core-site.xml (Hadoop 2.2)

hadoop.common.configuration.version version of this configuration file
Default:0.23.0
hadoop.tmp.dir A base for other temporary directories.
Default:/tmp/hadoop-${user.name}
io.native.lib.available Should native hadoop libraries, if present, be used.
Default:true
hadoop.http.filter.initializers A comma separated list of class names. Each class in the list must extend org.apache.hadoop.http.FilterInitializer. The corresponding Filter will be initialized. Then, the Filter will be applied to all user facing jsp and servlet web pages. The ordering of the list defines the ordering of the filters.
Default:org.apache.hadoop.http.lib.StaticUserWebFilter
hadoop.security.authorization Is service-level authorization enabled?
Default:false
hadoop.security.instrumentation.requires.admin Indicates if administrator ACLs are required to access instrumentation servlets (JMX, METRICS, CONF, STACKS).
Default:false
hadoop.security.authentication Possible values are simple (no authentication), and kerberos
Default:simple
hadoop.security.group.mapping Class for user to group mapping (get groups for a given user) for ACL. The default implementation, org.apache.hadoop.security.JniBasedUnixGroupsMappingWithFallback, will determine if the Java Native Interface (JNI) is available. If JNI is available the implementation will use the API within hadoop to resolve a list of groups for a user. If JNI is not available then the shell implementation, ShellBasedUnixGroupsMapping, is used. This implementation shells out to the Linux/Unix environment with the bash -c groups command to resolve a list of groups for a user.
Default:org.apache.hadoop.security.JniBasedUnixGroupsMappingWithFallback
hadoop.security.groups.cache.secs This is the config controlling the validity of the entries in the cache containing the user->group mapping. When this duration has expired, then the implementation of the group mapping provider is invoked to get the groups of the user and then cached back.
Default:300
hadoop.security.group.mapping.ldap.url The URL of the LDAP server to use for resolving user groups when using the LdapGroupsMapping user to group mapping.
Default:
hadoop.security.group.mapping.ldap.ssl Whether or not to use SSL when connecting to the LDAP server.
Default:false
hadoop.security.group.mapping.ldap.ssl.keystore File path to the SSL keystore that contains the SSL certificate required by the LDAP server.
Default:
hadoop.security.group.mapping.ldap.ssl.keystore.password.file The path to a file containing the password of the LDAP SSL keystore. IMPORTANT: This file should be readable only by the Unix user running the daemons.
Default:
hadoop.security.group.mapping.ldap.bind.user The distinguished name of the user to bind as when connecting to the LDAP server. This may be left blank if the LDAP server supports anonymous binds.
Default:
hadoop.security.group.mapping.ldap.bind.password.file The path to a file containing the password of the bind user. IMPORTANT: This file should be readable only by the Unix user running the daemons.
Default:
hadoop.security.group.mapping.ldap.base The search base for the LDAP connection. This is a distinguished name, and will typically be the root of the LDAP directory.
Default:
hadoop.security.group.mapping.ldap.search.filter.user An additional filter to use when searching for LDAP users. The default will usually be appropriate for Active Directory installations. If connecting to an LDAP server with a non-AD schema, this should be replaced with (&(objectClass=inetOrgPerson)(uid={0}). {0} is a special string used to denote where the username fits into the filter.
Default:(&(objectClass=user)(sAMAccountName={0}))
hadoop.security.group.mapping.ldap.search.filter.group An additional filter to use when searching for LDAP groups. This should be changed when resolving groups against a non-Active Directory installation. posixGroups are currently not a supported group class.
Default:(objectClass=group)
hadoop.security.group.mapping.ldap.search.attr.member The attribute of the group object that identifies the users that are members of the group. The default will usually be appropriate for any LDAP installation.
Default:member
hadoop.security.group.mapping.ldap.search.attr.group.name The attribute of the group object that identifies the group name. The default will usually be appropriate for all LDAP systems.
Default:cn
hadoop.security.group.mapping.ldap.directory.search.timeout The attribute applied to the LDAP SearchControl properties to set a maximum time limit when searching and awaiting a result. Set to 0 if infinite wait period is desired. Default is 10 seconds. Units in milliseconds.
Default:10000
hadoop.security.service.user.name.key For those cases where the same RPC protocol is implemented by multiple servers, this configuration is required for specifying the principal name to use for the service when the client wishes to make an RPC call.
Default:
hadoop.security.uid.cache.secs This is the config controlling the validity of the entries in the cache containing the userId to userName and groupId to groupName used by NativeIO getFstat().
Default:14400
hadoop.rpc.protection This field sets the quality of protection for secured sasl connections. Possible values are authentication, integrity and privacy. authentication means authentication only and no integrity or privacy; integrity implies authentication and integrity are enabled; and privacy implies all of authentication, integrity and privacy are enabled.
Default:authentication
hadoop.work.around.non.threadsafe.getpwuid Some operating systems or authentication modules are known to have broken implementations of getpwuid_r and getpwgid_r, such that these calls are not thread-safe. Symptoms of this problem include JVM crashes with a stack trace inside these functions. If your system exhibits this issue, enable this configuration parameter to include a lock around the calls as a workaround. An incomplete list of some systems known to have this issue is available at http://wiki.apache.org/hadoop/KnownBrokenPwuidImplementations
Default:false
hadoop.kerberos.kinit.command Used to periodically renew Kerberos credentials when provided to Hadoop. The default setting assumes that kinit is in the PATH of users running the Hadoop client. Change this to the absolute path to kinit if this is not the case.
Default:kinit
hadoop.security.auth_to_local Maps kerberos principals to local user names
Default:
io.file.buffer.size The size of buffer for use in sequence files. The size of this buffer should probably be a multiple of hardware page size (4096 on Intel x86), and it determines how much data is buffered during read and write operations.
Default:4096
io.bytes.per.checksum The number of bytes per checksum. Must not be larger than io.file.buffer.size.
Default:512
io.skip.checksum.errors If true, when a checksum error is encountered while reading a sequence file, entries are skipped, instead of throwing an exception.
Default:false
io.compression.codecs A comma-separated list of the compression codec classes that can be used for compression/decompression. In addition to any classes specified with this property (which take precedence), codec classes on the classpath are discovered using a Java ServiceLoader.
Default:
io.compression.codec.bzip2.library The native-code library to be used for compression and decompression by the bzip2 codec. This library could be specified either by by name or the full pathname. In the former case, the library is located by the dynamic linker, usually searching the directories specified in the environment variable LD_LIBRARY_PATH. The value of “system-native” indicates that the default system library should be used. To indicate that the algorithm should operate entirely in Java, specify “java-builtin”.
Default:system-native
io.serializations A list of serialization classes that can be used for obtaining serializers and deserializers.
Default:org.apache.hadoop.io.serializer.WritableSerialization, org.apache.hadoop.io.serializer.avro.AvroSpecificSerialization, org.apache.hadoop.io.serializer.avro.AvroReflectSerialization
io.seqfile.local.dir The local directory where sequence file stores intermediate data files during merge. May be a comma-separated list of directories on different devices in order to spread disk i/o. Directories that do not exist are ignored.
Default:${hadoop.tmp.dir}/io/local
io.map.index.skip Number of index entries to skip between each entry. Zero by default. Setting this to values larger than zero can facilitate opening large MapFiles using less memory.
Default:0
io.map.index.interval MapFile consist of two files – data file (tuples) and index file (keys). For every io.map.index.interval records written in the data file, an entry (record-key, data-file-position) is written in the index file. This is to allow for doing binary search later within the index file to look up records by their keys and get their closest positions in the data file.
Default:128
fs.defaultFS The name of the default file system. A URI whose scheme and authority determine the FileSystem implementation. The uri’s scheme determines the config property (fs.SCHEME.impl) naming the FileSystem implementation class. The uri’s authority is used to determine the host, port, etc. for a filesystem.
Default:file:///
fs.default.name Deprecated. Use (fs.defaultFS) property instead
Default:file:///
fs.trash.interval Number of minutes after which the checkpoint gets deleted. If zero, the trash feature is disabled. This option may be configured both on the server and the client. If trash is disabled server side then the client side configuration is checked. If trash is enabled on the server side then the value configured on the server is used and the client configuration value is ignored.
Default:0
fs.trash.checkpoint.interval Number of minutes between trash checkpoints. Should be smaller or equal to fs.trash.interval. If zero, the value is set to the value of fs.trash.interval. Every time the checkpointer runs it creates a new checkpoint out of current and removes checkpoints created more than fs.trash.interval minutes ago.
Default:0
fs.AbstractFileSystem.file.impl The AbstractFileSystem for file: uris.
Default:org.apache.hadoop.fs.local.LocalFs
fs.AbstractFileSystem.hdfs.impl The FileSystem for hdfs: uris.
Default:org.apache.hadoop.fs.Hdfs
fs.AbstractFileSystem.viewfs.impl The AbstractFileSystem for view file system for viewfs: uris (ie client side mount table:).
Default:org.apache.hadoop.fs.viewfs.ViewFs
fs.ftp.host FTP filesystem connects to this server
Default:0.0.0.0
fs.ftp.host.port FTP filesystem connects to fs.ftp.host on this port
Default:21
fs.df.interval Disk usage statistics refresh interval in msec.
Default:60000
fs.s3.block.size Block size to use when writing files to S3.
Default:67108864
fs.s3.buffer.dir Determines where on the local filesystem the S3 filesystem should store files before sending them to S3 (or after retrieving them from S3).
Default:${hadoop.tmp.dir}/s3
fs.s3.maxRetries The maximum number of retries for reading or writing files to S3, before we signal failure to the application.
Default:4
fs.s3.sleepTimeSeconds The number of seconds to sleep between each S3 retry.
Default:10
fs.automatic.close By default, FileSystem instances are automatically closed at program exit using a JVM shutdown hook. Setting this property to false disables this behavior. This is an advanced option that should only be used by server applications requiring a more carefully orchestrated shutdown sequence.
Default:true
fs.s3n.block.size Block size to use when reading files using the native S3 filesystem (s3n: URIs).
Default:67108864
io.seqfile.compress.blocksize The minimum block size for compression in block compressed SequenceFiles.
Default:1000000
io.seqfile.lazydecompress Should values of block-compressed SequenceFiles be decompressed only when necessary.
Default:true
io.seqfile.sorter.recordlimit The limit on number of records to be kept in memory in a spill in SequenceFiles.Sorter
Default:1000000
io.mapfile.bloom.size The size of BloomFilter-s used in BloomMapFile. Each time this many keys is appended the next BloomFilter will be created (inside a DynamicBloomFilter). Larger values minimize the number of filters, which slightly increases the performance, but may waste too much space if the total number of keys is usually much smaller than this number.
Default:1048576
io.mapfile.bloom.error.rate The rate of false positives in BloomFilter-s used in BloomMapFile. As this value decreases, the size of BloomFilter-s increases exponentially. This value is the probability of encountering false positives (default is 0.5%).
Default:0.005
hadoop.util.hash.type The default implementation of Hash. Currently this can take one of the two values: ‘murmur’ to select MurmurHash and ‘jenkins’ to select JenkinsHash.
Default:murmur
ipc.client.idlethreshold Defines the threshold number of connections after which connections will be inspected for idleness.
Default:4000
ipc.client.kill.max Defines the maximum number of clients to disconnect in one go.
Default:10
ipc.client.connection.maxidletime The maximum time in msec after which a client will bring down the connection to the server.
Default:10000
ipc.client.connect.max.retries Indicates the number of retries a client will make to establish a server connection.
Default:10
ipc.client.connect.timeout Indicates the number of milliseconds a client will wait for the socket to establish a server connection.
Default:20000
ipc.client.connect.max.retries.on.timeouts Indicates the number of retries a client will make on socket timeout to establish a server connection.
Default:45
ipc.server.listen.queue.size Indicates the length of the listen queue for servers accepting client connections.
Default:128
ipc.server.tcpnodelay Turn on/off Nagle’s algorithm for the TCP socket connection on the server. Setting to true disables the algorithm and may decrease latency with a cost of more/smaller packets.
Default:false
ipc.client.tcpnodelay Turn on/off Nagle’s algorithm for the TCP socket connection on the client. Setting to true disables the algorithm and may decrease latency with a cost of more/smaller packets.
Default:false
hadoop.rpc.socket.factory.class.default Default SocketFactory to use. This parameter is expected to be formatted as “package.FactoryClassName”.
Default:org.apache.hadoop.net.StandardSocketFactory
hadoop.rpc.socket.factory.class.ClientProtocol SocketFactory to use to connect to a DFS. If null or empty, use hadoop.rpc.socket.class.default. This socket factory is also used by DFSClient to create sockets to DataNodes.
Default:
hadoop.socks.server Address (host:port) of the SOCKS server to be used by the SocksSocketFactory.
Default:
net.topology.node.switch.mapping.impl The default implementation of the DNSToSwitchMapping. It invokes a script specified in net.topology.script.file.name to resolve node names. If the value for net.topology.script.file.name is not set, the default value of DEFAULT_RACK is returned for all node names.
Default:org.apache.hadoop.net.ScriptBasedMapping
net.topology.impl The default implementation of NetworkTopology which is classic three layer one.
Default:org.apache.hadoop.net.NetworkTopology
net.topology.script.file.name The script name that should be invoked to resolve DNS names to NetworkTopology names. Example: the script would take host.foo.bar as an argument, and return /rack1 as the output.
Default:
net.topology.script.number.args The max number of args that the script configured with net.topology.script.file.name should be run with. Each arg is an IP address.
Default:100
net.topology.table.file.name The file name for a topology file, which is used when the net.topology.node.switch.mapping.impl property is set to org.apache.hadoop.net.TableMapping. The file format is a two column text file, with columns separated by whitespace. The first column is a DNS or IP address and the second column specifies the rack where the address maps. If no entry corresponding to a host in the cluster is found, then /default-rack is assumed.
Default:
file.stream-buffer-size The size of buffer to stream files. The size of this buffer should probably be a multiple of hardware page size (4096 on Intel x86), and it determines how much data is buffered during read and write operations.
Default:4096
file.bytes-per-checksum The number of bytes per checksum. Must not be larger than file.stream-buffer-size
Default:512
file.client-write-packet-size Packet size for clients to write
Default:65536
file.blocksize Block size
Default:67108864
file.replication Replication factor
Default:1
s3.stream-buffer-size The size of buffer to stream files. The size of this buffer should probably be a multiple of hardware page size (4096 on Intel x86), and it determines how much data is buffered during read and write operations.
Default:4096
s3.bytes-per-checksum The number of bytes per checksum. Must not be larger than s3.stream-buffer-size
Default:512
s3.client-write-packet-size Packet size for clients to write
Default:65536
s3.blocksize Block size
Default:67108864
s3.replication Replication factor
Default:3
s3native.stream-buffer-size The size of buffer to stream files. The size of this buffer should probably be a multiple of hardware page size (4096 on Intel x86), and it determines how much data is buffered during read and write operations.
Default:4096
s3native.bytes-per-checksum The number of bytes per checksum. Must not be larger than s3native.stream-buffer-size
Default:512
s3native.client-write-packet-size Packet size for clients to write
Default:65536
s3native.blocksize Block size
Default:67108864
s3native.replication Replication factor
Default:3
ftp.stream-buffer-size The size of buffer to stream files. The size of this buffer should probably be a multiple of hardware page size (4096 on Intel x86), and it determines how much data is buffered during read and write operations.
Default:4096
ftp.bytes-per-checksum The number of bytes per checksum. Must not be larger than ftp.stream-buffer-size
Default:512
ftp.client-write-packet-size Packet size for clients to write
Default:65536
ftp.blocksize Block size
Default:67108864
ftp.replication Replication factor
Default:3
tfile.io.chunk.size Value chunk size in bytes. Default to 1MB. Values of the length less than the chunk size is guaranteed to have known value length in read time (See also TFile.Reader.Scanner.Entry.isValueLengthKnown()).
Default:1048576
tfile.fs.output.buffer.size Buffer size used for FSDataOutputStream in bytes.
Default:262144
tfile.fs.input.buffer.size Buffer size used for FSDataInputStream in bytes.
Default:262144
hadoop.http.authentication.type Defines authentication used for Oozie HTTP endpoint. Supported values are: simple | kerberos | #AUTHENTICATION_HANDLER_CLASSNAME#
Default:simple
hadoop.http.authentication.token.validity Indicates how long (in seconds) an authentication token is valid before it has to be renewed.
Default:36000
hadoop.http.authentication.signature.secret.file The signature secret for signing the authentication tokens. The same secret should be used for JT/NN/DN/TT configurations.
Default:${user.home}/hadoop-http-auth-signature-secret
hadoop.http.authentication.cookie.domain The domain to use for the HTTP cookie that stores the authentication token. In order to authentiation to work correctly across all Hadoop nodes web-consoles the domain must be correctly set. IMPORTANT: when using IP addresses, browsers ignore cookies with domain settings. For this setting to work properly all nodes in the cluster must be configured to generate URLs with hostname.domain names on it.
Default:
hadoop.http.authentication.simple.anonymous.allowed Indicates if anonymous requests are allowed when using ‘simple’ authentication.
Default:true
hadoop.http.authentication.kerberos.principal Indicates the Kerberos principal to be used for HTTP endpoint. The principal MUST start with ‘HTTP/’ as per Kerberos HTTP SPNEGO specification.
Default:HTTP/_HOST@LOCALHOST
hadoop.http.authentication.kerberos.keytab Location of the keytab file with the credentials for the principal. Referring to the same keytab file Oozie uses for its Kerberos credentials for Hadoop.
Default:${user.home}/hadoop.keytab
dfs.ha.fencing.methods List of fencing methods to use for service fencing. May contain builtin methods (eg shell and sshfence) or user-defined method.
Default:
dfs.ha.fencing.ssh.connect-timeout SSH connection timeout, in milliseconds, to use with the builtin sshfence fencer.
Default:30000
dfs.ha.fencing.ssh.private-key-files The SSH private key files to use with the builtin sshfence fencer.
Default:
hadoop.http.staticuser.user The user name to filter as, on static web filters while rendering content. An example use is the HDFS web UI (user to be used for browsing files).
Default:dr.who
ha.zookeeper.quorum A list of ZooKeeper server addresses, separated by commas, that are to be used by the ZKFailoverController in automatic failover.
Default:
ha.zookeeper.session-timeout.ms The session timeout to use when the ZKFC connects to ZooKeeper. Setting this value to a lower value implies that server crashes will be detected more quickly, but risks triggering failover too aggressively in the case of a transient error or network blip.
Default:5000
ha.zookeeper.parent-znode The ZooKeeper znode under which the ZK failover controller stores its information. Note that the nameservice ID is automatically appended to this znode, so it is not normally necessary to configure this, even in a federated environment.
Default:/hadoop-ha
ha.zookeeper.acl A comma-separated list of ZooKeeper ACLs to apply to the znodes used by automatic failover. These ACLs are specified in the same format as used by the ZooKeeper CLI. If the ACL itself contains secrets, you may instead specify a path to a file, prefixed with the ‘@’ symbol, and the value of this configuration will be loaded from within.
Default:world:anyone:rwcda
ha.zookeeper.auth A comma-separated list of ZooKeeper authentications to add when connecting to ZooKeeper. These are specified in the same format as used by the “addauth” command in the ZK CLI. It is important that the authentications specified here are sufficient to access znodes with the ACL specified in ha.zookeeper.acl. If the auths contain secrets, you may instead specify a path to a file, prefixed with the ‘@’ symbol, and the value of this configuration will be loaded from within.
Default:
hadoop.ssl.keystores.factory.class The keystores factory to use for retrieving certificates.
Default:org.apache.hadoop.security.ssl.FileBasedKeyStoresFactory
hadoop.ssl.require.client.cert Whether client certificates are required
Default:false
hadoop.ssl.hostname.verifier The hostname verifier to provide for HttpsURLConnections. Valid values are: DEFAULT, STRICT, STRICT_I6, DEFAULT_AND_LOCALHOST and ALLOW_ALL
Default:DEFAULT
hadoop.ssl.server.conf Resource file from which ssl server keystore information will be extracted. This file is looked up in the classpath, typically it should be in Hadoop conf/ directory.
Default:ssl-server.xml
hadoop.ssl.client.conf Resource file from which ssl client keystore information will be extracted This file is looked up in the classpath, typically it should be in Hadoop conf/ directory.
Default:ssl-client.xml
hadoop.ssl.enabled Whether to use SSL for the HTTP endpoints. If set to true, the NameNode, DataNode, ResourceManager, NodeManager, HistoryServer and MapReduceAppMaster web UIs will be served over HTTPS instead HTTP.
Default:false
hadoop.jetty.logs.serve.aliases Enable/Disable aliases serving from jetty
Default:true
fs.permissions.umask-mode The umask used when creating files and directories. Can be in octal or in symbolic. Examples are: “022” (octal for u=rwx,g=r-x,o=r-x in symbolic), or “u=rwx,g=rwx,o=” (symbolic for 007 in octal).
Default:022
ha.health-monitor.connect-retry-interval.ms How often to retry connecting to the service.
Default:1000
ha.health-monitor.check-interval.ms How often to check the service.
Default:1000
ha.health-monitor.sleep-after-disconnect.ms How long to sleep after an unexpected RPC error.
Default:1000
ha.health-monitor.rpc-timeout.ms Timeout for the actual monitorHealth() calls.
Default:45000
ha.failover-controller.new-active.rpc-timeout.ms Timeout that the FC waits for the new active to become active
Default:60000
ha.failover-controller.graceful-fence.rpc-timeout.ms Timeout that the FC waits for the old active to go to standby
Default:5000
ha.failover-controller.graceful-fence.connection.retries FC connection retries for graceful fencing
Default:1
ha.failover-controller.cli-check.rpc-timeout.ms Timeout that the CLI (manual) FC waits for monitorHealth, getServiceState
Default:20000
ipc.client.fallback-to-simple-auth-allowed 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.
Default:false
fs.client.resolve.remote.symlinks Whether to resolve symlinks when accessing a remote Hadoop filesystem. Setting this to false causes an exception to be thrown upon encountering a symlink. This setting does not apply to local filesystems, which automatically resolve local symlinks.
Default:true
nfs3.server.port Specify the port number used by Hadoop NFS.
Default:2049
nfs3.mountd.port Specify the port number used by Hadoop mount daemon.
Default:4242

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