{ config, lib, pkgs, ... }: with lib; let cfg = config.services.cassandra; defaultUser = "cassandra"; cassandraConfig = flip recursiveUpdate cfg.extraConfig ({ commitlog_sync = "batch"; commitlog_sync_batch_window_in_ms = 2; start_native_transport = cfg.allowClients; cluster_name = cfg.clusterName; partitioner = "org.apache.cassandra.dht.Murmur3Partitioner"; endpoint_snitch = "SimpleSnitch"; data_file_directories = [ "${cfg.homeDir}/data" ]; commitlog_directory = "${cfg.homeDir}/commitlog"; saved_caches_directory = "${cfg.homeDir}/saved_caches"; } // (lib.optionalAttrs (cfg.seedAddresses != []) { seed_provider = [{ class_name = "org.apache.cassandra.locator.SimpleSeedProvider"; parameters = [ { seeds = concatStringsSep "," cfg.seedAddresses; } ]; }]; }) // (lib.optionalAttrs (lib.versionAtLeast cfg.package.version "3") { hints_directory = "${cfg.homeDir}/hints"; }) ); cassandraConfigWithAddresses = cassandraConfig // ( if cfg.listenAddress == null then { listen_interface = cfg.listenInterface; } else { listen_address = cfg.listenAddress; } ) // ( if cfg.rpcAddress == null then { rpc_interface = cfg.rpcInterface; } else { rpc_address = cfg.rpcAddress; } ); cassandraEtc = pkgs.stdenv.mkDerivation { name = "cassandra-etc"; cassandraYaml = builtins.toJSON cassandraConfigWithAddresses; cassandraEnvPkg = "${cfg.package}/conf/cassandra-env.sh"; cassandraLogbackConfig = pkgs.writeText "logback.xml" cfg.logbackConfig; passAsFile = [ "extraEnvSh" ]; inherit (cfg) extraEnvSh; buildCommand = '' mkdir -p "$out" echo "$cassandraYaml" > "$out/cassandra.yaml" ln -s "$cassandraLogbackConfig" "$out/logback.xml" ( cat "$cassandraEnvPkg" echo "# lines from services.cassandra.extraEnvSh: " cat "$extraEnvShPath" ) > "$out/cassandra-env.sh" # Delete default JMX Port, otherwise we can't set it using env variable sed -i '/JMX_PORT="7199"/d' "$out/cassandra-env.sh" # Delete default password file sed -i '/-Dcom.sun.management.jmxremote.password.file=\/etc\/cassandra\/jmxremote.password/d' "$out/cassandra-env.sh" ''; }; defaultJmxRolesFile = builtins.foldl' (left: right: left + right) "" (map (role: "${role.username} ${role.password}") cfg.jmxRoles); fullJvmOptions = cfg.jvmOpts ++ lib.optionals (cfg.jmxRoles != []) [ "-Dcom.sun.management.jmxremote.authenticate=true" "-Dcom.sun.management.jmxremote.password.file=${cfg.jmxRolesFile}" ] ++ lib.optionals cfg.remoteJmx [ "-Djava.rmi.server.hostname=${cfg.rpcAddress}" ]; in { options.services.cassandra = { enable = mkEnableOption '' Apache Cassandra – Scalable and highly available database. ''; clusterName = mkOption { type = types.str; default = "Test Cluster"; description = '' The name of the cluster. This setting prevents nodes in one logical cluster from joining another. All nodes in a cluster must have the same value. ''; }; user = mkOption { type = types.str; default = defaultUser; description = "Run Apache Cassandra under this user."; }; group = mkOption { type = types.str; default = defaultUser; description = "Run Apache Cassandra under this group."; }; homeDir = mkOption { type = types.path; default = "/var/lib/cassandra"; description = '' Home directory for Apache Cassandra. ''; }; package = mkOption { type = types.package; default = pkgs.cassandra; defaultText = "pkgs.cassandra"; example = literalExample "pkgs.cassandra_3_11"; description = '' The Apache Cassandra package to use. ''; }; jvmOpts = mkOption { type = types.listOf types.str; default = []; description = '' Populate the JVM_OPT environment variable. ''; }; listenAddress = mkOption { type = types.nullOr types.str; default = "127.0.0.1"; example = literalExample "null"; description = '' Address or interface to bind to and tell other Cassandra nodes to connect to. You _must_ change this if you want multiple nodes to be able to communicate! Set listenAddress OR listenInterface, not both. Leaving it blank leaves it up to InetAddress.getLocalHost(). This will always do the Right Thing _if_ the node is properly configured (hostname, name resolution, etc), and the Right Thing is to use the address associated with the hostname (it might not be). Setting listen_address to 0.0.0.0 is always wrong. ''; }; listenInterface = mkOption { type = types.nullOr types.str; default = null; example = "eth1"; description = '' Set listenAddress OR listenInterface, not both. Interfaces must correspond to a single address, IP aliasing is not supported. ''; }; rpcAddress = mkOption { type = types.nullOr types.str; default = "127.0.0.1"; example = literalExample "null"; description = '' The address or interface to bind the native transport server to. Set rpcAddress OR rpcInterface, not both. Leaving rpcAddress blank has the same effect as on listenAddress (i.e. it will be based on the configured hostname of the node). Note that unlike listenAddress, you can specify 0.0.0.0, but you must also set extraConfig.broadcast_rpc_address to a value other than 0.0.0.0. For security reasons, you should not expose this port to the internet. Firewall it if needed. ''; }; rpcInterface = mkOption { type = types.nullOr types.str; default = null; example = "eth1"; description = '' Set rpcAddress OR rpcInterface, not both. Interfaces must correspond to a single address, IP aliasing is not supported. ''; }; logbackConfig = mkOption { type = types.lines; default = '' %-5level %date{HH:mm:ss,SSS} %msg%n ''; description = '' XML logback configuration for cassandra ''; }; seedAddresses = mkOption { type = types.listOf types.str; default = [ "127.0.0.1" ]; description = '' The addresses of hosts designated as contact points in the cluster. A joining node contacts one of the nodes in the seeds list to learn the topology of the ring. Set to 127.0.0.1 for a single node cluster. ''; }; allowClients = mkOption { type = types.bool; default = true; description = '' Enables or disables the native transport server (CQL binary protocol). This server uses the same address as the rpcAddress, but the port it uses is not rpc_port but native_transport_port. See the official Cassandra docs for more information on these variables and set them using extraConfig. ''; }; extraConfig = mkOption { type = types.attrs; default = {}; example = { commitlog_sync_batch_window_in_ms = 3; }; description = '' Extra options to be merged into cassandra.yaml as nix attribute set. ''; }; extraEnvSh = mkOption { type = types.lines; default = ""; example = "CLASSPATH=$CLASSPATH:\${extraJar}"; description = '' Extra shell lines to be appended onto cassandra-env.sh. ''; }; fullRepairInterval = mkOption { type = types.nullOr types.str; default = "3w"; example = literalExample "null"; description = '' Set the interval how often full repairs are run, i.e. nodetool repair --full is executed. See https://cassandra.apache.org/doc/latest/operating/repair.html for more information. Set to null to disable full repairs. ''; }; fullRepairOptions = mkOption { type = types.listOf types.str; default = []; example = [ "--partitioner-range" ]; description = '' Options passed through to the full repair command. ''; }; incrementalRepairInterval = mkOption { type = types.nullOr types.str; default = "3d"; example = literalExample "null"; description = '' Set the interval how often incremental repairs are run, i.e. nodetool repair is executed. See https://cassandra.apache.org/doc/latest/operating/repair.html for more information. Set to null to disable incremental repairs. ''; }; incrementalRepairOptions = mkOption { type = types.listOf types.str; default = []; example = [ "--partitioner-range" ]; description = '' Options passed through to the incremental repair command. ''; }; maxHeapSize = mkOption { type = types.nullOr types.str; default = null; example = "4G"; description = '' Must be left blank or set together with heapNewSize. If left blank a sensible value for the available amount of RAM and CPU cores is calculated. Override to set the amount of memory to allocate to the JVM at start-up. For production use you may wish to adjust this for your environment. MAX_HEAP_SIZE is the total amount of memory dedicated to the Java heap. HEAP_NEWSIZE refers to the size of the young generation. The main trade-off for the young generation is that the larger it is, the longer GC pause times will be. The shorter it is, the more expensive GC will be (usually). ''; }; heapNewSize = mkOption { type = types.nullOr types.str; default = null; example = "800M"; description = '' Must be left blank or set together with heapNewSize. If left blank a sensible value for the available amount of RAM and CPU cores is calculated. Override to set the amount of memory to allocate to the JVM at start-up. For production use you may wish to adjust this for your environment. HEAP_NEWSIZE refers to the size of the young generation. The main trade-off for the young generation is that the larger it is, the longer GC pause times will be. The shorter it is, the more expensive GC will be (usually). The example HEAP_NEWSIZE assumes a modern 8-core+ machine for decent pause times. If in doubt, and if you do not particularly want to tweak, go with 100 MB per physical CPU core. ''; }; mallocArenaMax = mkOption { type = types.nullOr types.int; default = null; example = 4; description = '' Set this to control the amount of arenas per-thread in glibc. ''; }; remoteJmx = mkOption { type = types.bool; default = false; description = '' Cassandra ships with JMX accessible *only* from localhost. To enable remote JMX connections set to true. Be sure to also enable authentication and/or TLS. See: https://wiki.apache.org/cassandra/JmxSecurity ''; }; jmxPort = mkOption { type = types.int; default = 7199; description = '' Specifies the default port over which Cassandra will be available for JMX connections. For security reasons, you should not expose this port to the internet. Firewall it if needed. ''; }; jmxRoles = mkOption { default = []; description = '' Roles that are allowed to access the JMX (e.g. nodetool) BEWARE: The passwords will be stored world readable in the nix-store. It's recommended to use your own protected file using jmxRolesFile Doesn't work in versions older than 3.11 because they don't like that it's world readable. ''; type = types.listOf (types.submodule { options = { username = mkOption { type = types.str; description = "Username for JMX"; }; password = mkOption { type = types.str; description = "Password for JMX"; }; }; }); }; jmxRolesFile = mkOption { type = types.nullOr types.path; default = if (lib.versionAtLeast cfg.package.version "3.11") then pkgs.writeText "jmx-roles-file" defaultJmxRolesFile else null; example = "/var/lib/cassandra/jmx.password"; description = '' Specify your own jmx roles file. Make sure the permissions forbid "others" from reading the file if you're using Cassandra below version 3.11. ''; }; }; config = mkIf cfg.enable { assertions = [ { assertion = (cfg.listenAddress == null) != (cfg.listenInterface == null); message = "You have to set either listenAddress or listenInterface"; } { assertion = (cfg.rpcAddress == null) != (cfg.rpcInterface == null); message = "You have to set either rpcAddress or rpcInterface"; } { assertion = (cfg.maxHeapSize == null) == (cfg.heapNewSize == null); message = "If you set either of maxHeapSize or heapNewSize you have to set both"; } { assertion = cfg.remoteJmx -> cfg.jmxRolesFile != null; message = '' If you want JMX available remotely you need to set a password using jmxRoles or jmxRolesFile if using Cassandra older than v3.11. ''; } ]; users = mkIf (cfg.user == defaultUser) { extraUsers.${defaultUser} = { group = cfg.group; home = cfg.homeDir; createHome = true; uid = config.ids.uids.cassandra; description = "Cassandra service user"; }; extraGroups.${defaultUser}.gid = config.ids.gids.cassandra; }; systemd.services.cassandra = { description = "Apache Cassandra service"; after = [ "network.target" ]; environment = { CASSANDRA_CONF = "${cassandraEtc}"; JVM_OPTS = builtins.concatStringsSep " " fullJvmOptions; MAX_HEAP_SIZE = toString cfg.maxHeapSize; HEAP_NEWSIZE = toString cfg.heapNewSize; MALLOC_ARENA_MAX = toString cfg.mallocArenaMax; LOCAL_JMX = if cfg.remoteJmx then "no" else "yes"; JMX_PORT = toString cfg.jmxPort; }; wantedBy = [ "multi-user.target" ]; serviceConfig = { User = cfg.user; Group = cfg.group; ExecStart = "${cfg.package}/bin/cassandra -f"; SuccessExitStatus = 143; }; }; systemd.services.cassandra-full-repair = { description = "Perform a full repair on this Cassandra node"; after = [ "cassandra.service" ]; requires = [ "cassandra.service" ]; serviceConfig = { User = cfg.user; Group = cfg.group; ExecStart = lib.concatStringsSep " " ([ "${cfg.package}/bin/nodetool" "repair" "--full" ] ++ cfg.fullRepairOptions); }; }; systemd.timers.cassandra-full-repair = mkIf (cfg.fullRepairInterval != null) { description = "Schedule full repairs on Cassandra"; wantedBy = [ "timers.target" ]; timerConfig = { OnBootSec = cfg.fullRepairInterval; OnUnitActiveSec = cfg.fullRepairInterval; Persistent = true; }; }; systemd.services.cassandra-incremental-repair = { description = "Perform an incremental repair on this cassandra node."; after = [ "cassandra.service" ]; requires = [ "cassandra.service" ]; serviceConfig = { User = cfg.user; Group = cfg.group; ExecStart = lib.concatStringsSep " " ([ "${cfg.package}/bin/nodetool" "repair" ] ++ cfg.incrementalRepairOptions); }; }; systemd.timers.cassandra-incremental-repair = mkIf (cfg.incrementalRepairInterval != null) { description = "Schedule incremental repairs on Cassandra"; wantedBy = [ "timers.target" ]; timerConfig = { OnBootSec = cfg.incrementalRepairInterval; OnUnitActiveSec = cfg.incrementalRepairInterval; Persistent = true; }; }; }; }