Key | Default | Type | Description
--- | --- | --- | ---

##### classloader.check-leaked-classloader

true

Boolean

Fails attempts at loading classes if the user classloader of a job is used after it has terminated. This is usually caused by the classloader being leaked by lingering threads or misbehaving libraries, which may also result in the classloader being used by other jobs. This check should only be disabled if such a leak prevents further jobs from running.

##### classloader.fail-on-metaspace-oom-error

true

Boolean

Fail Flink JVM processes if 'OutOfMemoryError: Metaspace' is thrown while trying to load a user code class.

##### classloader.parent-first-patterns.additional

List<String>

A (semicolon-separated) list of patterns that specifies which classes should always be resolved through the parent ClassLoader first. A pattern is a simple prefix that is checked against the fully qualified class name. These patterns are appended to "classloader.parent-first-patterns.default".

##### classloader.parent-first-patterns.default

"java.";"scala.";"org.apache.flink.";"com.esotericsoftware.kryo";"org.apache.hadoop.";"javax.annotation.";"org.xml";"javax.xml";"org.apache.xerces";"org.w3c";"org.rocksdb.";"org.slf4j";"org.apache.log4j";"org.apache.logging";"org.apache.commons.logging";"ch.qos.logback"

List<String>

A (semicolon-separated) list of patterns that specifies which classes should always be resolved through the parent ClassLoader first. A pattern is a simple prefix that is checked against the fully qualified class name. This setting should generally not be modified. To add another pattern we recommend to use "classloader.parent-first-patterns.additional" instead.

##### classloader.resolve-order

"child-first"

String

Defines the class resolution strategy when loading classes from user code, meaning whether to first check the user code jar ("child-first") or the application classpath ("parent-first"). The default settings indicate to load classes first from the user code jar, which means that user code jars can include and load different dependencies than Flink uses (transitively).

##### fs.allowed-fallback-filesystems

(none)

String

A (semicolon-separated) list of file schemes, for which Hadoop can be used instead of an appropriate Flink plugin. (example: s3;wasb)

##### fs.default-scheme

(none)

String

The default filesystem scheme, used for paths that do not declare a scheme explicitly. May contain an authority, e.g. host:port in case of an HDFS NameNode.

##### fs.output.always-create-directory

false

Boolean

File writers running with a parallelism larger than one create a directory for the output file path and put the different result files (one per parallel writer task) into that directory. If this option is set to "true", writers with a parallelism of 1 will also create a directory and place a single result file into it. If the option is set to "false", the writer will directly create the file directly at the output path, without creating a containing directory.

##### fs.overwrite-files

false

Boolean

Specifies whether file output writers should overwrite existing files by default. Set to "true" to overwrite by default,"false" otherwise.

##### io.tmp.dirs

'LOCAL_DIRS' on Yarn. System.getProperty("java.io.tmpdir") in standalone.

String

Directories for temporary files, separated by",", "|", or the system's java.io.File.pathSeparator.

##### parallelism.default

1

Integer

Default parallelism for jobs.