Once in a while I like to play with Advent Of Code problems 🎄. Today I decided to tackle an easy one and, since the answer was almost trivial to find, I wanted to go deeper and understand how to measure and improve the performance of the solution. ...
intro Resource isolation is an hot topic these days, and it’s a problem excellently solved by containerization. However, we can achieve isolation between internal tasks of an operating system by leveraging a technology exposed by the kernel: cgroups. This component is also used by Docker, and other Linux container technologies. Cgroups are the Linux way of organizing groups of processes: roughly speaking a cgroup is to a process what a process is to a thread: one can have many threads belonging to the same process, and in the same way one can join many processes inside the same cgroup. ...
the Apache module mod_status is very useful for inspecting your running webserver, but it gives you only realtime informations about workers, connections, and so on. I wanted a way to keep this data and then be able to do comparison, charts and more useful reports. The first step was configuring mod_status in order to be only accessible from localhost: andrea@myserver:~$ cat /etc/apache2/mods-enabled/status.conf <IfModule mod_status.c> # # Allow server status reports generated by mod_status, # with the URL of http://servername/server-status # Uncomment and change the "192.0.2.0/24" to allow access from other hosts. # <Location /server-status> SetHandler server-status Order deny,allow Deny from all Allow from 127.0.0.1 ::1 # Allow from 192.0.2.0/24 </Location> # Keep track of extended status information for each request ExtendedStatus On # Determine if mod_status displays the first 63 characters of a request or # the last 63, assuming the request itself is greater than 63 chars. # Default: Off #SeeRequestTail On <IfModule mod_proxy.c> # Show Proxy LoadBalancer status in mod_status ProxyStatus On </IfModule> </IfModule> now a little shell script to grab the status page together with other useful informations… ...