Package org.apache.hadoop.hdfs

Class HAUtil

java.lang.Object
org.apache.hadoop.hdfs.HAUtil
@Private public class HAUtil extends Object

  • Field Details

    • LOG

      public static final org.slf4j.Logger LOG

  • Method Details

    • isHAEnabled

      public static boolean isHAEnabled(org.apache.hadoop.conf.Configuration conf, String nsId)
      Returns true if HA for namenode is configured for the given nameservice
      Parameters:
      conf - Configuration
      nsId - nameservice, or null if no federated NS is configured
      Returns:
      true if HA is configured in the configuration; else false.

    • usesSharedEditsDir

      public static boolean usesSharedEditsDir(org.apache.hadoop.conf.Configuration conf)
      Returns true if HA is using a shared edits directory.
      Parameters:
      conf - Configuration
      Returns:
      true if HA config is using a shared edits dir, false otherwise.

    • getNameNodeId

      public static String getNameNodeId(org.apache.hadoop.conf.Configuration conf, String nsId)
      Get the namenode Id by matching the addressKey with the the address of the local node. If DFSConfigKeys.DFS_HA_NAMENODE_ID_KEY is not specifically configured, this method determines the namenode Id by matching the local node's address with the configured addresses. When a match is found, it returns the namenode Id from the corresponding configuration key.
      Parameters:
      conf - Configuration
      Returns:
      namenode Id on success, null on failure.
      Throws:
      org.apache.hadoop.HadoopIllegalArgumentException - on error

    • getNameNodeIdFromAddress

      public static String getNameNodeIdFromAddress(org.apache.hadoop.conf.Configuration conf, InetSocketAddress address, String... keys)
      Similar to DFSUtil.getNameServiceIdFromAddress(Configuration, InetSocketAddress, String...)

    • getNameNodeIdOfOtherNodes

      public static List<String> getNameNodeIdOfOtherNodes(org.apache.hadoop.conf.Configuration conf, String nsId)
      Get the NN ID of the other nodes in an HA setup.
      Parameters:
      conf - the configuration of this node
      Returns:
      a list of NN IDs of other nodes in this nameservice

    • getConfForOtherNodes

      public static List<org.apache.hadoop.conf.Configuration> getConfForOtherNodes(org.apache.hadoop.conf.Configuration myConf)
      Given the configuration for this node, return a list of configurations for the other nodes in an HA setup.
      Parameters:
      myConf - the configuration of this node
      Returns:
      a list of configuration of other nodes in an HA setup

    • shouldAllowStandbyReads

      public static boolean shouldAllowStandbyReads(org.apache.hadoop.conf.Configuration conf)
      This is used only by tests at the moment.
      Returns:
      true if the NN should allow read operations while in standby mode.

    • setAllowStandbyReads

      public static void setAllowStandbyReads(org.apache.hadoop.conf.Configuration conf, boolean val)

    • useLogicalUri

      public static boolean useLogicalUri(org.apache.hadoop.conf.Configuration conf, URI nameNodeUri) throws IOException
      Check whether logical URI is needed for the namenode and the corresponding failover proxy provider in the config.
      Parameters:
      conf - Configuration
      nameNodeUri - The URI of namenode
      Returns:
      true if logical URI is needed. false, if not needed.
      Throws:
      IOException - most likely due to misconfiguration.

    • getAddressOfActive

      public static InetSocketAddress getAddressOfActive(org.apache.hadoop.fs.FileSystem fs) throws IOException
      Get the internet address of the currently-active NN. This should rarely be used, since callers of this method who connect directly to the NN using the resulting InetSocketAddress will not be able to connect to the active NN if a failover were to occur after this method has been called.
      Parameters:
      fs - the file system to get the active address of.
      Returns:
      the internet address of the currently-active NN.
      Throws:
      IOException - if an error occurs while resolving the active NN.

    • getProxiesForAllNameNodesInNameservice

      public static List<org.apache.hadoop.hdfs.protocol.ClientProtocol> getProxiesForAllNameNodesInNameservice(org.apache.hadoop.conf.Configuration conf, String nsId) throws IOException
      Get an RPC proxy for each NN in an HA nameservice. Used when a given RPC call should be made on every NN in an HA nameservice, not just the active.
      Parameters:
      conf - configuration
      nsId - the nameservice to get all of the proxies for.
      Returns:
      a list of RPC proxies for each NN in the nameservice.
      Throws:
      IOException - in the event of error.

    • getProxiesForAllNameNodesInNameservice

      public static <T> List<org.apache.hadoop.hdfs.NameNodeProxiesClient.ProxyAndInfo<T>> getProxiesForAllNameNodesInNameservice(org.apache.hadoop.conf.Configuration conf, String nsId, Class<T> xface) throws IOException
      Get an RPC proxy for each NN in an HA nameservice. Used when a given RPC call should be made on every NN in an HA nameservice, not just the active.
      Parameters:
      conf - configuration
      nsId - the nameservice to get all of the proxies for.
      xface - the protocol class.
      Returns:
      a list of RPC proxies for each NN in the nameservice.
      Throws:
      IOException - in the event of error.

    • isAtLeastOneActive

      public static boolean isAtLeastOneActive(List<org.apache.hadoop.hdfs.protocol.ClientProtocol> namenodes) throws IOException
      Used to ensure that at least one of the given HA NNs is currently in the active state..
      Parameters:
      namenodes - list of RPC proxies for each NN to check.
      Returns:
      true if at least one NN is active, false if all are in the standby state.
      Throws:
      IOException - in the event of error.