HDFS-11314. Enforce set of enabled EC policies on the NameNode.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java

@@ -562,6 +562,8 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
   public static final String DFS_DATANODE_DISK_CHECK_TIMEOUT_DEFAULT =
       "10m";
 
+  public static final String  DFS_NAMENODE_EC_POLICIES_ENABLED_KEY = "dfs.namenode.ec.policies.enabled";
+  public static final String  DFS_NAMENODE_EC_POLICIES_ENABLED_DEFAULT = "RS-6-3-64k";
   public static final String  DFS_DN_EC_RECONSTRUCTION_STRIPED_READ_THREADS_KEY = "dfs.datanode.ec.reconstruction.stripedread.threads";
   public static final int     DFS_DN_EC_RECONSTRUCTION_STRIPED_READ_THREADS_DEFAULT = 20;
   public static final String  DFS_DN_EC_RECONSTRUCTION_STRIPED_READ_BUFFER_SIZE_KEY = "dfs.datanode.ec.reconstruction.stripedread.buffer.size";

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ErasureCodingPolicyManager.java

@@ -18,12 +18,17 @@
 package org.apache.hadoop.hdfs.server.namenode;
 
 import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.io.erasurecode.ErasureCodeConstants;
 
+import java.util.Arrays;
 import java.util.Map;
 import java.util.TreeMap;
+import java.util.stream.Collectors;
+
 
 /**
  * This manages erasure coding policies predefined and activated in the system.
@@ -61,21 +66,52 @@ public final class ErasureCodingPolicyManager {
           SYS_POLICY4, SYS_POLICY5};
 
   // Supported storage policies for striped EC files
-  private static final byte[] SUITABLE_STORAGE_POLICIES_FOR_EC_STRIPED_MODE = new byte[] {
-      HdfsConstants.HOT_STORAGE_POLICY_ID, HdfsConstants.COLD_STORAGE_POLICY_ID,
-      HdfsConstants.ALLSSD_STORAGE_POLICY_ID };
-
+  private static final byte[] SUITABLE_STORAGE_POLICIES_FOR_EC_STRIPED_MODE =
+      new byte[]{
+          HdfsConstants.HOT_STORAGE_POLICY_ID,
+          HdfsConstants.COLD_STORAGE_POLICY_ID,
+          HdfsConstants.ALLSSD_STORAGE_POLICY_ID};
   /**
-   * All active policies maintained in NN memory for fast querying,
+   * All supported policies maintained in NN memory for fast querying,
    * identified and sorted by its name.
    */
-  private final Map<String, ErasureCodingPolicy> activePoliciesByName;
-
-  ErasureCodingPolicyManager() {
+  private static final Map<String, ErasureCodingPolicy> SYSTEM_POLICIES_BY_NAME;
 
-    this.activePoliciesByName = new TreeMap<>();
+  static {
+    // Create a hashmap of all available policies for quick lookup by name
+    SYSTEM_POLICIES_BY_NAME = new TreeMap<>();
     for (ErasureCodingPolicy policy : SYS_POLICIES) {
-      activePoliciesByName.put(policy.getName(), policy);
+      SYSTEM_POLICIES_BY_NAME.put(policy.getName(), policy);
+    }
+  }
+
+  /**
+   * All enabled policies maintained in NN memory for fast querying,
+   * identified and sorted by its name.
+   */
+  private final Map<String, ErasureCodingPolicy> enabledPoliciesByName;
+
+  ErasureCodingPolicyManager(Configuration conf) {
+    // Populate the list of enabled policies from configuration
+    final String[] policyNames = conf.getTrimmedStrings(
+        DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_KEY,
+        DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_DEFAULT);
+    this.enabledPoliciesByName = new TreeMap<>();
+    for (String policyName : policyNames) {
+      ErasureCodingPolicy ecPolicy = SYSTEM_POLICIES_BY_NAME.get(policyName);
+      if (ecPolicy == null) {
+        String sysPolicies = Arrays.asList(SYS_POLICIES).stream()
+            .map(ErasureCodingPolicy::getName)
+            .collect(Collectors.joining(", "));
+        String msg = String.format("EC policy %s specified at %s is not a " +
+            "valid policy. Please choose from list of available policies: " +
+            "[%s]",
+            policyName,
+            DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_KEY,
+            sysPolicies);
+        throw new IllegalArgumentException(msg);
+      }
+      enabledPoliciesByName.put(ecPolicy.getName(), ecPolicy);
     }
 
     /**
@@ -104,10 +140,10 @@ public final class ErasureCodingPolicyManager {
   }
 
   /**
-   * Get system-wide policy by policy ID.
-   * @return ecPolicy
+   * Get a policy by policy ID.
+   * @return ecPolicy, or null if not found
    */
-  public static ErasureCodingPolicy getPolicyByPolicyID(byte id) {
+  public static ErasureCodingPolicy getPolicyByID(byte id) {
     for (ErasureCodingPolicy policy : SYS_POLICIES) {
       if (policy.getId() == id) {
         return policy;
@@ -117,36 +153,33 @@ public final class ErasureCodingPolicyManager {
   }
 
   /**
-   * Get all policies that's available to use.
-   * @return all policies
+   * Get a policy by policy name.
+   * @return ecPolicy, or null if not found
    */
-  public ErasureCodingPolicy[] getPolicies() {
-    ErasureCodingPolicy[] results =
-        new ErasureCodingPolicy[activePoliciesByName.size()];
-    return activePoliciesByName.values().toArray(results);
+  public static ErasureCodingPolicy getPolicyByName(String name) {
+    return SYSTEM_POLICIES_BY_NAME.get(name);
   }
 
   /**
-   * Get the policy specified by the policy name.
+   * Get the set of enabled policies.
+   * @return all policies
    */
-  public ErasureCodingPolicy getPolicyByName(String name) {
-    return activePoliciesByName.get(name);
+  public ErasureCodingPolicy[] getEnabledPolicies() {
+    ErasureCodingPolicy[] results =
+        new ErasureCodingPolicy[enabledPoliciesByName.size()];
+    return enabledPoliciesByName.values().toArray(results);
   }
 
   /**
-   * Get the policy specified by the policy ID.
+   * Get enabled policy by policy name.
    */
-  public ErasureCodingPolicy getPolicyByID(byte id) {
-    for (ErasureCodingPolicy policy : activePoliciesByName.values()) {
-      if (policy.getId() == id) {
-        return policy;
-      }
-    }
-    return null;
+  public ErasureCodingPolicy getEnabledPolicyByName(String name) {
+    return enabledPoliciesByName.get(name);
   }
 
   /**
-   * @return True if given policy is be suitable for striped EC Files.
+   * @return if the specified storage policy ID is suitable for striped EC
+   * files.
    */
   public static boolean checkStoragePolicySuitableForECStripedMode(
       byte storagePolicyID) {
@@ -164,6 +197,6 @@ public final class ErasureCodingPolicyManager {
    * Clear and clean up.
    */
   public void clear() {
-    activePoliciesByName.clear();
+    enabledPoliciesByName.clear();
   }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirErasureCodingOp.java

@@ -23,9 +23,10 @@ import java.io.DataInputStream;
 import java.io.DataOutputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
-import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.EnumSet;
 import java.util.List;
+import java.util.stream.Collectors;
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Lists;
@@ -34,6 +35,7 @@ import org.apache.hadoop.HadoopIllegalArgumentException;
 import org.apache.hadoop.fs.XAttr;
 import org.apache.hadoop.fs.XAttrSetFlag;
 import org.apache.hadoop.fs.permission.FsAction;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.XAttrHelper;
 import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
@@ -82,11 +84,23 @@ final class FSDirErasureCodingOp {
     fsd.writeLock();
     try {
       ErasureCodingPolicy ecPolicy = fsn.getErasureCodingPolicyManager()
-          .getPolicyByName(ecPolicyName);
+          .getEnabledPolicyByName(ecPolicyName);
       if (ecPolicy == null) {
-        throw new HadoopIllegalArgumentException("Policy '" +
-            ecPolicyName + "' does not match any supported erasure coding " +
-            "policies.");
+        final String sysPolicies =
+            Arrays.asList(
+                fsn.getErasureCodingPolicyManager().getEnabledPolicies())
+                .stream()
+                .map(ErasureCodingPolicy::getName)
+                .collect(Collectors.joining(", "));
+        final String message = String.format("Policy '%s' does not match any " +
+            "enabled erasure" +
+            " coding policies: [%s]. The set of enabled erasure coding " +
+            "policies can be configured at '%s'.",
+            ecPolicyName,
+            sysPolicies,
+            DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_KEY
+            );
+        throw new HadoopIllegalArgumentException(message);
       }
       iip = fsd.resolvePath(pc, src, DirOp.WRITE_LINK);
       // Write access is required to set erasure coding policy
@@ -118,26 +132,6 @@ final class FSDirErasureCodingOp {
           "for a file " + src);
     }
 
-    // Check that the EC policy is one of the active policies.
-    boolean validPolicy = false;
-    ErasureCodingPolicy[] activePolicies =
-        FSDirErasureCodingOp.getErasureCodingPolicies(fsd.getFSNamesystem());
-    for (ErasureCodingPolicy activePolicy : activePolicies) {
-      if (activePolicy.equals(ecPolicy)) {
-        validPolicy = true;
-        break;
-      }
-    }
-    if (!validPolicy) {
-      List<String> ecPolicyNames = new ArrayList<String>();
-      for (ErasureCodingPolicy activePolicy : activePolicies) {
-        ecPolicyNames.add(activePolicy.getName());
-      }
-      throw new HadoopIllegalArgumentException("Policy [ " +
-          ecPolicy.getName() + " ] does not match any of the " +
-          "supported policies. Please select any one of " + ecPolicyNames);
-    }
-
     final XAttr ecXAttr;
     DataOutputStream dOut = null;
     try {
@@ -291,7 +285,7 @@ final class FSDirErasureCodingOp {
   static ErasureCodingPolicy[] getErasureCodingPolicies(final FSNamesystem fsn)
       throws IOException {
     assert fsn.hasReadLock();
-    return fsn.getErasureCodingPolicyManager().getPolicies();
+    return fsn.getErasureCodingPolicyManager().getEnabledPolicies();
   }
 
   private static ErasureCodingPolicy getErasureCodingPolicyForPath(
@@ -307,8 +301,8 @@ final class FSDirErasureCodingOp {
         }
         if (inode.isFile()) {
           byte id = inode.asFile().getErasureCodingPolicyID();
-          return id < 0 ? null : fsd.getFSNamesystem().
-              getErasureCodingPolicyManager().getPolicyByID(id);
+          return id < 0 ? null :
+              ErasureCodingPolicyManager.getPolicyByID(id);
         }
         // We don't allow setting EC policies on paths with a symlink. Thus
         // if a symlink is encountered, the dir shouldn't have EC policy.
@@ -323,8 +317,8 @@ final class FSDirErasureCodingOp {
             ByteArrayInputStream bIn = new ByteArrayInputStream(xattr.getValue());
             DataInputStream dIn = new DataInputStream(bIn);
             String ecPolicyName = WritableUtils.readString(dIn);
-            return fsd.getFSNamesystem().getErasureCodingPolicyManager().
-                getPolicyByName(ecPolicyName);
+            return ErasureCodingPolicyManager
+                .getPolicyByName(ecPolicyName);
           }
         }
       }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSImageFormatPBINode.java

@@ -335,7 +335,7 @@ public final class FSImageFormatPBINode {
       assert ((!isStriped) || (isStriped && !f.hasReplication()));
       Short replication = (!isStriped ? (short) f.getReplication() : null);
       ErasureCodingPolicy ecPolicy = isStriped ?
-          ErasureCodingPolicyManager.getPolicyByPolicyID(
+          ErasureCodingPolicyManager.getPolicyByID(
               (byte) f.getErasureCodingPolicyID()) : null;
       Byte ecPolicyID = (isStriped ? ecPolicy.getId() : null);
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java

@@ -838,7 +838,7 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
       this.dir = new FSDirectory(this, conf);
       this.snapshotManager = new SnapshotManager(dir);
       this.cacheManager = new CacheManager(this, conf, blockManager);
-      this.ecPolicyManager = new ErasureCodingPolicyManager();
+      this.ecPolicyManager = new ErasureCodingPolicyManager(conf);
       this.topConf = new TopConf(conf);
       this.auditLoggers = initAuditLoggers(conf);
       this.isDefaultAuditLogger = auditLoggers.size() == 1 &&

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeFile.java

@@ -192,7 +192,7 @@ public class INodeFile extends INodeWithAdditionalFields
         Preconditions.checkArgument(replication == null &&
             erasureCodingPolicyID != null);
         Preconditions.checkArgument(ErasureCodingPolicyManager
-            .getPolicyByPolicyID(erasureCodingPolicyID) != null,
+            .getPolicyByID(erasureCodingPolicyID) != null,
             "Could not find EC policy with ID 0x" + StringUtils
                 .byteToHexString(erasureCodingPolicyID));
         layoutRedundancy |= BLOCK_TYPE_MASK_STRIPED;
@@ -514,7 +514,7 @@ public class INodeFile extends INodeWithAdditionalFields
     }
 
     ErasureCodingPolicy ecPolicy =
-        ErasureCodingPolicyManager.getPolicyByPolicyID(
+        ErasureCodingPolicyManager.getPolicyByID(
             getErasureCodingPolicyID());
     Preconditions.checkNotNull(ecPolicy, "Could not find EC policy with ID 0x"
         + StringUtils.byteToHexString(getErasureCodingPolicyID()));

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/ECAdmin.java

@@ -20,6 +20,7 @@ import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.conf.Configured;
 import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
 import org.apache.hadoop.tools.TableListing;
@@ -79,7 +80,7 @@ public class ECAdmin extends Configured implements Tool {
     }
   }
 
-  /** Command to list the set of available erasure coding policies */
+  /** Command to list the set of enabled erasure coding policies. */
   private static class ListECPoliciesCommand
       implements AdminHelper.Command {
     @Override
@@ -95,7 +96,9 @@ public class ECAdmin extends Configured implements Tool {
     @Override
     public String getLongUsage() {
       return getShortUsage() + "\n" +
-          "Get the list of supported erasure coding policies.\n";
+          "Get the list of enabled erasure coding policies.\n" +
+          "Policies can be enabled on the NameNode via `" +
+          DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_KEY + "`.\n";
     }
 
     @Override
@@ -109,10 +112,19 @@ public class ECAdmin extends Configured implements Tool {
       try {
         Collection<ErasureCodingPolicy> policies =
             dfs.getAllErasureCodingPolicies();
-        System.out.println("Erasure Coding Policies:");
-        for (ErasureCodingPolicy policy : policies) {
-          if (policy != null) {
-            System.out.println("\t" + policy.getName());
+        if (policies.isEmpty()) {
+          System.out.println("No erasure coding policies are enabled on the " +
+              "cluster.");
+          System.out.println("The set of enabled policies can be " +
+              "configured at '" +
+              DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_KEY + "' on the " +
+              "NameNode.");
+        } else {
+          System.out.println("Erasure Coding Policies:");
+          for (ErasureCodingPolicy policy : policies) {
+            if (policy != null) {
+              System.out.println("\t" + policy.getName());
+            }
           }
         }
       } catch (IOException e) {

hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml

@@ -2928,6 +2928,15 @@
   </description>
 </property>
 
+<property>
+  <name>dfs.namenode.ec.policies.enabled</name>
+  <value>RS-6-3-64k</value>
+  <description>Comma-delimited list of enabled erasure coding policies.
+    The NameNode will enforce this when setting an erasure coding policy
+    on a directory.
+  </description>
+</property>
+
 <property>
   <name>dfs.datanode.ec.reconstruction.stripedread.timeout.millis</name>
   <value>5000</value>

hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HDFSErasureCoding.md

@@ -56,19 +56,26 @@ Architecture
 
       3. _Transfer the generated data blocks to target nodes:_ Once decoding is finished, the recovered blocks are transferred to target DataNodes.
 
- *  **ErasureCoding policy**
-    To accommodate heterogeneous workloads, we allow files and directories in an HDFS cluster to have different replication and EC policies.
-    Information on how to encode/decode a file is encapsulated in an ErasureCodingPolicy class. Each policy is defined by the following 2 pieces of information:
+ *  **Erasure coding policies**
+    To accommodate heterogeneous workloads, we allow files and directories in an HDFS cluster to have different replication and erasure coding policies.
+    The erasure coding policy encapsulates how to encode/decode a file. Each policy is defined by the following pieces of information:
 
-      1. _The ECSchema:_ This includes the numbers of data and parity blocks in an EC group (e.g., 6+3), as well as the codec algorithm (e.g., Reed-Solomon).
+      1. _The EC schema:_ This includes the numbers of data and parity blocks in an EC group (e.g., 6+3), as well as the codec algorithm (e.g., Reed-Solomon, XOR).
 
       2. _The size of a striping cell._ This determines the granularity of striped reads and writes, including buffer sizes and encoding work.
 
-    Five policies are currently supported: RS-3-2-64k, RS-6-3-64k, RS-10-4-64k, RS-LEGACY-6-3-64k, and XOR-2-1-64k. All with default cell size of 64KB. The system default policy is RS-6-3-64k which use the default schema RS_6_3_SCHEMA with a cell size of 64KB.
+    Policies are named *codec*-*num data blocks*-*num parity blocks*-*cell size*. Currently, five built-in policies are supported: `RS-3-2-64k`, `RS-6-3-64k`, `RS-10-4-64k`, `RS-LEGACY-6-3-64k`, and `XOR-2-1-64k`.
+
+    By default, only `RS-6-3-64k` is enabled.
+
+    Similar to HDFS storage policies, erasure coding policies are set on a directory. When a file is created, it inherits the EC policy of its nearest ancestor directory.
+
+    Directory-level EC policies only affect new files created within the directory. Once a file has been created, its erasure coding policy can be queried but not changed. If an erasure coded file is renamed to a directory with a different EC policy, the file retains its existing EC policy. Converting a file to a different EC policy requires rewriting its data; do this by copying the file (e.g. via distcp) rather than renaming it.
 
  *  **Intel ISA-L**
-    Intel ISA-L stands for Intel Intelligent Storage Acceleration Library. ISA-L is a collection of optimized low-level functions used primarily in storage applications. It includes a fast block Reed-Solomon type erasure codes optimized for Intel AVX and AVX2 instruction sets.
-    HDFS EC can leverage this open-source library to accelerate encoding and decoding calculation. ISA-L supports most of major operating systems, including Linux and Windows. By default, ISA-L is not enabled in HDFS.
+    Intel ISA-L stands for Intel Intelligent Storage Acceleration Library. ISA-L is an open-source collection of optimized low-level functions designed for storage applications. It includes fast block Reed-Solomon type erasure codes optimized for Intel AVX and AVX2 instruction sets.
+    HDFS erasure coding can leverage ISA-L to accelerate encoding and decoding calculation. ISA-L supports most major operating systems, including Linux and Windows.
+    ISA-L is not enabled by default. See the instructions below for how to enable ISA-L.
 
 Deployment
 ----------
@@ -90,6 +97,10 @@ Deployment
 
 ### Configuration keys
 
+  The set of enabled erasure coding policies can be configured on the NameNode via `dfs.namenode.ec.policies.enabled`. This restricts what EC policies can be set by clients. It does not affect the behavior of already set file or directory-level EC policies.
+
+  By default, only the `RS-6-3-64k` policy is enabled. Typically, the cluster administrator will configure the set of enabled policies based on the size of the cluster and the desired fault-tolerance properties. For instance, for a cluster with 9 racks, a policy like `RS-10-4-64k` will not preserve rack-level fault-tolerance, and `RS-6-3-64k` or `RS-3-2-64k` might be more appropriate. If the administrator only cares about node-level fault-tolerance, `RS-10-4-64k` would still be appropriate as long as there are at least 14 DataNodes in the cluster.
+
   The codec implementation for Reed-Solomon and XOR can be configured with the following client and DataNode configuration keys:
   `io.erasurecode.codec.rs.rawcoder` for the default RS codec,
   `io.erasurecode.codec.rs-legacy.rawcoder` for the legacy RS codec,
@@ -106,13 +117,13 @@ Deployment
 ### Enable Intel ISA-L
 
   HDFS native implementation of default RS codec leverages Intel ISA-L library to improve the encoding and decoding calculation. To enable and use Intel ISA-L, there are three steps.
-  1. Build ISA-L library. Please refer to the offical site "https://github.com/01org/isa-l/" for detail information.
-  2. Build Hadoop with ISA-L support. Please refer to "Intel ISA-L build options" section in "Build instructions for Hadoop"(BUILDING.txt) document. Use -Dbundle.isal to copy the contents of the isal.lib directory into the final tar file. Deploy hadoop with the tar file. Make sure ISA-L library is available on both HDFS client and DataNodes.
-  3. Configure the `io.erasurecode.codec.rs.rawcoder` key with value `org.apache.hadoop.io.erasurecode.rawcoder.NativeRSRawErasureCoderFactory` on HDFS client and DataNodes.
+  1. Build ISA-L library. Please refer to the official site "https://github.com/01org/isa-l/" for detail information.
+  2. Build Hadoop with ISA-L support. Please refer to "Intel ISA-L build options" section in "Build instructions for Hadoop" in (BUILDING.txt) in the source code. Use `-Dbundle.isal` to copy the contents of the `isal.lib` directory into the final tar file. Deploy Hadoop with the tar file. Make sure ISA-L is available on HDFS clients and DataNodes.
+  3. Configure the `io.erasurecode.codec.rs.rawcoder` key with value `org.apache.hadoop.io.erasurecode.rawcoder.NativeRSRawErasureCoderFactory` on HDFS clients and DataNodes.
 
-  To check ISA-L library enable state, try "Hadoop checknative" command. It will tell you if ISA-L library is enabled or not.
+  To verify that ISA-L is correctly detected by Hadoop, run the `hadoop checknative` command.
 
-  It also requires three steps to enable the native implementation of XOR codec. The first two steps are the same as the above step 1 and step 2. In step 3, configure the `io.erasurecode.codec.xor.rawcoder` key with `org.apache.hadoop.io.erasurecode.rawcoder.NativeXORRawErasureCoderFactory` on both HDFS client and DataNodes.
+  To enable the native implementation of the XOR codec, perform the same first two steps as above to build and deploy Hadoop with ISA-L support. Afterwards, configure the `io.erasurecode.codec.xor.rawcoder` key with `org.apache.hadoop.io.erasurecode.rawcoder.NativeXORRawErasureCoderFactory` on both HDFS client and DataNodes.
 
 ### Administrative commands
 
@@ -130,20 +141,20 @@ Below are the details about each command.
 
  *  `[-setPolicy -policy <policyName> -path <path>]`
 
-    Sets an ErasureCoding policy on a directory at the specified path.
+    Sets an erasure coding policy on a directory at the specified path.
 
       `path`: An directory in HDFS. This is a mandatory parameter. Setting a policy only affects newly created files, and does not affect existing files.
 
-      `policyName`: The ErasureCoding policy to be used for files under this directory.
+      `policyName`: The erasure coding policy to be used for files under this directory.
 
  *  `[-getPolicy -path <path>]`
 
-     Get details of the ErasureCoding policy of a file or directory at the specified path.
+     Get details of the erasure coding policy of a file or directory at the specified path.
 
  *  `[-unsetPolicy -path <path>]`
 
-     Unset an ErasureCoding policy set by a previous call to "setPolicy" on a directory. If the directory inherits the ErasureCoding policy from an ancestor directory, "unsetPolicy" is a no-op. Unsetting the policy on a directory which doesn't have an explicit policy set will not return an error.
+     Unset an erasure coding policy set by a previous call to `setPolicy` on a directory. If the directory inherits the erasure coding policy from an ancestor directory, `unsetPolicy` is a no-op. Unsetting the policy on a directory which doesn't have an explicit policy set will not return an error.
 
  *  `[-listPolicies]`
 
-     Lists all supported ErasureCoding policies. These names are suitable for use with the `setPolicy` command.
+     Lists the set of enabled erasure coding policies. These names are suitable for use with the `setPolicy` command.

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/cli/TestErasureCodingCLI.java

@@ -45,6 +45,9 @@ public class TestErasureCodingCLI extends CLITestHelper {
   public void setUp() throws Exception {
     super.setUp();
 
+    conf.set(DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_KEY,
+        "RS-6-3-64k,RS-3-2-64k,XOR-2-1-64k");
+
     dfsCluster = new MiniDFSCluster.Builder(conf)
         .numDataNodes(NUM_OF_DATANODES).build();
     dfsCluster.waitClusterUp();

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/DFSTestUtil.java

@@ -68,6 +68,8 @@ import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.stream.Collectors;
+
 import com.google.common.base.Charsets;
 import com.google.common.base.Joiner;
 import com.google.common.base.Preconditions;
@@ -279,6 +281,15 @@ public class DFSTestUtil {
     Whitebox.setInternalState(fsn.getFSDirectory(), "editLog", newLog);
   }
 
+  public static void enableAllECPolicies(Configuration conf) {
+    // Enable all the available EC policies
+    String policies =
+        Arrays.asList(ErasureCodingPolicyManager.getSystemPolicies()).stream()
+        .map(ErasureCodingPolicy::getName)
+        .collect(Collectors.joining(","));
+    conf.set(DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_KEY, policies);
+  }
+
   /** class MyFile contains enough information to recreate the contents of
    * a single file.
    */

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSRSDefault10x4StripedInputStream.java

@@ -29,7 +29,7 @@ public class TestDFSRSDefault10x4StripedInputStream extends
     TestDFSStripedInputStream {
 
   public ErasureCodingPolicy getEcPolicy() {
-    return ErasureCodingPolicyManager.getPolicyByPolicyID(
+    return ErasureCodingPolicyManager.getPolicyByID(
         HdfsConstants.RS_10_4_POLICY_ID);
   }
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSRSDefault10x4StripedOutputStream.java

@@ -30,7 +30,7 @@ public class TestDFSRSDefault10x4StripedOutputStream
 
   @Override
   public ErasureCodingPolicy getEcPolicy() {
-    return ErasureCodingPolicyManager.getPolicyByPolicyID(
+    return ErasureCodingPolicyManager.getPolicyByID(
         HdfsConstants.RS_10_4_POLICY_ID);
   }
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSRSDefault10x4StripedOutputStreamWithFailure.java

@@ -30,7 +30,7 @@ public class TestDFSRSDefault10x4StripedOutputStreamWithFailure
 
   @Override
   public ErasureCodingPolicy getEcPolicy() {
-    return ErasureCodingPolicyManager.getPolicyByPolicyID(
+    return ErasureCodingPolicyManager.getPolicyByID(
         HdfsConstants.RS_10_4_POLICY_ID);
   }
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSStripedInputStream.java

@@ -94,6 +94,8 @@ public class TestDFSStripedInputStream {
 
     conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, blockSize);
     conf.setInt(DFSConfigKeys.DFS_NAMENODE_REPLICATION_MAX_STREAMS_KEY, 0);
+    conf.set(DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_KEY,
+        getEcPolicy().getName());
     if (ErasureCodeNative.isNativeCodeLoaded()) {
       conf.set(
           CodecUtil.IO_ERASURECODE_CODEC_RS_RAWCODER_KEY,

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSStripedOutputStream.java

@@ -88,6 +88,7 @@ public class TestDFSStripedOutputStream {
           CodecUtil.IO_ERASURECODE_CODEC_RS_RAWCODER_KEY,
           NativeRSRawErasureCoderFactory.class.getCanonicalName());
     }
+    DFSTestUtil.enableAllECPolicies(conf);
     cluster = new MiniDFSCluster.Builder(conf).numDataNodes(numDNs).build();
     cluster.getFileSystem().getClient().setErasureCodingPolicy("/", ecPolicy
         .getName());

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSStripedOutputStreamWithFailure.java

@@ -217,6 +217,7 @@ public class TestDFSStripedOutputStreamWithFailure {
           CodecUtil.IO_ERASURECODE_CODEC_RS_RAWCODER_KEY,
           NativeRSRawErasureCoderFactory.class.getCanonicalName());
     }
+    DFSTestUtil.enableAllECPolicies(conf);
     cluster = new MiniDFSCluster.Builder(conf).numDataNodes(numDNs).build();
     cluster.waitActive();
     dfs = cluster.getFileSystem();

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSXORStripedInputStream.java

@@ -27,7 +27,7 @@ import org.apache.hadoop.hdfs.server.namenode.ErasureCodingPolicyManager;
 public class TestDFSXORStripedInputStream extends TestDFSStripedInputStream{
 
   public ErasureCodingPolicy getEcPolicy() {
-    return ErasureCodingPolicyManager.getPolicyByPolicyID(
+    return ErasureCodingPolicyManager.getPolicyByID(
         HdfsConstants.XOR_2_1_POLICY_ID);
   }
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSXORStripedOutputStream.java

@@ -29,7 +29,7 @@ public class TestDFSXORStripedOutputStream extends TestDFSStripedOutputStream{
 
   @Override
   public ErasureCodingPolicy getEcPolicy() {
-    return ErasureCodingPolicyManager.getPolicyByPolicyID(
+    return ErasureCodingPolicyManager.getPolicyByID(
         HdfsConstants.XOR_2_1_POLICY_ID);
   }
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSXORStripedOutputStreamWithFailure.java

@@ -30,7 +30,7 @@ public class TestDFSXORStripedOutputStreamWithFailure
 
   @Override
   public ErasureCodingPolicy getEcPolicy() {
-    return ErasureCodingPolicyManager.getPolicyByPolicyID(
+    return ErasureCodingPolicyManager.getPolicyByID(
         HdfsConstants.XOR_2_1_POLICY_ID);
   }
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestErasureCodingPolicies.java

@@ -23,6 +23,7 @@ import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.hdfs.protocol.DirectoryListing;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.server.namenode.ErasureCodingPolicyManager;
 import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
@@ -34,6 +35,7 @@ import org.apache.hadoop.io.erasurecode.ECSchema;
 import org.apache.hadoop.security.AccessControlException;
 import org.apache.hadoop.security.UserGroupInformation;
 import org.junit.After;
+import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -64,6 +66,7 @@ public class TestErasureCodingPolicies {
   public void setupCluster() throws IOException {
     conf = new HdfsConfiguration();
     conf.setInt(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, BLOCK_SIZE);
+    DFSTestUtil.enableAllECPolicies(conf);
     cluster = new MiniDFSCluster.Builder(conf).
         numDataNodes(1).build();
     cluster.waitActive();
@@ -189,6 +192,40 @@ public class TestErasureCodingPolicies {
     } catch (IOException e) {
       assertExceptionContains("erasure coding policy for a file", e);
     }
+
+    // Verify that policies are successfully loaded even when policies
+    // are disabled
+    cluster.getConfiguration(0).set(
+        DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_KEY, "");
+    cluster.restartNameNodes();
+    cluster.waitActive();
+
+    // No policies should be enabled after restart
+    Assert.assertTrue("No policies should be enabled after restart",
+        fs.getAllErasureCodingPolicies().isEmpty());
+
+    // Already set directory-level policies should still be in effect
+    Path disabledPolicy = new Path(dir1, "afterDisabled");
+    Assert.assertEquals("Dir does not have policy set",
+        EC_POLICY,
+        fs.getErasureCodingPolicy(dir1));
+    fs.create(disabledPolicy).close();
+    Assert.assertEquals("File did not inherit dir's policy",
+        EC_POLICY,
+        fs.getErasureCodingPolicy(disabledPolicy));
+
+    // Also check loading disabled EC policies from fsimage
+    fs.setSafeMode(HdfsConstants.SafeModeAction.SAFEMODE_ENTER);
+    fs.saveNamespace();
+    fs.setSafeMode(HdfsConstants.SafeModeAction.SAFEMODE_LEAVE);
+    cluster.restartNameNodes();
+
+    Assert.assertEquals("Dir does not have policy set",
+        EC_POLICY,
+        fs.getErasureCodingPolicy(dir1));
+    Assert.assertEquals("File does not have policy set",
+        EC_POLICY,
+        fs.getErasureCodingPolicy(disabledPolicy));
   }
 
   @Test
@@ -310,7 +347,7 @@ public class TestErasureCodingPolicies {
           + "setting an invalid erasure coding policy");
     } catch (Exception e) {
       assertExceptionContains("Policy 'RS-4-2-128k' does not match " +
-          "any supported erasure coding policies",e);
+          "any enabled erasure coding policies", e);
     }
   }
 
@@ -320,7 +357,7 @@ public class TestErasureCodingPolicies {
         .getSystemPolicies();
     Collection<ErasureCodingPolicy> allECPolicies = fs
         .getAllErasureCodingPolicies();
-    assertTrue("All system policies should be active",
+    assertTrue("All system policies should be enabled",
         allECPolicies.containsAll(Arrays.asList(sysECPolicies)));
   }
 

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestUnsetAndChangeDirectoryEcPolicy.java

@@ -72,6 +72,7 @@ public class TestUnsetAndChangeDirectoryEcPolicy {
           CodecUtil.IO_ERASURECODE_CODEC_RS_RAWCODER_KEY,
           NativeRSRawErasureCoderFactory.class.getCanonicalName());
     }
+    DFSTestUtil.enableAllECPolicies(conf);
     cluster = new MiniDFSCluster.Builder(conf).numDataNodes(
         dataBlocks + parityBlocks).build();
     cluster.waitActive();
@@ -139,7 +140,7 @@ public class TestUnsetAndChangeDirectoryEcPolicy {
     final Path ec32FilePath = new Path(childDir, "ec_3_2_file");
     final Path ec63FilePath2 = new Path(childDir, "ec_6_3_file_2");
     final ErasureCodingPolicy ec32Policy = ErasureCodingPolicyManager
-        .getPolicyByPolicyID(HdfsConstants.RS_3_2_POLICY_ID);
+        .getPolicyByID(HdfsConstants.RS_3_2_POLICY_ID);
 
     fs.mkdirs(parentDir);
     fs.setErasureCodingPolicy(parentDir, ecPolicy.getName());
@@ -237,7 +238,7 @@ public class TestUnsetAndChangeDirectoryEcPolicy {
     final Path ec63FilePath = new Path(rootPath, "ec_6_3_file");
     final Path ec32FilePath = new Path(rootPath, "ec_3_2_file");
     final ErasureCodingPolicy ec32Policy = ErasureCodingPolicyManager
-        .getPolicyByPolicyID(HdfsConstants.RS_3_2_POLICY_ID);
+        .getPolicyByID(HdfsConstants.RS_3_2_POLICY_ID);
 
     fs.unsetErasureCodingPolicy(rootPath);
     fs.setErasureCodingPolicy(rootPath, ecPolicy.getName());

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestEnabledECPolicies.java

@@ -0,0 +1,151 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode;
+
+import org.apache.hadoop.hdfs.DFSConfigKeys;
+import org.apache.hadoop.hdfs.HdfsConfiguration;
+import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
+import org.apache.hadoop.test.GenericTestUtils;
+import org.junit.Assert;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.Timeout;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+/**
+ * Test that ErasureCodingPolicyManager correctly parses the set of enabled
+ * erasure coding policies from configuration and exposes this information.
+ */
+public class TestEnabledECPolicies {
+
+  private static final ErasureCodingPolicy[] SYSTEM_POLICIES =
+      ErasureCodingPolicyManager.getSystemPolicies();
+
+  @Rule
+  public Timeout testTimeout = new Timeout(60000);
+
+  private void expectInvalidPolicy(String value) {
+    HdfsConfiguration conf = new HdfsConfiguration();
+    conf.set(DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_KEY,
+        value);
+    try {
+      new ErasureCodingPolicyManager(conf);
+      fail("Expected exception when instantiating ECPolicyManager");
+    } catch (IllegalArgumentException e) {
+      GenericTestUtils.assertExceptionContains("is not a valid policy", e);
+    }
+  }
+
+  private void expectValidPolicy(String value, final int numEnabled) throws
+      Exception {
+    HdfsConfiguration conf = new HdfsConfiguration();
+    conf.set(DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_KEY,
+        value);
+    ErasureCodingPolicyManager manager = new ErasureCodingPolicyManager(conf);
+    assertEquals("Incorrect number of enabled policies",
+        numEnabled, manager.getEnabledPolicies().length);
+  }
+
+  @Test
+  public void testInvalid() throws Exception {
+    // Test first with an invalid policy
+    expectInvalidPolicy("not-a-policy");
+    // Test with an invalid policy and a valid policy
+    expectInvalidPolicy("not-a-policy," + ErasureCodingPolicyManager
+        .getSystemDefaultPolicy().getName());
+    // Test with a valid and an invalid policy
+    expectInvalidPolicy(ErasureCodingPolicyManager
+        .getSystemDefaultPolicy().getName() + ", not-a-policy");
+    // Some more invalid values
+    expectInvalidPolicy("not-a-policy, ");
+    expectInvalidPolicy("     ,not-a-policy, ");
+  }
+
+  @Test
+  public void testValid() throws Exception {
+    String ecPolicyName = ErasureCodingPolicyManager.getSystemDefaultPolicy()
+        .getName();
+    expectValidPolicy(ecPolicyName, 1);
+    expectValidPolicy(ecPolicyName + ", ", 1);
+    expectValidPolicy(",", 0);
+  }
+
+  @Test
+  public void testGetPolicies() throws Exception {
+    ErasureCodingPolicy[] enabledPolicies;
+    // Enable no policies
+    enabledPolicies = new ErasureCodingPolicy[]
+        {SYSTEM_POLICIES[1], SYSTEM_POLICIES[2]};
+    testGetPolicies(enabledPolicies);
+
+    // Enable one policy
+    enabledPolicies = new ErasureCodingPolicy[]
+        {SYSTEM_POLICIES[1]};
+    testGetPolicies(enabledPolicies);
+
+    // Enable two policies
+    enabledPolicies = new ErasureCodingPolicy[]
+        {SYSTEM_POLICIES[1], SYSTEM_POLICIES[2]};
+    testGetPolicies(enabledPolicies);
+  }
+
+  private void testGetPolicies(ErasureCodingPolicy[] enabledPolicies)
+      throws Exception {
+    HdfsConfiguration conf = new HdfsConfiguration();
+    conf.set(DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_KEY,
+        Arrays.asList(enabledPolicies).stream()
+            .map(ErasureCodingPolicy::getName)
+            .collect(Collectors.joining(", ")));
+    ErasureCodingPolicyManager manager = new ErasureCodingPolicyManager(conf);
+
+    // Check that returned values are unique
+    Set<String> found = new HashSet<>();
+    for (ErasureCodingPolicy p : manager.getEnabledPolicies()) {
+      Assert.assertFalse("Duplicate policy name found: " + p.getName(),
+          found.contains(p.getName()));
+      found.add(p.getName());
+    }
+    // Check that the policies specified in conf are found
+    for (ErasureCodingPolicy p: enabledPolicies) {
+      Assert.assertTrue("Did not find specified EC policy " + p.getName(),
+          found.contains(p.getName()));
+    }
+    Assert.assertEquals(enabledPolicies.length, found.size());
+    // Check that getEnabledPolicyByName only returns enabled policies
+    for (ErasureCodingPolicy p: SYSTEM_POLICIES) {
+      if (found.contains(p.getName())) {
+        // Enabled policy should be present
+        Assert.assertNotNull(
+            "getEnabledPolicyByName did not find enabled policy" + p.getName(),
+            manager.getEnabledPolicyByName(p.getName()));
+      } else {
+        // Disabled policy should not be present
+        Assert.assertNull(
+            "getEnabledPolicyByName found disabled policy " + p.getName(),
+            manager.getEnabledPolicyByName(p.getName()));
+      }
+    }
+  }
+}

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestFSImage.java

@@ -77,7 +77,7 @@ public class TestFSImage {
   private static final String HADOOP_2_7_ZER0_BLOCK_SIZE_TGZ =
       "image-with-zero-block-size.tar.gz";
   private static final ErasureCodingPolicy testECPolicy =
-      ErasureCodingPolicyManager.getPolicyByPolicyID(
+      ErasureCodingPolicyManager.getPolicyByID(
           HdfsConstants.RS_10_4_POLICY_ID);
 
   @Test
@@ -240,6 +240,7 @@ public class TestFSImage {
   @Test
   public void testSaveAndLoadStripedINodeFile() throws IOException{
     Configuration conf = new Configuration();
+    DFSTestUtil.enableAllECPolicies(conf);
     MiniDFSCluster cluster = null;
     try {
       cluster = new MiniDFSCluster.Builder(conf).build();
@@ -260,6 +261,7 @@ public class TestFSImage {
   public void testSaveAndLoadStripedINodeFileUC() throws IOException {
     // construct a INode with StripedBlock for saving and loading
     Configuration conf = new Configuration();
+    DFSTestUtil.enableAllECPolicies(conf);
     MiniDFSCluster cluster = null;
     try {
       cluster = new MiniDFSCluster.Builder(conf).build();
@@ -459,6 +461,7 @@ public class TestFSImage {
     final int BLOCK_SIZE = 8 * 1024 * 1024;
     Configuration conf = new HdfsConfiguration();
     conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, BLOCK_SIZE);
+    DFSTestUtil.enableAllECPolicies(conf);
     MiniDFSCluster cluster = null;
     try {
       cluster = new MiniDFSCluster.Builder(conf).numDataNodes(GROUP_SIZE)
@@ -468,7 +471,7 @@ public class TestFSImage {
       Path parentDir = new Path("/ec-10-4");
       Path childDir = new Path(parentDir, "ec-3-2");
       ErasureCodingPolicy ec32Policy = ErasureCodingPolicyManager
-          .getPolicyByPolicyID(HdfsConstants.RS_3_2_POLICY_ID);
+          .getPolicyByID(HdfsConstants.RS_3_2_POLICY_ID);
 
       // Create directories and files
       fs.mkdirs(parentDir);
@@ -516,7 +519,7 @@ public class TestFSImage {
       // check the information of file_3_2
       inode = fsn.dir.getINode(file_3_2.toString()).asFile();
       assertTrue(inode.isStriped());
-      assertEquals(ErasureCodingPolicyManager.getPolicyByPolicyID(
+      assertEquals(ErasureCodingPolicyManager.getPolicyByID(
           HdfsConstants.RS_3_2_POLICY_ID).getId(),
           inode.getErasureCodingPolicyID());
       blks = inode.getBlocks();

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/TestOfflineImageViewer.java

@@ -124,6 +124,10 @@ public class TestOfflineImageViewer {
     tempDir = Files.createTempDir();
     MiniDFSCluster cluster = null;
     try {
+      final ErasureCodingPolicy ecPolicy =
+          ErasureCodingPolicyManager.getPolicyByID(
+              HdfsConstants.XOR_2_1_POLICY_ID);
+
       Configuration conf = new Configuration();
       conf.setLong(
           DFSConfigKeys.DFS_NAMENODE_DELEGATION_TOKEN_MAX_LIFETIME_KEY, 10000);
@@ -134,6 +138,8 @@ public class TestOfflineImageViewer {
       conf.setBoolean(DFSConfigKeys.DFS_NAMENODE_ACLS_ENABLED_KEY, true);
       conf.set(CommonConfigurationKeysPublic.HADOOP_SECURITY_AUTH_TO_LOCAL,
           "RULE:[2:$1@$0](JobTracker@.*FOO.COM)s/@.*//" + "DEFAULT");
+      conf.set(DFSConfigKeys.DFS_NAMENODE_EC_POLICIES_ENABLED_KEY,
+          ecPolicy.getName());
       cluster = new MiniDFSCluster.Builder(conf).numDataNodes(3).build();
       cluster.waitActive();
       DistributedFileSystem hdfs = cluster.getFileSystem();
@@ -233,9 +239,6 @@ public class TestOfflineImageViewer {
       Path ecDir = new Path("/ec");
       hdfs.mkdirs(ecDir);
       dirCount++;
-      ErasureCodingPolicy ecPolicy =
-          ErasureCodingPolicyManager.getPolicyByPolicyID(
-              HdfsConstants.XOR_2_1_POLICY_ID);
       hdfs.getClient().setErasureCodingPolicy(ecDir.toString(),
           ecPolicy.getName());
       writtenFiles.put(ecDir.toString(), hdfs.getFileStatus(ecDir));
@@ -409,7 +412,7 @@ public class TestOfflineImageViewer {
             Assert.assertEquals("INode '"
                     + currentInodeName + "' has unexpected EC Policy!",
                 Byte.parseByte(currentECPolicy),
-                ErasureCodingPolicyManager.getPolicyByPolicyID(
+                ErasureCodingPolicyManager.getPolicyByID(
                     HdfsConstants.XOR_2_1_POLICY_ID).getId());
             Assert.assertEquals("INode '"
                     + currentInodeName + "' has unexpected replication!",

hadoop-hdfs-project/hadoop-hdfs/src/test/resources/testErasureCodingConf.xml

@@ -119,7 +119,7 @@
       <comparators>
         <comparator>
           <type>SubstringComparator</type>
-          <expected-output>Get the list of supported erasure coding policies</expected-output>
+          <expected-output>Get the list of enabled erasure coding policies</expected-output>
         </comparator>
         <comparator>
           <type>SubstringComparator</type>
@@ -359,7 +359,24 @@
       <comparators>
         <comparator>
           <type>SubstringComparator</type>
-          <expected-output>Policy 'invalidpolicy' does not match any supported erasure coding policies.</expected-output>
+          <expected-output>Policy 'invalidpolicy' does not match any enabled erasure coding policies</expected-output>
+        </comparator>
+      </comparators>
+    </test>
+
+    <test>
+      <description>setPolicy : illegal parameters - RS-10-4-64k</description>
+      <test-commands>
+        <command>-fs NAMENODE -mkdir /ecdir</command>
+        <ec-admin-command>-fs NAMENODE -setPolicy -policy RS-10-4-64k -path /ecdir</ec-admin-command>
+      </test-commands>
+      <cleanup-commands>
+        <command>-fs NAMENODE -rmdir /ecdir</command>
+      </cleanup-commands>
+      <comparators>
+        <comparator>
+          <type>SubstringComparator</type>
+          <expected-output>Policy 'RS-10-4-64k' does not match any enabled erasure coding policies</expected-output>
         </comparator>
       </comparators>
     </test>