diff --git a/nixos/big_data.nix b/nixos/big_data.nix
index 44e8aeb..d4d161e 100644
--- a/nixos/big_data.nix
+++ b/nixos/big_data.nix
@@ -40,6 +40,17 @@ let sparkConfDir = pkgs.stdenv.mkDerivation {
 in
 {
 
+  networking = {
+    hosts = {
+      "127.0.0.1" = [
+        "ds.my.engine"
+        "kdc.my.engine"
+        "my.engine"
+      ];
+    };
+
+  };
+
   services = {
     spark = {
       master = {
@@ -53,83 +64,181 @@ in
       confDir = sparkConfDir;
     };
 
-    hadoop = {
-      coreSite = {
-        "fs.defaultFS" = "hdfs://localhost:8020";
-      };
-      hdfsSite = {
-        "dfs.namenode.rpc-bind-host" = "0.0.0.0";
-        "dfs.permissions" = "false";
-        "dfs.namenode.name.dir" = "/hdfs/dfs/name";
-        "dfs.datanode.data.dir" = "/hdfs/dfs/data";
-      };
 
-      hdfs = {
-        namenode = {
-          enable = true;
-          formatOnInit = true;
-          restartIfChanged = true;
+
+    hadoop =
+      let
+        keytab_path = /etc/hadoop.keytab;
+      in
+
+      {
+        coreSite = {
+          # "fs.defaultFS" = "hdfs://0.0.0.0:8020";
+
+          # "hadoop.http.authentication.simple.anonymous.allowed" = "false";
+          # "hadoop.http.authentication.signature.secret.file" = "/var/lib/hadoop/security/http_secret";
+          # "hadoop.http.authentication.type" = "kerberos";
+          # "hadoop.http.authentication.kerberos.principal" = "http/my.engine@MY.ENGINE";
+          # "hadoop.http.authentication.cookie.domain" = "my.engine";
+
+          # "hadoop.security.authentication" = "kerberos";
+          # "hadoop.security.authorization" = "true";
+          # "hadoop.rpc.protection" = "authentication";
+
+
+          # "hadoop.rpc.protection" = "authentication";
+          # "hadoop.security.auth_to_local" = ''
+          #   RULE:[2:$1/$2@$0]([ndj]n/.*@MY.ENGINE)s/.*/hdfs/
+          #   RULE:[2:$1/$2@$0]([rn]m/.*@MY.ENGINE)s/.*/yarn/
+          #   RULE:[2:$1/$2@$0](jhs/.*@MY.ENGINE)s/.*/mapred/
+          #   DEFAULT
+          # '';
+          # "hadoop.proxyuser.superuser.hosts" = "*"; # TODO: restrict
+          # "hadoop.proxyuser.superuser.groups" = "*"; # TODO: restrict
+
+          "fs.defaultFS" = "hdfs://my.engine:8020";
+
+          # HDFS IMPERSONATION
+          "hadoop.proxyuser.hdfs.hosts" = "*";
+          "hadoop.proxyuser.hdfs.groups" = "*";
+
+          # HIVE IMPERSONATION
+          "hadoop.proxyuser.hive.hosts" = "*";
+          "hadoop.proxyuser.hive.groups" = "*";
+
+          # ENABLE AUTHENTICATION
+          "hadoop.security.authentication" = "kerberos";
+          "hadoop.security.authorization" = "true";
+          "hadoop.rpc.protection" = "privacy";
+
+          "hadoop.security.auth_to_local" = ''
+            RULE:[2:$1/$2@$0]([ndj]n/.*@MY\.ENGINE)s/.*/hdfs/
+            RULE:[2:$1/$2@$0]([rn]m/.*@MY\.ENGINE)s/.*/yarn/
+            RULE:[2:$1/$2@$0](jhs/.*@MY\.ENGINE)s/.*/mapred/
+            DEFAULT
+          '';
         };
-        datanode = {
-          enable = true;
-          restartIfChanged = true;
+        hdfsSite = {
+          # DATA
+          "dfs.namenode.name.dir" = "/hdfs/dfs/name";
+          "dfs.datanode.data.dir" = "/hdfs/dfs/data";
+
+          # HDFS SECURITY
+          "dfs.block.access.token.enable" = "true";
+
+          # NAME NODE SECURITY
+          "dfs.namenode.keytab.file" = keytab_path;
+          "dfs.namenode.kerberos.principal" = "nn/my.engine@MY.ENGINE";
+          "dfs.namenode.kerberos.internal.spnego.principal" = "HTTP/my.engine@MY.ENGINE";
+
+          # SECONDARY NAME NODE SECURITY
+          "dfs.secondary.namenode.keytab.file" = keytab_path;
+          "dfs.secondary.namenode.kerberos.principal" = "nn/my.engine@MY.ENGINE";
+          "dfs.secondary.namenode.kerberos.internal.spnego.principal" = "HTTP/my.engine@MY.ENGINE";
+
+          # DATA NODE SECURITY
+          "dfs.datanode.keytab.file" = keytab_path;
+          "dfs.datanode.kerberos.principal" = "dn/my.engine@MY.ENGINE";
+
+          # WEBHDFS SECURITY
+          "dfs.webhdfs.enabled" = "true";
+
+          # WEB AUTHENTICATION CONFIG
+          "dfs.web.authentication.kerberos.principal" = "HTTP/my.engine@MY.ENGINE";
+          "dfs.web.authentication.kerberos.keytab" = keytab_path;
+          "ignore.secure.ports.for.testing" = "true";
+          "dfs.http.policy" = "HTTP_ONLY";
+          "dfs.data.transfer.protection" = "privacy";
+
+          # ## MULTIHOMED
+          # "dfs.namenode.rpc-bind-host" = "0.0.0.0";
+          # "dfs.namenode.servicerpc-bind-host" = "0.0.0.0";
+          # "dfs.namenode.http-bind-host" = "0.0.0.0";
+          # "dfs.namenode.https-bind-host" = "0.0.0.0";
+          # "dfs.client.use.datanode.hostname" = "true"; # force connection by hostname
+          # "dfs.datanode.use.datanode.hostname" = "true"; # force connection by hostname
+
+
+          # "dfs.data.transfer.protection" = "privacy";
+          # "hadoop.rpc.protection" = "privacy";
+          # "dfs.http.policy" = "HTTP_ONLY";
+          # "dfs.datanode.address" = "0.0.0.0:10019";
+          # "dfs.datanode.http.address" = "0.0.0.0:10022";
+          # "dfs.datanode.https.address" = "0.0.0.0:10023";
+
+
+          # "dfs.datanode.kerberos.principal" = "dn/my.engine@MY.ENGINE";
+          # "dfs.datanode.keytab.file" = keytab_path;
+
+          # "dfs.namenode.kerberos.principal" = "nn/my.engine@MY.ENGINE";
+          # "dfs.namenode.keytab.file" = keytab_path;
+
+          # "dfs.block.access.token.enable" = "true";
+
+
         };
-        journalnode = {
-          enable = true;
-          restartIfChanged = true;
+        yarnSite = {
+          # "yarn.acl.enable" = "true";
+          # "yarn.admin.acl" = "*"; # TODO: restrict
         };
-        zkfc = {
-          enable = true;
-          restartIfChanged = true;
-        };
-        httpfs = {
-          enable = true;
-          restartIfChanged = true;
+        extraConfDirs = [ ];
+
+        hdfs = {
+          namenode = { enable = true; formatOnInit = true; restartIfChanged = true; };
+          datanode = { enable = true; restartIfChanged = true; };
+          journalnode = { enable = true; restartIfChanged = true; };
+          zkfc = { enable = true; restartIfChanged = true; };
+          httpfs = { enable = true; restartIfChanged = true; };
         };
+        yarn = { resourcemanager.enable = true; nodemanager.enable = true; };
       };
-      yarn = {
-        resourcemanager.enable = true;
-        nodemanager.enable = true;
-      };
-    };
 
     kerberos_server = {
       enable = true;
-      realms."ATHENA.MIT.EDU" = {
-        acl = [
-          { access = "all"; principal = "*/admin"; }
-          { access = "all"; principal = "admin"; }
-        ];
-      };
+      realms."MY.ENGINE".acl = [
+        { principal = "*/admin"; access = "all"; }
+        { principal = "admin"; access = "all"; }
+        { principal = "*/localhost"; access = "all"; }
+        { principal = "*/my.engine"; access = "all"; }
+        { principal = "nn/my.engine"; access = "all"; }
+        { principal = "hdfs"; access = "all"; }
+      ];
     };
   };
 
   krb5 = {
     enable = true;
-    realms."ATHENA.MIT.EDU" = {
-      admin_server = "localhost";
-      kdc = [
-        "localhost"
-      ];
-      kpasswd_server = "localhost";
+    realms = {
+      "MY.ENGINE" = {
+        admin_server = "kdc.my.engine";
+        kdc = "kdc.my.engine";
+        # default_domain = "my.engine";
+        # kpasswd_server = "odin";
+      };
     };
     domain_realm = {
-      ".athena.mit.edu" = "ATHENA.MIT.EDU";
-      "athena.mit.edu" = "ATHENA.MIT.EDU";
+      # ".my.engine" = "MY.ENGINE";
+      "my.engine" = "MY.ENGINE";
     };
     libdefaults = {
-      default_realm = "ATHENA.MIT.EDU";
-      dns_lookup_realm = false;
-      dns_lookup_kdc = false;
+      default_realm = "MY.ENGINE";
+      dns_lookup_realm = true;
+      dns_lookup_kdc = true;
+      ticket_lifetime = "24h";
+      renew_lifetime = "7d";
+      forwardable = true;
     };
     extraConfig = ''
       [logging]
-        default = FILE:/var/log/krb5.log
+        default = FILE:/var/log/krb5libs.log
+        kdc = FILE:/var/log/krb5kdc.log
+        admin_server = FILE:/var/log/kadmind.log
     '';
   };
 
 
 
+
   systemd.services.spark-history = {
     path = with pkgs; [ procps openssh nettools ];
     description = "spark history service.";