I don’t know how many of you know that I am a recovering gentoo user. One of the staples of my desktop used to be keychain. Keychain is a simple wrapper for ssh-agent and gpg-agent. It eases the use of a single long running agent per system instead of per login session. For some reason this tool had fallen out of my basket when I switched to debian several years ago.
Besides the gui/vnc consoles you can still use the equivlent of xm console in Citrix XenServer. On the host console: xe vm-list to get the list of domins running (just note the uuid of the domain you want). list_domains will list the domain name and the uuid of the domains. Match up your uuid so you get the proper dom_id xm console equivlent is /usr/lib/xen/bin/xenconsole dom_id Its not in the root users $PATH though I think it ought to be.
Don’t even start with me about how telnet is horrid. Out side of my control but I recently had issues trying to enable telnet on a server. Typically its pretty straightforward. yum install telnet-server chkconfig telnet on chkconfig xinetd on service xinetd start Unfortunately for me this was not working. Every time I tried to telnet to the host after enabling it I would get an error message.
I recently had a need to push out a few settings to a group of iLOMs on new Sun servers. I really despise using a web interface for everything so I took the ssh route. The first thing I tried to do after determining the commands I needed was to shove the commands in with ssh directly. I quickly became apparent that route just wasn’t going to work. When you log into the iLOM “daemons” need to initialize.
In the last week my wife and I have both experienced excellent customer service. All too often you only hear about a company when they do something bad (see all my fail posts). I just want to be sure to give kudos to both of these companies. 1) BornFree: My wife ordered some BornFree Spouts as we start transitioning our son to sippy cups. She said about 5 minutes after she hit the order button she realized she should have ordered more.
Citrix has released the beta for the next version of XenServer code named “Midnight Ride”. I’m looking forward to the enhanced snapshots (memory+disk), and memory over commit for lab environments. Get access to the beta program here
I know I’ve mentioned how much I love the sysstat package before. I use sar regularly to help with performance diagnostics (Analyzing Linux System Performance And Finding Bottle Necks, CPU Performance Analysis In Linux, Baseline Analysis Is Important, CPU Performance Analysis In Linux Revisited). I wrote this little Nagios plugin to collect the performance metrics that sar collects. I use this plugin with Zenoss and I set any performance thresholds there, more important to me was collecting the information for historical graphing.
If you hadn’t already guessed I am a big fan of the Xen hypervisor. Lately I have been using the Citrix XenServer release because it makes it quite palatable for my co-workers. One annoyance that I do have about XenServer is the requirement that you license it (with a free license) every year. If you fail to license it the GUI stops working. Now I hate relying on GUIs but the fact of the matter is others in my team expect to have a working GUI when they need to do something.
Have you ever had a machine that was a bit flaky? You know those ones that occasionally crash and don’t write anything useful into the log file. Sometimes you can capture those messages with netconsole. Just revisiting a small walk-through I wrote a while back. Remote kernel logging with netconsole for fun and profit
I like to have as little run in dom0 as possible. However some things you really need checked from dom0, like the status of your raid perhaps. Just some quick instructions on getting Nagios NRPE running in XenServer. Install EPEL repository and disable it by default (remember we don’t want to accidentally install unnecessary packages) wget http://download.fedora.redhat.com/pub/epel/5/$(uname -i)/epel-release-5-3.noarch.rpm rpm -hiv epel-release*.rpm sed -i ’s/enabled=1/enabled=0/g’ /etc/yum.repos.d/epel.repo Install nrpe and configure it to start on boot yum install –enablerepo=epel nrpe chkconfig nrpe on