Posts By: jonny

Querying Zookeeper from Python

Install the prerequisites. Below works for Debian-based distros such as Ubuntu/Mint:

Install python libraries:

Example code below shows making a connection, getting the names of some child nodes and pulling info from each of those child nodes:

Unfortunately I can’t get this installed on CentOS.    

Install check_mk on Ubuntu 18.04

Ubuntu 18.04 includes check-mk in the repository version but it is an older version 1.2.8 (at the time of writing). Download check mk raw (get the latest stable URL from the website) :

Try installing it:

You may get dependency issues which can be resolved with:

Then try the install again:

Read more »

iDRAC 9 Set Physical Disk to Non-RAID

In the update from iDRAC 8 to iDRAC 9 it has been infuriating searching the ‘Storage’ menu only to discover that the storage is managed under ‘Configuration > Storage Configuration’  I’m convinced the user experience could be better! At the very least a link through for configuration.

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 was checking this was at:

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 be optional and worked both ways for me…. Read more »

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 want e.g.

leaving me with two lines of… Read 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 include-list: : DatanodeRegistration One solution could be to ‘Refresh Node List’ as shown in the screenshot below. Find it by clicking… Read 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 the ntp server listed when re-running the command:

As shown below.

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 follows:

We can also… Read more »