Thursday, June 25, 2020

Linux - OpenStack installation on Redhat


OpenStack (RHOSP) - Redhat Version

OpenStack is a group of software stack together. There are lots of services and you install them based on your requirement.


Cloud Computing
Private Cloud Computing - When you use your resources such as computer power, CPU, Memory, Disk space, network, firewall, load balancer and other resources, with your company to provide services to your own user then its a private cloud computing.

Public Computing
You will be using computer resources from public companies such as AWS, AZURE or GCP, then its a public computing.


Installation Software Requirement
1. Virtualization tools - Virtual Box or VMware Workstation
2. Linux OS  - Redhat, Suse, Ubuntu
3. OpenStack Software
4. Other softwares

Experience Level
- You need to know basic unix/linux command

Resource Requirement
1. CPU = 2 core
2. Ram = 8 GB
3. Disk = 40 GB but 20 works as well.
4. hostname: openshit.exp.local 192.168.10.155

Tuning ancconfiguration change
1. On CPU - go to advance setting nad make sure to enable vt-x virtualization enable option.
2. Set up software repo


OS Installation
We will be using RHEL7.5 and will just use default installation


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When user request computer resources such as Disk, CPU, Mem or any other request, the request directly goes to cloud computing program. This program is a collection of different services. It includes diferent programs and drivers which knows the backend services such as storage, network and more behind the scene for the user.

So basically the user request comes to this cloud program which forwards the the particular driver and it get processed through. Say, user need 20 GB of storage from cloud provider such as AWS. so user puts a request on, the AWS cloud program takes the request on behalf of user, process through and delivers to the user right away.

User does not need to know what type of storage devlice the storage is allocated, what the maintenance or any other task user will be respobsbile for. End user only care about the resouce they needed.

If your infrastrucccture (hardware, network, software or product) is used by your internal team - its called private cloud computing. This is really important if your data are sensitive or due to rules and regulations you have to store your data locally on your infrasturcture or company, then you will be using private cloud.

OpenStack helps you to manage your
-  Compute resources CPU, Memory
- Storage
- Network
- Security, Load Balancer, Firewall .... and much more


1. Login to your system and
a. Verify you have enough resources available
# free # Check memory
# lscpu # verify CPU
# fdisk -l # Storage - partition

b. Mount your CDROM (To Copy OS content to create repo
# mount /dev/cdrom /mnt/cdrom

if you want your system to mount cdrom permanently, add entry to startup file
# vi /etc/rc.d/rc.local
mount /dev/cdrom /mnt/cdrom

# chmod +x /etc/rc.d/rc.local

c. Disable Network Manager service
# systemctl stop NetworkManager
# systemctl disable NetworkManger

d. Add hosts entry
openstak.exp.local 192.168.10.155

Verfiy it can ping and also outside the network
# ping 192.168.10.1 # your router, gateway
# ping goo.gl # for outside connectivity


2. Upload your software packages to Your RHEL 7 system and create repo
# mkdir /opt/software # winscp your software here
and mount the ISO images
# mount rhel7.5.... /mnt/iso2
# cp -a /mnt/iso2 /opt/software

Same way, mount and copy all the software to /opt/software directory

3. Create repo
# vi /etc/yum.repos.d/opens.repo
[oSoftware]
baseurl:///opt/software
gpgchk=0

# yum clean all
# yum repolist

# go to the software directory and run the comand
# createrepo -v .

If createrepo command is not found, install it
# yum install createrepo

When you create repo, system may cache your info on memory. You may want to free up your cache mem so thatyou will have more memory available. You can either reboot or run the command below or flush the memory.
# echo 3> /proc/sys/vm/drop-cache


4. Install packstack software
If you configure your repo, install openstack-packstack software
# yum install openstack-packstack


Openstack is a stack of software. you have to tell one by one what software you want to install. Rather than manually installing, you can automate this task by generating an answer file.

# packstack --gen-answer-file = answer.txt

you may have to install python-setuptools package

# rpm -qa | grep python-setuptools

Open your answer file and review one by one for your review.
Mostof the case, default installation is ok. If you have low resources, such as CPU/MEM, then you can set n to not to install on answer file next to the name of the software just by replacing y to  n.


Now, run packstack command to install openStack
# packstack --answer-file=answer.txt

It takes about 1-2 hours to complete this task.

Linux - How to install docker on your system

How to install Docker on your RHEL system

1. Go to https://get.docker.com and copy the script and save on your system or use curl to download.
# curl -fsSL https://get.docker.com -o get-docker.sh

2. Run the script. This script will start the installation process of docker.
# sh get-docker.sh

3. Run docker commands
# docker version
# docker ps

4. Start the docker service/daemon
# systemctl start docker
# systemctl enable docker

5. Set up docket account so that you can download docker images from hub.docker.com
Note: You have to create account at hub.docker.com before you set up the configuration
# docker login

6. Download the docker image from docker hub.
# docker pull httpd

Thursday, June 18, 2020

VMWare tools installation on Linux server

Auto install from VMWare console some times does not work. 
1. Mount the VMWare tools
2. Login to command prompt
3. Mount image
# mkdir /many/CD-ROM; mount /dev/CD-ROM /mnt/cdrom
# cd /tmp
# cp /mntri/CD-ROM/VMWareTools-10.3.21.-14772444.tar.gz .
# tar -xzvf VMWare ....Tar.gz
# VMware..../vmware-install.pl

Follow the standard procedure to complete..

Sunday, June 7, 2020

RHEL7-Centos stucks at SELinux policy


Nessus appliance server keep crashing. (I think its a CentOS image).

Upon rebooting system, it was stuck at

systemd[1]: Failed to load SELinux policy. Freezing .

Every time you reboot, power cycle, it just stucks there. No progress,

Solution:
Boot your system, select the kernel line and pres e to edit it.

Now, go to line "linux16" and add selinux=0 value at the end of the line.
Press CTRL + x to boot the system.


After server came up, performed the following tasks..

# sestatus
# yum reinstall selinux-policy-targeted
# touch /.autorelabel
# systemctl reboot

again it stuck at SELinux.So we end up rebuilding it.