How to add extra space to Linux VM in XenServer

Before we start you will need to do the following in XenCenter

  • Shutdown the VM
  • Increase the virtual hard drive size of the Linux VM
  • Boot the VM back up

Before starting any of the following, it is a good idea to backup any data you would not want to lose.  You should not lose any data following these steps, but there is always the possibility for something to go wrong.

What is going to happen

  1. Delete the main partition.  We are going to recreate it.
  2. Create a new partition that starts on the same boundary as the previous partition
  3. Write changes to disk and reboot
  4. Resize the Disk
  5. Check that everything went well

The path to the disk is “/dev/xvda” the LVM path/name is “/dev/VolGroup/lv_root”  The goal is to increase lv_root’s size from about 8GB to about 12GB. If for some reason your drive is not “xvda” or your LVM name is different, change the commands accordingly.

Here are the commands in a nutshell.

fdisk /dev/xvda                        <-- Edit the Partition Table
reboot                                 <-- Reboot to apply the partition table updates
pvdisplay                              <-- Display Physical Volume info
pvresize /dev/xvda2                    <-- Resize Physical Volume
lvresize /dev/xvda2 -l +100%FREE       <-- Resize Logical Volume
resize2fs /dev/VolGroup/lv_root        <-- Resize File System

Example:

You may be able to substitute all the fdisk commands with
`parted /dev/xvda resizepart 2 100%`
Change 2 for the actual partition you need to resize.

All the keys and command that were hit and executed are in bold.

[root@localhost ~]# fdisk /dev/xvda

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): p

Disk /dev/xvda: 12.9 GB, 12884901888 bytes
255 heads, 63 sectors/track, 1566 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00066ace

    Device Boot      Start         End      Blocks   Id  System
/dev/xvda1   *           1          64      512000   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/xvda2              64        1045     7875584   8e  Linux LVM
Command (m for help): d
Partition number (1-4): 2

Command (m for help): p

Disk /dev/xvda: 12.9 GB, 12884901888 bytes
255 heads, 63 sectors/track, 1566 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00066ace

    Device Boot      Start         End      Blocks   Id  System
/dev/xvda1   *           1          64      512000   83  Linux
Partition 1 does not end on cylinder boundary.

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 2
First cylinder (64-1566, default 64): 
Command (m for help): p

Disk /dev/xvda: 12.9 GB, 12884901888 bytes
255 heads, 63 sectors/track, 1566 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00066ace

    Device Boot      Start         End      Blocks   Id  System
/dev/xvda1   *           1          64      512000   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/xvda2              64        1566    12065871   83  Linux

Command (m for help): wq
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
[root@localhost ~]# reboot

Show the current size of the Physical Volume

pvdisplay
[root@localhost ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/xvda2
  VG Name               VolGroup
  PV Size               7.51 GiB / not usable 3.00 MiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              1922
  Free PE               0
  Allocated PE          1922
  PV UUID               zKmGEt-Uf0A-I14h-NDYc-53rf-micT-VxNqsP
   
[root@localhost ~]#

Resize the Physical Volume

pvresize /dev/xvda2
[root@localhost ~]# pvresize /dev/xvda2
  Physical volume "/dev/xvda2" changed
  1 physical volume(s) resized / 0 physical volume(s) not resized
[root@localhost ~]#

Run pvdisplay again.  You should see more space under PV Size.

[root@localhost ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/xvda2
  VG Name               VolGroup
  PV Size               11.51 GiB / not usable 2.08 MiB
  Allocatable           yes 
  PE Size               4.00 MiB
  Total PE              2945
  Free PE               1023
  Allocated PE          1922
  PV UUID               zKmGEt-Uf0A-I14h-NDYc-53rf-micT-VxNqsP
   
[root@localhost ~]#

Notice the “Free PE” section above.  If it says 0 then you won’t be able to run the next command.

Resize LVM

the “+100%FREE” part of the command tells it to uses up all of the free space available

lvresize /dev/VolGroup/lv_root -l +100%FREE
[root@localhost ~]# lvresize /dev/VolGroup/lv_root -l +100%FREE
  Extending logical volume lv_root to 10.71 GiB
  Logical volume lv_root successfully resized
[root@localhost ~]#

Resize the File System

resize2fs /dev/VolGroup/lv_root
[root@localhost ~]# lvresize /dev/VolGroup/lv_root -l +100%FREE
  Extending logical volume lv_root to 10.71 GiB
  Logical volume lv_root successfully resized
[root@localhost ~]#

And that is it.  Check out the extra space.

[root@localhost ~]# df -h /
Filesystem                    Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root   11G  733M  9.3G   8% /
[root@localhost ~]# exit

How to Backup and Restore UniFi data from the Command Line

Backup

backup the UniFi directory

tar zcvf unifi-backup.tgz /usr/UniFi/

Move the tar archive off site.

Restore

Upload the backup file to the server.

Note: You will need to have the UniFi controller install already.

Copy the archive to the root directory and then extract it.

mv unifi-backup.tgz /
cd /
tar zxvf unifi-backup.tgz

Reboot the server and login to the UniFi controller.

reboot

Set up Minecraft Server on CentOS 6

Update system

yum update -y

Install Java and wget

yum install -y java wget

Allow Minecraft port through the firewall

Insert the following line in your iptables config file, found in “/etc/sysconfig/iptables”

-A INPUT -m state --state NEW -m tcp -p tcp --dport 25565 -j ACCEPT

Example:

vi /etc/sysconfig/iptables
# Firewall configuration written by system-config-firewall
 # Manual customization of this file is not recommended.
 *filter
 :INPUT ACCEPT [0:0]
 :FORWARD ACCEPT [0:0]
 :OUTPUT ACCEPT [0:0]
 -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
 -A INPUT -p icmp -j ACCEPT
 -A INPUT -i lo -j ACCEPT
 -A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
 -A INPUT -m state --state NEW -m tcp -p tcp --dport 25565 -j ACCEPT <--- Added Rule
 -A INPUT -j REJECT --reject-with icmp-host-prohibited
 -A FORWARD -j REJECT --reject-with icmp-host-prohibited
 COMMIT
 ~
 ~
 :wq
"/etc/sysconfig/iptables" 14L, 544C written
 [root@localhost ~]# service iptables restart
 iptables: Setting chains to policy ACCEPT: filter [ OK ]
 iptables: Flushing firewall rules: [ OK ]
 iptables: Unloading modules: [ OK ]
 iptables: Applying firewall rules: [ OK ]
 [root@localhost ~]#

 

Setup your network.

you will need to edit the network config file in “/etc/sysconfig/network-scripts/ifcfg-eth0”

DHCP

If your using DHCP then just change “ONBOOT=no” to “ONBOOT=yes”

Static

If you need a static address, then change “ONBOOT=no” to “ONBOOT=yes” and change “BOOTPROTO=dhcp” to “BOOTPROTO=static”

add the following to “/etc/sysconfig/network-scripts/ifcfg-eth0”

IPADDR=192.168.1.100
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
BROADCAST=192.168.1.255
DNS1=1.1.1.1

 

Start Minecraft server on system boot

Create user

useradd -m steve

Create password for steve

passwd steve

Login as your new user.

su steve

Go to user root directory

cd ~/

Download the minecraft server jar

wget https://s3.amazonaws.com/Minecraft.Download/versions/1.8.7/minecraft_server.1.8.7.jar

Create a directory for the start up script and create start up script.

mkdir /home/steve/mc
touch /home/steve/mc/mcstart.sh

Copy and paste the following text into mcstart.sh

#! /bin/sh
# /etc/init.d/mcserver

### BEGIN INIT INFO
# Minecraft CraftBukkit Start script
### END INIT INFO

case "$1" in
  start)
    echo "Starting mcserver"
    MCDIR="/home/steve/"
    cd "$MCDIR"
    java -Xmx512M -jar minecraft_server.1.8.7.jar -o true &
;;
  stop)
    echo "Stopping mcserver"
    kill `pgrep mcserver`
    ;;
  *)
    echo "Usage: /etc/init.d/mcserver {start|stop}"
    exit 1
    ;;
esac
exit 0

Make the script executable

chmod +x /home/steve/mc/mcstart.sh

Add mcstart.sh to the crontab

Access the crontab by running the following command

crontab -e

Add the following to the crontab.

@reboot /home/steve/mc/mcstart.sh start

Start the server.

/home/steve/mc/mcstart.sh start

Note: Starting the server will fail because you need to agree to the end user license agreement.

Agree to the eula

sed -i s/false/true/g eula.txt

Reboot the server and connect to your new Minecraft server.

Upload ssh key to multiple servers automatically

Here is a quick script I created to automate copying a ssh key to multiple remote servers.

Basic command – the command uses sshpass to upload the ssh key to a remote server, this allows you to execute the command and not have to enter in a password to authenticate.

sshpass -p password ssh-copy-id -o StrictHostKeyChecking=no admin@remotehost

Script

#!/bin/bash

remotehosts="$1"
username="admin"
password="MyCoolPassword123"

for host in `cat ${remotehosts}`
do
sshpass -p${password} ssh-copy-id -o StrictHostKeyChecking=no ${username}@${host}
echo "Uploaded key to " ${host}
done

echo "Finished!"

 

Using the script

  1. Download here.
  2. Make it executable
    chmod +x sshcopy.sh
    
  3. Edit the script and change the username and password.
  4. Create a file that contains each host’s IP address or hostname.
  5. Run script (change hostlist.txt to your host list you created in step 3.)
    ./sshcopy.sh hostlist.txt
  6. Wait for the script to finish.

Example:

wget www.incredigeek.com/home/downloads/SSHCopy/sshcopy.sh
chmod +x sshcopy.sh
sed -i s/admin/bob/g sshcopy.sh                      <-- Change username - you can just manually edit the file,
sed -i s/MyCoolPassword123/password/g sshcopy.sh     <-- Change password - it might be easier than using sed
echo "192.168.1.100" >> host.txt                     <-- Add 192.168.1.100 to the host list
echo "Bob" >> host.txt                               <-- Add hostname bob to host list
./sshcopy.sh host.txt                                <-- Upload ssh key to all host's in the host file i.e. "bob" and "192.168.1.100"

Install VirtualBox Guest Additions for Fedora 22

Install kernel headers, dkms, etc

dnf -y kernel-headers kernel-devel dkms gcc gcc-c++

Reboot the VM

reboot

Mount the Guest Additions by going to menu > Devices > Insert Guest Additions CD image… or you can hit “Host + D”.

The Host key is typically the Right Ctrl(On Windows) or CMD(On OS X) key.

 

Installing the Guest Additions

Via the GUI

Mount the Guest Additions from your file browser, and then launch the “VBoxLinuxAdditions.run”.

You will need root privileges, so either launch your file browser as root, or drag and drop the “VBoxLinuxAdditions.run”, into a root terminal and hit Enter.

Via Command Line

mkdir /tmp/vbox
sudo mount /dev/cdrom /tmp/vbox
sudo /tmp/vbox/VBoxLinuxAdditions.run

If you run into any errors, try ejecting, and remounting the Guest Additions cd.

cPanel Logs

How to view the logs

There are multiple ways to view log files, here are some common ways.

tail the log, shows the 10 most recent log entries.

tail /var/log/messages

tail the log and keep monitoring it for new entries.

tail -f /var/log/messages

Find specific info in log file

cat /var/log/messages | grep texttosearch

cPanel Log Paths

Main log

/var/log/messages

Access logs

/usr/local/cpanel/logs/access_log

Access logs for a specific domain

/home/user/access-logs/domainname.com

Account Transfers/miscellaneous logs

/var/cpanel/logs

Auditing Log (Account creation and deletions)

/var/cpanel/accounting.log

Backup Logs

/usr/local/cpanel/logs/cpbackup

CPHULKD Log

/usr/local/cpanel/logs/cphulkd.log

DNSAdmin, DNS Clustering

/usr/local/cpanel/logs/dnsadmin_log

Task Queue Processing Daemon

/usr/local/cpanel/logs/queueprocd.log

DBMapping

/usr/local/cpanel/logs/setupdbmap_log

Easy Apache Build logs

/usr/local/cpanel/logs/easy/apache/

Error logs

/usr/local/cpanel/logs/error_log
/var/log/cpanel

License log

/usr/local/cpanel/logs/license_log

local database modifications

/usr/local/cpanel/logs/build_locale_database_log

Login errors CPSRVD

/usr/local/cpanel/logs/login_log

Bandwidth History

/var/cpanel/bandwidth/{USERNAME}

Service Status Logs

/var/log/chkservd.log

Tailwatch log

/usr/local/cpanel/logs/tailwatch_log

Update Analysis Reporting

/usr/local/cpanel/logs/updated_analysis/{TIMESTAMP}.log

Update log UPCP

/var/cpanel/updatelogs/updated.{TIMESTAMP}.log

cPanel Email Logs

 

Horde log

/var/cpanel/horde/log/

RoundCube

/var/cpanel/roundcube/log/

Squirrel Mail

/var/cpanel/squirrelmail/

Panic log

/usr/local/cpanel/logs/panic_log

Delivery and receipt log

/var/log/exim_mainlog

Incoming mail queue

/var/spool/exim/input/

Log of messages rejected based on ACLS or other policies

/var/log/exim_rejectlog

Unexpected/Fatal error log

/var/log/exim_paniclog

IMAP, POP login attempts, transactions, fatal errors and spam scoring

/var/log/maillog

Mailman

/usr/local/cpanel/3rdparty/mailmain/logs

MySQL

MySQL error log

/var/lib/mysql/{SERVER_NAME}.err

MySQL slow query log (if enabled in my.cnf)

/var/log/slowqueries

How to Install a ZenPack in Zenoss 5

Log into your Zenoss server via ssh.

ssh root@zenossserver

Create working direcotry

 mkdir /tmp/zenpack && cd /tmp/zenpack/

Now upload the ZenPack to “/tmp/zenpack/” on your Zenoss server with your favorite ftp tool.

Stop the Zenoss service

serviced service stop zenoss.core

Restart the services needed to import the ZenPack i.e. the following.

ZooKeeper
mariadb
RabbitMQ
redis
zeneventserver
Zope

You can start all of them with the following commands

serviced service start ZooKeeper
serviced service start mariadb 
serviced service start RabbitMQ
serviced service start redis
serviced service start zeneventserver 
serviced service start Zope

Install ZenPack with the following command

serviced service run zope zenpack install ZenPack.xxx.xxx.egg

Restart Zenoss

serviced service restart zenoss.core

Log into Zenoss and make sure that it is working right.

How To change the Hostname in CentOS 7

Check current hostname with the hostname command.

hostname

Change hostname with hostnamectl

hostnamectl set-hostname newhostname

 

Example:

Changing hostname from “localhost” to “newhost”.

[root@localhost ~]# hostname
localhost
[root@localhost ~]# hostnamectl set-hostname newhost
[root@localhost ~]# hostname
newhost
[root@localhost ~]# 

 

 

How to Install Zenoss 5 on CentOS 7

Note:

  1. This is not a comprehensive guide, if you need more info, refer to the installation manual here.
  2. This assumes that all your partitions are going to be on one drive

Installing CentOS 7

Note: If you have issues installing CentOS via the default install interface, try using the Fallback graphics mode, found in the Grub boot menu under “trubbleshooting”.

Install CentOS like you normally would, just be sure to leave at least 60GB of free space for Docker/Zenoss

2

You can Select Automatic Partitioning, but you will need to make additional space available.  I just configured it manually.3

 Note that I have about 75GB of free space, this will be used for “/var/lib/docker” and “/opt/serviced/var/volumes”.  We’ll set these up later on.1

You don’t necessarily need to setup a user, but you can if you want to.  4

Once your finished reboot and login.5

 

Configuring CentOS for Zenoss

Setup network

You will need to setup your network settings.  Refer to this post to set a static IP address if needed.

 

Note: In CentOS 7 ifconfig is not installed by default.  If you need to check the IP address use the following command.

ip addr sh

After your connected to the internet you can install ifconfig with

yum install -y net-tools

Setup Hostname

Zenoss seems to have issues if you change the hostname after it is installed so be sure to set up the hostname before you start installing zenoss.

Check current hostname

hostname

Change the hostname.  Replace “newhostname” with your new hostname.

hostnamectl set-hostname newhostname

After you finish configuring the hostname, add it to “/etc/hosts” with the following command.  Change the IP address and the hostname “zenoss” to your systems IP address and hostname.

echo "192.168.56.101   zenoss" >> /etc/hosts

Update your system

yum update -y

Disable Firewall

systemctl stop firewalld && systemctl disable firewalld

Enable persistent log storage

mkdir -p /var/log/journal && systemctl restart systemd-journald

Create two Btrfs file systems

First create two normal linux partitions using your favorite disk utility.  I am using cfdisk.  Each partition should be over 30GB.

cfdisk /dev/sda

6

Create two Primary partitions and put them at the end and then write and exit.

7

Take note of the two new partitions names.  Mine are “sda4” and “sda3”.

After the above changes are made, it would be a good idea to reboot the machine so the partition table can be updated.

reboot

Now we will reformat the two partitions as Btrfs

Create mount point.

mkdir -p /var/lib/docker /opt/serviced/var/volumes

Change “/dev/sda3” and “/dev/sda4” to your partitions names if they are different.

DOCKER_PART=/dev/sda3
APP_PART=/dev/sda4
mkfs -t btrfs --nodiscard $DOCKER_PART
mkfs -t btrfs --nodiscard $APP_PART

Add the new file systems to fstab, so they automatically mount on boot.

APP_PATH="/opt/serviced/var/volumes"
echo "$DOCKER_PART /var/lib/docker btrfs rw,noatime,nodatacow 0 0" >> /etc/fstab
echo "$APP_PART $APP_PATH btrfs rw,noatime,nodatacow 0 0" >> /etc/fstab

Mount the new filesystems, and make sure that they mounted

mount -a
if [[ `mount | egrep 'docker|serviced'` ]]; then echo "Mounted" ; else echo "Not Mounted" ; fi

You can manually check by running the following command.

mount | egrep 'docker|serviced'

you should receive something like the following

/dev/sda3 on /var/lib/docker type btrfs (rw,noatime,seclabel,nodatasum,nodatacow,space_cache)
/dev/sda4 on /opt/serviced/var/volumes type btrfs (rw,noatime,seclabel,nodatasum,nodatacow,space_cache)

Disable SELinux

By default SELinux is installed and enabled.  To disable SELinux either edit the config file “/etc/selinux/config” and change “SELINUX=enforcing” to “SELINUX=disabled”, or you can run the following command.

EXT=$(date +"%j-%H%M%S")
sudo sed -i.${EXT} -e 's/^SELINUX=.*/SELINUX=disabled/g' \
/etc/selinux/config && \
grep '^SELINUX=' /etc/selinux/config

Enable Dnsmasq

systemctl enable dnsmasq && systemctl start dnsmasq

Install and Configure NTP

yum install -y ntp && systemctl enable ntpd

Have NTP start on system boot and then start NTP

echo "systemctl start ntpd" >> /etc/rc.d/rc.local
chmod +x /etc/rc.d/rc.local
systemctl start ntpd

Download and install the Zenoss repository

rpm -ivh http://get.zenoss.io/yum/zenoss-repo-1-1.x86_64.rpm
yum clean all

Final Reboot

reboot

 

Installing Zenoss

 

Once your logged back into the system start installing zenoss

Install the Zenoss-core service and start docker

yum --enablerepo=zenoss-stable install -y zenoss-core-service
systemctl start docker

Add the Btrfs and DNS flags to the Docker startup options

Identify ip for docker

ip addr | grep -A 2 'docker0:' | grep inet

Add the docker startup options.  Change the ip address if needed.  It should match the one from the previous command.

echo 'DOCKER_OPTS="-s btrfs --dns=172.17.42.1"' >> /etc/sysconfig/docker

Change the volume type for application data

You can manually edit the serviced file “/etc/default/serviced” and change the variable “SERVICED_FS_TYPE” from “rsync” to “btrfs” or run the following command.

EXT=$(date +"%j-%H%M%S")
 sudo sed -i.${EXT} \
 -e 's|^#[^S]*\(SERVICED_FS_TYPE=\).*$|\1btrfs|' \
 /etc/default/serviced

Restart docker

systemctl stop docker && systemctl start docker

Start the control center

systemctl start serviced

you can monitor the process with

journalctl -u serviced -f

Serviced has about 5-10 minutes worth of work to do before you’ll be able to login to the Control Center interface.  If the service fails to start, reboot the server.

Setting up name resolution

To setup name resolution on you local computer just add the following line to your “hosts” file.  On Linux and OS X this is located in “/etc/hosts” On Windows machines it is under “\Windows\Sytem32\Drivers\etc\hosts”

192.168.56.101 hostname zenoss5.hostname hbase.hostname opentsdb.hostname rabbitmq.hostname

Be sure to change the IP address and “hostname”  to the IP address and hostname of your server.  You also might need administrative privileges to edit the hosts file.

10

Logging into the Control Center.

Now open up a web browser and go the following URL.  Change the IP address to your servers IP.

https://192.168.56.101

Login with the Zenoss server root username and password.  If you want to setup a user other then root, please refer to the Zenoss Installation guide here.

11

Change the hostname to your Zenoss server hostname12

Select the check boxes in the next two steps.13 14

Give it a deployment id and deploy it.15 16

Once it is deployed Make sure that it is started.  Once it finishes go log into Zenoss.  It can take awhile for Zenoss to start up, depending on your hardware, so be patient.

The Direct URL for Zenoss is

https://zenoss5.hostname