I’m attempting to use a Windows Active Directory for user authentication in an OpenSUSE Linux environment. The configuration tools in OpenSUSE’s Yast take care of just about everything, or try to at least. But I found one instance where a default samba setting just doesn’t make the cut.
Sanlock helps you avoid screwing things up by starting the same virtual machine on multiple hosts, which will quickly mangle the guest file systems. But you’ll quickly find live migration no longer works from the virt-manager GUI.
I was in shock when I first saw this migration error from virt-manager!
Internal error cannot use migrate v2 protocol with lock manager sanlock? But alas, all is not lost.
Migration from the virsh command shell works just fine for me. And it’s quicker and more efficient than doing it pointy-clicky style from a gui anyway. If i’m migrating a guest from one host to another, it’s usually because I need to shut down the host hardware. I’m not migrating just one guest, i’m migrating one at a time.
With the shell method, I repeat the migration command in a loop and move them all, one after another automatically. Monday migrate, tuesday migrate, everybody. It’ll get in your bones!
root@host1~# for x in 1 2 3 4 5 6 7 8; do
virsh migrate –live guest$x qemu+ssh://host2/system
When I first set up sanlock for qemu locking, I saw errors during migration of several hosts that were already up and running with local locking before sanlock locking was implemented.
error: … Read More »
The fastestmirror plugin for yum is supposed to make updates and installations faster right? What if you have to wait for a fastestmirror timeout before yum continues installing?
More like slowestmirror
If all the mirrors are timing out and appear dead because of some network issue such as a restricted firewall or proxy, the wait is painful.
Turn on verbosity first. Edit /etc/yum/pluginconf.d/fastestmirror.conf and set verbose=1 then try updating or installing a package.
After a short delay you should start to see responses from all the mirrors.
# yum install patchutils
Loaded plugins: fastestmirror, presto
Loading mirror speeds from cached hostfile
* centos.mirror.constant.com : dead
* centos.mirror.constant.com : 99999999999.000000 secs
* centosmirror.quintex.com : dead
* centosmirror.quintex.com : 99999999999.000000 secs
* mirror.linux.duke.edu : dead
* mirror.linux.duke.edu : 99999999999.000000 secs
* mirrors.liquidweb.com : dead
* mirrors.liquidweb.com : 99999999999.000000 secs
* mirror.cs.vt.edu : dead
* mirror.cs.vt.edu : 99999999999.000000 secs
* mirror.liberty.edu : dead
* mirror.liberty.edu : 99999999999.000000 secs
* mirror.rackspace.com : dead
* mirror.rackspace.com : 99999999999.000000 secs
* bay.uchicago.edu : dead
* bay.uchicago.edu : 99999999999.000000 secs
* mirror.raystedman.net : dead
* mirror.raystedman.net : 99999999999.000000 secs
* ftp.osuosl.org : dead
* ftp.osuosl.org : 99999999999.000000 secs
If you’ve just got a few timing out, just add exclude’s to the configuration file so it skips them. Conversely, you can add a whitelist of the fastest responders to speed things up.
Fastestmirror timeout still?
If your firewall or proxy is completely blocking the fastestmirror plugin because it’s ignoring http_proxy style environtment variables and your proxy setting in yum.conf, then you’re pretty much out of luck with this plugin.
You can’t remove the package because of dependencies, so just turn it off in the config. Edit /etc/yum/pluginconf.d/fastestmirror.conf and set enabled=0
If you’re behind a proxy and don’t have yum configured yet, try adding your proxy to yum.conf first.
Let’s start by configuring networking, then install a bunch of packages. After that we’ll configure services and create a gfs2 cluster file system. Finally we’ll relocate libvirt to the clustered storage so live migration will just work right out of the box.
How to use Paramiko SSH in Python to launch remote applications. A simple thread class example with implementation.
Proxies are the devil. If you pick a random software application and try to do anything network related behind a proxy, it’s a coin toss as to whether the developer gave proxy support a second thought. In the case of git, it didn’t work right out of the box for me. But it didn’t take more than a minute to figure out a working solution either.
There are quite a few online companies that offer to monitor your website and alert you when it becomes inaccessible from different places around the globe. They send you email and SMS messages along with reporting features. And there are a few good ones that offer this service in a limited function for free.