CT's Tech Notes

Send BREAK command when router is booting up. Router went into rommon mode Putty Terminal can send Break command rommon 1 > confreg 0x2142 Reset or power cycle for new config to take effect rommon 2 > reset

This note focuses on manual creation and manipulation of LVM. Create Physical Volume pvcreate /dev/sdax Create Logical Volume Group vgcreate vgx /dev/sdax Create Logical Volume lvcreate -n vmxx --size 6g vgx Create Patition of logical Volume fdisk /dev/vgx/vmxx Map and mount kpartx -v -a /dev/vgx/vmxx mount /dev/mapper/vmxxp1 /foo Remove mapping kpartx -v -d /dev/vgx/vmxx ================================= #Walk through lvcreate -n storage --size 40g vg0 fdisk /dev/vg0/storage ------------------------------ n - new partition p - primary partition 1 - partition number 1 Enter Enter Just create new parition ------------------------------- kpartx -v -a /dev/vg0/storage mkfs.ext3 /dev/mapper/storage1 mkdir /foo <---- THE DIRECOTRY TO MOUNT mount /dev/mapper/storage1 /foo

In this lab, we already install Openvz container kernel at host system. Create new empty VM mkdir /vz/root/101 /vz/private/101 cat /etc/vz/conf/ve-vps.basic.conf-sample > /etc/vz/conf/101.conf Copy data from Physical to VM directory rsync -arvpz --numeric-ids --exclude dev --exclude proc --exclude tmp --exclude sys --exclude mnt -e "ssh -l root@x.x.x.x" root@x.x.x.x:/ /vz/private/101/ Create /etc/vz/conf/101.conf VE_ROOT="/vz/root/$VEID" VE_PRIVATE="/vz/private/$VEID" OSTEMPLATE="centos-5" IP_ADDRESS="192.168.1.1" HOSTNAME="penguin" NAMESERVER="8.8.8.8" #Making adjustments Edit /vz/private/101/etc/inittab sed -i -e '/getty/d' /vz/private/101/etc/inittab Edit /vz/private/101/etc/mtab rm -f /vz/private/101/etc/mtab ln -s /proc/mounts /vz/private/101/etc/mtab Edit /vz/private/101/etc/fstab cp /vz/private/101/etc/fstab /vz/private/101/etc/fstab.old grep devpts /vz/private/101/etc/f...

At a start, install CentOS minimal installation Update OS using yum yum -y update Install NTP for time sync (Xen HOST only) yum -y install ntp sed -i -e 's/^restrict -6/#restrict -6/' /etc/ntp.conf ntpdate pool.ntp.org hwclock --systohc /etc/rc.d/init.d/ntpd start chkconfig ntpd on Reboot with lastest patches reboot Install Xen and Xen Kernel yum -y install xen kernel-xen Enable booting Xen Kernel sed -i -e 's/^default=1/default=0/' /boot/grub/grub.conf Reboot for new XEN kernel reboot Commands for LVM creation pvcreate /dev/sdax vgcreate vg0 /dev/sdax lvcreate -n vm01 --size 6g vg0 lvcreate -n vm02 --size 6g vg0 Sample config for VM01 to be save to: /etc/xen/vm01 name = "vm01" disk = [ "phy:/dev/vg0/vm01,xvda,w" ] maxmem = 512 memory = 512 vcpus = 2 bootloader = "/usr/bin/pygrub" vif = [ "bridge=xenbr0" ] Populate the Xen VM partition with minimal OS fdisk /dev/vg0/vm01 kpartx -v -a /dev/vg0/...

Default baud rate for Cisco Switch is 9600 Switch to supervisor mode ena(enable) Go into configuration terminal config t (configuration terminal) Set hostname hostname myciscoswitch Enable password and encrypt enable secret p@ssw0rd service password-encry VLAN related show vlan Name VLAN 1 vlan 1 name myvlan1 Configure access port interface fastethernet 0/x switchport access vlan 2 Configure trunk port  interface fastethernet0/x switchport mode trunk switchport trunk encapsulation dot1q switchport trunk allow vlan 10-15,20 Exit from configuration mode exit Write current configuration to startup configuration in order to make it permanent upon reboot. write memory

cpio is a useful tool to archive Linux system. In this article, we are going to archive / partition which is mounted from sda11 partition. ###Archive ssh root@192.168.1.104 "find / -xdev -print0 | cpio --null --create" > sda11.cpio ###Extract cpio --extract --no-absolute-filenames --file=sda11.cpio For the /dev directory, recommended to be archived by tar command ssh root@192.168.1.104 "tar -c /dev" > dev.tar