Journald - log rate limiting
It seems to be an easy task, make available logging from haproxy to syslog. Configuration on haproxy side was pretty easy, log file start growing, but from time to time there were some pauses. Rsyslog was the first victim, I dig into limiting configuration area, but default limits doesn't ...read more
After one year break I'm back. This time with new ideas more concentrating on dev side of sysadmin. The first new project called infomarquee published on github. Project brings user defined alerts in TV news station style. First iteration consist of two headlines with user defined alerts with duration ...read more
How domains are being resolved ?
Not so far ago I was doing some cleanup work with static entries in /etc/hosts. I was wondering how many of these static entries are being actively used. To figure out I started digging, but without much luck. Tools like strace, ltrace doesnt give me a clear look which ...read more
How safely change ip address on remote host ?
Routine task change ip address on remote host without cut off. There are a lot of possibilites i.e. from reboot with new ip address to some fancy stuff with cron job. But there is a one method to make it clear and elegant.
echo 1 > /proc/sys ...
New look and feel
After couple months of inactivity I am starting with new look of blog site. It's not only a new theme, but it's completly rewrite engine. No more complexity of Wordpress on top of Varnish,Nginx,PHP,MySQL just pure static content generated by Pelican. Static website is served ...read more
Jesień Linuksowa 2013
Zerofree your filesystem
Lets assume that you have file image:
dd if=/dev/zero of=file.1 bs=4k count=128
on top of it you create filesystem ext3/ext4
mount it, create remove some files etc. and you gonna make it more space efficient, that's ...read more
Some notes about memory ballooning in VMware
Couple days ago I found out that memory usage grow rapidly on one server. After couple minutes of investigation, it was clear that memory balloon take place. Of course it will happen only if you have vmware tools installed. To find out what was happening, you can look at vmware ...read more
Manage your hard disks
Make one step forward after rediscovering newly added hard disk, simply how to resize it. In virtual world simply put the new disk size, but how to reflect this change in guest operating system:
echo 1 > /sys/block/<devname>/device/rescan partprobe
Continuing how to make them unavailable first to ...read more
Sign your scripts
Remote command execution from one host to another is nothing new in more complex infrastructure. It is usually going to happen at low user level privilege and it's also password less ssh communication based on ssh keys. But what happens when ssh keys leaked or this account was compromised ...read more