| ~~ |
| ~~ 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. |
| ~~ |
| |
| Lens server deployment |
| |
| This document describes the deployment of lens server in a distributed cluster. |
| Make sure you have finished {{{../lenshome/install-and-run.html} Install and Run}} documentation, |
| before proceeding. |
| |
| Lens server requires Hive metastore for providing OLAP cube metastore. Its also requires a DB for storing system |
| tables, which can be shared with Hive metastore server's underlying DB as well. Hive server is required if Hive is |
| one of the execution engines. |
| |
| Typical deployment suggested is depicted in the following diagram (the boxes and lines in blue show server level |
| components, the ones in green show execution components) |
| |
| [/images/deployment.png] Lens Server deployment |
| |
| Its recommended HiveMetastore server, HiveServer2 and Lens Server running on different machines. |
| |
| * Dependencies and their versions |
| |
| * Requires java 1.7+. |
| |
| * Requires Hadoop 2.x+. Tested upto hadoop 2.4. |
| |
| * Requires Hive metastore 0.13+ |
| |
| * Requires Hive server2 0.13+ |
| |
| * Restart and recovery |
| |
| Lens server should not have problems with Hive Metastore server, Hive Server2 or Hadoop restarts. Lens server can |
| persist its state before going and recover from previous state upon restart. |
| |
| * Recoverability |
| |
| ** To enable lens server with recoverability, i.e. to allow users access queries before restart, lens server should be |
| started with lens.server.restart.enabled set to true. Admin can set this to false if no recoverability is required. |
| |
| * Restarting |
| |
| ** To start the lens server a fresh lens.server.recover.onrestart should be disabled. If it is true, the server will |
| load its persisted state before restart. |
| |
| * Server modes |
| |
| Lens server can be started in various modes. The server mode can be specified via configuration when it is starting |
| up. Available modes are |
| |
| * READ_ONLY : Allows all requests on sesssion resource and Only GET requests on all other resources |
| |
| * METASTORE_READONLY : Allows Only GET requests on metastore service and all other requests on other services |
| |
| * METASTORE_NODROP: DELETE requests on metastore are not accepted, all other requests are accepted |
| |
| * OPEN: This is the default mode. All requests are accepted |
| |
| * Serving logs over REST |
| |
| Lens server comes with LogResource which can serve logs under LENS_LOG_DIR over REST. To enable serving logs, |
| administrator can enable log resource by adding log to configuration property "lens.server.ws.resourcenames". |
| Config changes look the following : |
| |
| === |
| |
| <property> |
| <name>lens.server.ws.resourcenames</name> |
| <value>session,metastore,query,index,log</value> |
| <description>These JAX-RS resources would be started in the specified order when lens-server starts up</description> |
| </property> |
| |
| <property> |
| <name>lens.server.log.ws.resource.impl</name> |
| <value>org.apache.lens.server.LogResource</value> |
| <description>Implementation class for Log Resource</description> |
| </property> |
| |
| === |
| |
| If resourcenames does not contain "log", it is not enabled. |
