It’s the cable problem, D***!

 Triviality  No Responses »
Jan 302014
 

I had two servers that always run at 100Mbps, which was OK but whenever I turned them to GlusterFS bricks, things became obviously not working.

It sounds like simple, right? Yea, I tried ethtool to force them running on GigE, didn’t work; I tried to change to another switch port, didn’t work … after blocking myself from the servers for several times (ethtool!), I finally decided to change to use 2nd NIC on those two servers. They were good, running at GigE immediately after plugging into the switch. Continue reading »

Virtualization, GlusterFS, and automation

 Triviality  1 Response »
Jan 272014
 

Finally I got some time playing with GlusterFS and libvirt.

I’m not going to step into GlusterFS setup as it’s really easy and straight forward, I did CentOS kickstart (non-attendance) installation as well since it may help me in future deployment. Note that I assume you have glusterd running the host node, other all localhost below should be replaced by the hostname that is running glusterd. Continue reading »

Get rendered HTML

 Triviality  No Responses »
Jan 152014
 

Search team is doing crawling and some web sites are heavily using JavaScript to generate content. Whenever I said “heavily” I mean none of the UI elements was from HTML, instead, JavaScript runs after the page loaded, then shown to users.

I’m doing a prototype so that they can take as a reference and later on do something fit into their system better. The prototype as based on PhantomJS, it was in Ubuntu (12.04 LTS) repository which makes my life much easier. Again, I need to install xvfb so that I can run X-based application in command line. Continue reading »

Interesting iptable use cases

 Triviality  1 Response »
Jan 132014
 

I’m working on migrate office LAN from one subnet to another subnet, it brings lots of network inter-connection issues, and it seems iptable is Swiss knife that can solve anything :P.

One case is that I need to let machines in new subnet accessing the old subnet, since the dump router is busy enough to handle uplink and VPN and port forwarding, I decided to use a Linux box to get things done, all that I did: Continue reading »

Enable console on VMs

 Triviality  1 Response »
Jan 032014
 

Finally I decide to turn on console on all my VMs so that I don’t have to rely on VNC for remote access whenever network is having problem – I’m trying to join corp network now and there are lots of network glitches during last week and I believe there will still be some in the coming week.

Actually it’s not that complicated, on CentOS (5 or 6) machines, add following line to /etc/inittab (do a dmesg | grep tty to make sure it is ttyS0 for you, but I believe they are all the same for kvm based VMs): Continue reading »