Sparklyr: java.net.UnknownHostException: $HOST: $HOST: Name or service not known

[isomorphisms]

isomorphisms@scheherezade:~/spark/spark-2.4.3-bin-hadoop2.7$ bin/spark-shell --master local[2]
Exception in thread "main" java.lang.ExceptionInInitializerError
        at org.apache.spark.SparkConf$.<init>(SparkConf.scala:716)
        at org.apache.spark.SparkConf$.<clinit>(SparkConf.scala)
        at org.apache.spark.SparkConf$$anonfun$getOption$1.apply(SparkConf.scala:389)
        at org.apache.spark.SparkConf$$anonfun$getOption$1.apply(SparkConf.scala:389)
        at scala.Option.orElse(Option.scala:289)
        at org.apache.spark.SparkConf.getOption(SparkConf.scala:389)
        at org.apache.spark.SparkConf.get(SparkConf.scala:251)
        at org.apache.spark.deploy.SparkHadoopUtil$.org$apache$spark$deploy$SparkHadoopUtil$$appendS3AndSparkHadoopConfigurations(SparkHadoopUtil.scala:463)
        at org.apache.spark.deploy.SparkHadoopUtil$.newConfiguration(SparkHadoopUtil.scala:436)
        at org.apache.spark.deploy.SparkSubmit$$anonfun$2.apply(SparkSubmit.scala:334)
        at org.apache.spark.deploy.SparkSubmit$$anonfun$2.apply(SparkSubmit.scala:334)
        at scala.Option.getOrElse(Option.scala:121)
        at org.apache.spark.deploy.SparkSubmit.prepareSubmitEnvironment(SparkSubmit.scala:334)
        at org.apache.spark.deploy.SparkSubmit.submit(SparkSubmit.scala:143)
        at org.apache.spark.deploy.SparkSubmit.doSubmit(SparkSubmit.scala:86)
        at org.apache.spark.deploy.SparkSubmit$$anon$2.doSubmit(SparkSubmit.scala:924)
        at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:933)
        at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
Caused by: java.net.UnknownHostException: scheherezade: scheherezade: Name or service not known
        at java.net.InetAddress.getLocalHost(InetAddress.java:1505)
        at org.apache.spark.util.Utils$.findLocalInetAddress(Utils.scala:946)
        at org.apache.spark.util.Utils$.org$apache$spark$util$Utils$$localIpAddress$lzycompute(Utils.scala:939)
        at org.apache.spark.util.Utils$.org$apache$spark$util$Utils$$localIpAddress(Utils.scala:939)
        at org.apache.spark.util.Utils$$anonfun$localCanonicalHostName$1.apply(Utils.scala:996)
        at org.apache.spark.util.Utils$$anonfun$localCanonicalHostName$1.apply(Utils.scala:996)
        at scala.Option.getOrElse(Option.scala:121)
        at org.apache.spark.util.Utils$.localCanonicalHostName(Utils.scala:996)
        at org.apache.spark.internal.config.package$.<init>(package.scala:302)
        at org.apache.spark.internal.config.package$.<clinit>(package.scala)
        ... 18 more
Caused by: java.net.UnknownHostException: scheherezade: Name or service not known
        at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
        at java.net.InetAddress$2.lookupAllHostAddr(InetAddress.java:928)
        at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323)
        at java.net.InetAddress.getLocalHost(InetAddress.java:1500)
        ... 27 more

[isomorphisms]

https://stackoverflow.com/a/26686229/563329

1. Do echo $HOSTNAME on your terminal.
2. Whatever hostname it shows (lets say scheherezade), try to ping it : ping scheherezade. If it returns ping: cannot resolve scheherezade: Unknown host then add an entry into your /etc/hosts file.
3. For that cat >> /etc/hosts and add following:

127.0.0.1 scheherezade

[ConstantSun]

in step 3, i typed: cat >> /etc/hosts , then i got:
bash: /etc/hosts: Permission denied
However, i typed: sudo nano /etc/hosts, then typed my password, and replace : 127.0.1.1 OLD_HOSTNAME (mine is hero) with 127.0.1.1 CURRENT_HOSTNAME ( it's the name in your terminal, right after '@' sign, e.g: shaun@iamshaun then CURRENT_HOSTNAME is iamshaun )

[sany2k8]

https://stackoverflow.com/a/26686229/563329

1. Do echo $HOSTNAME on your terminal.
2. Whatever hostname it shows (lets say scheherezade), try to ping it : ping scheherezade. If it returns ping: cannot resolve scheherezade: Unknown host then add an entry into your /etc/hosts file.
3. For that cat >> /etc/hosts and add following:

127.0.0.1 scheherezade

Thanks for the snippets :)