Github user vanzin commented on a diff in the pull request:
https://github.com/apache/spark/pull/4688#discussion_r25915171
--- Diff:
yarn/src/main/scala/org/apache/spark/deploy/yarn/YarnSparkHadoopUtil.scala ---
@@ -82,6 +102,180 @@ class YarnSparkHadoopUtil extends SparkHadoopUtil {
if (credentials != null) credentials.getSecretKey(new Text(key)) else
null
}
+ private[spark] override def scheduleLoginFromKeytab(): Unit = {
+ val principal = System.getenv("SPARK_PRINCIPAL")
+ val keytab = System.getenv("SPARK_KEYTAB")
+ if (principal != null) {
+ val delegationTokenRenewerThread =
+ new Runnable {
+ override def run(): Unit = {
+ if (!loggedInViaKeytab) {
+ // Keytab is copied by YARN to the working directory of the
AM, so full path is
+ // not needed.
+ loggedInUGI =
UserGroupInformation.loginUserFromKeytabAndReturnUGI(
+ principal, keytab)
+ loggedInViaKeytab = true
+ }
+ val nns = getNameNodesToAccess(sparkConf)
+ val newCredentials = loggedInUGI.getCredentials
+ obtainTokensForNamenodes(nns, conf, newCredentials)
+ val remoteFs = FileSystem.get(conf)
+ val stagingDirPath =
+ new Path(remoteFs.getHomeDirectory,
System.getenv("SPARK_YARN_STAGING_DIR"))
+ val tokenPathStr = sparkConf.get("spark.yarn.credentials.file")
+ val tokenPath = new Path(stagingDirPath.toString, tokenPathStr)
+ val tempTokenPath = new Path(stagingDirPath.toString,
tokenPathStr + ".tmp")
+ val stream = remoteFs.create(tempTokenPath, true)
+ // Now write this out to HDFS
+ newCredentials.writeTokenStorageToStream(stream)
+ stream.hflush()
+ stream.close()
+ // HDFS does reads by inodes now, so just doing a rename
should be fine. But I could
+ // not find a clear explanation of when the blocks on HDFS are
deleted. Ideally, we
+ // would not need this, but just be defensive to ensure we
don't mess up the
+ // credentials. So create a file to show that we are currently
updating - if the
+ // reader sees this file, they go away and come back later.
Then delete old token and
+ // rename the old to new.
+ val updatingPath = new Path(stagingDirPath, "_UPDATING")
+ if (remoteFs.exists(updatingPath)) {
+ remoteFs.delete(updatingPath, true)
+ }
+ remoteFs.create(updatingPath).close()
+ if (remoteFs.exists(tokenPath)) {
+ remoteFs.delete(tokenPath, true)
+ }
+ remoteFs.rename(tempTokenPath, tokenPath)
+ remoteFs.delete(updatingPath, true)
+ delegationTokenRenewer.schedule(
+ this, (0.75 * (getLatestValidity -
System.currentTimeMillis())).toLong,
+ TimeUnit.MILLISECONDS)
+ }
+ }
+ val timeToRenewal = (0.75 * (getLatestValidity -
System.currentTimeMillis())).toLong
+ delegationTokenRenewer.schedule(
+ delegationTokenRenewerThread, timeToRenewal, TimeUnit.MILLISECONDS)
+ }
+ }
+
+ override def updateCredentialsIfRequired(): Unit = {
+ try {
+ val credentialsFile = sparkConf.get("spark.yarn.credentials.file")
+ if (credentialsFile != null && !credentialsFile.isEmpty) {
+ val remoteFs = FileSystem.get(conf)
+ val sparkStagingDir = System.getenv("SPARK_YARN_STAGING_DIR")
+ val stagingDirPath = new Path(remoteFs.getHomeDirectory,
sparkStagingDir)
+ val credentialsFilePath = new Path(stagingDirPath, credentialsFile)
+ // If an update is currently in progress, come back later!
+ if (remoteFs.exists( new Path(stagingDirPath, "_UPDATING"))) {
+
delegationTokenRenewer.schedule(delegationTokenExecuterUpdaterThread, 1,
TimeUnit.HOURS)
+ }
+ // Now check if the file exists, if it does go get the credentials
from there
+ if (remoteFs.exists(credentialsFilePath)) {
+ val status = remoteFs.getFileStatus(credentialsFilePath)
+ val modTimeAtStart = status.getModificationTime
+ if (modTimeAtStart > lastCredentialsRefresh) {
+ val newCredentials = getCredentialsFromHDFSFile(remoteFs,
credentialsFilePath)
+ val newStatus = remoteFs.getFileStatus(credentialsFilePath)
+ // File was updated after we started reading it, lets come
back later and try to read
+ // it.
+ if (newStatus.getModificationTime != modTimeAtStart) {
+ delegationTokenRenewer
+ .schedule(delegationTokenExecuterUpdaterThread, 1,
TimeUnit.HOURS)
+ } else {
+
UserGroupInformation.getCurrentUser.addCredentials(newCredentials)
+ lastCredentialsRefresh = status.getModificationTime
+ val totalValidity = getLatestValidity -
lastCredentialsRefresh
+ val timeToRunRenewal = lastCredentialsRefresh + (0.8 *
totalValidity).toLong
+ val timeFromNowToRenewal = timeToRunRenewal -
System.currentTimeMillis()
+
delegationTokenRenewer.schedule(delegationTokenExecuterUpdaterThread,
+ timeFromNowToRenewal, TimeUnit.MILLISECONDS)
+ }
+ } else {
+ // Check every hour to see if new credentials arrived.
+
delegationTokenRenewer.schedule(delegationTokenExecuterUpdaterThread, 1,
TimeUnit.HOURS)
+ }
+ }
+ }
+ } catch {
+ // Since the file may get deleted while we are reading it, catch the
Exception and come
+ // back in an hour to try again
+ case e: Exception =>
+ logWarning(
+ "Error encountered while trying to update credentials, will try
again in 1 hour", e)
+
delegationTokenRenewer.schedule(delegationTokenExecuterUpdaterThread, 1,
TimeUnit.HOURS)
+ }
+ }
+
+ private[spark] def getCredentialsFromHDFSFile(
+ remoteFs: FileSystem,
+ tokenPath: Path
+ ): Credentials = {
--- End diff --
nit: I think the style is for these to go on the previous line (and for the
previous lines to be double-indented). That is, if all this doesn't fit in a
single line...
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