A Technical I.T./DevOps Blog
Two problem scenarios and solutions.
Problem scenario: You installed Cloudera 5 (Hadoop) on CentOS 7.2 for the first time. You tried to start the Cloudera database service. But you get an error that it failed.
You run this: systemctl status cloudera-scm-server-db.service
The results include this fragment: ” … Failed to start LSB: Cloudera SCM Server’s Embedded DB.”
How do you start the Cloudera DB service?
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Continue reading “How Do You Configure Linux To Be Ready for Cloudera 5 (Hadoop)?”
Question
What is TCP port 8080 typically used for?
Answer
Jenkins, Docker, NodeJS, Apache Ambari, Apache Marathon, Apache Tomcat, Amazon Web Services’ Elastic Load Balancer, JBoss Application Server, GitLab, M2MLogger (remote monitoring), InfoSphere BigInsights Console (IBM’s proprietary Hadoop and Spark solution), JasperReports (because of Apache Tomcat), remote management of physical routers, and enterprise network proxy services all commonly use port 8080.
In part, taken from Learning AWS,
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Continue reading “What is TCP port 8080 typically used for?”
Updated on 1/1/18
You may want to see this different posting that works for Linux SUSE as well as other non-SUSE distributions of Linux.
Problem scenario
You want to install the open source version of Hadoop 3.0.0 on Linux SUSE 12 SP3. What do you do?
Solution
These directions would work on a non-SUSE distribution if you install Java a different way from the first command in the script.
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Updated 1/5/18
THESE DIRECTIONS ARE OUTDATED. They are here as a reference for legacy purposes only. For directions on how to install Hadoop on a RedHat or CentOS server, see this article.
Problem scenario
You want to install an open source version on a RedHat derivative distribution of Linux in a public cloud. How do you do this?
Solution
These directions will allow you install Hadoop on a RedHat derivative (e.g.,
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Problem scenario: On Ubuntu, after installing Hadoop, when you enter the command ‘/usr/local/hadoop/bin/hadoop namenode -format’ and you get this error:
“Error: JAVA_HOME is not set and could not be found.”
Solution: Verify Java is installed (‘java -version’). If it is not installed, you can use ‘apt-get install -y default-jre’.
Next, go to hadoop-env.sh. Find the export JAVA_HOME stanza. Change the ‘${JAVA_HOME}’ value to ‘/usr’ with no quotes.
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Continue reading “How To Get Hadoop Installed on Ubuntu When There Is a Java Error”
Some open source projects don’t always listen to contributors’ feedback. We reported a couple errors that we found in OpenStack documentation to openstack.org. Here are the errors we saw (as of 2/2/17):
#1 If you go to this link, you’ll find two “Storm EDP” links:
http://specs.openstack.org/openstack/sahara-specs/
One points to this link: http://specs.openstack.org/openstack/sahara-specs/specs/liberty/storm-scaling.html
We see no reason why the title/header of this above page is “Storm EDP” and not “Storm Scaling.” My attempt at a contribution was to not have two “Storm EDP” links in the first link of this post.
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