linux

Monit mysql monitoring problem with mysqld.pid missing

Monit is a nice tool, it lets you monitor daemons like apache and mysql, and not only sends you alerts when these services fail but also it automagically restarts those services. But I have always faced problem with having monit properly detect whether mysql is running or not. The default monit config file /etc/monit/monitrc has this entry for mysql:

check process mysql with pidfile /var/run/mysqld/mysqld.pid
group database
start program = "/etc/init.d/mysql start"
stop program = "/etc/init.d/mysql stop"
if failed host 127.0.0.1 port 3306 then restart

Locking Down Your Linux Server with APF + BFD

If you allow SSH access to your server, there are some simple steps you can take to restrict access and protect yourself from brute force attacks. Two of my favorite scripts to do this are Advanced Policy Firewall coupled with Brute Force Detection, both by R-FX Networks.

3 Steps to Perform SSH Login Without Password Using ssh-keygen & ssh-copy-id

You can login to a remote Linux server without entering password in 3 simple steps using ssky-keygen and ssh-copy-id as explained in this article.

ssh-keygen creates the public and private keys. ssh-copy-id copies the local-host’s public key to the remote-host’s authorized_keys file. ssh-copy-id also assigns proper permission to the remote-host’s home, ~/.ssh, and ~/.ssh/authorized_keys.

This article also explains 3 minor annoyances of using ssh-copy-id and how to use ssh-copy-id along with ssh-agent.

Tags:

Securing .bash_history file. Make sure your Linux system users won’t hide or delete their .bash_history

If you’re running multi user login Linux system, you have probably realized that there are some clever users that prefer to prevent their command line executed commands to be logged in .bash_history.
To achieve that they use a number of generally known methodologist to prevent the Linux system from logging into their $HOME/.bash_history file (of course if running bash as a default user shell).

Tags:

How to list all installed packages in Ubuntu, CentOS and other Linux systems?

There are several ways to list installed packages in Ubuntu, like: sudo dpkg-query -Wf '${Installed-Size} - ${Package}n \n' | sort -n sudo aptitude search '?installed' In CentOS run one of these commands: yum list installed On any Linux machine with rpm installed: You need to use rpm command to display all installed packages in Linux.

Red Hat/Fedora Core/CentOS Linux

Type the following command to get list of all installed software
# rpm -qa | less

An easy way of extending Linux logical volumes

Some vendors like 1and1 deliver Linux servers with pre-configured partitioning scheme with reduced logical volumes. A Logical Volume Manager (LVM) manager is here to help us.

First we need to see if we have an extra space at all by running pvs command on Ubuntu and pvs -av on CentOS (http://www.centos.org/docs/5/html/Cluster_Logical_Volume_Manager/move_ne... recommends runing pvs -o+pv_used, however it did not work on CentOS 5.8)

root@host:~# pvs

Pages

Subscribe to RSS - linux