiolum.nix
       ./exim-smarthost.nix
       ./github-hosts-sync.nix
diff --git a/krebs/4lib/infest/finalize.sh b/krebs/4lib/infest/finalize.sh
new file mode 100644
index 000000000..ced5a4d4d
--- /dev/null
+++ b/krebs/4lib/infest/finalize.sh
@@ -0,0 +1,65 @@
+#! /bin/sh
+set -eux
+{
+  umount /mnt/nix || [ $? -eq 32 ]
+  umount /mnt/boot || [ $? -eq 32 ]
+  umount /mnt/root || [ $? -eq 32 ]
+  umount /mnt || [ $? -eq 32 ]
+  umount /boot || [ $? -eq 32 ]
+
+  PATH=$(set +f; for i in /nix/store/*coreutils*/bin; do :; done; echo $i)
+  export PATH
+
+  mkdir /oldshit
+
+  mv /bin /oldshit/
+  mv /newshit/bin /
+
+  # TODO ensure /boot is empty
+  rmdir /newshit/boot
+
+  # skip /dev
+  rmdir /newshit/dev
+
+  mv /etc /oldshit/
+  mv /newshit/etc /
+
+  # skip /nix (it's already there)
+  rmdir /newshit/nix
+
+  # skip /proc
+  rmdir /newshit/proc
+
+  # skip /run
+  rmdir /newshit/run
+
+  # skip /sys
+  rmdir /newshit/sys
+
+  # skip /root
+  rmdir /newshit/root
+
+  # skip /tmp
+  # TODO rmdir /newshit/tmp
+
+  mv /home /oldshit/
+  mv /newshit/home /
+
+  mv /usr /oldshit/
+  mv /newshit/usr /
+
+  mv /var /oldshit/
+  mv /newshit/var /
+
+  mv /lib /oldshit/
+  mv /lib64 /oldshit/
+  mv /sbin /oldshit/
+  mv /srv /oldshit/
+  mv /opt /oldshit/
+
+
+  mv /newshit /root/  # TODO this one shoult be empty
+  mv /oldshit /root/
+
+  sync
+}
diff --git a/krebs/4lib/infest/install-nix.sh b/krebs/4lib/infest/install-nix.sh
new file mode 100644
index 000000000..88c8c3e1e
--- /dev/null
+++ b/krebs/4lib/infest/install-nix.sh
@@ -0,0 +1,57 @@
+#! /bin/sh
+set -efu
+
+nix_url=https://nixos.org/releases/nix/nix-1.10/nix-1.10-x86_64-linux.tar.bz2
+nix_sha256=504f7a3a85fceffb8766ae5e1005de9e02e489742f5a63cc3e7552120b138bf4
+
+install_nix() {(
+
+  # install nix on host (cf. https://nixos.org/nix/install)
+  if ! test -e /root/.nix-profile/etc/profile.d/nix.sh; then
+    (
+      verify() {
+        printf '%s  %s\n' $nix_sha256  $(basename $nix_url) | sha256sum -c
+      }
+      if ! verify; then
+        curl -C - -O "$nix_url"
+        verify
+      fi
+    )
+    nix_src_dir=$(basename $nix_url .tar.bz2)
+    tar jxf $nix_src_dir.tar.bz2
+    mkdir -v -m 0755 -p /nix
+    $nix_src_dir/install
+  fi
+
+  #TODO: make this general or move to prepare
+  if ! mount | grep -Fq '/dev/mapper/centos-root on /mnt/nix type xfs'; then
+    mkdir -p /mnt/nix
+    mount --bind /nix /mnt/nix
+  fi
+
+  . /root/.nix-profile/etc/profile.d/nix.sh
+
+  for i in \
+    bash \
+    coreutils \
+    # This line intentionally left blank.
+  do
+    if ! nix-env -q $i | grep -q .; then
+      nix-env -iA nixpkgs.pkgs.$i
+    fi
+  done
+
+  # install nixos-install
+  if ! type nixos-install 2>/dev/null; then
+    nixpkgs_expr='import <nixpkgs> { system = builtins.currentSystem; }'
+    nixpkgs_path=$(find /nix/store -mindepth 1 -maxdepth 1 -name *-nixpkgs-* -type d)
+    nix-env \
+      --arg config "{ nix.package = ($nixpkgs_expr).nix; }" \
+      --arg pkgs "$nixpkgs_expr" \
+      --arg modulesPath 'throw "no modulesPath"' \
+      -f $nixpkgs_path/nixpkgs/nixos/modules/installer/tools/tools.nix \
+      -iA config.system.build.nixos-install
+  fi
+)}
+
+install_nix "$@"
diff --git a/krebs/4lib/infest/prepare.sh b/krebs/4lib/infest/prepare.sh
new file mode 100644
index 000000000..07c00c3a5
--- /dev/null
+++ b/krebs/4lib/infest/prepare.sh
@@ -0,0 +1,74 @@
+#! /bin/sh
+set -efu
+
+prepare() {(
+  if test -e /etc/os-release; then
+    . /etc/os-release
+    case $ID in
+      centos)
+        case $VERSION_ID in
+          7)
+            prepare_centos7 "$@"
+            exit
+            ;;
+        esac
+        ;;
+    esac
+  fi
+  echo "$0 prepare: unknown OS" >&2
+  exit -1
+)}
+
+prepare_centos7() {
+  type bzip2 2>/dev/null || yum install -y bzip2
+  type git   2>/dev/null || yum install -y git
+  type rsync 2>/dev/null || yum install -y rsync
+  if ! getent group nixbld >/dev/null; then
+    groupadd -g 30000 -r nixbld
+  fi
+  for i in `seq 1 10`; do
+    if ! getent passwd nixbld$i 2>/dev/null; then
+      useradd \
+        -c "CentOS Nix build user $i" \
+        -d /var/empty \
+        -g 30000 \
+        -G 30000 \
+        -l \
+        -M \
+        -s /sbin/nologin \
+        -u $(expr 30000 + $i) \
+        nixbld$i
+      rm -f /var/spool/mail/nixbld$i
+    fi
+  done
+
+  #
+  # mount install directory
+  #
+
+  if ! mount | grep -Fq '/dev/mapper/centos-root on /mnt type xfs'; then
+    mkdir -p /newshit
+    mount --bind /newshit /mnt
+  fi
+
+  if ! mount | grep -Fq '/dev/sda1 on /mnt/boot type xfs'; then
+    mkdir -p /mnt/boot
+    mount /dev/sda1 /mnt/boot
+  fi
+
+  mount | grep 'on /mnt\>' >&2
+
+  #
+  # prepare install directory
+  #
+
+  mkdir -p /mnt/etc/nixos
+  mkdir -m 0555 -p /mnt/var/empty
+
+  if ! mount | grep -Fq '/dev/mapper/centos-root on /mnt/root type xfs'; then
+    mkdir -p /mnt/root
+    mount --bind /root /mnt/root
+  fi
+}
+
+prepare "$@"
diff --git a/krebs/default.nix b/krebs/default.nix
new file mode 100644
index 000000000..0ec4c6079
--- /dev/null
+++ b/krebs/default.nix
@@ -0,0 +1,263 @@
+{ current-date
+, current-host-name
+, current-user-name
+}@current: rec {
+
+  deploy =
+    { system ? current-host-name
+    , target ? system
+    }@args: let
+      config = lib.get-config system;
+    in ''
+      #! /bin/sh
+      # ${current-date} ${current-user-name}@${current-host-name}
+      # krebs.deploy
+      set -efu
+      (${lib.populate args})
+      ${lib.rootssh target ''
+        ${lib.install args}
+        ${config.krebs.build.profile}/bin/switch-to-configuration switch
+      ''}
+      echo OK
+    '';
+
+  infest =
+    { system ? current-host-name
+    , target ? system
+    }@args: let
+    in ''
+      #! /bin/sh
+      # ${current-date} ${current-user-name}@${current-host-name}
+      # krebs.infest
+      set -efu
+
+      # XXX type -p is non-standard
+      #export RSYNC_RSH; RSYNC_RSH="$(type -p ssh) \
+      #  -o 'HostName $ {target.host.infest.addr}' \
+      #  -o 'Port $ {toString target.host.infest.port}' \
+      #"
+      #ssh() {
+      #  eval "$RSYNC_RSH \"\$@\""
+      #}
+
+      ${lib.rootssh target ''
+        ${builtins.readFile ./4lib/infest/prepare.sh}
+        ${builtins.readFile ./4lib/infest/install-nix.sh}
+      ''}
+
+      (${lib.populate args})
+
+      ${lib.rootssh target ''
+        export PATH; PATH=/root/.nix-profile/bin:$PATH
+
+        src=$(type -p nixos-install)
+        cat_src() {
+          sed < "$src" "$(
+            { sed < "$src" -n '
+                  /^if ! test -e "\$mountPoint\/\$NIXOS_CONFIG/,/^fi$/=
+                  /^nixpkgs=/=
+                  /^NIX_PATH=/,/^$/{/./=}
+
+                  # Disable: Copy the NixOS/Nixpkgs sources to the target as
+                  # the initial contents of the NixOS channel.
+                  /^srcs=/,/^ln -sfn /=
+                '
+            } | sed 's:$:s/^/#krebs#/:'
+          )"
+        }
+
+        # Location to insert lib.install
+        i=$(sed -n '/^echo "building the system configuration/=' "$src")
+
+        {
+          cat_src | sed -n "1,$i{p}"
+          cat ${lib.doc (lib.install args)}
+          cat_src | sed -n "$i,\''${$i!p}"
+        } > nixos-install
+        chmod +x nixos-install
+
+        ## Wrap inserted lib.install into chroot.
+        #nix_env=$(cat_src | sed -n '
+        #  s:.*\(/nix/store/[a-z0-9]*-nix-[0-9.]\+/bin/nix-env\).*:\1:p;T;q
+        #')
+        #echo nix-env is $nix_env
+        #sed -i '
+        #  s:^nix-env:chroot $mountPoint '"$nix_env"':
+        #' nixos-install
+
+        ./nixos-install
+
+        ${builtins.readFile ./4lib/infest/finalize.sh}
+      ''}
+    '';
+
+  init =
+    { system ? current-host-name
+    }@args: let
+      config = lib.get-config system;
+    in ''
+      #! /bin/sh
+      # ${current-date} ${current-user-name}@${current-host-name}
+      # krebs.init
+      set -efu
+
+      system=${lib.shell.escape system}
+      secrets_dir=${config.krebs.build.source.dir.secrets.path}
+      key_type=ed25519
+      key_file=$secrets_dir/ssh.id_$key_type
+      key_comment=$system
+
+      if test -e "$key_file"; then
+        echo "Warning: privkey already exists: $key_file" >&2
+      else
+        ssh-keygen \
+            -C "$key_comment" \
+            -t "$key_type" \
+            -f "$key_file" \
+            -N ""
+        rm "$key_file.pub"
+      fi
+
+      pubkey=$(ssh-keygen -y -f "$key_file")
+
+      cat<<EOF
+      # put following into config.krebs.hosts.$system:
+      ssh.pubkey = $(echo $pubkey | jq -R .);
+      EOF
+    '';
+
+  lib = import ./4lib { lib = import <nixpkgs/lib>; } // rec {
+
+    stockholm = import ../. current;
+
+    get-config = system:
+      stockholm.${current-user-name}.${system}.config
+        or (abort "unknown system: ${system}");
+
+    doc = s:
+      let b = "EOF${builtins.hashString "sha256" s}"; in
+      ''
+      <<\${b}
+      ${s}
+      ${b}
+      '';
+
+    rootssh = target: script:
+      "ssh root@${target} -T ${lib.doc ''
+        set -efu
+        ${script}
+      ''}";
+
+    install =
+      { system ? current-host-name
+      , target ? system
+      }:
+      let
+        stockholm = import ../. {
+          inherit current-date;
+          inherit current-host-name;
+          inherit current-user-name;
+        };
+
+        config = stockholm.${current-user-name}.${system}.config
+          or (abort "unknown system: ${system}");
+
+        nix-path =
+          lib.concatStringsSep ":"
+            (lib.mapAttrsToList (name: _: "${name}=/root/${name}")
+              (config.krebs.build.source.dir //
+               config.krebs.build.source.git));
+      in ''
+        set -efu
+        NIX_PATH=${lib.shell.escape nix-path} \
+        nix-env \
+          --show-trace \
+          -f '<stockholm>' \
+          -Q \
+          --argstr current-date ${lib.shell.escape current-date} \
+          --argstr current-host-name ${lib.shell.escape current-host-name} \
+          --argstr current-user-name ${lib.shell.escape current-user-name} \
+          --profile ${lib.shell.escape config.krebs.build.profile} \
+          --set \
+          -A ${lib.escapeShellArg (lib.concatStringsSep "." [
+                config.krebs.build.user.name
+                config.krebs.build.host.name
+                "system"
+              ])}
+      '';
+
+    populate =
+      { system ? current-host-name
+      , target ? system
+      }@args:
+      let out = ''
+          #! /bin/sh
+          # ${current-date} ${current-user-name}@${current-host-name}
+          set -efu
+          ${lib.concatStringsSep "\n"
+            (lib.concatMap
+              (type: lib.mapAttrsToList (_: methods.${type})
+                                        config.krebs.build.source.${type})
+              ["dir" "git"])}
+        '';
+
+        stockholm = import ../. {
+          inherit current-date;
+          inherit current-host-name;
+          inherit current-user-name;
+        };
+
+        config = stockholm.${current-user-name}.${system}.config
+            or (abort "unknown system: ${system}");
+
+        current-host = config.krebs.hosts.${current-host-name};
+        current-user = config.krebs.users.${current-user-name};
+
+        target-host = config.krebs.hosts.${system};
+
+        methods.dir = config:
+          let
+            can-link = config.host.name == target-host.name;
+            can-push = config.host.name == current-host.name;
+            push-method = ''
+              rsync \
+                --exclude .git \
+                --exclude .graveyard \
+                --exclude old \
+                --exclude tmp \
+                --rsync-path='mkdir -p ${config.target-path} && rsync' \
+                --delete-excluded \
+                -vrLptgoD \
+                ${config.path}/ \
+                root@${target}:${config.target-path}
+            '';
+            url = "file://${config.host.name}${config.path}";
+          in
+          #if can-link then link-method else
+          if can-push then push-method else
+          throw "cannot source ${url}";
+
+        methods.git = config:
+          lib.rootssh target ''
+            mkdir -p ${config.target-path}
+            cd ${config.target-path}
+            if ! test -e .git; then
+              git init
+            fi
+            if ! cur_url=$(git config remote.origin.url 2>/dev/null); then
+              git remote add origin ${config.url}
+            elif test "$cur_url" != ${config.url}; then
+              git remote set-url origin ${config.url}
+            fi
+            if test "$(git rev-parse --verify HEAD 2>/dev/null)" != ${config.rev}; then
+              git fetch origin
+              git checkout ${config.rev} -- .
+              git checkout -q ${config.rev}
+              git submodule init
+              git submodule update
+            fi
+            git clean -dxf
+          '';
+      in out;
+  };
+}
-- 
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