Algo de Redes

#----Conexiones no exitosas.
#nc -zv 172.168.1.1 80

#----Visualizar por que interfaz de red sale el trafico
#/sbin/ip route get 10.11.34.1

#Borrar ip vieja:
#ip addr del 10.75.255.15/22 dev eth2.150

#Desactivar ZEROCONF 
#En la salida del comando route se ve algo como esto:
#169.254.0.0     0.0.0.0         255.255.0.0     U     0      0        0
#add the following NOZEROCONF value to the end of the file:
#NETWORKING=YES
#HOSTNAME=localhost.localdomain
#NOZEROCONF=yes

# Rutas en rhel7
ip route
ip route get 10.0.0.1
cat > /etc/sysconfig/network-scripts/route-{$ifname} << EOF
10.0.0.0 via 10.0.2.1 dev ${ifname}
EOF
systemctl restart network

# Netcat para puerto en escucha local
nc -l 8080 

# Netcat para test tcp
nc -z -n -v ip_servidor port
nc -z -n -v 10.0.0.2 8888

# Netcat Conexion TCP
Server A
nc -l 8888 > output_file

Server B, client.
nc server_a_ip 8888 < send_file

Web Server
while true ; do nc -l -p 8443 -c 'echo -e "HTTP/1.1 200 OK\n

\n $(date) $(hostname)"'; done

Reglas Udev Oracle

cd /etc/udev/rules.d


vi 96-dm-oracle-permissions.rules

##### SE AGREGA LINEA POR CADA DISCO ######

ENV{DM_NAME}=="mpdata01", OWNER:="oracle", GROUP:="oinstall", MODE:="660"
ENV{DM_NAME}=="mpdata01p1", OWNER:="oracle", GROUP:="oinstall", MODE:="660"

ENV{DM_NAME}=="mpdata02", OWNER:="oracle", GROUP:="oinstall", MODE:="660"
ENV{DM_NAME}=="mpdata02p1", OWNER:="oracle", GROUP:="oinstall", MODE:="660"

#################################################

luego ejecutar:

[root@linux]# udevadm control --reload-rules
[root@linux]# udevadm trigger --type=devices --action=change

Esto te muestra las propiedades y te puede ayudar:
udevadm info –query=property –name /dev/xxxxxx

LVM (cortitos)

#pvcreate /dev/mapper/mp_u00p1
#vgcreate vg_u00 /dev/mapper/mp_u00p1
#lvcreate -n lv_u00 -l 100%FREE vg_u00
#mkdir /u00
#mkfs.ext4 /dev/vg_u00/lv_u00
#tune2fs -c -1 /dev/vg_u00/lv_u00

RESIZE FS  
#RHEL 5 y 6
#lvresize -L +8G /dev/<volumegroup>/<logicalvolume>
#resize2fs -p /dev/<volumegroup>/<logicalvolume>10G

#RHEL4
#ext2online /dev/<volumegroup>/<logicalvolume>

Falla en la desinstalacion de Access Control

Si al intentar desisntalar el access control, nos tira un error del tipo:

[root@app4 lbin]# /opt/CA/eTrustAccessControl/lbin/Uninstall

ERROR: Another CA ControlMinder process is currently running.
Wait until the process completes and run uninstallation again,
or remove /tmp/pre_install.
[root@app4 lbin]#

La solucion es borrar el /tmp/pre-install

[root@app4 lbin]# rm -fr /tmp/pre_install
[root@app4 lbin]# /opt/CA/eTrustAccessControl/lbin/Uninstall
Removing CA ControlMinder service from /etc/services
Removing CA ControlMinder system call loader.
Trying to remove references to CA ControlMinder from the system init files.
Removing CA ControlMinder PAM module from your system.
Restoring /etc/pam.d/login by removing last changes made to file
Removing CA ControlMinder Admin tools binaries and directories.
Removing CA ControlMinder Admin tools X-resource files.
The CA ControlMinder Admin tools files have now
been removed from your system.
Removing seos.ini from /etc
The token global.AC_Version, now set to 'none', (was '12.xx.0.2919')
Removing ControlMinder from AccessControl Shared dependency list
Removing AccessControl Shared
Removing CAPKI.
Removing CA ControlMinder binaries and directories.

UnInstall complete.

The CA ControlMinder files have now been removed.

Warning: If you have replaced /bin/passwd with sepass,
         You must restore the original /bin/passwd.

         You may edit your /etc/passwd and /etc/group
         files, in order to remove unnecessary users.

[root@app4 lbin]#

Upgrade version de SO desde el satellite

subscription-manager register --org="miOrga" --activationkey="ak_miOrga"
subscription-manager release --set=6.9
subscription-manager release --show
yum --releasever=6.9 update

Agregar VIP al cluster 6.6

Editar el archivo /etc/cluster/cluster.conf y agregar la ip como servicio y como recurso

[root@cluster01]# vim cluster.conf

<resources>
      <ip address="10.5.254.3" monitor_link="1"/>
</resources>

<service autostart="1" domain="fd-mbdvdes" name="svc-mbd" recovery="relocate">
              <ip ref="10.5.254.3"/>
</service>

Verificar la version actual del archivo de configuracion del cluster, con el siguiente comando

[root@cluster01]# cman_tool version
6.2.0 config 24
[root@cluster01]#

Ahora con ese dato, editar el archivo de configuracion del cluster ( en ambos nodos del cluster ) y en la primera linea modificarle al version ( sumaremos 1 a la actual, en este caso sera 25 )

[root@cluster01]# vim cluster.conf
<?xml version="1.0"?>
<cluster config_version="25" name="cl-cluster">

Ahora si, replicar la configuracion con el siguiente comando ( ejecutarlo solo en uno de los nodos ) :

cman_tool version -r -S

Ahora chequeo si levanto la ip VIP del cluster

[root@cluster01]# ip ad sh |grep glo |grep bond0

    inet 10.5.252.2/22 brd 10.5.255.255 scope global bond0.150
    inet 10.5.254.3/22 scope global secondary bond0.150
[root@cluster01]#

Habilitar core dumps (crash dumps)

cat /etc/kdump.conf |grep -v "#"
path /var/crash
core_collector  makedumpfile -c --message-level 1 -d 31

[root@prod5 ]# service kdump restart
Stopping kdump:                                            [  OK  ]
Detected change(s) the following file(s):

  /etc/kdump.conf
Rebuilding /boot/initrd-2.6.32-358.el6.x86_64kdump.img
No module seos found for kernel 2.6.32-358.el6.x86_64, aborting.
Failed to run mkdumprd
Starting kdump:                                            [FAILED]
Solucion
secons -sk
SEOS_load -u
y reintentar
si no funciona bootearlo sin ac
chkconfig seos off
reboot
service kdump restart

Probar kdump

#probar kdump
#Then type the following commands at a shell prompt:
#echo 1 > /proc/sys/kernel/sysrq
#echo c > /proc/sysrq-trigger