Just as in Hadoop where you add site-specific HDFS configuration
to the hdfs-site.xml file,
for HBase, site specific customizations go into
the file conf/hbase-site.xml.
For the list of configurable properties, see
???
below or view the raw hbase-default.xml
source file in the HBase source code at
src/main/resources.
Not all configuration options make it out to
hbase-default.xml. Configuration
that it is thought rare anyone would change can exist only
in code; the only way to turn up such configurations is
via a reading of the source code itself.
Currently, changes here will require a cluster restart for HBase to notice the change.
<configuration> <property> <name>hbase.rootdir</name> <value>file:///tmp/hbase-${user.name}/hbase</value> <description>The directory shared by region servers and into which HBase persists. The URL should be 'fully-qualified' to include the filesystem scheme. For example, to specify the HDFS directory '/hbase' where the HDFS instance's namenode is running at namenode.example.org on port 9000, set this value to: hdfs://namenode.example.org:9000/hbase. By default HBase writes into /tmp. Change this configuration else all data will be lost on machine restart. </description> </property> <property> <name>hbase.master.port</name> <value>60000</value> <description>The port the HBase Master should bind to.</description> </property> <property> <name>hbase.cluster.distributed</name> <value>false</value> <description>The mode the cluster will be in. Possible values are false for standalone mode and true for distributed mode. If false, startup will run all HBase and ZooKeeper daemons together in the one JVM. </description> </property> <property> <name>hbase.tmp.dir</name> <value>${java.io.tmpdir}/hbase-${user.name}</value> <description>Temporary directory on the local filesystem. Change this setting to point to a location more permanent than '/tmp' (The '/tmp' directory is often cleared on machine restart). </description> </property> <property> <name>hbase.local.dir</name> <value>${hbase.tmp.dir}/local/</value> <description>Directory on the local filesystem to be used as a local storage. </description> </property> <property> <name>hbase.master.info.port</name> <value>60010</value> <description>The port for the HBase Master web UI. Set to -1 if you do not want a UI instance run. </description> </property> <property> <name>hbase.master.info.bindAddress</name> <value>0.0.0.0</value> <description>The bind address for the HBase Master web UI </description> </property> <property> <name>hbase.client.write.buffer</name> <value>2097152</value> <description>Default size of the HTable clien write buffer in bytes. A bigger buffer takes more memory -- on both the client and server side since server instantiates the passed write buffer to process it -- but a larger buffer size reduces the number of RPCs made. For an estimate of server-side memory-used, evaluate hbase.client.write.buffer * hbase.regionserver.handler.count </description> </property> <property> <name>hbase.regionserver.port</name> <value>60020</value> <description>The port the HBase RegionServer binds to. </description> </property> <property> <name>hbase.regionserver.info.port</name> <value>60030</value> <description>The port for the HBase RegionServer web UI Set to -1 if you do not want the RegionServer UI to run. </description> </property> <property> <name>hbase.regionserver.info.port.auto</name> <value>false</value> <description>Whether or not the Master or RegionServer UI should search for a port to bind to. Enables automatic port search if hbase.regionserver.info.port is already in use. Useful for testing, turned off by default. </description> </property> <property> <name>hbase.regionserver.info.bindAddress</name> <value>0.0.0.0</value> <description>The address for the HBase RegionServer web UI </description> </property> <property> <name>hbase.regionserver.class</name> <value>org.apache.hadoop.hbase.ipc.HRegionInterface</value> <description>The RegionServer interface to use. Used by the client opening proxy to remote region server. </description> </property> <property> <name>hbase.client.pause</name> <value>1000</value> <description>General client pause value. Used mostly as value to wait before running a retry of a failed get, region lookup, etc.</description> </property> <property> <name>hbase.client.retries.number</name> <value>14</value> <description>Maximum retries. Used as maximum for all retryable operations such as fetching of the root region from root region server, getting a cell's value, starting a row update, etc. Default: 14. </description> </property> <property> <name>hbase.bulkload.retries.number</name> <value>0</value> <description>Maximum retries. This is maximum number of iterations to atomic bulk loads are attempted in the face of splitting operations 0 means never give up. Default: 0. </description> </property> <property> <name>hbase.client.scanner.caching</name> <value>1</value> <description>Number of rows that will be fetched when calling next on a scanner if it is not served from (local, client) memory. Higher caching values will enable faster scanners but will eat up more memory and some calls of next may take longer and longer times when the cache is empty. Do not set this value such that the time between invocations is greater than the scanner timeout; i.e. hbase.regionserver.lease.period </description> </property> <property> <name>hbase.client.keyvalue.maxsize</name> <value>10485760</value> <description>Specifies the combined maximum allowed size of a KeyValue instance. This is to set an upper boundary for a single entry saved in a storage file. Since they cannot be split it helps avoiding that a region cannot be split any further because the data is too large. It seems wise to set this to a fraction of the maximum region size. Setting it to zero or less disables the check. </description> </property> <property> <name>hbase.regionserver.lease.period</name> <value>60000</value> <description>HRegion server lease period in milliseconds. Default is 60 seconds. Clients must report in within this period else they are considered dead.</description> </property> <property> <name>hbase.regionserver.handler.count</name> <value>10</value> <description>Count of RPC Listener instances spun up on RegionServers. Same property is used by the Master for count of master handlers. Default is 10. </description> </property> <property> <name>hbase.regionserver.msginterval</name> <value>3000</value> <description>Interval between messages from the RegionServer to Master in milliseconds. </description> </property> <property> <name>hbase.regionserver.optionallogflushinterval</name> <value>1000</value> <description>Sync the HLog to the HDFS after this interval if it has not accumulated enough entries to trigger a sync. Default 1 second. Units: milliseconds. </description> </property> <property> <name>hbase.regionserver.regionSplitLimit</name> <value>2147483647</value> <description>Limit for the number of regions after which no more region splitting should take place. This is not a hard limit for the number of regions but acts as a guideline for the regionserver to stop splitting after a certain limit. Default is set to MAX_INT; i.e. do not block splitting. </description> </property> <property> <name>hbase.regionserver.logroll.period</name> <value>3600000</value> <description>Period at which we will roll the commit log regardless of how many edits it has.</description> </property> <property> <name>hbase.regionserver.logroll.errors.tolerated</name> <value>2</value> <description>The number of consecutive WAL close errors we will allow before triggering a server abort. A setting of 0 will cause the region server to abort if closing the current WAL writer fails during log rolling. Even a small value (2 or 3) will allow a region server to ride over transient HDFS errors.</description> </property> <property> <name>hbase.regionserver.hlog.reader.impl</name> <value>org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogReader</value> <description>The HLog file reader implementation.</description> </property> <property> <name>hbase.regionserver.hlog.writer.impl</name> <value>org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogWriter</value> <description>The HLog file writer implementation.</description> </property> <property> <name>hbase.regionserver.separate.hlog.for.meta</name> <value>false</value> </property> <property> <name>hbase.regionserver.nbreservationblocks</name> <value>4</value> <description>The number of resevoir blocks of memory release on OOME so we can cleanup properly before server shutdown. </description> </property> <property> <name>hbase.zookeeper.dns.interface</name> <value>default</value> <description>The name of the Network Interface from which a ZooKeeper server should report its IP address. </description> </property> <property> <name>hbase.zookeeper.dns.nameserver</name> <value>default</value> <description>The host name or IP address of the name server (DNS) which a ZooKeeper server should use to determine the host name used by the master for communication and display purposes. </description> </property> <property> <name>hbase.regionserver.dns.interface</name> <value>default</value> <description>The name of the Network Interface from which a region server should report its IP address. </description> </property> <property> <name>hbase.regionserver.dns.nameserver</name> <value>default</value> <description>The host name or IP address of the name server (DNS) which a region server should use to determine the host name used by the master for communication and display purposes. </description> </property> <property> <name>fail.fast.expired.active.master</name> <value>false</value> <description>If abort immediately for the expired master without trying to recover its zk session.</description> </property> <property> <name>hbase.master.dns.interface</name> <value>default</value> <description>The name of the Network Interface from which a master should report its IP address. </description> </property> <property> <name>hbase.master.dns.nameserver</name> <value>default</value> <description>The host name or IP address of the name server (DNS) which a master should use to determine the host name used for communication and display purposes. </description> </property> <property> <name>hbase.balancer.period </name> <value>300000</value> <description>Period at which the region balancer runs in the Master. </description> </property> <property> <name>hbase.regions.slop</name> <value>0.2</value> <description>Rebalance if any regionserver has average + (average * slop) regions. Default is 20% slop. </description> </property> <property> <name>hbase.master.logcleaner.ttl</name> <value>600000</value> <description>Maximum time a HLog can stay in the .oldlogdir directory, after which it will be cleaned by a Master thread. </description> </property> <property> <name>hbase.master.logcleaner.plugins</name> <value>org.apache.hadoop.hbase.master.cleaner.TimeToLiveLogCleaner</value> <description>A comma-separated list of LogCleanerDelegate invoked by the LogsCleaner service. These WAL/HLog cleaners are called in order, so put the HLog cleaner that prunes the most HLog files in front. To implement your own LogCleanerDelegate, just put it in HBase's classpath and add the fully qualified class name here. Always add the above default log cleaners in the list. </description> </property> <property> <name>hbase.regionserver.global.memstore.upperLimit</name> <value>0.4</value> <description>Maximum size of all memstores in a region server before new updates are blocked and flushes are forced. Defaults to 40% of heap </description> </property> <property> <name>hbase.regionserver.global.memstore.lowerLimit</name> <value>0.35</value> <description>When memstores are being forced to flush to make room in memory, keep flushing until we hit this mark. Defaults to 35% of heap. This value equal to hbase.regionserver.global.memstore.upperLimit causes the minimum possible flushing to occur when updates are blocked due to memstore limiting. </description> </property> <property> <name>hbase.server.thread.wakefrequency</name> <value>10000</value> <description>Time to sleep in between searches for work (in milliseconds). Used as sleep interval by service threads such as log roller. </description> </property> <property> <name>hbase.server.versionfile.writeattempts</name> <value>3</value> <description> How many time to retry attempting to write a version file before just aborting. Each attempt is seperated by the hbase.server.thread.wakefrequency milliseconds. </description> </property> <property> <name>hbase.regionserver.optionalcacheflushinterval</name> <value>3600000</value> <description> Maximum amount of time an edit lives in memory before being automatically flushed. Default 1 hour. Set it to 0 to disable automatic flushing. </description> </property> <property> <name>hbase.hregion.memstore.flush.size</name> <value>134217728</value> <description> Memstore will be flushed to disk if size of the memstore exceeds this number of bytes. Value is checked by a thread that runs every hbase.server.thread.wakefrequency. </description> </property> <property> <name>hbase.hregion.preclose.flush.size</name> <value>5242880</value> <description> If the memstores in a region are this size or larger when we go to close, run a "pre-flush" to clear out memstores before we put up the region closed flag and take the region offline. On close, a flush is run under the close flag to empty memory. During this time the region is offline and we are not taking on any writes. If the memstore content is large, this flush could take a long time to complete. The preflush is meant to clean out the bulk of the memstore before putting up the close flag and taking the region offline so the flush that runs under the close flag has little to do. </description> </property> <property> <name>hbase.hregion.memstore.block.multiplier</name> <value>2</value> <description> Block updates if memstore has hbase.hregion.block.memstore time hbase.hregion.flush.size bytes. Useful preventing runaway memstore during spikes in update traffic. Without an upper-bound, memstore fills such that when it flushes the resultant flush files take a long time to compact or split, or worse, we OOME. </description> </property> <property> <name>hbase.hregion.memstore.mslab.enabled</name> <value>true</value> <description> Enables the MemStore-Local Allocation Buffer, a feature which works to prevent heap fragmentation under heavy write loads. This can reduce the frequency of stop-the-world GC pauses on large heaps. </description> </property> <property> <name>hbase.hregion.max.filesize</name> <value>10737418240</value> <description> Maximum HStoreFile size. If any one of a column families' HStoreFiles has grown to exceed this value, the hosting HRegion is split in two. Default: 10G. </description> </property> <property> <name>hbase.hstore.compactionThreshold</name> <value>3</value> <description> If more than this number of HStoreFiles in any one HStore (one HStoreFile is written per flush of memstore) then a compaction is run to rewrite all HStoreFiles files as one. Larger numbers put off compaction but when it runs, it takes longer to complete. </description> </property> <property> <name>hbase.hstore.blockingStoreFiles</name> <value>7</value> <description> If more than this number of StoreFiles in any one Store (one StoreFile is written per flush of MemStore) then updates are blocked for this HRegion until a compaction is completed, or until hbase.hstore.blockingWaitTime has been exceeded. </description> </property> <property> <name>hbase.hstore.blockingWaitTime</name> <value>90000</value> <description> The time an HRegion will block updates for after hitting the StoreFile limit defined by hbase.hstore.blockingStoreFiles. After this time has elapsed, the HRegion will stop blocking updates even if a compaction has not been completed. Default: 90 seconds. </description> </property> <property> <name>hbase.hstore.compaction.max</name> <value>10</value> <description>Max number of HStoreFiles to compact per 'minor' compaction. </description> </property> <property> <name>hbase.hregion.majorcompaction</name> <value>86400000</value> <description>The time (in miliseconds) between 'major' compactions of all HStoreFiles in a region. Default: 1 day. Set to 0 to disable automated major compactions. </description> </property> <property> <name>hfile.block.cache.size</name> <value>0.25</value> <description> Percentage of maximum heap (-Xmx setting) to allocate to block cache used by HFile/StoreFile. Default of 0.25 means allocate 25%. Set to 0 to disable but it's not recommended. </description> </property> <property> <name>hbase.hash.type</name> <value>murmur</value> <description>The hashing algorithm for use in HashFunction. Two values are supported now: murmur (MurmurHash) and jenkins (JenkinsHash). Used by bloom filters. </description> </property> <property> <name>hfile.block.index.cacheonwrite</name> <value>false</value> <description> This allows to put non-root multi-level index blocks into the block cache at the time the index is being written. </description> </property> <property> <name>hbase.regionserver.checksum.verify</name> <value>false</value> <description> Allow hbase to do checksums rather than using hdfs checksums. This is a backwards incompatible change. </description> </property> <property> <name>hfile.index.block.max.size</name> <value>131072</value> <description> When the size of a leaf-level, intermediate-level, or root-level index block in a multi-level block index grows to this size, the block is written out and a new block is started. </description> </property> <property> <name>hfile.format.version</name> <value>2</value> <description> The HFile format version to use for new files. Set this to 1 to test backwards-compatibility. The default value of this option should be consistent with FixedFileTrailer.MAX_VERSION. </description> </property> <property> <name>io.storefile.bloom.block.size</name> <value>131072</value> <description> The size in bytes of a single block ("chunk") of a compound Bloom filter. This size is approximate, because Bloom blocks can only be inserted at data block boundaries, and the number of keys per data block varies. </description> </property> <property> <name>io.storefile.bloom.cacheonwrite</name> <value>false</value> <description> Enables cache-on-write for inline blocks of a compound Bloom filter. </description> </property> <property> <name>hbase.rs.cacheblocksonwrite</name> <value>false</value> <description> Whether an HFile block should be added to the block cache when the block is finished. </description> </property> <property> <name>hbase.rpc.engine</name> <value>org.apache.hadoop.hbase.ipc.WritableRpcEngine</value> <description>Implementation of org.apache.hadoop.hbase.ipc.RpcEngine to be used for client / server RPC call marshalling. </description> </property> <property> <name>hbase.rpc.timeout</name> <value>60000</value> <description>This is for the RPC layer to define how long HBase client applications take for a remote call to time out. It uses pings to check connections but will eventually throw a TimeoutException.</description> </property> <property> <name>hbase.rpc.shortoperation.timeout</name> <value>10000</value> <description>This is another version of "hbase.rpc.timeout". For those RPC operation within cluster, we rely on this configuration to set a short timeout limitation for short operation. For example, short rpc timeout for region server's trying to report to active master can benefit quicker master failover process.</description> </property> <property> <name>hbase.regionserver.region.split.policy</name> <value>org.apache.hadoop.hbase.regionserver.IncreasingToUpperBoundRegionSplitPolicy</value> <description> A split policy determines when a region should be split. The various other split policies that are available currently are ConstantSizeRegionSplitPolicy, DisabledRegionSplitPolicy, DelimitedKeyPrefixRegionSplitPolicy, KeyPrefixRegionSplitPolicy etc. </description> </property> <property> <name>hbase.master.keytab.file</name> <value></value> <description>Full path to the kerberos keytab file to use for logging in the configured HMaster server principal. </description> </property> <property> <name>hbase.master.kerberos.principal</name> <value></value> <description>Ex. "hbase/_HOST@EXAMPLE.COM". The kerberos principal name that should be used to run the HMaster process. The principal name should be in the form: user/hostname@DOMAIN. If "_HOST" is used as the hostname portion, it will be replaced with the actual hostname of the running instance. </description> </property> <property> <name>hbase.regionserver.keytab.file</name> <value></value> <description>Full path to the kerberos keytab file to use for logging in the configured HRegionServer server principal. </description> </property> <property> <name>hbase.regionserver.kerberos.principal</name> <value></value> <description>Ex. "hbase/_HOST@EXAMPLE.COM". The kerberos principal name that should be used to run the HRegionServer process. The principal name should be in the form: user/hostname@DOMAIN. If "_HOST" is used as the hostname portion, it will be replaced with the actual hostname of the running instance. An entry for this principal must exist in the file specified in hbase.regionserver.keytab.file </description> </property> <property> <name>hadoop.policy.file</name> <value>hbase-policy.xml</value> <description>The policy configuration file used by RPC servers to make authorization decisions on client requests. Only used when HBase security is enabled. </description> </property> <property> <name>hbase.superuser</name> <value></value> <description>List of users or groups (comma-separated), who are allowed full privileges, regardless of stored ACLs, across the cluster. Only used when HBase security is enabled. </description> </property> <property> <name>hbase.auth.key.update.interval</name> <value>86400000</value> <description>The update interval for master key for authentication tokens in servers in milliseconds. Only used when HBase security is enabled. </description> </property> <property> <name>hbase.auth.token.max.lifetime</name> <value>604800000</value> <description>The maximum lifetime in milliseconds after which an authentication token expires. Only used when HBase security is enabled. </description> </property> <property> <name>zookeeper.session.timeout</name> <value>180000</value> <description>ZooKeeper session timeout. HBase passes this to the zk quorum as suggested maximum time for a session (This setting becomes zookeeper's 'maxSessionTimeout'). See http://hadoop.apache.org/zookeeper/docs/current/zookeeperProgrammers.html#ch_zkSessions "The client sends a requested timeout, the server responds with the timeout that it can give the client. " In milliseconds. </description> </property> <property> <name>zookeeper.znode.parent</name> <value>/hbase</value> <description>Root ZNode for HBase in ZooKeeper. All of HBase's ZooKeeper files that are configured with a relative path will go under this node. By default, all of HBase's ZooKeeper file path are configured with a relative path, so they will all go under this directory unless changed. </description> </property> <property> <name>zookeeper.znode.rootserver</name> <value>root-region-server</value> <description>Path to ZNode holding root region location. This is written by the master and read by clients and region servers. If a relative path is given, the parent folder will be ${zookeeper.znode.parent}. By default, this means the root location is stored at /hbase/root-region-server. </description> </property> <property> <name>hbase.ipc.client.fallback-to-simple-auth-allowed</name> <value>false</value> <description> When a client is configured to attempt a secure connection, but attempts to connect to an insecure server, that server may instruct the client to switch to SASL SIMPLE (unsecure) authentication. This setting controls whether or not the client will accept this instruction from the server. When false (the default), the client will not allow the fallback to SIMPLE authentication, and will abort the connection. This setting is only used by the secure RPC engine. </description> </property> <property> <name>zookeeper.znode.acl.parent</name> <value>acl</value> <description>Root ZNode for access control lists.</description> </property> <property> <name>hbase.coprocessor.region.classes</name> <value></value> <description>A comma-separated list of Coprocessors that are loaded by default on all tables. For any override coprocessor method, these classes will be called in order. After implementing your own Coprocessor, just put it in HBase's classpath and add the fully qualified class name here. A coprocessor can also be loaded on demand by setting HTableDescriptor. </description> </property> <property> <name>hbase.coprocessor.master.classes</name> <value></value> <description>A comma-separated list of org.apache.hadoop.hbase.coprocessor.MasterObserver coprocessors that are loaded by default on the active HMaster process. For any implemented coprocessor methods, the listed classes will be called in order. After implementing your own MasterObserver, just put it in HBase's classpath and add the fully qualified class name here. </description> </property> <property> <name>hbase.zookeeper.quorum</name> <value>localhost</value> <description>Comma separated list of servers in the ZooKeeper Quorum. For example, "host1.mydomain.com,host2.mydomain.com,host3.mydomain.com". By default this is set to localhost for local and pseudo-distributed modes of operation. For a fully-distributed setup, this should be set to a full list of ZooKeeper quorum servers. If HBASE_MANAGES_ZK is set in hbase-env.sh this is the list of servers which we will start/stop ZooKeeper on. </description> </property> <property> <name>hbase.zookeeper.peerport</name> <value>2888</value> <description>Port used by ZooKeeper peers to talk to each other. See http://hadoop.apache.org/zookeeper/docs/r3.1.1/zookeeperStarted.html#sc_RunningReplicatedZooKeeper for more information. </description> </property> <property> <name>hbase.zookeeper.leaderport</name> <value>3888</value> <description>Port used by ZooKeeper for leader election. See http://hadoop.apache.org/zookeeper/docs/r3.1.1/zookeeperStarted.html#sc_RunningReplicatedZooKeeper for more information. </description> </property> <property> <name>hbase.zookeeper.useMulti</name> <value>false</value> <description>Instructs HBase to make use of ZooKeeper's multi-update functionality. This allows certain ZooKeeper operations to complete more quickly and prevents some issues with rare ZooKeeper failure scenarios (see the release note of HBASE-6710 for an example). IMPORTANT: only set this to true if all ZooKeeper servers in the cluster are on version 3.4+ and will not be downgraded. ZooKeeper versions before 3.4 do not support multi-update and will not fail gracefully if multi-update is invoked (see ZOOKEEPER-1495). </description> </property> <property> <name>hbase.zookeeper.property.initLimit</name> <value>10</value> <description>Property from ZooKeeper's config zoo.cfg. The number of ticks that the initial synchronization phase can take. </description> </property> <property> <name>hbase.zookeeper.property.syncLimit</name> <value>5</value> <description>Property from ZooKeeper's config zoo.cfg. The number of ticks that can pass between sending a request and getting an acknowledgment. </description> </property> <property> <name>hbase.zookeeper.property.dataDir</name> <value>${hbase.tmp.dir}/zookeeper</value> <description>Property from ZooKeeper's config zoo.cfg. The directory where the snapshot is stored. </description> </property> <property> <name>hbase.zookeeper.property.clientPort</name> <value>2181</value> <description>Property from ZooKeeper's config zoo.cfg. The port at which the clients will connect. </description> </property> <property> <name>hbase.zookeeper.property.maxClientCnxns</name> <value>300</value> <description>Property from ZooKeeper's config zoo.cfg. Limit on number of concurrent connections (at the socket level) that a single client, identified by IP address, may make to a single member of the ZooKeeper ensemble. Set high to avoid zk connection issues running standalone and pseudo-distributed. </description> </property> <property> <name>hbase.rest.port</name> <value>8080</value> <description>The port for the HBase REST server.</description> </property> <property> <name>hbase.rest.readonly</name> <value>false</value> <description> Defines the mode the REST server will be started in. Possible values are: false: All HTTP methods are permitted - GET/PUT/POST/DELETE. true: Only the GET method is permitted. </description> </property> <property> <name>hbase.defaults.for.version</name> <value>@@@VERSION@@@</value> <description> This defaults file was compiled for version @@@VERSION@@@. This variable is used to make sure that a user doesn't have an old version of hbase-default.xml on the classpath. </description> </property> <property> <name>hbase.defaults.for.version.skip</name> <value>false</value> <description> Set to true to skip the 'hbase.defaults.for.version' check. Setting this to true can be useful in contexts other than the other side of a maven generation; i.e. running in an ide. You'll want to set this boolean to true to avoid seeing the RuntimException complaint: "hbase-default.xml file seems to be for and old version of HBase (@@@VERSION@@@), this version is X.X.X-SNAPSHOT" </description> </property> <property> <name>hbase.coprocessor.abortonerror</name> <value>false</value> <description> Set to true to cause the hosting server (master or regionserver) to abort if a coprocessor throws a Throwable object that is not IOException or a subclass of IOException. Setting it to true might be useful in development environments where one wants to terminate the server as soon as possible to simplify coprocessor failure analysis. </description> </property> <property> <name>hbase.online.schema.update.enable</name> <value>false</value> <description> Set true to enable online schema changes. This is an experimental feature. There are known issues modifying table schemas at the same time a region split is happening so your table needs to be quiescent or else you have to be running with splits disabled. </description> </property> <property> <name>dfs.support.append</name> <value>true</value> <description>Does HDFS allow appends to files? This is an hdfs config. set in here so the hdfs client will do append support. You must ensure that this config. is true serverside too when running hbase (You will have to restart your cluster after setting it). </description> </property> <property> <name>hbase.regionserver.thrift.framed</name> <value>false</value> <description>Use Thrift TFramedTransport on the server side. This is the recommended transport for thrift servers and requires a similar setting on the client side. Setting this to false will select the default transport, vulnerable to DoS when malformed requests are issued due to THRIFT-601. </description> </property> <property> <name>hbase.regionserver.thrift.framed.max_frame_size_in_mb</name> <value>2</value> <description>Default frame size when using framed transport</description> </property> <property> <name>hbase.regionserver.thrift.compact</name> <value>false</value> <description>Use Thrift TCompactProtocol binary serialization protocol.</description> </property> <property> <name>hbase.thrift.minWorkerThreads</name> <value>16</value> <description> The "core size" of the thread pool. New threads are created on every connection until this many threads are created. </description> </property> <property> <name>hbase.thrift.maxWorkerThreads</name> <value>1000</value> <description> The maximum size of the thread pool. When the pending request queue overflows, new threads are created until their number reaches this number. After that, the server starts dropping connections. </description> </property> <property> <name>hbase.thrift.maxQueuedRequests</name> <value>1000</value> <description> The maximum number of pending Thrift connections waiting in the queue. If there are no idle threads in the pool, the server queues requests. Only when the queue overflows, new threads are added, up to hbase.thrift.maxQueuedRequests threads. </description> </property> <property> <name>hbase.thrift.htablepool.size.max</name> <value>1000</value> <description>The upper bound for the table pool used in the Thrift gateways server. Since this is per table name, we assume a single table and so with 1000 default worker threads max this is set to a matching number. For other workloads this number can be adjusted as needed. </description> </property> <property> <name>hbase.offheapcache.percentage</name> <value>0</value> <description> The amount of off heap space to be allocated towards the experimental off heap cache. If you desire the cache to be disabled, simply set this value to 0. </description> </property> <property> <name>hbase.data.umask.enable</name> <value>false</value> <description>Enable, if true, that file permissions should be assigned to the files written by the regionserver </description> </property> <property> <name>hbase.data.umask</name> <value>000</value> <description>File permissions that should be used to write data files when hbase.data.umask.enable is true </description> </property> <property> <name>hbase.metrics.showTableName</name> <value>true</value> <description>Whether to include the prefix "tbl.tablename" in per-column family metrics. If true, for each metric M, per-cf metrics will be reported for tbl.T.cf.CF.M, if false, per-cf metrics will be aggregated by column-family across tables, and reported for cf.CF.M. In both cases, the aggregated metric M across tables and cfs will be reported. </description> </property> <property> <name>hbase.table.archive.directory</name> <value>.archive</value> <description>Per-table directory name under which to backup files for a table. Files are moved to the same directories as they would be under the table directory, but instead are just one level lower (under table/.archive/... rather than table/...). Currently only applies to HFiles.</description> </property> <property> <name>hbase.master.hfilecleaner.plugins</name> <value>org.apache.hadoop.hbase.master.cleaner.TimeToLiveHFileCleaner</value> <description>A comma-separated list of HFileCleanerDelegate invoked by the HFileCleaner service. These HFiles cleaners are called in order, so put the cleaner that prunes the most files in front. To implement your own HFileCleanerDelegate, just put it in HBase's classpath and add the fully qualified class name here. Always add the above default log cleaners in the list as they will be overwritten in hbase-site.xml. </description> </property> <property> <name>hbase.rest.threads.max</name> <value>100</value> <description> The maximum number of threads of the REST server thread pool. Threads in the pool are reused to process REST requests. This controls the maximum number of requests processed concurrently. It may help to control the memory used by the REST server to avoid OOM issues. If the thread pool is full, incoming requests will be queued up and wait for some free threads. The default is 100. </description> </property> <property> <name>hbase.rest.threads.min</name> <value>2</value> <description> The minimum number of threads of the REST server thread pool. The thread pool always has at least these number of threads so the REST server is ready to serve incoming requests. The default is 2. </description> </property> <property> <name>hbase.lease.recovery.timeout</name> <value>900000</value> <description> How long we wait on dfs lease recovery in total before giving up. </description> </property> <property> <name>hbase.lease.recovery.dfs.timeout</name> <value>61000</value> <description> How long between dfs recover lease invocations. Should be just larger than how long it takes the namenode to timeout trying to reach a datanode; usually dfs.socket.timeout. If HBase asked hdfs its cluster configs, we would not need this config. See the end of HBASE-8389 for more. </description> </property> <property> <name>hbase.dynamic.jars.dir</name> <value>${hbase.rootdir}/.lib</value> <description> The directory from which the custom filter/co-processor jars can be loaded dynamically by the region server without the need to restart. However, an already loaded filter/co-processor class would not be un-loaded. See HBASE-1936 for more details. </description> </property> <property> <name>hbase.security.authentication</name> <value>simple</value> <description> Controls whether or not secure authentication is enabled for HBase. Possible values are 'simple' (no authentication), and 'kerberos'. </description> </property> </configuration>Set HBase environment variables in this file.
Examples include options to pass the JVM on start of
an HBase daemon such as heap size and garbarge collector configs.
You can also set configurations for HBase configuration, log directories,
niceness, ssh options, where to locate process pid files,
etc. Open the file at
conf/hbase-env.sh and peruse its content.
Each option is fairly well documented. Add your own environment
variables here if you want them read by HBase daemons on startup.
Changes here will require a cluster restart for HBase to notice the change.
Edit this file to change rate at which HBase files are rolled and to change the level at which HBase logs messages.
Changes here will require a cluster restart for HBase to notice the change though log levels can be changed for particular daemons via the HBase UI.
Since the HBase Master may move around, clients bootstrap by looking to ZooKeeper for
current critical locations. ZooKeeper is where all these values are kept. Thus clients
require the location of the ZooKeeper ensemble information before they can do anything else.
Usually this the ensemble location is kept out in the hbase-site.xml and
is picked up by the client from the CLASSPATH.
If you are configuring an IDE to run a HBase client, you should
include the conf/ directory on your classpath so
hbase-site.xml settings can be found (or
add src/test/resources to pick up the hbase-site.xml
used by tests).
Minimally, a client of HBase needs several libraries in its CLASSPATH when connecting to a cluster, including:
commons-configuration (commons-configuration-1.6.jar) commons-lang (commons-lang-2.5.jar) commons-logging (commons-logging-1.1.1.jar) hadoop-core (hadoop-core-1.0.0.jar) hbase (hbase-0.92.0.jar) log4j (log4j-1.2.16.jar) slf4j-api (slf4j-api-1.5.8.jar) slf4j-log4j (slf4j-log4j12-1.5.8.jar) zookeeper (zookeeper-3.4.2.jar)
An example basic hbase-site.xml for client only
might look as follows:
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>hbase.zookeeper.quorum</name>
<value>example1,example2,example3</value>
<description>The directory shared by region servers.
</description>
</property>
</configuration>
The configuration used by a Java client is kept
in an HBaseConfiguration instance.
The factory method on HBaseConfiguration, HBaseConfiguration.create();,
on invocation, will read in the content of the first hbase-site.xml found on
the client's CLASSPATH, if one is present
(Invocation will also factor in any hbase-default.xml found;
an hbase-default.xml ships inside the hbase.X.X.X.jar).
It is also possible to specify configuration directly without having to read from a
hbase-site.xml. For example, to set the ZooKeeper
ensemble for the cluster programmatically do as follows:
Configuration config = HBaseConfiguration.create();
config.set("hbase.zookeeper.quorum", "localhost"); // Here we are running zookeeper locally
If multiple ZooKeeper instances make up your ZooKeeper ensemble,
they may be specified in a comma-separated list (just as in the hbase-site.xml file).
This populated Configuration instance can then be passed to an
HTable,
and so on.