summaryrefslogtreecommitdiffstats
path: root/krebs/3modules/sync-containers3.nix
blob: 7bec27b0fb0f5eb0fffe85ebaad6bb0458506b9d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
{ config, lib, pkgs, ... }: let
  cfg = config.krebs.sync-containers3;
  slib = import ../../lib/pure.nix { inherit lib; };
in {
  options.krebs.sync-containers3 = {
    inContainer = {
      enable = lib.mkEnableOption "container config for syncing";
      pubkey = lib.mkOption {
        type = lib.types.str; # TODO ssh key
      };
    };
    containers = lib.mkOption {
      default = {};
      type = lib.types.attrsOf (lib.types.submodule ({ config, ... }: {
        options = {
          name = lib.mkOption {
            type = lib.types.str;
            default = config._module.args.name;
          };
          sshKey = lib.mkOption {
            type = slib.types.absolute-pathname;
          };
          luksKey = lib.mkOption {
            type = slib.types.absolute-pathname;
            default = config.sshKey;
          };
          ephemeral = lib.mkOption {
            type = lib.types.bool;
            default = false;
          };
          runContainer = lib.mkOption {
            type = lib.types.bool;
            default = true;
          };
          startCommand = lib.mkOption {
            type = lib.types.str;
            default = ''
              set -efu
              mkdir -p /var/state/var_src
              ln -Tfrs /var/state/var_src /var/src
              if test -e /var/src/nixos-config; then
                /run/current-system/sw/bin/nixos-rebuild -I /var/src switch || :
              fi
            '';
          };
        };
      }));
    };
  };
  config = lib.mkMerge [
    (lib.mkIf (cfg.containers != {}) {

      containers = lib.mapAttrs' (n: ctr: lib.nameValuePair ctr.name {
        config = {
          environment.systemPackages = [
            pkgs.dhcpcd
            pkgs.git
            pkgs.jq
          ];
          networking.useDHCP = lib.mkForce true;
          systemd.services.autoswitch = {
            environment = {
              NIX_REMOTE = "daemon";
            };
            wantedBy = [ "multi-user.target" ];
            serviceConfig.ExecStart = pkgs.writers.writeDash "autoswitch" ctr.startCommand;
            unitConfig.X-StopOnRemoval = false;
          };
        };
        autoStart = false;
        enableTun = true;
        ephemeral = ctr.ephemeral;
        privateNetwork = true;
        hostBridge = "ctr0";
        bindMounts = {
          "/var/lib/self/disk" = {
            hostPath = "/var/lib/sync-containers3/${ctr.name}/disk";
            isReadOnly = false;
          };
          "/var/state" = {
            hostPath = "/var/lib/sync-containers3/${ctr.name}/state";
            isReadOnly = false;
          };
        };
      }) (lib.filterAttrs (_: ctr: ctr.runContainer) cfg.containers);

      systemd.services = lib.foldr lib.recursiveUpdate {} (lib.flatten (map (ctr: [
        { "${ctr.name}_syncer" = {
          path = with pkgs; [
            coreutils
            inetutils
            consul
            rsync
            openssh
            systemd
          ];
          startAt = "*:0/1";
          serviceConfig = {
            User = "${ctr.name}_container";
            LoadCredential = [
              "ssh_key:${ctr.sshKey}"
            ];
            ExecCondition = pkgs.writers.writeDash "${ctr.name}_checker" ''
              set -efu
              ! systemctl is-active --quiet container@${ctr.name}.service
            '';
            ExecStart = pkgs.writers.writeDash "${ctr.name}_syncer" ''
              set -efux
              consul lock sync_${ctr.name} ${pkgs.writers.writeDash "${ctr.name}-sync" ''
                set -efux
                if ping -c 1 ${ctr.name}.r; then
                  nice --adjustment=30 rsync -a -e "ssh -i $CREDENTIALS_DIRECTORY/ssh_key" --timeout=30 --inplace --sparse container_sync@${ctr.name}.r:disk "$HOME"/disk.rsync
                  touch "$HOME"/incomplete
                  nice --adjustment=30 rsync --inplace "$HOME"/disk.rsync "$HOME"/disk
                  rm -f "$HOME"/incomplete
                fi
              ''}
            '';
          };
        }; }
        { "${ctr.name}_watcher" = lib.mkIf ctr.runContainer {
          path = with pkgs; [
            coreutils
            inetutils
            consul
            cryptsetup
            curl
            mount
            util-linux
            jq
            retry
          ];
          serviceConfig = {
            ExecStart = pkgs.writers.writeDash "${ctr.name}_watcher" ''
              set -efux
              while sleep 5; do
                # get the payload
                # check if the host reacted recently
                case $(curl -s -o /dev/null --retry 10 --retry-delay 10 -w '%{http_code}' http://127.0.0.1:8500/v1/kv/containers/${ctr.name}) in
                  404)
                    echo 'got 404 from kv, should kill the container'
                    break
                    ;;
                  500)
                    echo 'got 500 from kv, will kill container'
                    break
                    ;;
                  200)
                    # echo 'got 200 from kv, will check payload'
                    payload=$(consul kv get containers/${ctr.name}) || continue
                    export payload
                    if [ "$(jq -rn 'env.payload | fromjson.host')" = '${config.networking.hostName}' ]; then
                      # echo 'we are the host, trying to reach container'
                      if $(retry -t 10 -d 10 -- ping -q -c 1 ${ctr.name}.r > /dev/null); then
                        # echo 'container is reachable, continueing'
                        continue
                      else
                        # echo 'container seems dead, killing'
                        break
                      fi
                    else
                      echo 'we are not host, killing container'
                      break
                    fi
                    ;;
                  *)
                    echo 'unknown state, continuing'
                    continue
                    ;;
                esac
              done
              /run/current-system/sw/bin/nixos-container stop ${ctr.name} || :
              umount /var/lib/sync-containers3/${ctr.name}/state || :
              cryptsetup luksClose ${ctr.name} || :
            '';
          };
        }; }
        { "${ctr.name}_scheduler" = lib.mkIf ctr.runContainer {
          wantedBy = [ "multi-user.target" ];
          path = with pkgs; [
            coreutils
            inetutils
            consul
            cryptsetup
            mount
            util-linux
            curl
            systemd
            jq
            retry
            bc
          ];
          serviceConfig = {
            Restart = "always";
            RestartSec = "30s";
            ExecStart = pkgs.writers.writeDash "${ctr.name}_scheduler" ''
              set -efux
              # get the payload
              # check if the host reacted recently
              case $(curl -s -o /dev/null --retry 10 -w '%{http_code}' http://127.0.0.1:8500/v1/kv/containers/${ctr.name}) in
                404)
                  # echo 'got 404 from kv, will create container'
                  ;;
                500)
                  # echo 'got 500 from kv, retrying again'
                  exit 0
                  ;;
                200)
                  # echo 'got 200 from kv, will check payload'
                  export payload=$(consul kv get containers/${ctr.name})
                  if [ "$(jq -rn 'env.payload | fromjson.host')" = '${config.networking.hostName}' ]; then
                    echo 'we are the host, starting container'
                  else
                    # echo 'we are not host, checking timestamp'
                    # if [ $(echo "$(date +%s) - $(jq -rn 'env.payload | fromjson.time') > 100" | bc) -eq 1 ]; then
                    if [ "$(jq -rn 'env.payload | fromjson.time | now - tonumber > 100')" = 'true' ]; then
                      echo 'last beacon is more than 100s ago, taking over'
                    else
                      # echo 'last beacon was recent. trying again'
                      exit 0
                    fi
                  fi
                  ;;
                *)
                  echo 'unknown state, bailing out'
                  exit 0
                  ;;
              esac
              consul kv put containers/${ctr.name} "$(jq -cn '{host: "${config.networking.hostName}", time: now}')" >/dev/null
              consul lock -verbose -monitor-retry=100 -timeout 30s -name container_${ctr.name} container_${ctr.name} ${pkgs.writers.writeBash "${ctr.name}-start" ''
                set -efu
                cryptsetup luksOpen --key-file ${ctr.luksKey} /var/lib/sync-containers3/${ctr.name}/disk ${ctr.name} || :
                mkdir -p /var/lib/sync-containers3/${ctr.name}/state
                mountpoint /var/lib/sync-containers3/${ctr.name}/state || mount /dev/mapper/${ctr.name} /var/lib/sync-containers3/${ctr.name}/state
                /run/current-system/sw/bin/nixos-container start ${ctr.name}
                # wait for system to become reachable for the first time
                systemctl start ${ctr.name}_watcher.service
                retry -t 10 -d 10 -- ping -q -c 1 ${ctr.name}.r > /dev/null
                while systemctl is-active container@${ctr.name}.service >/devnull && ping -q -c 3 ${ctr.name}.r >/dev/null; do
                  consul kv put containers/${ctr.name} "$(jq -cn '{host: "${config.networking.hostName}", time: now}')" >/dev/null
                  sleep 10
                done
              ''}
            '';
          };
        }; }
        { "container@${ctr.name}" = lib.mkIf ctr.runContainer {
          serviceConfig = {
            ExecStop = pkgs.writers.writeDash "remove_interface" ''
              ${pkgs.iproute2}/bin/ip link del vb-${ctr.name}
            '';
          };
        }; }
      ]) (lib.attrValues cfg.containers)));

      systemd.timers = lib.mapAttrs' (n: ctr: lib.nameValuePair "${ctr.name}_syncer" {
        timerConfig = {
          RandomizedDelaySec = 100;
        };
      }) cfg.containers;

      users.groups = lib.mapAttrs' (_: ctr: lib.nameValuePair "${ctr.name}_container" {
      }) cfg.containers;
      users.users = lib.mapAttrs' (_: ctr: lib.nameValuePair "${ctr.name}_container" ({
        group = "${ctr.name}_container";
        isNormalUser = true;
        uid = slib.genid_uint31 "container_${ctr.name}";
        home = "/var/lib/sync-containers3/${ctr.name}";
        createHome = true;
        homeMode = "705";
      })) cfg.containers;

      environment.systemPackages = lib.mapAttrsToList (_: ctr: (pkgs.writers.writeDashBin "${ctr.name}_init" ''
        set -efux
        export PATH=${lib.makeBinPath [
          pkgs.coreutils
          pkgs.cryptsetup
          pkgs.libxfs.bin
        ]}:$PATH
        truncate -s 5G /var/lib/sync-containers3/${ctr.name}/disk
        cryptsetup luksFormat /var/lib/sync-containers3/${ctr.name}/disk ${ctr.luksKey}
        cryptsetup luksOpen --key-file ${ctr.luksKey} /var/lib/sync-containers3/${ctr.name}/disk ${ctr.name}
        mkfs.xfs /dev/mapper/${ctr.name}
        mkdir -p /var/lib/sync-containers3/${ctr.name}/state
        mountpoint /var/lib/sync-containers3/${ctr.name}/state || mount /dev/mapper/${ctr.name} /var/lib/sync-containers3/${ctr.name}/state
        /run/current-system/sw/bin/nixos-container start ${ctr.name}
        /run/current-system/sw/bin/nixos-container run ${ctr.name} -- ${pkgs.writeDash "init" ''
          mkdir -p /var/state
        ''}
      '')) cfg.containers;
    })
    (lib.mkIf (cfg.containers != {}) {
      # networking

      # needed because otherwise we lose local dns
      environment.etc."resolv.conf".source = lib.mkForce "/run/systemd/resolve/resolv.conf";

      boot.kernel.sysctl."net.ipv4.ip_forward" = lib.mkForce 1;
      systemd.network.networks.ctr0 = {
        name = "ctr0";
        address = [
          "10.233.0.1/24"
        ];
        networkConfig = {
          # IPForward = "yes";
          # IPMasquerade = "both";
          ConfigureWithoutCarrier = true;
          DHCPServer = "yes";
        };
      };
      systemd.network.netdevs.ctr0.netdevConfig = {
        Kind = "bridge";
        Name = "ctr0";
      };
      networking.networkmanager.unmanaged = [ "ctr0" ];
      krebs.iptables.tables.filter.INPUT.rules = [
        { predicate = "-i ctr0"; target = "ACCEPT"; }
      ];
      krebs.iptables.tables.filter.FORWARD.rules = [
        { predicate = "-i ctr0"; target = "ACCEPT"; }
        { predicate = "-o ctr0"; target = "ACCEPT"; }
      ];
      krebs.iptables.tables.nat.POSTROUTING.rules = [
        { v6 = false; predicate = "-s 10.233.0.0/24"; target = "MASQUERADE"; }
      ];
    })
    (lib.mkIf cfg.inContainer.enable {
      users.groups.container_sync = {};
      users.users.container_sync = {
        group = "container_sync";
        uid = slib.genid_uint31 "container_sync";
        isNormalUser = true;
        home = "/var/lib/self";
        createHome = true;
        openssh.authorizedKeys.keys = [
          cfg.inContainer.pubkey
        ];
      };

      networking.useHostResolvConf = false;
      networking.useNetworkd = true;
      systemd.network = {
        enable = true;
        networks.eth0 = {
          matchConfig.Name = "eth0";
          DHCP = "yes";
          dhcpV4Config.UseDNS = true;
        };
      };
    })
  ];
}