VMware: Prepare list of VMs with snapshots using PowerShell

VMware snapshots plays important role for VM backup. It is recommended to remove old snapshots as they consume space and may create problems if somebody revert the VM with old snapshot. If you have handsome amount of Virtual Machines, then it will be difficult and time consuming for you to manage those snapshots manually. 

NSClient - ERROR: Could not get data for 5 perhaps we don't collect data this far back?

Error : NSClient - ERROR: Could not get data for 5 perhaps we don't collect data this far back? 
This is the error I received a notification from my monitoring tool Nagios for a host against CPU Usage, which is quite annoying to deal with. I made some research around it and finally got a solution to fix this issue.

Explanation: This issue is around the performance counter of the server. Somehow Nagios is not able to read those performance counter.

Error: Could not open command file ‘/usr/local/nagios/var/rw/nagios.cmd’ for update!

Error: Could not open command file ‘/usr/local/nagios/var/rw/nagios.cmd’ for update!,An error that comes up from time to time and is quite annoying to deal with, I found a way to fix the problem, it is not the best way, but it is simple and fast.

MySQL Master Slave Replication

MySQL replication is a process that allows us to easily maintain multiple copies of a MySQL data. MySQL data get automatically copied from a master to a slave database. This concept is helpful for many reasons including 
a. Automatically backing up for the data.
b. Providing alternate database server if master server get crashed somehow.
To check the replication status in Master Slave environment (MySQL). Just need to follow these steps:

Nagios: Unable to check HTTPS service using check_http

Nagios is a powerful IT infrastructure monitoring solution available in market. It provides monitoring graphically. I installed Nagios Core on a server and after the completion of nagios configuration, I checked that Nagios is not able to ping the host on which https is enabled. 

Configure Gmail SMTP Relay

SMTP stands for Simple Mail Transfer Protocol, lets you send email messages through your email account using your existing email service. This email service is subject to your interest. It could be any like: Gmail Relay, Snail Mail etc.

In this post we are going to configure Gmail Relay to send emails.

Nagios HTTP WARNING: HTTP/1.1 403 Forbidden Solved

I setup a nagios server and after the setup, I encounter a warning "Nagios HTTP WARNING: HTTP/1.1 403 Forbidden".

Nagios Server Configuration for different hosts

In our previous posts, we learn how to install nagios, how to install NRPE or NSClient++. Now let's have a look on configuring hosts in nagios in best practical way Nagios Server Configuration for different hosts.

It will be good practice if we configure the client hosts in groups on Nagios Server.

Steps to Group clients servers:

1. Create locations for host configuration files:

In our configuration, we are grouping servers in 4 main categories:

Nagios NRPE Installation

In previous article, we learn how to install nagios (monitoring tool). Now we'll learn how to install nagios agent on the system, which needs to be monitored in nagios. This Agent tool is known as Nagios NRPE (for linux). To monitor system having Windows operating system, we need to install NSClient++. NSClient++ is very easy to install as it is simply a .exe file. Here are the steps to install NRPE plugin (agent) on linux machine:

Nagios Installation

NAGIOS: It's a monitoring tool used widely in server administration. When we have large no. of system like in data centers then we need some technology to monitor our data base servers, application servers, routers, other machines etc. 

Nagios provides a complete solution for this. Nagios provides graphical reports and monitoring of our network & servers. In order to setup nagios successfully, we need to install nagios on one server and different machines, servers will be configred in it. To communicate with configured hosts (servers), we need to install NRPE agents on servers, which need to be monitored.