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This article mainly explains "how to build CentOS7.0 JDK configuration in Hadoop2.X/YARN environment". The content in this article is simple and clear, and it is easy to learn and understand. Please follow the editor's ideas to study and learn "how to build CentOS7.0 JDK configuration in Hadoop2.X/YARN environment".

Hadoop is written by Java, so he cannot use OpenJDK preinstalled by Linux, so you need to install JDK (above) before installing hadoop.

Raw material: 32-bit JDK downloaded from Oracle's official website:

Description:

1, the CentOS 7.0system now has only 64-bit, but Hadoop generally supports 32-bit, there will be Warning in 64-bit environment, to avoid real problems, choose i586 JDK (that is, 32-bit), of course, 64-bit CentOS 7 is definitely compatible with 32-bit JDK, remember: 64-bit systems are definitely compatible with 32-bit software, 32-bit systems are not compatible with 64-bit software. 64-bit only shows that the number of bits in a CPU operation is 64-bit, which is more than 32-bit, and the performance of 64-bit is higher.

2. The previous Linux version JDK has ".bin" files available for download, but now the official website only provides rpm installation package and tar.gz package. Rpm installation package is a unique installation file of RedHat series system (RedHat/RHEL/Fedora/CentOS), which can be run directly, but we do not know the configuration method. So, in order to get close to the bottom, I chose tar.gz 's zip package to install.

Installation method:

You can't have both the built-in OpenJDK and the later installed JDK, so there are two operations: 1. Uninstall and delete the original OpenJDK, and then install JDK 2. The two still coexist, but which configuration is the really effective JDK?

Method 1: uninstall and delete the original OpenJDK, and then install JDK

Step 1: uninstall and delete OpenJDK

To uninstall and delete OpenJDK, you first need to know what to delete:

[Randy@localhost ~] $rpm-qa | grep openjdk-I # looks up the installed OpenJDK,-i and ignores the case of "openjdk"

Now delete them all:

[Randy@localhost ~] $sudo yum remove java-1.6.0-openjdk-devel-1.6.0.0-6.1.13.4.el7_0.x86_64 java-1.7.0-openjdk-devel-1.7.0.65-2.5.1.2.el7_0.x86_64 java-1.7.0-openjdk-headless-1.7.0.65-2.5.1.2.el7_0.x86_64 java-1.7 .0-openjdk-1.7.0.65-2.5.1.2.el7_0.x86_64 java-1.6.0-openjdk-1.6.0.0-6.1.13.4.el7_0.x86_64# deletes the openjdk using the yum that comes with the RedHat series system Yum, similar to apt-get in ubuntu, is used to install, uninstall and update the software that comes with the system. Note: the above are all separated by spaces.

Step 2: install JDK

1. Decompression

First decompress the downloaded JDK: (JDK's tar.gz package is placed in the ~ / dev directory)

[Randy@localhost ~] $sudo mkdir / usr/lib/jdk # if there is no / usr/lib/jdk path Then execute this sentence to create the jdk folder [Randy@localhost ~] $sudo tar-zxvf jdk-8u11-linux-i586.tar.gz-C / usr/lib/jdk # Note:-C -- directory=DIR changes to directory DIR [Randy@localhost ~] $ls / usr/lib/jdkjdk1.8.0_11 [Randy@localhost ~] $ls / usr/lib/jdk/jdk1.8.0_11/bin javafx-src.zip man THIRDPARTYLICENSEREADME-JAVAFX.txtCOPYRIGHT jre README.html THIRDPARTYLICENSEREADME.txtdb lib releaseinclude LICENSE src.zip [Randy@localhost ~] $

Move the files in jdk1.8.0_11 to / usr/lib/jdk and delete the jdk1.8.0_11 folder:

[Randy@localhost ~] $sudo cp-rf / usr/lib/jdk/jdk1.8.0_11/* / usr/lib/jdk/ # Mobile [Randy@localhost ~] $[Randy@localhost ~] $ls / usr/lib/jdkbin javafx-src.zip LICENSE src.zipCOPYRIGHT jdk1.8.0_11 man THIRDPARTYLICENSEREADME-JAVAFX.txtdb jre README.html THIRDPARTYLICENSEREADME.txtinclude lib release [ Randy@localhost ~] $sudo rm-rf / usr/lib/jdk/jdk1.8.0_11/ # Delete [Randy@localhost ~] $ls / usr/lib/jdkbin javafx-src.zip man THIRDPARTYLICENSEREADME-JAVAFX.txtCOPYRIGHT jre README.html THIRDPARTYLICENSEREADME.txtdb lib releaseinclude LICENSE src.zip [Randy@localhost ~] $

2. Configure environment variables

[Randy@localhost ~] $sudo vim / etc/profile insert on the last line: # JAVA Environmentexport JAVA_HOME=/usr/lib/jdkexport JRE_HOME=/usr/lib/jdk/jreexport PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATHexport CLASSPATH=$CLASSPATH:.:$JAVA_HOME/lib:$JRE_HOME/lib

3. Modify the default JDK of the system

[Randy@localhost ~] $sudo update-alternatives-- install / usr/bin/java java / usr/lib/jdk/bin/java 300 # makes the default java command in / usr/lib/jdk/bin java command [Randy@localhost ~] $sudo update-alternatives-- install / usr/bin/javac javac / usr/lib/jdk/bin/javac 300 # makes the system default javac command is the javac command in / usr/lib/jdk/bin [Randy@localhost ~ ] $sudo update-alternatives-- install / usr/bin/jar jar / usr/lib/jdk/bin/jar 300 # makes the default jar command in / usr/lib/jdk/bin jar command [Randy@localhost ~] $sudo update-alternatives-- config java # configuration default java command has 1 program that provides "java". Option command-- * + 1 / usr/lib/jdk/bin/java press Enter to keep the current option [+], or type the option number: 1 [Randy@localhost ~] $sudo update-alternatives-- config javac # configuration default java command has one program that provides "java". Option command-- * + 1 / usr/lib/jdk/bin/javac press Enter to keep the current option [+], or type the option number: 1

Step 3: test JDK

[Randy@localhost ~] $java-versionjava version "1.8.0 11" Java (TM) SE Runtime Environment (build 1.8.0_11-b12) Java HotSpot (TM) Server VM (build 25.11-b03, mixed mode) [Randy@localhost ~] $javac-versionjavac 1.8.0 11

The test encountered a problem:

[Randy@localhost ~] $java-bash: / usr/bin/java: / lib/ld-linux.so.2: bad ELF interpreter: no file or directory [Randy@localhost ~] $ls / lib/ld-linuxls: unable to access / lib/ld-linux: no file or directory [Randy@localhost ~] $java- version-bash: / usr/bin/java: / lib/ld-linux.so.2: bad ELF interpreter: There is no file or directory [Randy@localhost ~] $

The solution is:

[Randy@localhost ~] $sudo yum install glibc.i686 # execute 32-bit programs on 64 systems. If / lib/ld-linux.so.2: bad ELF interpreter: No such file or directory appears, install glic.

Method 2: the coexistence of the two, which configuration is the really effective JDK

Similar to Method1, except that there is no need to uninstall and delete OpenJDK

1. Decompression

First decompress the downloaded JDK: (JDK's tar.gz package is placed in the ~ / dev directory)

[Randy@localhost ~] $sudo mkdir / usr/lib/jdk # if there is no / usr/lib/jdk path Then execute this sentence to create the jdk folder [Randy@localhost ~] $sudo tar-zxvf jdk-8u11-linux-i586.tar.gz-C / usr/lib/jdk # Note:-C -- directory=DIR changes to directory DIR [Randy@localhost ~] $ls / usr/lib/jdkjdk1.8.0_11 [Randy@localhost ~] $ls / usr/lib/jdk/jdk1.8.0_11/bin javafx-src.zip man THIRDPARTYLICENSEREADME-JAVAFX.txtCOPYRIGHT jre README.html THIRDPARTYLICENSEREADME.txtdb lib releaseinclude LICENSE src.zip [Randy@localhost ~] $

Move the files in jdk1.8.0_11 to / usr/lib/jdk and delete the jdk1.8.0_11 folder:

[Randy@localhost ~] $sudo cp-rf / usr/lib/jdk/jdk1.8.0_11/* / usr/lib/jdk/ # Mobile [Randy@localhost ~] $[Randy@localhost ~] $ls / usr/lib/jdkbin javafx-src.zip LICENSE src.zipCOPYRIGHT jdk1.8.0_11 man THIRDPARTYLICENSEREADME-JAVAFX.txtdb jre README.html THIRDPARTYLICENSEREADME.txtinclude lib release [ Randy@localhost ~] $sudo rm-rf / usr/lib/jdk/jdk1.8.0_11/ # Delete [Randy@localhost ~] $ls / usr/lib/jdkbin javafx-src.zip man THIRDPARTYLICENSEREADME-JAVAFX.txtCOPYRIGHT jre README.html THIRDPARTYLICENSEREADME.txtdb lib releaseinclude LICENSE src.zip [Randy@localhost ~] $

2. Configure environment variables

[Randy@localhost ~] $sudo vim / etc/profile insert on the last line: # JAVA Environmentexport JAVA_HOME=/usr/lib/jdkexport JRE_HOME=/usr/lib/jdk/jreexport PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATHexport CLASSPATH=$CLASSPATH:.:$JAVA_HOME/lib:$JRE_HOME/lib

3. Modify the default JDK of the system

[Randy@localhost ~] $sudo update-alternatives-- install / usr/bin/java java / usr/lib/jdk/bin/java 300 # makes the default java command in / usr/lib/jdk/bin java command [Randy@localhost ~] $sudo update-alternatives-- install / usr/bin/javac javac / usr/lib/jdk/bin/javac 300 # makes the system default javac command is the javac command in / usr/lib/jdk/bin [Randy@localhost ~ ] $sudo update-alternatives-- install / usr/bin/jar jar / usr/lib/jdk/bin/jar 300 # makes the default jar command in / usr/lib/jdk/bin jar command [Randy@localhost ~] $sudo update-alternatives-- config java # configures the default java command with a total of three programs that provide "java". Option command-* 1 / usr/lib/jvm/java-1.7.0-openjdk-1.7.0.65-2.5.1.2.el7_0.x86_64/jre/bin/java / usr/lib/jvm/jre -1.6.0-openjdk.x86_64/bin/java + 3 / usr/lib/jdk/bin/java keep the current option by Enter [+] Or type the option number: 3 [Randy@localhost ~] $sudo update-alternatives-- config javac # configure the default java command with three programs that provide "javac". Option command-* 1 / usr/lib/jvm/java-1.7.0-openjdk-1.7.0.65-2.5.1.2.el7_0.x86_64/jre/bin/javac / usr/lib/jvm/jre -1.6.0-openjdk.x86_64/bin/javac + 3 / usr/lib/jdk/bin/javac keep the current option by Enter [+] Or type the option number: 3 [Randy@localhost ~] $

Step 3: test JDK

[Randy@localhost ~] $java-versionjava version "1.8.0 11" Java (TM) SE Runtime Environment (build 1.8.0_11-b12) Java HotSpot (TM) Server VM (build 25.11-b03, mixed mode) [Randy@localhost ~] $javac-versionjavac 1.8.0 11

The test encountered a problem:

[Randy@localhost ~] $java-bash: / usr/bin/java: / lib/ld-linux.so.2: bad ELF interpreter: no file or directory [Randy@localhost ~] $ls / lib/ld-linuxls: unable to access / lib/ld-linux: no file or directory [Randy@localhost ~] $java- version-bash: / usr/bin/java: / lib/ld-linux.so.2: bad ELF interpreter: There is no file or directory [Randy@localhost ~] $

The solution is:

[Randy@localhost ~] $sudo yum install glibc.i686 # execute 32-bit programs on 64 systems. If / lib/ld-linux.so.2: bad ELF interpreter: No such file or directory appears, install glic.

Attached:

After talking about the environment configuration of JDK, let's talk about the settings of MariaDB, the database that comes with CentOS 7.

Today, RHEL 7/CentOS 7's native databases are no longer MySQL, mainly because of the greater open source capabilities, and now google is also moving its data from MySQL to MariaDB. In order to experience the most advanced ideas, my Hive database platform will be MariaDB

After the system is installed, the mariadb service of the system is in stop state, so you should start the service first:

[Randy@localhost ~] $sudo systemctl start mariadb # before CentOS version executes sudo service mariadb start, and CentOS7 executes service command can also take effect, but prompt: Redirecting to / bin/systemctl start mariadb.service [Randy@localhost ~] $sudo systemctl stop mariadb # stop mariadb service [Randy@localhost ~] $sudo systemctl status mariadb # View mariadb status [Randy@localhost ~] $

Set the root password of mariadb to "root":

Command format:

Sudo mysqladmin-u username password "new password"

If root has already set a password, use the following methods:

Sudo mysqladmin-u username password old password "new password"

Because there is no password after installing the system, set the root user password to "root":

[Randy@localhost ~] $sudo mysqladmin-u root password "root"

Test:

[Randy@localhost] $mysql-u root-proot

Display:

Welcome to the MariaDB monitor. Commands end with; or\ g.Your MariaDB connection id is 3Server version: 5.5.37-MariaDB-log MariaDB ServerCopyright (c) 2000, 2014, Oracle, Monty Program Ab and others.Type 'help;' or'\ h' for help. Type'\ c'to clear the current input statement.MariaDB [(none)] > Thank you for reading. The above is the content of "how to build CentOS7.0 JDK configuration in Hadoop2.X/YARN environment". After the study of this article, I believe you have a deeper understanding of how to build CentOS7.0 JDK configuration in Hadoop2.X/YARN environment, and the specific usage needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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