Installing Zabbix Server on Centos6

Zabbix as stated on official website is an “enterprise-level software designed for monitoring availability and performance of IT infrastructure components”.
It’s handy if you need to monitor a handful of servers and supports most major linux distributions, Windows, VMware and Java Applications. It’s also fairly easy to setup and understand with a short learning curve offering many built in “scenarios” and fancy graphs. I personally prefer it over other similar solutions like Nagios.
So let’s go through installing and configuring. There are two options, you can either use the official guide where you’ll have to go through all the steps and manually setup things or use a fancy ansible script and do things automagically! We’ll use the ansible script to make our lives easier.
Ansible is an automation tool that is able to deploy and configure software on multiple hosts simultaneously. Comparing it to other similar tools (chef, puppet, etc.) i find it much easier to read, write and maintain, has a big set of premade scripts that are expanding all the time at ansible galaxy and is agentless. All you need is ssh access to your machines. So let’s go through installing ansible and running our playbook.
You can install ansible on any machine you’d like and we’ll run the playbooks from there. On Fedora you can install it through the official repos with

sudo yum install ansible -y

We’ll use a premade playbook that i’ve found on ansible galaxy that installs zabbix server and agent on a Centos 6 system with MySQL and apache. First fetch the playbook.

sudo ansible-galaxy install akamine.c6-zabbix

Then edit the default configuration here /etc/ansible/roles/akamine.c6-zabbix/defaults/main.yml and follow the below steps.

 mkdir zabbix-ansible
cd zabbix-ansible
vi hosts
vi zabbix.yml
ansible-playbook -i hosts zabbix.yml

On the hosts file you’ll put the hosts you wish the playbook to run.
An example is as follows


And on zabbix.yml

- hosts: all
  - akamine.c6-zabbix

When playing the book you should see it output what is doing similar to this:

akis@localhost ansible$ ansible-playbook -i zabbix.yml 

PLAY [all] ******************************************************************** 

GATHERING FACTS *************************************************************** 
ok: []

TASK: [akamine.c6-zabbix | install libselinux-python] ************************* 
changed: []

TASK: [akamine.c6-zabbix | install MySQL-python] ****************************** 
changed: []

TASK: [akamine.c6-zabbix | change selinux mode to permissive] ***************** 
changed: []

TASK: [akamine.c6-zabbix | disable iptables] ********************************** 
changed: []

TASK: [akamine.c6-zabbix | install ntp] *************************************** 
changed: []

TASK: [akamine.c6-zabbix | Start and enable ntp service] ********************** 
changed: []

TASK: [akamine.c6-zabbix | install epel repo rpm key] ************************* 
changed: []

TASK: [akamine.c6-zabbix | setup epel repo] *********************************** 
changed: []

TASK: [akamine.c6-zabbix | install htop] ************************************** 
changed: []

TASK: [akamine.c6-zabbix | install tmux] ************************************** 
changed: []

TASK: [akamine.c6-zabbix | install mysql server] ****************************** 
changed: []

TASK: [akamine.c6-zabbix | enable mysql server] ******************************* 
changed: []

TASK: [akamine.c6-zabbix | set innodb_buffer_size in /etc/my.cnf] ************* 
changed: []

TASK: [akamine.c6-zabbix | enable event_scheduler in /etc/my.cnf] ************* 
changed: []

TASK: [akamine.c6-zabbix | install zabbix rpm key] **************************** 
changed: []

TASK: [akamine.c6-zabbix | setup zabbix repo] ********************************* 
changed: []

TASK: [akamine.c6-zabbix | install zabbix-server-mysql] *********************** 
changed: []

TASK: [akamine.c6-zabbix | install zabbix-web-mysql] ************************** 
changed: []

TASK: [akamine.c6-zabbix | install zabbix-agent] ****************************** 
changed: []

TASK: [akamine.c6-zabbix | create database zabbix] **************************** 
changed: []

TASK: [akamine.c6-zabbix | ensure mysqld is running] ************************** 
ok: []

TASK: [akamine.c6-zabbix | initialize zabbix database] ************************ 
changed: [] => (item=schema.sql)
changed: [] => (item=images.sql)
changed: [] => (item=data.sql)

TASK: [akamine.c6-zabbix | copy sql scripts for database partitioning] ******** 
changed: [] => (item=alter_table_indexes.sql)
changed: [] => (item=stored_procedures.sql)
changed: [] => (item=event_schedule.sql)

TASK: [akamine.c6-zabbix | alter table indexes] ******************************* 
changed: []

TASK: [akamine.c6-zabbix | add stored procedures for partitioning] ************ 
changed: []

TASK: [akamine.c6-zabbix | add partitioning event to schedule] **************** 
changed: []

TASK: [akamine.c6-zabbix | create mysql user] ********************************* 
changed: []

TASK: [akamine.c6-zabbix | modify /etc/zabbix/zabbix_server.conf] ************* 
changed: []

TASK: [akamine.c6-zabbix | modify /etc/httpd/conf.d/zabbix.conf] ************** 
changed: []

TASK: [akamine.c6-zabbix | add e-mail sending script to /usr/lib/zabbix/alertscripts] *** 
changed: []

TASK: [akamine.c6-zabbix | enable httpd] ************************************** 
changed: []

TASK: [akamine.c6-zabbix | enable zabbix server] ****************************** 
changed: []

TASK: [akamine.c6-zabbix | enable and start zabbix agent] ********************* 
changed: []

NOTIFIED: [akamine.c6-zabbix | restart zabbix server] ************************* 
changed: []

NOTIFIED: [akamine.c6-zabbix | restart httpd] ********************************* 
changed: []

NOTIFIED: [akamine.c6-zabbix | restart mysqld] ******************************** 
changed: []

PLAY RECAP ********************************************************************    : ok=37   changed=35   unreachable=0    failed=0

Next all you need to do is login to your new zabbix server instance on with username Admin and pass zabbix.
Will go through configuring the server and installing agents in a later post.
Happy playing around with zabbix!

PS: Some quick notes..
The ansible playbook installs mysql-server with default options, meaning no root password.
You can go further editing the playbook adding these to zabbix-database-init.yml

- name: Update mysql root password for all root accounts
  mysql_user: name=root host={{ item }} password=huhu
  with_items: [ '{{ ansible_hostname }}', '', '::1', 'localhost' ]

- name: Delete anonymous mysql user
  mysql_user: user="" host={{ item }} state=absent
  with_items: [ '{{ ansible_hostname }}', 'localhost' ]

- name: Remove test database
  mysql_db: db=test state=absent

This will setup a password for root account and remove test database.
I’ll probably do a fork of the repo and add some bits and pieces to it and update this post but for the time being this should do.


#alternative, #centos, #linux, #monitor, #monitoring, #nagios, #server, #zabbix

Enabling automatic updates on Centos6.

First install package yum-cron.

sudo yum -y install yum-cron

Then edit /etc/sysconfig/yum-cron if needed. The options are self-explanatory.
Finally to start the service and enable it to auto start on boot issue the following commands.

sudo service yum cron-start
sudo chkconfig yum-cron on

Updates will be run daily.

#centos, #linux, #updates

Virtualbox: Kernel driver not installed (rc=-1908) CentOS/Fedora

Virtualbox Error

Virtualbox Error

This happens after a kernel update. Just install the following meta-package and reboot.


sudo yum install kmod-VirtualBox.x86_64

or for 32bit

sudo yum install kmod-VirtualBox.i686

#1908, #centos, #error, #fedora, #kernel-driver, #virtualbox, #virtualization

Migrating VMware ESXi

Recently one of our VMware ESXi servers started acting up weird.
Situation was that we had no means of accessing ESXi through SSH ( user/pass got refused although it was the right one) and the console was also unaccesible for each VM.
After invastigating a bit through the Vsphere Client it appearead that the system couldn’t find the necessary pam modules and thus no authentication for us.
Hopefully at least we had access through the VSphere Client and also to the Web-Based datastore Browser.
Anyway to make long story short we had to find a way of getting our VMs from there and moving them to another machine.
Typically and afaik we would simply login on our ESXi console and scp our files through the servers. In our case that was no option since we had no ssh access at all. So we came up with two solutions.

General Prerequisites 

  1. Power off your VM while transferring.
  2. Make sure there are no snapshots.
  3. If you got snapshots  take care of them and delete. You can’t move snapshots and you have to have only “the current working branch” .

Transferring (Having a shell access)

  1. scp [[user@]from-host:]source-file [[user@]to-host:][destination-file]  
  2. Example: scp

Transferring (Alternative way, no ssh required)

    1. I’ve found this very handy little script . What it does is accessing your datastore through the web interface and downloads to local .
    2. So to make things faster we can have this script download the files on a remote box and then transfer from there to our new ESXi server.

# Change if you want to use an alternate user
# (you'll be prompted for the password each time)
if ! $(which curl > /dev/null); then
echo "ERROR: curl not found in your path" >&2
echo "" >&2
echo "You'll need to install curl on your system for this script to work." >&2
exit 1
usage() {
echo "USAGE: $0 <get|put> <hostname> <ds> <ds path> <local_path> [thread_count]" >&2
echo "" >&2
echo "one of source or target must be a datastore path" >&2
echo "Example: $0 put hostname datastore /file.iso ./file.iso'" >&2
echo "" >&2
echo "If you set the thread_count then this script will" >&2
echo "use that many parallel threads when downloading the file." >&2
echo "Warning: you'll need ~2x the file size in available space locally for this approach" >&2
urlescape() {
TMP=$(echo $1 | sed \
-e ' {
s/ /%20/g
}' )
echo ${TMP}
if [ $# -lt 5 ] ; then
exit 1
DATASTORE=$(urlescape "$3")
REMOTE_PATH=$(urlescape "$4")
if [ $# == 6 ] ; then
# Default to 4 threads for better performance
if [ "${OPERATION}" == "get" ]; then
if [ ${THREADS} -gt 1 ] ; then
echo -n "Enter password for ${USER}@${HOSTNAME}: "
stty -echo
stty echo
echo ""
# Note: This is somewhat insecure as the password will show up on the
#    command line. Consider switching to use netrc or SSPI
#	   see the curl man page for more details.
#    This first curl invocation grabs just the header to get the size
LENGTH=$(curl ${CURL_ARGS} -s -u "${USER}:${PASSWORD}" "$URL" -I | awk '/Content-Length:/ { print $2 }'|sed -e "s/\r//g")
echo "Starting download (${THREADS} parallel threads)..."
while [ ${COUNT} -le ${THREADS} ] ; do
END=$((START + CHUNK - 1))
# Progress reporting with multiple threads gets jumbled up, so be silent
curl -s ${CURL_ARGS} -u "${USER}:${PASSWORD}" --create-dirs --range ${START}-${END} "$URL" -o "${LOCAL_PATH}.${COUNT}" &
COUNT=$((COUNT + 1))
START=$((END + 1))
# Merge the files back together
rm -f "${LOCAL_PATH}"
touch "${LOCAL_PATH}"
while [ ${COUNT} -le ${THREADS} ] ; do
cat "${LOCAL_PATH}.${COUNT}" >> "${LOCAL_PATH}"
rm -f "${LOCAL_PATH}.${COUNT}"
COUNT=$((COUNT + 1))
echo "Done"
curl ${CURL_ARGS} -u ${USER} --create-dirs "$URL" -o "${LOCAL_PATH}"
elif [ "${OPERATION}" == "put" ]; then
if [ ! -f ${LOCAL_PATH} ] ; then
echo "ERROR: ${LOCAL_PATH} does not exist" >&2
echo "" >&2
exit 1
curl ${CURL_ARGS} -u ${USER} -T "${LOCAL_PATH}" "$URL"
exit 1

Configuration of the VM to the new ESXi

  1. After having transfer all our files ( *-flat.vmdk *.vmdk *.vmx) we now have to create a new VM on the new server.
  2. Create a new VM using the exact same options as on the old ESXi.
  3. Choose Advanced options and select an existing hard disk.
  4. Finsh and boot.

Final Configuration

  1. Since you are now propably on a new network you need to reconfigure your network and your VMAC address.
  2. Create a VMAC address from your host panel.
  3. On CentOS goto /etc/udev/rules.d/70-persistent-net.rules and edit making sure eth0 uses the newly created VMAC.
  4. Goto /etc/sysconfig/network-scripts and edit ifcfg-eth0 accordingly with your new ip, gateway and hwaddr.
  5. Edit /etc/sysconfig/network-scripts/route-eth0 and configure your gateway.


Et voila! You have now succesfully migrated ! 🙂

Suggestions or alternative methods are really appreciated 🙂

#centos, #datastore, #esxi, #esxi4, #esxi5, #migration, #moving, #vmware-2