In a Cloudera cluster we had a few nodes reporting the following error message in the logs under hadoop-cmf-hdfs-DATANODE-whatever.com.log.out The error included: Datanode denied communication with namenode because the host is not in the... » More
On the Windows Domain Controller I checked the current NTP settings with: I tried a few alternative commands and got errors such as "the rpc server is unavailable". The command that worked was: After issuing that command I could see... » More
I wanted to add some checks to a Windows server and the methods seem to have changed a little over the years. At the moment I have amended the nsclient.ini file on the Windows box with: Then from the Nagios box I can check CPU with a threshold as... » More
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,... » More
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... » More
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... » More
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... » More
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... » More
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... » More
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... » More
In a Cloudera cluster we had a few nodes reporting the following error message in the logs under hadoop-cmf-hdfs-DATANODE-whatever.com.log.out The error included: Datanode denied communication with namenode because the host is not in the... » More
