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Redhat training notes.md

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cmd subcommand -paramter(s) argument ls cd netstat nmcli man nmcli

click console on workstation student / student root / redhat

  1. lab finish <script> lab start <script>
  2. on rol lab interface
    • reset / shutdown / start
    • stop all VMs/ re-start all vMs
  3. Delete / re-create the whole lab

unix/linux

  • vi

  • vim

i I o O a A x dd dw cw

yy 2y p P

:w! :q :wq! :q! ZZ :100,105 move :20,40 copy :1,4 delete :s { } u undo last action U undo all action on that line :e! -- undo all changes . redo / repeat last action

/text ?text n N

global substitution

:%s/old-text/new-text :%s/old-text/new-text/g

YAML

set ts=2 sts expandtab set list set number set nonu

rsh/ telnet (clear)

ssh

  • disable password-based authentication
  • enable key-based --> password-less

username / password ssh

  • private (passphrase)

root

your account (username)

  • remote db server (admin)

rsa dsa ecdsa

IBM Control / Insights

Netapp Insights

  • netapp
  • cisco
  • ibm

RabbitMQ

  • messaging platform

disk-based network-based (NFS / CIFS) pseudo (memory-based

Redhat

  • during installation PCI-DSS \

UEFI df -k / /var /home

EFI

/boot GRUB

characters/raw/sectors

  • 512b / unit

block

  • 4k / unit

/var/www/html

partition --> mkfs (ext2-4,xfs).

soft/symbolic link

  • shortcut link / pointer
  • point using file path
  • original file and the link can be in same/different file system
  • ln -s link-name
  • target can be file/directory vs hard link
  • backup link
  • point using inode
  • original file and the link must be in same file system
  • ln link-name
  • only file

{} [] * ~

`` ~ ''

Redhat cloud (private)

  • insights
  • openshift
  • ansible (AAP)

rpm

  • local package management
  • display/check/verify yum
  • configure repository dnf
  • configure repository
  • better/improvised caching

Air gap

kernel-5.14 -- /boot/ kernel-5.15 -- /boot/

redhat v6

yum group info

yum group list

redhatv7

yum group info

yum groupinfo

yum group list

yum grouplist

BaseOSv1 --> v2 kernel vi binaries

Developmentv1 X-->v2 java python

CentOS -> alma / rocky remove baseos keep appstream

ini [section]

wget http://lab.domain19.example.com/redhat/aaa.gpg

1.8" 2.5" 3.5" HDD (spinder, platters)

  • big capacity
  • price lowest SSD (flash-based)
  • latency / speed

NVMe-SSD

lsblk

block(4k) - fileA (5k) block(4k) - fileB (1k)

fsck-level ufsdump-level (backup)

CPU (6GHz) -- RAM DDR5 (5GHz) NVME-SSD microsecond

RAID vs LVM

  • 0 = mirroring
  • 1 = concatenation
  • 2,3,4
  • 5 = stripe set with parity
  • 6 = stripe set with double parity
  • 10

spanned

linear LV

stratisFS vdo

/data1

ext4 lvresize resize2fs

xfs lvresize xfs_growfs

compression

  • utilize idle cpu cycles
  • big file 100m --algorithm-->20m
  • compressive-friendly: database 80%-85% , virtualization 70-75%, oil & gas
  • not compressive media (jpg, gif, mp4, mp3, mkv) vs deduplication
  • utilize RAM to create the hashed table
  • delete duplicate data / file

Netapp

Hard disk (1T) ==> sales volume (500G) <-- ==> hr volume (500g) ==> finance volume (500g)

Rootful Container login as root podman run --name web1 -p 80:80 -d httpd

  • full access to networking (IP/dns/routing table/gateway)
  • when the VM reboots, container restart
  • systemctl enable/start/stop/disable

Rootless Container login as non-root (rootless) podman run --name web1 -p 8080:80 -d httpd

  • limited
  • when the VM reboots, container stop ephmeral
  • container ephemeral storage
  • container can automatically if following:

    1. configure the container to start with
      systemd

      • container start when user ssh / graphical (login) podman generate systemd or podman generate systemd --new

    2. enable linger

      • when the VM reboots, container restart
  • systemctl --user enable/start/stop/disable

useradd -d -u -g ali

  • rootless

nmcli con show nmcli con add nmcli con mod nmcli con up

wget http:/

    /gpg...

    configure repo vi /etc/yum.repos.d/exam-objective-base.repo [baseos] name="description" baseurl=http://.... enabled=1 gpgcheck=0 gpgkey=...

    vi /etc/yum.repos.d/exam-objective-appstream.repo [baseos] name="description" baseurl=http://.... enabled=1 gpgcheck=0 gpgkey=...

    dnf repolist dnf list dnf install -y httpd mariadb mysql

    firewall-cmd --permanent --add-service={http,mysql} firewall-cmd --permanent --add-port=8080/tcp firewall-cmd reload

    semanage -l semanage fcontext -at semanage port -at

    systemctl enable --now httpd systemctl enable --now mariadbd

    rpm -q

    useradd -g -G ali usermod userdel groupadd groupdel groupmod passwd

    su - ali

    crontab -e

            • script/cmd

    dnf -y install crond systemctl enable crond --now

    mkdir

    dnf -y install chrony vi /etc/chronyd.conf under pool line server <hostname/ip> systemctl enable chronyd --noew

    dnf -y install autofs vi /etc/auto.master /rhome auto.home vi /etc/auto.home ali utility.servera.example.com:/rhome/ali abu utility.servera.example.com:/rhome/abu #* utility.servera.example.com:/rhome/&

    systemctl enable autofs --now ls -ld /dir/findfile mkdir /dir/findfile find / -user abu --exec cp {} /dir/findfile ;

    grep tar

    podman run --name test01 -v "/host-dir:/container-dir:Z" podman generate systemd --new --file mv test01.service ~/.config/container/systemd/user/ systemctl --user enable/top/start test01 loginctl enable-linger

    chmod

    su - ali vi .bashrc umask 027

    reset password

    vgcreate lvcreate -l 60 | -L 60M

    vg PE=16M

    mkfs lvresize xfs_growfs

    parted fdisk

    mkswap

    create normal parition lsblk vi /etc/fstab UUID= /dev/vgname/lvname /mnt xfs defaults 0 0 UUID=<swap-uuid swap swap defaults 0 0

    systemctl daemon-reload

    dnf -y install tuned tuneadm recommend ==> balanced tuneadm profile balanced systemctl enable tuned --now

    Exam voucher

    • expiring

    Quintegral

    wired

    • usb