Tuesday, December 23, 2014

VMware ESXi 5.5 and LSI RAID monitoring

Adding LSI RAID controller status to VI client and connecting to ESX using MSM (Megaraid Storage Manager) running on Windows.

Sunday, December 21, 2014

Adding pagespeed module to nginx 1.7.8 on Ubuntu 14.04

Wanted run fresh nginx version with Google Pagespeed on Ubuntu 14.04.

Saturday, December 20, 2014

Installing Ubuntu 14.04 LTS with Cacti 0.8.8c

Ubuntu provides only Cacti 0.8.8b so we need to compile our own package with 0.8.8c after installing OS.

Virtualizing old Centos 5 server with software RAID disks

VMware Converter does decent job converting old physical servers to virtual machines, but it refuses to do anything to servers using software RAID. I really don't get why such arbitary limitation is in place. It really doesn't matter if physical server used RAID, software or not, because everything is copied by Converter on file lever rather than block level.

Remapping bad sectors with Linux and dd

I have one faulty non-RAID disk on server which I can't replace right now so I wanted to see if I could mask problems by manually triggering bad sector reallocation.

Sunday, December 14, 2014

Using Sonera 6rd IPv6 with Cisco IOS router

Sonera recently started offering 6rd tunnels to their customers in Finland. Based on this Comcast example it was easy to get Sonera 6rd up with Cisco 892 running IOS 15.5(1)T.

Saturday, December 13, 2014

Prefer IPv4 over IPv6 on CentOS 6

To prefer IPv4 (A) addresses over IPv6 (AAAA) on CentOS 6 you need to add new file named /etc/gai.conf with following content. Last line is what controls if IPv4 or IPv6 should be tried first.

Enable UserDir with Centos 6 and SELinux

I had unfortunate opportunity to play with RedHat / Fedora / CentOS distribution today. I have to say that as much as I hate Ubuntu, CentOS is even worse than it was few years ago when CentOS5 was still current.

And now we're ignoring RHEL7 / CentOS7 where headless server installer requires GUI that's optimized for touch screen and tries to imitate Ipad. Recommended solution? Use VNC to connect installer. Aargh! I should probably have Ipad to run that VNC client - for improved user experience you know.

Wednesday, December 10, 2014

Remote conversion of 64-bit CentOS 6.5 to 64-bit Ubuntu 14.04

For 32-bit source to 64-bit see my older post.

Old install was using software RAID-1, but did not have LVM. Small 200MB /boot partition, 8GB swap and rest as one root partition. We're redoing it completely so what it used to be doesn't really matter. All existing data on root will be lost.

Oddities of dnsmasq when used with IPv6 resolvers

# dnsmasq --version
Dnsmasq version 2.68  Copyright (c) 2000-2013 Simon Kelley
Compile time options: IPv6 GNU-getopt DBus i18n IDN DHCP DHCPv6 no-Lua TFTP conntrack ipset auth

# md5sum dnsmasq*
8a704b6aa977df9485b3faf940cc5e35  dnsmasq_2.68-1_all.deb
60bafb9b863671bb02595505a447270c  dnsmasq-base_2.68-1_amd64.deb

There was odd "[icmp6 sum ok] ICMP6, destination unreachable, unreachable port" going out from my server every time DNS reply was received. Turns out it was because dnsmasq IPv6 support is buggy.

Sunday, December 07, 2014

Headless Ubuntu 14.04 Server with full disk encryption, remote unlock, software RAID, LVM and EFI for over 2TB disk support

Headless Ubuntu 14.01 LTS server with full disk encryption, remote unlock over SSH, software RAID, LVM and support for over 2TB disks with EFI and BIOS MBR boot. That's what this post is about. Oh, and pics are at the end.

Thursday, December 04, 2014

Cisco EEM applet to monitor and repair broken DHCP leases

Dirty hack to renew DHCP lease on Cisco 881 if Internet access is lost. This can happen when Cisco has valid DHCP lease from ISP and then cable modem or DSL router is power cycled but switch between Cisco and upstream device keeps link-state up. Options are either to fix it manually (pull cable / change config / reboot Cisco) or hack something like below. I'm also pinging over VPN tunnel to Intranet as it would be shame to break this due Level 3 and Google blocking ICMP which might happen one day.

/31 aka 255.255.255.254 netmask with Windows

Windows GUI prevents you from setting this with helpful error message of "All of the bits in the host address portion of the IP address are set to 0". IP stack seems to be fine with /31 networks so just set it from CLI.

netsh interface show interface

netsh interface ip set address name="Local Area Connection" source=static addr=10.71.219.238 mask=255.255.255.254 gateway=10.71l.219.239

Monday, December 01, 2014

Moving VMs between datastores with free ESXi (and very fast GhettoVCB restores)

Trying to move virtual machine between datastores (local or remote) can be painful without vCenter and SVmotion. Easy and fast way is to use traditional VI Client to move contents of virtual machine directory via datastore browser (Move To feature). Processing stays within ESXi and goes quickly. VMware converter could also be used, but it's SLOOOOOW and everything goes via management PC which is dumb design.

GhettoVCB restores aren't fastest either. This is quite obvious workaround, but I have to admit didn't realize this until today. Since backups are NFS mounted I can simply import VMX file from backup directory using datastore browser. Yes, this will result in changes to backup which is not that great, but at least it's quick - even biggest VM can be restored in couple minutes. And that issue with changes to backup could be easily solved with ZFS snapshots.