sync-containers3: lass -> krebs

2 files changed, 344 insertions, 0 deletions

diff --git a/krebs/3modules/default.nix b/krebs/3modules/default.nix
index bff7e135f..6d763afed 100644
--- a/krebs/3modules/default.nix
+++ b/krebs/3modules/default.nix
@@ -53,6 +53,7 @@ let
       ./sitemap.nix
       ./ssl.nix
       ./sync-containers.nix
+      ./sync-containers3.nix
       ./systemd.nix
       ./tinc.nix
       ./tinc_graphs.nix
diff --git a/krebs/3modules/sync-containers3.nix b/krebs/3modules/sync-containers3.nix
new file mode 100644
index 000000000..4a00b23ab
--- /dev/null
+++ b/krebs/3modules/sync-containers3.nix
@@ -0,0 +1,343 @@
+{ config, lib, pkgs, ... }: let
+  cfg = config.krebs.sync-containers3;
+  slib = pkgs.stockholm.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;
+          };
+        };
+      }));
+    };
+  };
+  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" ''
+              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
+            '';
+            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: [
+        { "${ctr.name}_syncer" = {
+          path = with pkgs; [
+            coreutils
+            consul
+            rsync
+            openssh
+            systemd
+          ];
+          startAt = "*:0/1";
+          serviceConfig = {
+            User = "${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 /run/wrappers/bin/ping -c 1 ${ctr.name}.r; then
+                  nice --adjustment=30 rsync -a -e "ssh -i $CREDENTIALS_DIRECTORY/ssh_key" --timeout=30 container_sync@${ctr.name}.r:disk "$HOME"/disk
+                  rm -f "$HOME"/incomplete
+                fi
+              ''}
+            '';
+          };
+        }; }
+        { "${ctr.name}_watcher" = lib.mkIf ctr.runContainer {
+          path = with pkgs; [
+            coreutils
+            consul
+            cryptsetup
+            curl
+            mount
+            util-linux
+            jq
+            retry
+          ];
+          serviceConfig = {
+            ExecStart = pkgs.writers.writeDash "${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 -- /run/wrappers/bin/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
+            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 -- /run/wrappers/bin/ping -q -c 1 ${ctr.name}.r > /dev/null
+                while systemctl is-active container@${ctr.name}.service >/devnull && /run/wrappers/bin/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;
+        };
+      };
+    })
+  ];
+}