feat(ipa): add AuthorizedKeysCommand + enroll tailscale-router

- modules/ipa/client.nix: add AuthorizedKeysCommand so sshd fetches SSH
  public keys from IPA via sss_ssh_authorizedkeys, enabling pubkey login
  without per-host authorized_keys files

- hosts/tailscale-router/host.nix: add IPA client module + networking.domain
  so SSSD runs and wayne can authenticate on this host

- secrets/tailscale-router.keytab: sops-encrypted keytab for
  tailscale-router.sweet.home (generated by create-nixos-ipa-host-account.sh)

- .sops.yaml: creation rule for secrets/tailscale-router.keytab

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.sops.yaml

@@ -127,6 +127,16 @@ creation_rules:
   # scripts/secrets/sync-host-keys.sh yet, so whichever variant is actually
   # deployed next needs its recipient added here (and `sops updatekeys` rerun)
   # before it can decrypt this.
+  # Host keytab for tailscale-router FreeIPA enrollment (binary sops file).
+  # Generated by scripts/ipa/create-nixos-ipa-host-account.sh.
+  - path_regex: secrets/tailscale-router\.keytab$
+    key_groups:
+      - age:
+          - *admin
+          - *lxc-tailscale-router
+          - *proxmox-tailscale-router
+          - *linode-tailscale-router
+
   - path_regex: secrets/gui\.yaml$
     key_groups:
       - age:

hosts/tailscale-router/host.nix

@@ -6,10 +6,15 @@
       name = "tailscale-router";
       sopsFile = ../../secrets/tailscale-router.yaml;
     })
+    (import ../../modules/ipa/client.nix {
+      keytabSopsFile = ../../secrets/tailscale-router.keytab;
+      caCertFile = ../../certs/ipa-ca.crt;
+    })
   ];
 
   networking = {
     hostName = "tailscale-router";
+    domain = vars.homeDomain;
     useDHCP = false;
     interfaces.${vars.lxcLanInterface}.ipv4.addresses = [{
       address = vars.tailscaleRouterIp;

modules/ipa/client.nix

@@ -60,6 +60,14 @@ in
     cacheCredentials = true;
   };
 
+  # Fetch SSH public keys from IPA so users can log in with the key stored
+  # in their IPA profile rather than needing ~/.ssh/authorized_keys on every
+  # host. sss_ssh_authorizedkeys queries SSSD (which queries IPA LDAP).
+  services.openssh.extraConfig = ''
+    AuthorizedKeysCommand ${pkgs.sssd}/bin/sss_ssh_authorizedkeys %u
+    AuthorizedKeysCommandUser nobody
+  '';
+
   # Host keytab: pre-provisioned on the IPA server, sops-encrypted binary.
   # Placed at /etc/krb5.keytab before SSSD starts so the host authenticates
   # to IPA without running ipa-client-install.

secrets/tailscale-router.keytab

@@ -0,0 +1,26 @@
+{
+	"data": "ENC[AES256_GCM,data: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,iv:kUlVXF4Yl5HGvoLwu9loiuuDVtz0kARRiUU3K+BPL2A=,tag:pVaGzQAX9Etoqc5XMGmNeg==,type:str]",
+	"sops": {
+		"age": [
+			{
+				"enc": "-----BEGIN AGE ENCRYPTED FILE-----\nYWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSB6OUVUdkoxM1M5THlYZ1ky\nYWJ5RjhtRGoxTldwRkI2T1p6dHR4Y3gwR1ZrCjRDS1hTM01lZ0FSalBYQ1B0bENs\nUytXNmlrUkV4TmJkMUM1QW1ZaExIcGMKLS0tIHdHKzdEcUxvM0ZYUEp0a2d6SHp5\nYXQydy9uNG15V2FhUUd4NEFTMTNNMEUKkIzKEoYzoVs+nhnpkHFgDkQqrWykatND\ntsNxcr1SXSKeEW1m/QpXZnn/aW3zSQR09PqOHf7PYU47/AdkwrUaAg==\n-----END AGE ENCRYPTED FILE-----\n",
+				"recipient": "age1njap586hc0q43kr03g6c8eqhdsmk8zcafkl3f83xwlc2gqhlmfgs4tmwad"
+			},
+			{
+				"enc": "-----BEGIN AGE ENCRYPTED FILE-----\nYWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSByZENrck42dWJjR2hYUVBl\ncERtRjR6dTdING5nWXlBc3o3eXFhaSs5NkFRCk43QXFUeTBJR0U5dG9YTDRmQ0Yx\naEo2blUvUXNZY3dpbEZRTUx1elNzdkkKLS0tIHJwNjRNM3V6WktWZ1BlUUtLRTNI\nMTVEbCtYbllIbTdxTGozWUluS3pIRXMKZCruDIkD/JofdAHWgPuaaKTDsz408ZkY\n77mhO8J+kd03qwt6qhFC5KF1lyjhwEnqrOE195+R/8Yl7hA/DsL2ZQ==\n-----END AGE ENCRYPTED FILE-----\n",
+				"recipient": "age1k7d2du5mejsmv5rzavm4xwgpthqvcfsehduquv28nzs53zppa3kqngfxq2"
+			},
+			{
+				"enc": "-----BEGIN AGE ENCRYPTED FILE-----\nYWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBxaC95RjYybzVlU2tYdHdU\naGJ4M2IvNkJwVlNIU0VCZEFUZk5VaksrVnpFCmJXS3luTG9WejR0Rk9DbHA3dngy\nRElFWjU1N2xuc3JaKzQ0L0U2Yktib1kKLS0tIFlrK3F0ZFh5Ync3ejVWMzRKTUx2\nZDhxdEMwa3B4TFZUcWdTdktDeGt1QUEKfgYnK2lW3cZuJGaw+bAKDipLuC4S5vK2\nxK2eJB5TP/xXrp0F3lx9sc2b1FOY9Vt9IQ7zVlBqJFkzJrcw8zYJJw==\n-----END AGE ENCRYPTED FILE-----\n",
+				"recipient": "age1zhfyuzlq40reuqlr34gf77852nhs3t6mqfzrqmas8z6sxk7tcfhsungrm0"
+			},
+			{
+				"enc": "-----BEGIN AGE ENCRYPTED FILE-----\nYWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBwOGFkSXNxTUIzLzR1Skk5\nMGZveHFDN3YwVmpwT3VTYkppWEU1aGVpdkhRCjZtRC92bVphd0ZFbzFxVzRUcGk4\nMUd1aWdEbFRaM01FT25JSVRoMTRsNUUKLS0tIDAybmcrYjFVWkFYaGY5TFZjcjFO\nYlZoQjJjN2lFNzd4RlJuSHFlRlNCOFEKgUIPnL2/OJgz9oMYt86/llHa7adTkhs6\n8yGYGV1wtU9aYtUMIR907SfYyZ6M4z8jH2wwzpQLbwQQMLgkejl1jg==\n-----END AGE ENCRYPTED FILE-----\n",
+				"recipient": "age1f7usptjx9rv4rxauasve200gxtdt9jkqhhdqstlf20wvlm7u75rsjfw50m"
+			}
+		],
+		"lastmodified": "2026-07-27T23:14:51Z",
+		"mac": "ENC[AES256_GCM,data:CYhzR0Y29GXvWUBbb13s16v9hDQ4k4Xmd4FUpcyNtHe0L/IrDGkx1WHzAohNGZjGMNB9W3BgiEH85OoOo8r1F82El4/8s2prEJi8AARvQU3+2cmRjjhNCCYQWmJkoF/cZNpw6nVyWzZdfUpPvHjbuf6utlI3rtR0qiCpSo/32S0=,iv:XLKTU2Ute4jMkfRAbXiVGxqP9+fjSs6HwRv1JfTTe7w=,tag:oIqS/1HWQZ7mLWaO7GwLFA==,type:str]",
+		"version": "3.13.2"
+	}
+}