RHEV host and Self hosted engine upgrade to RHEV 3.6

RHEL Host (RHEV) upgrade: ==================== Applying RHEV updates on Red Hat Enterprise Linux 6 Enable Repos: #subscription-manager repos --disable=* #subscription-manager repos --enable=rhel-6-server-rpms #subscription-manager repos --enable=rhel-6-server-optional-rpms #subscription-manager repos --enable=rhel-6-server-rhev-mgmt-agent-rpms #subscription-manager repos –enable=rhel-6-server-supplementary-rpms Set hosted-engine status to maintenance: #hosted-engine --vm-status #hosted-engine --set-maintenance --mode=global Before installing an update, make sure all previously released errata relevant to the system have been applied. To access updates when using Red Hat Enterprise Linux 6, launch the graphical update tool through System -> Administration -> Software Update, or from the command line via the following command: # gpk-update-viewer For a command line interface, use the following command to update the operating system: # yum update To install a specific package, such as vsftpd, use the following command: # yum install vsftpd  UPGRADING RED HAT ENTERPRISE VIRTUALIZATION MANAGER 3.6 https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Virtualization/3.6/html-single/Upgrade_Guide/index.html#Upgrading_the_Self-Hosted_Engine1 The following procedure outlines the process for upgrading Red Hat Enterprise Virtualization Manager 3.5 to Red Hat Enterprise Virtualization Manager 3.6. This procedure assumes that the system on which the Manager is installed is subscribed to the entitlements for receiving Red Hat Enterprise Virtualization 3.5 packages at the start of the procedure. IMPORTANT If the upgrade fails, the engine-setup command will attempt to roll your Red Hat Enterprise Virtualization Manager installation back to its previous state. For this reason, the repositories required by Red Hat Enterprise Virtualization 3.5 must not be removed until after the upgrade is complete as outlined below. If the upgrade fails, detailed instructions display that explain how to restore your installation. Procedure 3.1. Upgrading to Red Hat Enterprise Virtualization Manager 3.6 Subscribe the system on which the Red Hat Enterprise Virtualization Manager is installed to the required entitlements for receiving Red Hat Enterprise Virtualization Manager 3.6 packages: With RHN Classic: # rhn-channel --add --channel=rhel-x86_64-server-6-rhevm-3.6 With Subscription Manager: # subscription-manager repos --enable=rhel-6-server-rhevm-3.6-rpms Update the rhevm setup packages: # yum update rhevm\*setup\* Run the following command and follow the prompts to upgrade the Red Hat Enterprise Virtualization Manager: # engine-setup Remove or disable the Red Hat Enterprise Virtualization Manager 3.5 channel to ensure the system does not use any Red Hat Enterprise Virtualization Manager 3.5 packages: With RHN Classic: # rhn-channel --remove --channel=rhel-x86_64-server-6-rhevm-3.5 With Subscription Manager: # subscription-manager repos --disable=rhel-6-server-rhevm-3.5-rpms Update the base operating system: # yum update

How to Use Rsync to Sync New or Changed/Modified Files in Linux

by Aaron Kili | Published: August 19, 2016 | Last Updated: August 19, 2016

Download Your Free eBooks NOW - 10 Free Linux eBooks for Administrators | 4 Free Shell Scripting eBooks

As a system administrator or Linux power user, you may have probably come across or even on several occasions, used the versatile Linux Rsync tool, which enables users to expeditiously copy or synchronize files locally and remotely. It is as well a great tool popularly used for backup operations and mirroring.
Some of its eminent features and advantages include; it is exceptionally versatile in that, it can copy locally, to/from a remote shell or remote rsync, it is also remarkably flexible, allowing users to specify any number of files to copy.

Suggested Read: 10 Practical Examples of Rsync Command in Linux

Furthermore, it permits copying of links, devices, file or directory owner, groups and the permissions. It also supports usage without root privileges coupled with many more.
One imperative differential of rsync in comparison to other file-coying commands in Linux is its use of the remote-update protocol, to transfer only the difference between files or directory content.
Therefore, in this article, we shall examine how rsync can help us only sync new or changed files or directory content while making backups and beyond in Linux.
To start with, you need remember that the conventional and simplest form of using rsync is as follows:

# rsync options source destination 

That said, let us dive into some examples to uncover how the concept above actually works.

Syncing Files Locally Using Rsync

Using the command below, am able to copy files from my Documents directory to /tmp/documents directory locally:

$ rsync -av Documents/* /tmp/documents

In the command above, the option:

1. -a – means archive mode
2. -v – means verbose, showing details of ongoing operations

Sync Files Locally

By default, rsync only copies new or changed files from a source to destination, when I add a new file into my Documents directory, this is what happens after running the same command second time:

$ rsync -av Documents/* /tmp/documents

Sync New Updated Files

As you can observe and notice from the output of the command, only the new file is copied to the destination directory.

Suggested Read: How to Sync Two Apache Web Servers/Websites Using Rsync

The --update or -u option allows rsync to skip files that are still new in the destination directory, and one important option, --dry-run or -n enables us to execute a test operation without making any changes. It shows us what files are to be copied.

$ rsync -aunv Documents/* /tmp/documents

Dry Run Rsync Before Syncing Files

After executing a test run, we can then do away with the -n and perform a real operation:

$ rsync -auv Documents/* /tmp/documents

Sync Updated Files

Syncing Files From Local to Remote Linux

In the example below, I am copying files from my local machine to a remote sever with the IP address – 10.42.1.5. So as to only sync new files on the local machine, that do not exist on the remote machine, we can include the --ignore-existing option:

$ rsync -av --ignore-existing Documents/* aaronkilik@10.42.1.5:~/all/

Sync Files Local to Remote Linux

Subsequently, to sync only updated or modified files on the remote machine that have changed on the local machine, we can perform a dry run before copying files as below:

$ rsync -av --dry-run --update Documents/* aaronkilik@10.42.1.5:~/all/
$ rsync -av --update Documents/* aaronkilik@10.42.1.5:~/all/

Check Sync Only Updated Files

To update existing files and prevent creation of new files in the destination, we utilize the --existing option.
You can run through the rsync man page to discover additionally useful options for advanced usage, as I had mentioned earlier on, rsync is a very powerful and versatile Linux tool and many System Administrator and Linux power users know just how advantageous it is.
Most importantly, you can as well share your view on the examples we have covered here or even better still, offer us valuable tips on using this vital command line tool through the comment section below.

Migrating VMWARE Image (OVA) to RHEV 3.5 as a VM

I would like to share with you this secret way of migrating any VM from any hypervisor to RHEV. Red Hat has not mentioned this anywhere on the internet so I would recommend you to do this only on test environments:

1) Extract the OVA image using: tar xvf CFusion-server.ova

2) Convert the extracted VMDK disk file to raw lvm image using: qemu-img convert -f vmdk CFusion-server-disk1.vmdk -O raw CFusion-server-disk1.img

3) SCP the image (.img file) to you NFS exports server (also, Check the VM size)

4) In RHEVM, create a VM with same sized disk (preallocated)

5) Export that VM (to export NFS) and delete the newly created VM

6) Check the export VM image in images folder on NFS export location

7) Put export in maintenance mode and on nfs server, use dd command to write the main exported disk file under images folder

8) Now, activate the export again

9) Create a VM with THIN disk from exported image

You can see that VM is ready for its first run!

KVM CLUSTER USING PACEMAKER

http://www.unixarena.com/2015/12

UBUNTU (Zero2Pro)

UBUNTU TRAINING DOCUMENT

PREPARED BY: RAM NATH (ALPHA DATA LLC)

Download Ubuntu.

http://www.ubuntu.com/download/server/download

Add a user

[1] If you'd like to add new user, Add like follows.

# add a new user "ubuntu"

ram@ubuntu:~$ sudo adduser ubuntu

[2] If you'd like to give privileges to a new user, Do like follows.

ram@:~$ sudo usermod -G sudo ubuntu

ram@ubuntu:~$ su - ubuntu

ubuntu@ubuntu:~$ sudo reboot

[sudo] password for ubuntu: # password for 'ubuntu'

Enable root Account:

The root Account in Ubuntu is disabled by default bcause his password is not set. But if you'd like to use root Account by some reason, it's possible to use like follows.

[1] The user account added during installation is set an administrative account with Sudo, so it's easy to get root account's shell like follows.

ram@ubuntu:~$ sudo -s

[sudo] password for ram: # own password

root@ubuntu:~# # switched

[2] Or it's possible to switch to root account with su command to set root account's password.

ram@ubuntu~$ sudo passwd root

ram@ubuntu:~$ su -

Password:# input root password

root@ubuntu:~#

The examples on this site shows as a root account. If you use Sudo, add "sudo" on the head of commands. It had better to limit user if you enable root account.

For using by Sudo, it's possible to limit to prohibit shells in sudoers config, refer to details about Sudo Settings.

[3] For limit to do su command, set like follows.

root@ubuntu:~# vi /etc/pam.d/su

# line 15: uncomment and add a group which is allow to do su command

auth required pam_wheel.so group=adm

root@ubuntu:~# usermod -G adm ubuntu

root@ubuntu:~# vi /etc/network/interfaces

# add these lines

iface eth0 inet static

address 10.0.0.30# IP address

network 10.0.0.0# network address

netmask 255.255.255.0# subnet mask

broadcast 10.0.0.255# broadcast address

gateway 10.0.0.1# default gateway

dns-nameservers 10.0.0.10# name server

root@ubuntu:~# ifdown eth0 && ifup eth0

Disable IPv6:

root@ubuntu:~# echo "net.ipv6.conf.all.disable_ipv6 = 1" >> /etc/sysctl.conf

root@ubuntu:~# sysctl -p

Configure Services

Configure Services (Upstart and SysVinit)

UPSTART:

The one with "start/running" is executed when booting the system.

root@ubuntu:~# initctl list

mountnfs-bootclean.sh start/running

rsyslog start/running, process 689

tty4 start/running, process 1090

udev start/running, process 531

upstart-udev-bridge start/running, process 520

[2] For Upstart one, the configuration file is under "/etc/init". Jobs are controled by them.

For example, if you'd like to stop "atd" and disable autostart, set like follows.

root@ubuntu:~# initctl stop atd

atd stop/waiting

root@ubuntu:~# vi /etc/init/atd.conf

# Comment out

# start on runlevel [2345]

[3] It's possible to know jobs like follows which are executed when booting. And also it's possible to know the meanings for "start on ***" with "man upstart-events".

root@ubuntu:~# grep "start on" /etc/init/*

/etc/init/acpid.conf:start on runlevel [2345]

/etc/init/apport.conf:start on runlevel [2345]

/etc/init/atd.conf:#start on runlevel [2345]

root@ubuntu:~# man upstart-events

Table 1: Well-Known System Events Summary.

[4] For SysVinit one, for example, NTP, it's easy to manage them to install a tool like follows.

root@ubuntu:~# aptitude -y install sysv-rc-conf

root@ubuntu:~# sysv-rc-conf --list # list services

root@ubuntu:~# sysv-rc-conf ntp on # set auto-start for NTP

root@ubuntu:~# sysv-rc-conf ntp off # disable auto-start for NTP

Update System:

Run Aptitude repository update:

root@ubuntu:~# aptitude update

Run update the system

root@ubuntu:~# aptitude -y upgrade

Configuring SUDO

root@ubuntu:~# aptitude install sudo -y

To edit sudoers file, we use:

root@ubuntu:~# visudo

To give specific command permissions to certain user:

You can then give a specific user privileges to those commands like so:

The logs for sudo are kept in '/var/log/auth.log', but there are many kind of logs in it. So if you'd like to keep only sudo's log in a file, Set like follows:

root@ubuntu:~#visudo

--

# add at the last

Defaults syslog=local1

--

root@ubuntu:~# vi /etc/rsyslog.d/50-default.conf

# line 8: add

local1.* /var/log/sudo.log

auth,authpriv.* /var/log/auth.log

*.*;auth,authpriv.none -/var/log/syslog

root@ubuntu:~# initctl restart rsyslog

Install NTPd and Configure NTP server for time adjustment. NTP uses 123/UDP

root@ubuntu:~# aptitude -y install ntp

Comment-out existing servers and Add below servers as NTP servers:

vi /etc/ntp.conf

#server 0.ubuntu.pool.ntp.org

#server 1.ubuntu.pool.ntp.org

#server 2.ubuntu.pool.ntp.org

#server 3.ubuntu.pool.ntp.org

 3.asia.pool.ntp.org (128.199.219.72)

 2.asia.pool.ntp.org (157.7.208.12)

1.asia.pool.ntp.org (45.118.133.241)

# line 48: add the network range you allow to receive requests

restrict 10.0.0.0 mask 255.255.255.0 nomodify notrap

#service ntp restart

#ntpq -p #to check

You can also use crony as an alternative (to ntp).

Client also check /etc/ntp.cong for server. You need to specify the at Client side:

vi /etc/ntp.conf

server

To Update time instantly:

ntpdate

SSH server configuration:

root@ubuntu:~# aptitude install openssh-server -y

You can change below configuration for root direct login (enable/disable)

root@ubuntu:~# grep -i root /etc/ssh/sshd_config

PermitRootLogin without-password

Install ssh Client :

root@ubuntu:~# aptitude -y install openssh-client

To ssh to a remote machine, use:

#ssh -l

Transferring a file:

root@ubuntu:~# scp ram@ubuntu:/tmp/test /var/tmp/test

ram@ubuntu's password:

test 100% 245 0.2KB/s 00:00

ram@ubuntu's password:

Connected to ubuntu.

Fetching /tmp/test to /var/tmp/test

/tmp/test 100% 245 0.2KB/s 00:00

root@ubuntu:~# sftp ram@ubuntu

ram@ubuntu's password:

Connected to ubuntu.

sftp> pwd

Remote working directory: /home/ram

When using Windows, use WINSCP to connect to the ssh server and transfer files

https://winscp.net/download/winscp577setup.exe

SSH KEY-PAIR AUTHENTICATION

ram@ubuntu:~$ ssh-keygen #optionally you can use rsa or dsa using type (-t) option

ram@ubuntu:~$ ls .ssh

id_rsa id_rsa.pub

ram@ubuntu:~$ ssh-copy-id 192.168.171.171 #ssh Client IP

And now, you have password less access to ssh-server. If you set "PasswordAuthentication no", it's more secure.

ram@ubuntu:~$ grep PasswordAuthentication /etc/ssh/sshd_config

#PasswordAuthentication yes

root@ubuntu:~# initctl restart ssh

ssh start/running, process 2637

Windows ssh client putty:

http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html

DNS FILES

/etc/resolv.conf # File where you specify DNS SERVER INFO

/etc/hosts #File acts as local dns resolver

/etc/nsswitch.conf #File to specify which dns (file or server ) gets resolve priority

File Sharing methods in Linux:

NFS

Samba

SFTP

FTP

SCP

RSYNC

Linux can serve any (all) of the following Storage Server(s):

LVM

NFS

ISCSI

Ceph

Gluster

SMB

Linux can use any (all) of the following Storage as Client:

LVM

NFS

ISCSI

FC

Ceph

Glusterfs

SMB

NFS Server and Client Configurations:

1) Install NFS server

#aptitude -y install nfs-kernel-server

2) introduce an NFS share

#vi /etc/exports

3) Restart NFS Server

# /etc/init.d/nfs-kernel-server restart

 Client Configuration:

#aptitude -y install nfs-common

#initctl restart idmapd

#showmount -e

#mount -t nfs 192.168.171.171:/srv/nfs4 /mnt

#df -kh

#mount

#vi /etc/fstab

ISCSI Server installation (For Testing):

Install ISCSI server:

aptitude -y install iscsitarget iscsitarget-dkms

Create a Test Disk

dd if=/dev/zero of=/iscsi_disks/disk01.img count=0 bs=1 seek=500M

Make sure that ISCSITARGET_ENABLE is true, run following command to check this:

root@ubuntu:~# grep ISCSITARGET_ENABLE /etc/default/iscsitarget

ISCSITARGET_ENABLE=true

Update configuration file

#vi /etc/iet/ietd.conf

--

# add follows to the end

# if you set some devices, add *** and set the same way with follows

# naming rule : [ iqn.yaer-month.domain:any name ]

Target iqn.2015-05.world.srv:target00

# provide device as a iSCSI target

Lun 0 Path=/iscsi_disks/disk01.img,Type=fileio

# iSCSI Initiator's IP address you allow to connect

initiator-address 192.168.171.171

# authentication info ( set anyone you like for "username", "password" )

incominguser ram password

--

Restart the ISCSI Daemon:

/etc/init.d/iscsitarget restart

Confirm status

ietadm --op show –tid=1

CLIENT Configurations:

Client package Installation:

#aptitude -y install open-iscsi

Specify the authentication:

root@ubuntu:~# vi /etc/iscsi/iscsid.conf

# authentication by the target(s), uncomment the following lines:

node.session.auth.username = ram

node.session.auth.password = password

Discover Targets:

root@ubuntu:~# iscsiadm -m discovery -t sendtargets -p 192.168.171.171

192.168.171.171:3260,1 iqn.2015-05.world.srv:target00

Confirm Status After Discovery:

root@ubuntu:~# iscsiadm -m node -o show 

Login to the target:

root@ubuntu:~# iscsiadm -m node --login

Logging in to [iface: default, target: iqn.2015-05.world.srv:target00, portal: 192.168.171.171,3260] (multiple)

Login to [iface: default, target: iqn.2015-05.world.srv:target00, portal: 192.168.171.171,3260] successful.

Check sessions:

root@ubuntu:~# iscsiadm -m session -o show

tcp: [1] 192.168.171.171:3260,1 iqn.2015-05.world.srv:target00

Confirm Partition:

root@ubuntu:~# cat /proc/partitions

major minor #blocks name

8 0 20971520 sda

8 1 19921920 sda1

8 2 1 sda2

8 5 1046528 sda5

11 0 1048575 sr0

8 16 512000 sdb ← Our newly added lun

root@ubuntu:~# fdisk -l /dev/sdb

Disk /dev/sdb: 524 MB, 524288000 bytes

17 heads, 59 sectors/track, 1020 cylinders, total 1024000 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk identifier: 0x00000000

Disk /dev/sdb doesn't contain a valid partition table

You have an up and online LUN in your system.

Disk Management tools:

fdisk

parted

Install Parted:

root@ubuntu:~#aptitude -y install parted

Create a label:

root@ubuntu:~# parted --script /dev/sdb "mklabel msdos"

Create a partition:

root@ubuntu:~# parted --script /dev/sdb "mkpart primary 0% 100%"

Create EXT4 Filesystem:

root@ubuntu:~# mkfs.ext4 /dev/sdb1

Mount the file system and check:

root@ubuntu:~# mount /dev/sdb1 /mnt

root@ubuntu:~# df -hT

FDISK

Create a partition on disk

root@ubuntu:~# fdisk /dev/sdb

Command (m for help): m # Use 'm' print the menu

Command action

a toggle a bootable flag

b edit bsd disklabel

c toggle the dos compatibility flag

d delete a partition

l list known partition types

m print this menu

n add a new partition

o create a new empty DOS partition table

p print the partition table

q quit without saving changes

s create a new empty Sun disklabel

t change a partition's system id

u change display/entry units

v verify the partition table

w write table to disk and exit

x extra functionality (experts only)

Search tools (commands):

Find

locate

grep

Linux can serve as any of the following Virtual server :

KVM

Xen

LXC (for containers)

Docker (for Container)

Openstack (Cloud computing)

Cloud-stack (Cloud computing)

VMware Workstation

Virtualbox (Oracle)

Many more

This is a rough (initial) document. Please share your feedback on this. I would be coming as with Proper Ubuntu "Zero2Pro" document soon.