diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/IndicesClientIT.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/IndicesClientIT.java
index 2c421597c68d0..927183ba7715f 100644
--- a/client/rest-high-level/src/test/java/org/elasticsearch/client/IndicesClientIT.java
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/IndicesClientIT.java
@@ -534,6 +534,9 @@ public void testUpdateAliases() throws IOException {
 
         IndicesAliasesRequest aliasesAddRequest = new IndicesAliasesRequest();
         AliasActions addAction = new AliasActions(AliasActions.Type.ADD).index(index).aliases(alias);
+        if (randomBoolean()) {
+            addAction.writeIndex(randomBoolean());
+        }
         addAction.routing("routing").searchRouting("search_routing").filter("{\"term\":{\"year\":2016}}");
         aliasesAddRequest.addAliasAction(addAction);
         AcknowledgedResponse aliasesAddResponse = execute(aliasesAddRequest, highLevelClient().indices()::updateAliases,
@@ -548,6 +551,8 @@ public void testUpdateAliases() throws IOException {
         Map<String, Object> filter = (Map<String, Object>) getAlias.get("filter");
         Map<String, Object> term = (Map<String, Object>) filter.get("term");
         assertEquals(2016, term.get("year"));
+        Boolean isWriteIndex = (Boolean) getAlias.get("is_write_index");
+        assertThat(isWriteIndex, equalTo(addAction.writeIndex()));
 
         String alias2 = "alias2";
         IndicesAliasesRequest aliasesAddRemoveRequest = new IndicesAliasesRequest();
diff --git a/server/src/main/java/org/elasticsearch/action/admin/indices/alias/IndicesAliasesRequest.java b/server/src/main/java/org/elasticsearch/action/admin/indices/alias/IndicesAliasesRequest.java
index 9249550871c12..c1d921ff0324f 100644
--- a/server/src/main/java/org/elasticsearch/action/admin/indices/alias/IndicesAliasesRequest.java
+++ b/server/src/main/java/org/elasticsearch/action/admin/indices/alias/IndicesAliasesRequest.java
@@ -472,6 +472,9 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             if (false == Strings.isEmpty(searchRouting)) {
                 builder.field(SEARCH_ROUTING.getPreferredName(), searchRouting);
             }
+            if (null != writeIndex) {
+                builder.field(IS_WRITE_INDEX.getPreferredName(), writeIndex);
+            }
             builder.endObject();
             builder.endObject();
             return builder;
@@ -491,6 +494,7 @@ public String toString() {
                     + ",routing=" + routing
                     + ",indexRouting=" + indexRouting
                     + ",searchRouting=" + searchRouting
+                    + ",writeIndex=" + writeIndex
                     + "]";
         }
 
@@ -507,12 +511,13 @@ public boolean equals(Object obj) {
                     && Objects.equals(filter, other.filter)
                     && Objects.equals(routing, other.routing)
                     && Objects.equals(indexRouting, other.indexRouting)
-                    && Objects.equals(searchRouting, other.searchRouting);
+                    && Objects.equals(searchRouting, other.searchRouting)
+                    && Objects.equals(writeIndex, other.writeIndex);
         }
 
         @Override
         public int hashCode() {
-            return Objects.hash(type, indices, aliases, filter, routing, indexRouting, searchRouting);
+            return Objects.hash(type, indices, aliases, filter, routing, indexRouting, searchRouting, writeIndex);
         }
     }
 
diff --git a/test/framework/src/main/java/org/elasticsearch/index/alias/RandomAliasActionsGenerator.java b/test/framework/src/main/java/org/elasticsearch/index/alias/RandomAliasActionsGenerator.java
index d4d2d78789b8e..e8a554ca4aaae 100644
--- a/test/framework/src/main/java/org/elasticsearch/index/alias/RandomAliasActionsGenerator.java
+++ b/test/framework/src/main/java/org/elasticsearch/index/alias/RandomAliasActionsGenerator.java
@@ -82,6 +82,9 @@ public static AliasActions randomAliasAction(boolean useStringAsFilter) {
                     action.indexRouting(randomRouting().toString());
                 }
             }
+            if (randomBoolean()) {
+                action.writeIndex(randomBoolean());
+            }
         }
         return action;
     }