| <!DOCTYPE HTML> |
| <html lang="en"> |
| <head> |
| <!-- Generated by javadoc (17) --> |
| <title>Source code</title> |
| <meta name="viewport" content="width=device-width, initial-scale=1"> |
| <meta name="description" content="source: package: org.apache.hadoop.hbase, class: ZNodeClearer"> |
| <meta name="generator" content="javadoc/SourceToHTMLConverter"> |
| <link rel="stylesheet" type="text/css" href="../../../../../stylesheet.css" title="Style"> |
| </head> |
| <body class="source-page"> |
| <main role="main"> |
| <div class="source-container"> |
| <pre><span class="source-line-no">001</span><span id="line-1">/*</span> |
| <span class="source-line-no">002</span><span id="line-2"> * Licensed to the Apache Software Foundation (ASF) under one</span> |
| <span class="source-line-no">003</span><span id="line-3"> * or more contributor license agreements. See the NOTICE file</span> |
| <span class="source-line-no">004</span><span id="line-4"> * distributed with this work for additional information</span> |
| <span class="source-line-no">005</span><span id="line-5"> * regarding copyright ownership. The ASF licenses this file</span> |
| <span class="source-line-no">006</span><span id="line-6"> * to you under the Apache License, Version 2.0 (the</span> |
| <span class="source-line-no">007</span><span id="line-7"> * "License"); you may not use this file except in compliance</span> |
| <span class="source-line-no">008</span><span id="line-8"> * with the License. You may obtain a copy of the License at</span> |
| <span class="source-line-no">009</span><span id="line-9"> *</span> |
| <span class="source-line-no">010</span><span id="line-10"> * http://www.apache.org/licenses/LICENSE-2.0</span> |
| <span class="source-line-no">011</span><span id="line-11"> *</span> |
| <span class="source-line-no">012</span><span id="line-12"> * Unless required by applicable law or agreed to in writing, software</span> |
| <span class="source-line-no">013</span><span id="line-13"> * distributed under the License is distributed on an "AS IS" BASIS,</span> |
| <span class="source-line-no">014</span><span id="line-14"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span> |
| <span class="source-line-no">015</span><span id="line-15"> * See the License for the specific language governing permissions and</span> |
| <span class="source-line-no">016</span><span id="line-16"> * limitations under the License.</span> |
| <span class="source-line-no">017</span><span id="line-17"> */</span> |
| <span class="source-line-no">018</span><span id="line-18">package org.apache.hadoop.hbase;</span> |
| <span class="source-line-no">019</span><span id="line-19"></span> |
| <span class="source-line-no">020</span><span id="line-20">import java.io.BufferedReader;</span> |
| <span class="source-line-no">021</span><span id="line-21">import java.io.BufferedWriter;</span> |
| <span class="source-line-no">022</span><span id="line-22">import java.io.File;</span> |
| <span class="source-line-no">023</span><span id="line-23">import java.io.FileNotFoundException;</span> |
| <span class="source-line-no">024</span><span id="line-24">import java.io.FileReader;</span> |
| <span class="source-line-no">025</span><span id="line-25">import java.io.FileWriter;</span> |
| <span class="source-line-no">026</span><span id="line-26">import java.io.IOException;</span> |
| <span class="source-line-no">027</span><span id="line-27">import org.apache.hadoop.conf.Configuration;</span> |
| <span class="source-line-no">028</span><span id="line-28">import org.apache.hadoop.hbase.zookeeper.MasterAddressTracker;</span> |
| <span class="source-line-no">029</span><span id="line-29">import org.apache.hadoop.hbase.zookeeper.ZKWatcher;</span> |
| <span class="source-line-no">030</span><span id="line-30">import org.apache.yetus.audience.InterfaceAudience;</span> |
| <span class="source-line-no">031</span><span id="line-31">import org.slf4j.Logger;</span> |
| <span class="source-line-no">032</span><span id="line-32">import org.slf4j.LoggerFactory;</span> |
| <span class="source-line-no">033</span><span id="line-33"></span> |
| <span class="source-line-no">034</span><span id="line-34">/**</span> |
| <span class="source-line-no">035</span><span id="line-35"> * <p></span> |
| <span class="source-line-no">036</span><span id="line-36"> * Contains a set of methods for the collaboration between the start/stop scripts and the servers.</span> |
| <span class="source-line-no">037</span><span id="line-37"> * It allows to delete immediately the znode when the master or the regions server crashes. The</span> |
| <span class="source-line-no">038</span><span id="line-38"> * region server / master writes a specific file when it starts / becomes main master. When they end</span> |
| <span class="source-line-no">039</span><span id="line-39"> * properly, they delete the file.</span> |
| <span class="source-line-no">040</span><span id="line-40"> * </p></span> |
| <span class="source-line-no">041</span><span id="line-41"> * <p></span> |
| <span class="source-line-no">042</span><span id="line-42"> * In the script, we check for the existence of these files when the program ends. If they still</span> |
| <span class="source-line-no">043</span><span id="line-43"> * exist we conclude that the server crashed, likely without deleting their znode. To have a faster</span> |
| <span class="source-line-no">044</span><span id="line-44"> * recovery we delete immediately the znode.</span> |
| <span class="source-line-no">045</span><span id="line-45"> * </p></span> |
| <span class="source-line-no">046</span><span id="line-46"> * <p></span> |
| <span class="source-line-no">047</span><span id="line-47"> * The strategy depends on the server type. For a region server we store the znode path in the file,</span> |
| <span class="source-line-no">048</span><span id="line-48"> * and use it to delete it. for a master, as the znode path constant whatever the server, we check</span> |
| <span class="source-line-no">049</span><span id="line-49"> * its content to make sure that the backup server is not now in charge.</span> |
| <span class="source-line-no">050</span><span id="line-50"> * </p></span> |
| <span class="source-line-no">051</span><span id="line-51"> */</span> |
| <span class="source-line-no">052</span><span id="line-52">@InterfaceAudience.Private</span> |
| <span class="source-line-no">053</span><span id="line-53">public final class ZNodeClearer {</span> |
| <span class="source-line-no">054</span><span id="line-54"> private static final Logger LOG = LoggerFactory.getLogger(ZNodeClearer.class);</span> |
| <span class="source-line-no">055</span><span id="line-55"></span> |
| <span class="source-line-no">056</span><span id="line-56"> private ZNodeClearer() {</span> |
| <span class="source-line-no">057</span><span id="line-57"> }</span> |
| <span class="source-line-no">058</span><span id="line-58"></span> |
| <span class="source-line-no">059</span><span id="line-59"> /**</span> |
| <span class="source-line-no">060</span><span id="line-60"> * Logs the errors without failing on exception.</span> |
| <span class="source-line-no">061</span><span id="line-61"> */</span> |
| <span class="source-line-no">062</span><span id="line-62"> public static void writeMyEphemeralNodeOnDisk(String fileContent) {</span> |
| <span class="source-line-no">063</span><span id="line-63"> String fileName = ZNodeClearer.getMyEphemeralNodeFileName();</span> |
| <span class="source-line-no">064</span><span id="line-64"> if (fileName == null) {</span> |
| <span class="source-line-no">065</span><span id="line-65"> LOG.warn("Environment variable HBASE_ZNODE_FILE not set; znodes will not be cleared "</span> |
| <span class="source-line-no">066</span><span id="line-66"> + "on crash by start scripts (Longer MTTR!)");</span> |
| <span class="source-line-no">067</span><span id="line-67"> return;</span> |
| <span class="source-line-no">068</span><span id="line-68"> }</span> |
| <span class="source-line-no">069</span><span id="line-69"></span> |
| <span class="source-line-no">070</span><span id="line-70"> FileWriter fstream;</span> |
| <span class="source-line-no">071</span><span id="line-71"> try {</span> |
| <span class="source-line-no">072</span><span id="line-72"> fstream = new FileWriter(fileName);</span> |
| <span class="source-line-no">073</span><span id="line-73"> } catch (IOException e) {</span> |
| <span class="source-line-no">074</span><span id="line-74"> LOG.warn("Can't write znode file " + fileName, e);</span> |
| <span class="source-line-no">075</span><span id="line-75"> return;</span> |
| <span class="source-line-no">076</span><span id="line-76"> }</span> |
| <span class="source-line-no">077</span><span id="line-77"></span> |
| <span class="source-line-no">078</span><span id="line-78"> BufferedWriter out = new BufferedWriter(fstream);</span> |
| <span class="source-line-no">079</span><span id="line-79"></span> |
| <span class="source-line-no">080</span><span id="line-80"> try {</span> |
| <span class="source-line-no">081</span><span id="line-81"> try {</span> |
| <span class="source-line-no">082</span><span id="line-82"> out.write(fileContent + "\n");</span> |
| <span class="source-line-no">083</span><span id="line-83"> } finally {</span> |
| <span class="source-line-no">084</span><span id="line-84"> try {</span> |
| <span class="source-line-no">085</span><span id="line-85"> out.close();</span> |
| <span class="source-line-no">086</span><span id="line-86"> } finally {</span> |
| <span class="source-line-no">087</span><span id="line-87"> fstream.close();</span> |
| <span class="source-line-no">088</span><span id="line-88"> }</span> |
| <span class="source-line-no">089</span><span id="line-89"> }</span> |
| <span class="source-line-no">090</span><span id="line-90"> } catch (IOException e) {</span> |
| <span class="source-line-no">091</span><span id="line-91"> LOG.warn("Can't write znode file " + fileName, e);</span> |
| <span class="source-line-no">092</span><span id="line-92"> }</span> |
| <span class="source-line-no">093</span><span id="line-93"> }</span> |
| <span class="source-line-no">094</span><span id="line-94"></span> |
| <span class="source-line-no">095</span><span id="line-95"> /**</span> |
| <span class="source-line-no">096</span><span id="line-96"> * read the content of znode file, expects a single line.</span> |
| <span class="source-line-no">097</span><span id="line-97"> */</span> |
| <span class="source-line-no">098</span><span id="line-98"> public static String readMyEphemeralNodeOnDisk() throws IOException {</span> |
| <span class="source-line-no">099</span><span id="line-99"> String fileName = getMyEphemeralNodeFileName();</span> |
| <span class="source-line-no">100</span><span id="line-100"> if (fileName == null) {</span> |
| <span class="source-line-no">101</span><span id="line-101"> throw new FileNotFoundException("No filename; set environment variable HBASE_ZNODE_FILE");</span> |
| <span class="source-line-no">102</span><span id="line-102"> }</span> |
| <span class="source-line-no">103</span><span id="line-103"> FileReader znodeFile = new FileReader(fileName);</span> |
| <span class="source-line-no">104</span><span id="line-104"> BufferedReader br = null;</span> |
| <span class="source-line-no">105</span><span id="line-105"> try {</span> |
| <span class="source-line-no">106</span><span id="line-106"> br = new BufferedReader(znodeFile);</span> |
| <span class="source-line-no">107</span><span id="line-107"> String file_content = br.readLine();</span> |
| <span class="source-line-no">108</span><span id="line-108"> return file_content;</span> |
| <span class="source-line-no">109</span><span id="line-109"> } finally {</span> |
| <span class="source-line-no">110</span><span id="line-110"> if (br != null) br.close();</span> |
| <span class="source-line-no">111</span><span id="line-111"> }</span> |
| <span class="source-line-no">112</span><span id="line-112"> }</span> |
| <span class="source-line-no">113</span><span id="line-113"></span> |
| <span class="source-line-no">114</span><span id="line-114"> /**</span> |
| <span class="source-line-no">115</span><span id="line-115"> * Get the name of the file used to store the znode contents</span> |
| <span class="source-line-no">116</span><span id="line-116"> */</span> |
| <span class="source-line-no">117</span><span id="line-117"> public static String getMyEphemeralNodeFileName() {</span> |
| <span class="source-line-no">118</span><span id="line-118"> return System.getenv().get("HBASE_ZNODE_FILE");</span> |
| <span class="source-line-no">119</span><span id="line-119"> }</span> |
| <span class="source-line-no">120</span><span id="line-120"></span> |
| <span class="source-line-no">121</span><span id="line-121"> /**</span> |
| <span class="source-line-no">122</span><span id="line-122"> * delete the znode file</span> |
| <span class="source-line-no">123</span><span id="line-123"> */</span> |
| <span class="source-line-no">124</span><span id="line-124"> public static void deleteMyEphemeralNodeOnDisk() {</span> |
| <span class="source-line-no">125</span><span id="line-125"> String fileName = getMyEphemeralNodeFileName();</span> |
| <span class="source-line-no">126</span><span id="line-126"></span> |
| <span class="source-line-no">127</span><span id="line-127"> if (fileName != null) {</span> |
| <span class="source-line-no">128</span><span id="line-128"> new File(fileName).delete();</span> |
| <span class="source-line-no">129</span><span id="line-129"> }</span> |
| <span class="source-line-no">130</span><span id="line-130"> }</span> |
| <span class="source-line-no">131</span><span id="line-131"></span> |
| <span class="source-line-no">132</span><span id="line-132"> /**</span> |
| <span class="source-line-no">133</span><span id="line-133"> * See HBASE-14861. We are extracting master ServerName from rsZnodePath example:</span> |
| <span class="source-line-no">134</span><span id="line-134"> * "/hbase/rs/server.example.com,16020,1448266496481"</span> |
| <span class="source-line-no">135</span><span id="line-135"> * @param rsZnodePath from HBASE_ZNODE_FILE</span> |
| <span class="source-line-no">136</span><span id="line-136"> * @return String representation of ServerName or null if fails</span> |
| <span class="source-line-no">137</span><span id="line-137"> */</span> |
| <span class="source-line-no">138</span><span id="line-138"></span> |
| <span class="source-line-no">139</span><span id="line-139"> public static String parseMasterServerName(String rsZnodePath) {</span> |
| <span class="source-line-no">140</span><span id="line-140"> String masterServerName = null;</span> |
| <span class="source-line-no">141</span><span id="line-141"> try {</span> |
| <span class="source-line-no">142</span><span id="line-142"> String[] rsZnodeParts = rsZnodePath.split("/");</span> |
| <span class="source-line-no">143</span><span id="line-143"> masterServerName = rsZnodeParts[rsZnodeParts.length - 1];</span> |
| <span class="source-line-no">144</span><span id="line-144"> } catch (IndexOutOfBoundsException e) {</span> |
| <span class="source-line-no">145</span><span id="line-145"> LOG.warn("String " + rsZnodePath + " has wrong format", e);</span> |
| <span class="source-line-no">146</span><span id="line-146"> }</span> |
| <span class="source-line-no">147</span><span id="line-147"> return masterServerName;</span> |
| <span class="source-line-no">148</span><span id="line-148"> }</span> |
| <span class="source-line-no">149</span><span id="line-149"></span> |
| <span class="source-line-no">150</span><span id="line-150"> /**</span> |
| <span class="source-line-no">151</span><span id="line-151"> * Delete the master znode if its content (ServerName string) is the same as the one in the znode</span> |
| <span class="source-line-no">152</span><span id="line-152"> * file. (env: HBASE_ZNODE_FILE). I case of master-rs colloaction we extract ServerName string</span> |
| <span class="source-line-no">153</span><span id="line-153"> * from rsZnode path.(HBASE-14861)</span> |
| <span class="source-line-no">154</span><span id="line-154"> * @return true on successful deletion, false otherwise.</span> |
| <span class="source-line-no">155</span><span id="line-155"> */</span> |
| <span class="source-line-no">156</span><span id="line-156"> public static boolean clear(Configuration conf) {</span> |
| <span class="source-line-no">157</span><span id="line-157"> Configuration tempConf = new Configuration(conf);</span> |
| <span class="source-line-no">158</span><span id="line-158"> tempConf.setInt("zookeeper.recovery.retry", 0);</span> |
| <span class="source-line-no">159</span><span id="line-159"></span> |
| <span class="source-line-no">160</span><span id="line-160"> ZKWatcher zkw;</span> |
| <span class="source-line-no">161</span><span id="line-161"> try {</span> |
| <span class="source-line-no">162</span><span id="line-162"> zkw = new ZKWatcher(tempConf, "clean znode for master", new Abortable() {</span> |
| <span class="source-line-no">163</span><span id="line-163"> @Override</span> |
| <span class="source-line-no">164</span><span id="line-164"> public void abort(String why, Throwable e) {</span> |
| <span class="source-line-no">165</span><span id="line-165"> }</span> |
| <span class="source-line-no">166</span><span id="line-166"></span> |
| <span class="source-line-no">167</span><span id="line-167"> @Override</span> |
| <span class="source-line-no">168</span><span id="line-168"> public boolean isAborted() {</span> |
| <span class="source-line-no">169</span><span id="line-169"> return false;</span> |
| <span class="source-line-no">170</span><span id="line-170"> }</span> |
| <span class="source-line-no">171</span><span id="line-171"> });</span> |
| <span class="source-line-no">172</span><span id="line-172"> } catch (IOException e) {</span> |
| <span class="source-line-no">173</span><span id="line-173"> LOG.warn("Can't connect to zookeeper to read the master znode", e);</span> |
| <span class="source-line-no">174</span><span id="line-174"> return false;</span> |
| <span class="source-line-no">175</span><span id="line-175"> }</span> |
| <span class="source-line-no">176</span><span id="line-176"></span> |
| <span class="source-line-no">177</span><span id="line-177"> String znodeFileContent;</span> |
| <span class="source-line-no">178</span><span id="line-178"> try {</span> |
| <span class="source-line-no">179</span><span id="line-179"> znodeFileContent = ZNodeClearer.readMyEphemeralNodeOnDisk();</span> |
| <span class="source-line-no">180</span><span id="line-180"> return MasterAddressTracker.deleteIfEquals(zkw, znodeFileContent);</span> |
| <span class="source-line-no">181</span><span id="line-181"> } catch (FileNotFoundException fnfe) {</span> |
| <span class="source-line-no">182</span><span id="line-182"> // If no file, just keep going -- return success.</span> |
| <span class="source-line-no">183</span><span id="line-183"> LOG.warn("Can't find the znode file; presume non-fatal", fnfe);</span> |
| <span class="source-line-no">184</span><span id="line-184"> return true;</span> |
| <span class="source-line-no">185</span><span id="line-185"> } catch (IOException e) {</span> |
| <span class="source-line-no">186</span><span id="line-186"> LOG.warn("Can't read the content of the znode file", e);</span> |
| <span class="source-line-no">187</span><span id="line-187"> return false;</span> |
| <span class="source-line-no">188</span><span id="line-188"> } finally {</span> |
| <span class="source-line-no">189</span><span id="line-189"> zkw.close();</span> |
| <span class="source-line-no">190</span><span id="line-190"> }</span> |
| <span class="source-line-no">191</span><span id="line-191"> }</span> |
| <span class="source-line-no">192</span><span id="line-192">}</span> |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| </pre> |
| </div> |
| </main> |
| </body> |
| </html> |
