nixos/hadoop: package rewrite and module improvements

nixos/modules/services/cluster/hadoop/conf.nix

@@ -1,4 +1,4 @@
-{ hadoop, pkgs }:
+{ cfg, pkgs, lib }:
 let
   propertyXml = name: value: ''
     <property>
@@ -13,19 +13,31 @@ let
       ${builtins.concatStringsSep "\n" (pkgs.lib.mapAttrsToList propertyXml properties)}
     </configuration>
   '';
+  cfgLine = name: value: ''
+    ${name}=${builtins.toString value}
+  '';
+  cfgFile = fileName: properties: pkgs.writeTextDir fileName ''
+    # generated by NixOS
+    ${builtins.concatStringsSep "" (pkgs.lib.mapAttrsToList cfgLine properties)}
+  '';
   userFunctions = ''
     hadoop_verify_logdir() {
       echo Skipping verification of log directory
     }
   '';
+  hadoopEnv = ''
+    export HADOOP_LOG_DIR=/tmp/hadoop/$USER
+  '';
 in
-pkgs.buildEnv {
-  name = "hadoop-conf";
-  paths = [
-    (siteXml "core-site.xml" hadoop.coreSite)
-    (siteXml "hdfs-site.xml" hadoop.hdfsSite)
-    (siteXml "mapred-site.xml" hadoop.mapredSite)
-    (siteXml "yarn-site.xml" hadoop.yarnSite)
-    (pkgs.writeTextDir "hadoop-user-functions.sh" userFunctions)
-  ];
-}
+pkgs.runCommand "hadoop-conf" {} ''
+  mkdir -p $out/
+  cp ${siteXml "core-site.xml" cfg.coreSite}/* $out/
+  cp ${siteXml "hdfs-site.xml" cfg.hdfsSite}/* $out/
+  cp ${siteXml "mapred-site.xml" cfg.mapredSite}/* $out/
+  cp ${siteXml "yarn-site.xml" cfg.yarnSite}/* $out/
+  cp ${cfgFile "container-executor.cfg" cfg.containerExecutorCfg}/* $out/
+  cp ${pkgs.writeTextDir "hadoop-user-functions.sh" userFunctions}/* $out/
+  cp ${pkgs.writeTextDir "hadoop-env.sh" hadoopEnv}/* $out/
+  cp ${cfg.log4jProperties} $out/log4j.properties
+  ${lib.concatMapStringsSep "\n" (dir: "cp -r ${dir}/* $out/") cfg.extraConfDirs}
+''

nixos/modules/services/cluster/hadoop/default.nix

@@ -1,5 +1,7 @@
 { config, lib, pkgs, ...}:
-
+let
+  cfg = config.services.hadoop;
+in
 with lib;
 {
   imports = [ ./yarn.nix ./hdfs.nix ];
@@ -17,7 +19,9 @@ with lib;
     };
 
     hdfsSite = mkOption {
-      default = {};
+      default = {
+        "dfs.namenode.rpc-bind-host" = "0.0.0.0";
+      };
       type = types.attrsOf types.anything;
       example = literalExpression ''
         {
@@ -28,27 +32,81 @@ with lib;
     };
 
     mapredSite = mkOption {
-      default = {};
+      default = {
+        "mapreduce.framework.name" = "yarn";
+        "yarn.app.mapreduce.am.env" = "HADOOP_MAPRED_HOME=${cfg.package}/lib/${cfg.package.untarDir}";
+        "mapreduce.map.env" = "HADOOP_MAPRED_HOME=${cfg.package}/lib/${cfg.package.untarDir}";
+        "mapreduce.reduce.env" = "HADOOP_MAPRED_HOME=${cfg.package}/lib/${cfg.package.untarDir}";
+      };
       type = types.attrsOf types.anything;
       example = literalExpression ''
-        {
-          "mapreduce.map.cpu.vcores" = "1";
+        options.services.hadoop.mapredSite.default // {
+          "mapreduce.map.java.opts" = "-Xmx900m -XX:+UseParallelGC";
         }
       '';
       description = "Hadoop mapred-site.xml definition";
     };
 
     yarnSite = mkOption {
-      default = {};
+      default = {
+        "yarn.nodemanager.admin-env" = "PATH=$PATH";
+        "yarn.nodemanager.aux-services" = "mapreduce_shuffle";
+        "yarn.nodemanager.aux-services.mapreduce_shuffle.class" = "org.apache.hadoop.mapred.ShuffleHandler";
+        "yarn.nodemanager.bind-host" = "0.0.0.0";
+        "yarn.nodemanager.container-executor.class" = "org.apache.hadoop.yarn.server.nodemanager.LinuxContainerExecutor";
+        "yarn.nodemanager.env-whitelist" = "JAVA_HOME,HADOOP_COMMON_HOME,HADOOP_HDFS_HOME,HADOOP_CONF_DIR,CLASSPATH_PREPEND_DISTCACHE,HADOOP_YARN_HOME,HADOOP_HOME,LANG,TZ";
+        "yarn.nodemanager.linux-container-executor.group" = "hadoop";
+        "yarn.nodemanager.linux-container-executor.path" = "/run/wrappers/yarn-nodemanager/bin/container-executor";
+        "yarn.nodemanager.log-dirs" = "/var/log/hadoop/yarn/nodemanager";
+        "yarn.resourcemanager.bind-host" = "0.0.0.0";
+        "yarn.resourcemanager.scheduler.class" = "org.apache.hadoop.yarn.server.resourcemanager.scheduler.fifo.FifoScheduler";
+      };
       type = types.attrsOf types.anything;
       example = literalExpression ''
-        {
-          "yarn.resourcemanager.ha.id" = "resourcemanager1";
+        options.services.hadoop.yarnSite.default // {
+          "yarn.resourcemanager.hostname" = "''${config.networking.hostName}";
         }
       '';
       description = "Hadoop yarn-site.xml definition";
     };
 
+    log4jProperties = mkOption {
+      default = "${cfg.package}/lib/${cfg.package.untarDir}/etc/hadoop/log4j.properties";
+      type = types.path;
+      example = literalExpression ''
+        "''${pkgs.hadoop}/lib/''${pkgs.hadoop.untarDir}/etc/hadoop/log4j.properties";
+      '';
+      description = "log4j.properties file added to HADOOP_CONF_DIR";
+    };
+
+    containerExecutorCfg = mkOption {
+      default = {
+        # must be the same as yarn.nodemanager.linux-container-executor.group in yarnSite
+        "yarn.nodemanager.linux-container-executor.group"="hadoop";
+        "min.user.id"=1000;
+        "feature.terminal.enabled"=1;
+      };
+      type = types.attrsOf types.anything;
+      example = literalExpression ''
+        options.services.hadoop.containerExecutorCfg.default // {
+          "feature.terminal.enabled" = 0;
+        }
+      '';
+      description = "Yarn container-executor.cfg definition";
+    };
+
+    extraConfDirs = mkOption {
+      default = [];
+      type = types.listOf types.path;
+      example = literalExpression ''
+        [
+          ./extraHDFSConfs
+          ./extraYARNConfs
+        ]
+      '';
+      description = "Directories containing additional config files to be added to HADOOP_CONF_DIR";
+    };
+
     package = mkOption {
       type = types.package;
       default = pkgs.hadoop;
@@ -64,6 +122,12 @@ with lib;
       users.groups.hadoop = {
         gid = config.ids.gids.hadoop;
       };
+      environment = {
+        systemPackages = [ cfg.package ];
+        etc."hadoop-conf".source = let
+          hadoopConf = "${import ./conf.nix { inherit cfg pkgs lib; }}/";
+        in "${hadoopConf}";
+      };
     })
 
   ];

nixos/modules/services/cluster/hadoop/hdfs.nix

@@ -1,24 +1,54 @@
 { config, lib, pkgs, ...}:
+with lib;
 let
   cfg = config.services.hadoop;
-  hadoopConf = import ./conf.nix { hadoop = cfg; pkgs = pkgs; };
+  hadoopConf = "${import ./conf.nix { inherit cfg pkgs lib; }}/";
+  restartIfChanged  = mkOption {
+    type = types.bool;
+    description = ''
+      Automatically restart the service on config change.
+      This can be set to false to defer restarts on clusters running critical applications.
+      Please consider the security implications of inadvertently running an older version,
+      and the possibility of unexpected behavior caused by inconsistent versions across a cluster when disabling this option.
+    '';
+    default = false;
+  };
 in
-with lib;
 {
   options.services.hadoop.hdfs = {
-    namenode.enabled = mkOption {
-      type = types.bool;
-      default = false;
-      description = ''
-        Whether to run the Hadoop YARN NameNode
-      '';
+    namenode = {
+      enabled = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to run the HDFS NameNode
+        '';
+      };
+      inherit restartIfChanged;
+      openFirewall = mkOption {
+        type = types.bool;
+        default = true;
+        description = ''
+          Open firewall ports for namenode
+        '';
+      };
     };
-    datanode.enabled = mkOption {
-      type = types.bool;
-      default = false;
-      description = ''
-        Whether to run the Hadoop YARN DataNode
-      '';
+    datanode = {
+      enabled = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to run the HDFS DataNode
+        '';
+      };
+      inherit restartIfChanged;
+      openFirewall = mkOption {
+        type = types.bool;
+        default = true;
+        description = ''
+          Open firewall ports for datanode
+        '';
+      };
     };
   };
 
@@ -27,10 +57,7 @@ with lib;
       systemd.services.hdfs-namenode = {
         description = "Hadoop HDFS NameNode";
         wantedBy = [ "multi-user.target" ];
-
-        environment = {
-          HADOOP_HOME = "${cfg.package}";
-        };
+        inherit (cfg.hdfs.namenode) restartIfChanged;
 
         preStart = ''
           ${cfg.package}/bin/hdfs --config ${hadoopConf} namenode -format -nonInteractive || true
@@ -40,24 +67,34 @@ with lib;
           User = "hdfs";
           SyslogIdentifier = "hdfs-namenode";
           ExecStart = "${cfg.package}/bin/hdfs --config ${hadoopConf} namenode";
+          Restart = "always";
         };
       };
+
+      networking.firewall.allowedTCPPorts = (mkIf cfg.hdfs.namenode.openFirewall [
+        9870 # namenode.http-address
+        8020 # namenode.rpc-address
+      ]);
     })
     (mkIf cfg.hdfs.datanode.enabled {
       systemd.services.hdfs-datanode = {
         description = "Hadoop HDFS DataNode";
         wantedBy = [ "multi-user.target" ];
-
-        environment = {
-          HADOOP_HOME = "${cfg.package}";
-        };
+        inherit (cfg.hdfs.datanode) restartIfChanged;
 
         serviceConfig = {
           User = "hdfs";
           SyslogIdentifier = "hdfs-datanode";
           ExecStart = "${cfg.package}/bin/hdfs --config ${hadoopConf} datanode";
+          Restart = "always";
         };
       };
+
+      networking.firewall.allowedTCPPorts = (mkIf cfg.hdfs.datanode.openFirewall [
+        9864 # datanode.http.address
+        9866 # datanode.address
+        9867 # datanode.ipc.address
+      ]);
     })
     (mkIf (
         cfg.hdfs.namenode.enabled || cfg.hdfs.datanode.enabled