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Tuesday, December 31, 2013

Enable IPv6 on OpenVZ node


This page provides a guideline for setting up IPv6 on a CentOS 6.2 OpenVZ host node. We used SolusVM, but this guide is applicable to any deployment.

1) Check

/etc/sysctl.conf
It should contain the following:

net.ipv4.ip_forward = 1
net.ipv6.conf.default.forwarding = 1
net.ipv6.conf.all.forwarding = 1
net.ipv4.conf.default.proxy_arp = 0
net.ipv4.conf.all.rp_filter = 1
kernel.sysrq = 1
net.ipv4.conf.default.send_redirects = 1
net.ipv4.conf.all.send_redirects = 0
net.ipv6.conf.all.proxy_ndp = 1
2) Check

/etc/sysconfig/network
It should contain the following:

NETWORKING=yes
HOSTNAME=eb1.evoboxes.org #Your Hostname goes here
GATEWAY=192.168.1.1 #Your IPv4 Gateway Goes here
NETWORKING_IPV6=yes
IPV6_DEFAULTGW="2001:123:123:1::ffff" #Your IPv6 Gateway goes here
IPV6FORWARDING=yes
3) Check

/etc/sysconfig/network-scripts/ifcfg-eth0
(or ethX depending on your configuration)

It should contain the following:

DEVICE="eth0"
BOOTPROTO="static"
BROADCAST="192.168.1.127" #Your Broadcast Address
DNS1="4.2.2.1"
GATEWAY="192.168.1.1" #Your IPv4 Gateway
HWADDR="00:25:90:55:3C:5A"
IPADDR="192.168.100.1" #Your IPv4 Address
NETMASK="255.255.255.0" #Your IPv6 Address
NM_CONTROLLED="yes"
ONBOOT="yes"
TYPE="Ethernet"
IPV6INIT="yes"
IPV6ADDR="2001:123:123:1::1" #Your IPv6 address, just use the first address from your prefix
IPV6_AUTOCONF=no
4)Run the following command:

cat /proc/sys/net/ipv6/conf/default/disable_ipv6
If the value is 0, you can skip to step 6.

5) If the value of the above command is 1: Run the following command:

echo 0 > /proc/sys/net/ipv6/conf/default/disable_ipv6
6) Disable ip6tables to prevent any issues:

service ip6tables stop
chkconfig ip6tables off
7) Restart Networking:

service networking restart
Make sure you don’t see any errors

8) If you are using SolusVM, proceed to step 10.

9)Add IPv6 address to a VPS:

vzctl set <CTID> -ipadd <ipv6_addr> --save
Currently it seems that OpenVZ cannot add an address prefix, only a single address or /128.

10) If you followed step 9, skip this step. Add the IPv6 block in SolusVM: IP Blocks -> Add IPv6 Block Add IPv6 addresss to the block: IP Blocks -> List IP Blocks -> Manage Addresses and follow the directions Add the IPv6 addresses to the VPS: Virtual Servers -> List Virtual Servers -> Pick one -> IP’s -> Add Additional IPv6.

11) Login to the VPS and Test: SSH into the Host Node

vzctl enter <CTID>
ping6 ipv6.google.com
ping6 comcast6.net
12) Enjoy!

Sunday, December 22, 2013

Install grub from rescue mode: Software raid 1





I use CentOS CD and boot into Linuxrescue. From there i fixed master boot record.

1. open grub
2. grub> find /grub/grub.conf
3. This provide some thing like:
(hd0,2)
(hd1,2)
4. root (hd0,2)
5. setup (hd0)
6. root (hd1,2)
7. setup (hd1)
8. quit grub