User:Tom/RHCSA EX200

Lab setup

Physical host         host1
Virtual machine 1     server1   192.168.122.110
Virtual machine 2     server2   192.168.122.120

Hoofdstuk 02 Using basic Linux Tools

ssh host
ssh -l user host
ssh -X host
ls pwd cd mkdir 
tty who uptime whoami logname
if groups 
last lastb lastlog 
uname 
hostnamectl
timedatectl list-time-zones
clear 
which wc
lspci lscpu
gzip gunzip bzip2 bunzip2 tar star
vi
man apropos mandb whatis info

Hoofdstuk 03 Working with files and file permissions

/boot /var/ /usr /opt /home /dev /proc /sys /tmp
file touch cat less head tail
cp mv rm lsattr chattr
find 
ln, ln -s
chmod chown chgrp
umask files en directories. Initial permissions for file 666 and for directories 777.

Special permissions setuid setgid sticky. setuid s set on owner of executable files, setgid  s set on group of executable files.
Examples are su and wall.
setgid on directory group; new files inherit directory's owning group.

Hoofdstuk 04 Dealing with the Bash shell, processes and scheduling

variables, local and environment
export unset
> >> &>
HISTFILE history
set -o vi
grep * ? \
ps pidof pgrep
nice  renice
kill pkill killall
at crontab 

Hoofdstuk 05 Managing software packages

RHSM Red Hat Subscription Management
SAM Subscription Asset Manager
subscription-manager
rpm rpm2cpio
mount /dev/cdrom /mnt
mount -o loop /.../*.iso /mnt

yum-config-manager
yum check-update clean, group install, group info, group list, group remove,
    repolist, repolist all, repository-packages
    info, install, list, search, update, history
createrepo

man yum.conf for info about repository files

gnome-packagekit

/etc/yum.conf
/etc/yum.repos.d

Hoofdstuk 06 Configuring server virtualization and network installing RHEL7

lscpu
yum -y group install 

virt-install
virsh list pool-list pool-info
virt-manager

brctl

Kickstart anaconda-ks.cfg
ksvalidator
wget

/etc/sysconfig/network-scripts

Hoofdstuk 07 Booting RHEL 7, updating Kernel and logging messages

lsmod
modinfo
modprobe
grub2-mkconfig -o /boot/grub2/grub.cfg
grub2-set-default

rootpw init=/sysroot/bin/sh, chroot /sysroot, mount -o remount,rw /, passwd, touch /.autorelabel, exit, reboot

yum list installed kernel

/boot
/etc/grub.d

systemctl 
systemd-analyze
systemd-cgtop

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

Hoofdstuk 08 Managing users and groups

pwck 
pwconv
grpconv

useradd, usermod, userdel
chage

vigr
vipw 

groupadd, groupmod, groupdel 
gpasswd
/etc/default/useradd
/etc/passwd
/etc/shadow
/etc/login.defs
/etc/skel
/etc/group
/etc/gshadow

/etc/bashrc
/etc/profile
/etc/profile.d
.bashrc
./bash_profile

Hoofdstuk 09 Partitioning and managing disk storage

Master Boot Record (MBR) on BIOS-based systems versus GUID Partition Tabel (GPT) on UEFI-based systems.

parted, gdisk, fdisk
partprobe
lsblk 

pvs
vgs
lvs
vgdisplay 
lvdisplay 
lvmdiskscan

pvcreate 
vgcreate
vgextend
vgreduce
vgremove

lvextend
lvresize
lvreduce
lvremove

/etc/lvm/backup  Contains volume group details

Hoofdstuk 10 Constructing and using filesystems and swap

Filesystem administration commands.

e2fsck
fsck.ext3
fsck.ext4
mke2fs
mkfs.xfs
resize2fs
tune2fs

Commands common to all filesystems.

blkid - Used to dermine UUID of a partition / logical volume / filesystem
mount
umount

NFS filesystems

Package nfs-utils
mount -t nfs 192.168.1.110:/aapje /aap
/etc/fstab: 192.168.1.110:/aapje /aap nfs _netdev 0 0 

AutoFS

Package autofs
Daemon automount

/etc/sysconfig/autofs
/etc/auto.master

UUID universally Unique IDentifier

Swap Space

free -h lvcreate mkswap swapon

ACL's

chacl
getfacl file1
setfacl -m user:aap:rw file1

mount options: defaults,acl

Hoofdstuk 11 Controlling Access through Firewall and SELinux

SELinux

context for subjects and objects
context contains a type or domain and a security level with subject and object information
-u user, _r role, _t domain

Domain transitioning allows a proces in one domain to enter another domain to execute an application authrized to run in that domain only, a proper rule must exist to support such a transition.

Commands

id -Z                                                      View context set on Linux user
ls -Z                                                      Determine context for files
ps -eZ                                                     Determine context on processes
seinfo -u                                                  List available SELinux users
semanage
sestatus                                                   SELinux status tool
getsebool -a                                               Show all SELinux Boolean variables
setsebool                                                  Set a boolean variable
getenforce                                                 Get the current mode of SELinux
setenforce
cp --preserve=context                                      Preserve specified attributes
sealert                                                    SELinux troubleshooter

Packages

libselinux-utils
policycoreutils
setools-console                                            contains seinfo command
setroubleshoot-server                                         Troub

Files

/etc/sestatus.conf
/etc/selinux/config                                         Controls state of SELinux (enforcing, permissive or disabled
/etc/selinux/targeted/contexts/files/file_contexts.local    custom context
/sys/fs/selinux/booleans

Hoofdstuk 12 Administering Network Interfaces and Network Clients

Hostname

Commands

arp -a
ip neighbor
hostname
hostnamectl
ifdown ifup
nmcli
nm-connection-editor
nmtui
uname 
systemctl restart systemd-hostnamed

yum install *ldap* packages
authconfig
authconfig-gtk
authconfig-tui
system-config-authentication

Files

/etc/hosts
/etc/resolv.conf
/etc/sysconfig/network-scripts

/etc/sssd/sssd.conf

Hoofdstuk 13 Securing access with SSH and TCP wrappers

ssh-keygen
ssh-copy-id

sftp

yum info tcp_wrappers
/etc/sshd/sshd_config
/etc/sshd/ssh_config
/etc/hosts.allow
/etc/hosts.deny
/var/log/secure

Hints

repo
kernel update
acl
ntp
autofs
ldap
swap create lvm en partitie
lv in nieuwe vg