Vladimir Melnik

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Creating and removing snapshots in Apache CloudStack with a neat schedule

Here’s an example of the configuration file of my make_snapshots.pl script based on the MonkeyMan framework.

Frankly speaking, I really can’t imagine how to deal with snapshots without this […]

CloudStack Management Cluster

My new CloudStack-driven cloud is being managed by a cluster that consists of 8 virtual machines that are running on 2 different physical hosts. I can shut down any of […]

Synchronizing records about the occupied IP-addresses between two CloudStack databases

Sometimes it’s necessary to maintain 2 different CloudStack setups (let’s call them Cloud-A and Cloud-B) sharing the same IP-address ranges. For example, we might need that when we’re building a […]

How to find out where exactly the packet is being lost

It’s a pretty common occurrence when you have 2 hosts pinging each other and some packets are being lost. And sometimes you need to make sure, that the routing device […]

How to test a TCP-connection

Sometimes it’s not enough to estimate the packet loss ratio only, but to make sure that a TCP-connections are stable. Run the “server” instance (sockping -m server -p 65513) on […]

How to check all the sensors (a Nagios plugin)

Ever fancied a Nagios plugin to check all the sensors on the host without any hassle? Try this one, it collects all the sensors’ input values, compares it to their […]

How to determine on which hop your datagrams are being lost without the mtr utility

Sometimes you need to detect which host loses IP-packets being sent by you. It’s good when you can use the mtr utility, but what to do if you can’t install it?

IP-address Round-Robin for Postifx

Here’s a short and pretty self-desctriptive recipe to make your Postfix to send outgoing messages from different IP-addresses switching them on a round-robin basis. First of all, we’ll need the […]

Virtualization Cluster Network in a Nutshell

To be honest, I’m not keen on drawing diagrams, but today I had to spend a couple of hours to sketch this one. It was needed to illustrate Ethernet-links between […]

A simple todo list for your shell

This simple script lists today’s tasks every time you log in (or create a new window in your screen).

Adding a new task is as easy as typing something […]