Posts By: jonny

Browsing Hadoop HDFS on the Command Line

Using the Hadoop command we can send fairly regular filesystem commands to navigate HDFS. On Cloudera I am sending commands to port 8020 of the active name node. If you don’t have the hadoop command available on your system you need to download hadoop, extract it and add the bin directory to your path. For… Read more »

Labeling Partitions with LABEL and PARTLABEL

So working on a system that had incorrect partitioning configured.  In /etc/fstab the partitions were configured with:

but the partitions did not have PARTLABELS set. The LABEL and PARTLABEL can be viewed with:

To set the label property use:

To set the partlabel on a GPT partition first install gdisk:

Then… Read more »

Cloudera Hue User Password Reset

I needed to access the Hue file browser service  and for my version of cloudera this was: cd /opt/cloudera/parcels/CDH-5.7.6-1.cdh5.7.6.p0.6/lib/hue Run the createuser command: ./build/env/bin/hue createsuperuser Username (leave blank to use ‘joebloggs’): Email address: joebloggs@whatever.tld Password: Password (again): Superuser created successfully.

Mkr Fox 1200 Beginner Tutorial

Download the latest version of the Arduino IDE as the version in the Ubuntu/Mint/Debian repositories is a little old: https://www.arduino.cc/en/Main/Software At the time of writing I am using version 1.8.5 Configure Arduino IDE First we need to import everything we need to operate the MKR Fox 1200 so first visit Tools > Board > Board… Read more »

Zookeeper install on CentOS 7

Good concise article here on devopscube for installing zookeeper cluster. I’ve added some of my own bits: Firewall Disable firewalld or allow ports 2181 3888 2888 Install Java

User Create a zookeeper user

Install Zookeeper Download ZooKeeper from the Apache:

Set the permissions:

Add the following:

Test the service:… Read more »

Yakuake not restoring window height & width

git branch

I found that Yakuake was re-opening with an 80% width and about 30% height but I prefer 100% wide and 80% high. So it looks like my settings were saving into the file:

But this was possibly not the file that was being read when Yakuake started. I added the

entries to the… Read more »

Tab Separated File Returns Wrong Number of Fields

Shell

So we had a CSV/TSV file with tabs separating each field but one of the fields was a description field that contained spaces. When parsing this TSV file some programs interpreted the spaces as field delimiters (TSV might be a bad idea!). Input file similar to:

The ‘Time Warner Cable’ field is all one… Read more »

Install Python Linters in Atom

I installed the relevant Python packages first e.g.

Then on the Atom menu use: Edit > Preferences then search for atom packages such as flake8, pep8, pep257 and pylint: Then click the install button. After restarting style advice is shown in the editor:    

Manic Miner on Linux

I was reminded about how much time I had spent as a kid playing Manic Miner on an Amstrad 464 and decided to give it a try on my current desktop (Linux Mint) so for future reference… I grabbed the code created by here:

Installed a few dependencies:

Run the make file:

Read more »

MySQL Percona Slave Replication Change Channel Name

I had inadvertently set up slave replication using the wrong channel name – which is a minor issue except that it caused some issues with an already configured Nagios check. To ‘change’ the channel name I stopped the slave process, removed all the slave definitions and used ‘CHANGE MASTER’ to re-create the slave from the… Read more »