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CLI System Monitoring Tools

November 12, 2017 – 12:24 pm

The multitude of sophisticated centralized monitoring tools available these days excel at one thing: telling you what happened while you’ve been sleeping. But what if you’re awake and need to know what’s going on right …

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Networking

Unix and Linux network configuration. Multiple network interfaces. Bridged NICs. High-availability network configurations.

Applications

Reviews of latest Unix and Linux software. Helpful tips for application support admins. Automating application support.

Data

Disk partitioning, filesystems, directories, and files. Volume management, logical volumes, HA filesystems. Backups and disaster recovery.

Monitoring

Distributed server monitoring. Server performance and capacity planning. Monitoring applications, network status and user activity.

Commands & Shells

Cool Unix shell commands and options. Command-line tools and application. Things every Unix sysadmin needs to know.

Commands & Shells »

Export WP Posts and Sync to Sharepoint

November 14, 2017 – 12:24 pm
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Long story short: old wiki is overloaded and broken; new wiki is not a wiki but SharePoint – a glorified file server; people are forced to improvise and put documentation on a WP wiki; bosses still want to see documentation in SharePoint; need a way to automatically sync new and updated posts from WP to SharePoint. Read the full story »

Useful MySQL One-Liners

November 8, 2017 – 12:16 pm
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I am by no means an expert SQL programmer. Having said that, I’ve been using MySQL for a very long time. This is a collection of simple but useful SQL queries and MySQL configuration options. …

Plotting Log Data

August 9, 2017 – 10:13 pm
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While I am on the subject of selecting time ranges from logs, a practical application presented itself. A lonely server in a far-away land with a habit of running out of memory could only be …

Croncal – the Cron Calendar

August 9, 2017 – 10:52 am
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The croncal is a clever Perl script that reads entries in your crontab and outputs a schedule, showing the time when cron jobs will run.

Install and Configure Etckeeper

June 23, 2017 – 8:05 am
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Etckeeper is a handy tool that uses git to keep track of changes to anything in /etc (or any other folder you choose). It’s very simple to use and can help you quickly identify and undo stupid …

Using IPTables to Allow Access to Private Networks

June 22, 2017 – 9:46 am
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Below is a quick example of how to use iptables to allow port access for all types of private networks. In this case we’re allowing access to ports 10000 and 20000, commonly used by webmin and usermin.

Get a List of all ESX Hosts in a Datacenter

April 17, 2017 – 3:18 pm
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Another simple one-liner to get a list of hostnames of all ESX servers in the vCenter. This can be useful for a number of things, specifically as input for other PowerCLI scripts.

Use PowerCLI to Change NIC Type

April 17, 2017 – 11:52 am
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This is a quick PowerCLI script that reads from a list of VM names and for each VM with network adapter type “E1000” changes it to “Vmxnet3”. Nothing fancy, no reboot is needed. MAC should …

Pushing SSH Keys

March 21, 2017 – 10:54 am
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This is just a quick note for me on pushing SSH keys using sshpass and xargs. The ~/hosts.txt file contains a list of remote hosts, one per line. And the ~/.passwd.txt contains your password. Make sure to chmod 400 …

Configure and Run esxcli on Red Hat

March 20, 2017 – 3:58 pm
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The esxcli utility is used to interface with the vSphere and ESX hosts. It is a useful tool for getting to some basic VMWare functionality from Unix shell. It is also a pre-requisite for some of …

Wget Examples

March 1, 2017 – 9:25 pm
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This is a follow-up to my previous wget notes (1, 2, 3, 4). From time to time I find myself googling wget syntax even though I think I’ve used every option of this excellent utility over the …

Samba Flexible Character Mapping

March 1, 2017 – 6:33 pm
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This is probably old news to most of you, but I just found out: Samba v 3.5+ has a new option for flexible mapping of filename characters. Unix filenames allow certain characters that Windows filename …

Install Webmin on CentOS and Redhat

February 27, 2017 – 2:10 pm
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Just a quick short-hand to installing Webmin on CentOS/RHEL. The latest Webmin version comes with a cool new interface theme. You should check it out.

Managing VMs with PowerCLI

February 20, 2017 – 5:45 pm
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Below is a collection of useful Power-CLI one-liners (or thereabouts) that can speed up your script-writing efforts. As everything Windows, things change often and for no obvious reason, so expect to see type is deprecated and …

Sun T-Series ILOM and Solaris 11 Network Configuration

February 20, 2017 – 11:16 am
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Just some quick notes on setting up Oracle Sun T-series server ILOM and network aggregation with LACP. I don’t get to do this very often, so every time it’s a struggle to remember, with much …

Monitoring DNS Queries

January 27, 2017 – 7:20 am
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Recently I’ve been decommissioning old DNS servers and those things are notoriously hard to get rid of. The problem was that the IP addresses could not be preserved. I needed to track down every incoming …

Google Search Tips

January 15, 2017 – 10:17 pm
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Google has some advanced search features that few people use, which is a shame. Here are some of them. I am sure there are a few more, but these are the more useful ones.

Verify Network Port Access

December 27, 2016 – 1:06 pm
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There are several tools you can use to verify access to a remote network port: nc, tcping, telnet. Unfortunately, nc from the netcat package has been replaced by the one from nmap, which lacks the -z option, making …

Rsync Time Backup

December 22, 2016 – 3:46 pm
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This is a simple wrapper for the awesome rsync-time-backup script by Laurent Cozic. Through clever use of hard links rsync-time-backup greatly speeds up incremental backups and saves disk space.

Grepping for IPs

December 11, 2016 – 5:47 pm
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This is a small collection of tools and examples for working with IP addresses and ranges in Bash. This post is not meant to be a complete reference, rather a practical how-to guide.

Copying a VM between VCenters

November 12, 2016 – 6:13 pm
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I had a little task: clone an operational VM from one VCenter to another. Normally, for such a task I would use the Standalone Converter. Unfortunately, this time I ran into an annoying SSH key …

Agedu – Finding Old Files

November 7, 2016 – 3:35 pm
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I almost never delete anything (not on purpose anyway). Having said that, sometimes I do need to find old data on a server and offload it to a NAS. Agedu has been around for ages. …

Monitoring Solr Cores

November 1, 2016 – 10:50 pm
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The Cloud tab of the Solr Web UI is convenient, but not for monitoring purposes. Just like you, I hate XML and parsing it from shell is more convoluted that it needed to be. But …