Reinstalling GRUB2 over an existing (and un-bootable) CentOS 7 box

Every now and then, you might need to “recover” from your un-bootable CentOS. I’m not referring to serious and/or hardware problems, like broken HDD or corrupted filesystem. I’m referring to changes in “geometry” of your HDD/partitions, changes in partitions UUIDs, switch from MBR to GPT, etc. etc.. In other words, I’m referring to system changes … [Read more…]

DNS (bind) issues and… (missing) security policies

Yesterday morning I’ve been notified, by the monitoring platform running at a customer site (NAGIOS, actually), that two distinct DNS services (two BIND instances running on two different Linux hosts – different distributions and different bind versions) gone down at mostly the same time: [08-05-2015 02:09:33] SERVICE ALERT: srv-*****;dns;CRITICAL;HARD;3;CRITICAL – Plugin timed out while executing … [Read more…]