nixos/test-lab/ha/common.nix

# Shared HA stack config for both test nodes.
# These are throwaway test VMs — not production hosts.
# No sops-nix, no clan, no home-manager.
{ lib, pkgs, vars, ... }:

let
  node1Ip = "192.168.2.200";
  node2Ip = "192.168.2.201";
  drbdPort = 7789;

  # Test-only corosync authkey (128 bytes = 1024 bits minimum for corosync).
  # Not secret — this is a disposable test cluster, not production.
  testAuthKey = "ha-test-cluster-auth-key-NOT-FOR-PRODUCTION-use-corosync-keygen-for-real-clusters-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
in
{
  system.stateVersion = "26.05";

  # ── Hardware (Proxmox VM) ──────────────────────────────────────────────
  imports = [
    ../../modules/hardware-configuration/vm/proxmox.nix
    ../../modules/boot/efi.nix
    ../../modules/ha/pacemaker-stack.nix
    ../../modules/ha/iscsi-target.nix
  ];

  # ── Nix settings ──────────────────────────────────────────────────────
  nix.settings.experimental-features = [ "nix-command" "flakes" ];

  users.users.root.openssh.authorizedKeys.keys = [
    vars.adminSshKey
    # Claude Code session key (this machine) — test-lab only
    "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIGygkCljN6uKpdJbHTOQtn8ZnH+wKXDLAwrDFbLrE/65 nixos@nixos"
  ];

  # ── Services ──────────────────────────────────────────────────────────
  services = {
    openssh = {
      enable = true;
      settings.PermitRootLogin = "yes";
    };

    # Allow QEMU guest exec for key injection fallback
    qemuGuest.enable = true;

    drbd = {
      enable = true;
      config = ''
        global {
          usage-count yes;
        }

        common {
          net {
            protocol C;
            ping-int 1;
            verify-alg sha256;
            after-sb-0pri discard-zero-changes;
            after-sb-1pri discard-secondary;
          }
          disk {
            # dont-care: DRBD itself won't fence before promoting.  Production
            # clusters should use resource-only here and configure a STONITH
            # fence agent (e.g. fence_pve_ssh) in Pacemaker so DRBD can safely
            # protect against split-brain without risking dual-Primary.
            # For this test cluster (no fence device) dont-care lets promotion
            # proceed; the DRBD kernel module still refuses dual-Primary without
            # allow-two-primaries in net {}.
            fencing dont-care;
            # LVM before/after-resync-target handlers omitted: the LVM snapshot
            # scripts (/usr/lib/drbd/snapshot-resync-target-lvm.sh) don't exist
            # on NixOS paths.  If present, DRBD calls them on resync and exits 127,
            # dropping the peer connection and leaving the secondary Outdated.
          }
        }

        resource ha-data {
          volume 0 {
            device    /dev/drbd0;
            disk      /dev/sdb;   # scsi1 in Proxmox VM → sdb
            meta-disk internal;
          }

          on ha-test-node1 {
            address ${node1Ip}:${toString drbdPort};
          }

          on ha-test-node2 {
            address ${node2Ip}:${toString drbdPort};
          }
        }
      '';
    };

    # services.corosync.enable = true is set by modules/ha/pacemaker-stack.nix
    corosync = {
      clusterName = "ha-test";
      nodelist = [
        { nodeid = 1; name = "ha-test-node1"; ring_addrs = [ node1Ip ]; }
        { nodeid = 2; name = "ha-test-node2"; ring_addrs = [ node2Ip ]; }
      ];
    };
  };

  # Corosync authkey (test-only, not secret — generated with
  # `corosync-keygen` for production).
  environment.etc."corosync/authkey" = {
    source = builtins.toFile "authkey" testAuthKey;
    mode = "0400";
  };

  # ── Packages ──────────────────────────────────────────────────────────
  # corosync, pacemaker, ocf-resource-agents, targetcli-fb already added
  # by the ha/ modules; add the remaining stack-specific tools here.
  environment.systemPackages = with pkgs; [
    # Storage
    drbd # drbdadm, drbdsetup, drbdmon
    xfsprogs # mkfs.xfs, xfs_admin, xfs_info

    # Networking / debug
    iproute2 # ip, ss
    iputils # ping
    tcpdump
    lsof

    # Scripting / config
    python3
    curl
    jq
    vim
    htop
  ];

  # ── Networking ────────────────────────────────────────────────────────
  networking = {
    useDHCP = false;
    defaultGateway = "192.168.2.1";
    nameservers = [ "192.168.2.1" "8.8.8.8" ];

    firewall = {
      enable = true;
      allowedTCPPorts = [
        22 # SSH
        3260 # iSCSI
        3121 # pacemaker-remoted
        2224 # pcsd
        drbdPort
      ];
      allowedUDPPorts = [
        5404 # corosync
        5405 # corosync
        5407 # corosync crypto
      ];
      extraCommands = ''
        iptables -A INPUT -s ${node1Ip}/32 -j ACCEPT
        iptables -A INPUT -s ${node2Ip}/32 -j ACCEPT
      '';
    };
  };

  # ── Locale / time ─────────────────────────────────────────────────────
  time.timeZone = vars.timeZone;
  i18n.defaultLocale = "en_AU.UTF-8";
}