I sometimes want to omit directories from my disk usage (du -sh *) checks. This includes virtual files systems such as proc / dev and also mounts to other filesystems (data in the example below). This is what works for me: du... » More
I was checking the memory on approximately 140 servers using ansible: ansible --user root -k -i servers.list -m shell -a "free -h; mysql" test but the output appears over several lines e.g. server103.domain.dev | SUCCESS | rc=0 >> total used... » 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
On the Windows Domain Controller I checked the current NTP settings with: w32tm /query /configuration I tried a few alternative commands and got errors such as "the rpc server is unavailable". The command that worked was: w32tm /config... » 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: CheckDisk=1 CheckSystem=1 Then from the Nagios box I can check... » 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: PARTLABEL=data1 /data1 ext4 defaults 0 0 PARTLABEL=data2 /data2 ext4 defaults 0 0 but the partitions did not have PARTLABELS set.... » 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 yum install java-1.8.0-openjdk Install Zookeeper Download ZooKeeper from the... » More
I sometimes want to omit directories from my disk usage (du -sh *) checks. This includes virtual files systems such as proc / dev and also mounts to other filesystems (data in the example below). This is what works for me: du... » More
