Clearing old Journald Logs

Journald logs can be cleared by timescale or size as follows. Keep only 5 days worth of logs journalctl --vacuum-time=5d Retain only the past 500 MB: journalctl --vacuum-size=500M

Checking if Puppet is Disabled

The puppet agent can be disabled from running with: And it can be re-enabled with: But to check if puppet is currently disabled there is no check command. Instead look for the existence of the agent_disabled.lock file under: For the systems I... » More

Exclude Directories for Disk Usage (du)

ncdu 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: The equals sign appears to... » More

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Joining Multi-line Output with Paste

Shell I was checking the memory on approximately 140 servers using ansible: but the output appears over several lines e.g. but what I wanted was the server name and the total memory available. So I first grepped the output to remove the lines I didn't... » More

Datanode denied communication with namenode

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

Set NTP Server on Windows Domain Controller

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

Windows Nagios Checks using NSClient

Munin Alternative Template 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

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... » 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... » More