207 A Block, Lake Point Towers, LPT Avenue Road, Bengaluru 560068

Installing Node JS on Ubuntu 16.04 LTS

Add NodeJS PPA sudo apt-get install python-software-properties curl -sL https://deb.nodesource.com/setup_6.x | sudo -E bash – 2. Install nodejs sudo apt-get install nodejs Verify version name@host:~$node -v v6.8.0 name@host:~$npm -v 3.10.8 Optional – To test installation Create a file server.js with the following contents var http = require(‘http’); http.createServer(function (req, res) { res.writeHead(200, {‘Content-Type’: ‘text/plain’}); res.end(‘Test […]

Read More »

Tomcat Deploy Web App takes long time

Observed that deployment of WAR files was taking a long time. On searching for info came to know it could be because of the bug http://bugs.java.com/bugdatabase/view_bug.do?bug_id=4705093 The solution was to add the following line in $CATALINA_HOME/bin/setenv.sh file (create one if it is not there) [ java.awt.headless is not associated with the issue] export JAVA_OPTS=”$JAVA_OPTS -Djava.security.egd=file:/dev/./urandom […]

Read More »

Configure Reverse Proxy – CentOS 7 – httpd

By default mod_proxy is included in http package. Had created a new VM – So installing httpd yum clean all yum -y update yum -y install httpd firewall-cmd –permanent –add-port=80/tcp firewall-cmd –permanent –add-port=8080/tcp systemctl start httpd systemctl enable httpd systemctl status httpd Configure the proxy/reverse proxy. Create new config file <os-prompt># vi /etc/httpd/conf.d/r_proxy.conf <IfModule mod_proxy.c> […]

Read More »

MySQL – Disable Full Group By

Encountered the exception : java.sql.SQLSyntaxErrorException: Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column ‘IAM_DB.this_.ID’ which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by. Fix was to update global settings in MySQL In MySQL SELECT @@sql_mode; +——————————————————————————————————————————————-+ | ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION | +——————————————————————————————————————————————-+ Change […]

Read More »

MySQL 5.6/7 on Debian 7.x

Debian 7.6 was installed on the VM.  Default mysql-server which was getting installed using apt-get was 5.5.  One of the updates in mysql 5.6 was to support more than one current_timestamp column with default value of current time stamp. So to install this is what I did wget http://dev.mysql.com/get/mysql-apt-config_0.3.5-1debian7_all.deb dpkg -i mysql-apt-config_0.3.5-1debian7_all.deb apt-get update apt-get […]

Read More »

Neo4J – Linux – Configurations

After installing the community edition of Neo4J on Debian VM  understood from manuals about the need to increase the number of files limit for Neo4J. cat /proc/sys/fs/file-max The output was 3273723 – So no issues.  In case if it is less you can update it (Set it to lower value if needed, I decided not to […]

Read More »

Multiple Tomcat instances

Had to start two instances of Tomcat on the same VM (Linux) – Did the following without even knowing whether the steps were correct or not – will check later – but it worked. Unzipped the tomcat zip file into two folders In the second folder made the following changes to server.xml in conf/ folder […]

Read More »

Oracle Java 8 – Debian

Wanted to install Oracle Java on a new Wheezy system – On searching the net got the following information which worked for me apt-get install software-properties-common python-software-properties add-apt-repository ppa:webupd8team/java Edit /etc/apt/sources.list.d/webupd8team-java-wheezy.list and replace “wheezy” with “trusty” apt-get install oracle-java8-installer and that’s all!

Read More »

Neo4J – Indexes, Constraints

Cypher allows the creation of indexes over a property for all nodes that have a given label.   Neo4j CQL has provided “CREATE INDEX” command to create indexes on NODE’s or Relationship’s properties. CREATE INDEX ON :Person(name) CREATE INDEX ON :Customer (name) Neo4j CQL has provided “DROP INDEX” command to drop an existing index of a […]

Read More »