I’m run into some error message like: “Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column”. It’s turns out that this is caused by MySQL updating the way it behave in relation to aggregate functions since MySQL 5.7. Here is how I solved it on Ubuntu . You can … Read more
If you are trying get sar working you might get this error message: “Cannot open /var/log/sysstat/sa08: No such file or directory”. Essentially, you need to enable data collection. You do this by editing /etc/default/sysstat nano /etc/default/sysstat Then change: ENABLED=”false” to ENABLED=”true” Hope this helps someone.
I’m just going through PCI Compliance for a company that I work for. The security scan picked an apparent vulnerability in the open-ssh server. The vulnerability had been patched in Ubuntu 14.04 and so this is a false positive. I thought that I post put about it because I found lots of posts where people … Read more
I just upgraded one of my Ubuntu Servers to Ubuntu 16.04. The media wiki installation shopped working because it now comes with PHP 7. I tried upgrading mediawiki to the latest version but this didn’t seem to work either. I can’t seem to find out if Mediawiki support PHP 7. So, I thought I would … Read more
I have just started to upgrade some servers to Ubuntu 16.04. It looked good until I rebooted to the server and the Apache2 service didn’t start up properly. I view the logs in systemd. Using the command: systemctl status apache2.service ● apache2.service – LSB: Apache2 web server Loaded: loaded (/etc/init.d/apache2; bad; vendor preset: enabled) Drop-In: … Read more
We have a server running apt-cacher to help cache Ubuntu repositories. However, after about 2 years of usage the disk on the server has filled up. I discovered this after trying to update my Ubuntu desktop and got the following error: Here is how to clear the apt-cache cache.
I just tried to install the htpasswd command and got the following error: Unable to locate package htpasswd. Turns out you need apache2-utils: <code>sudo apt-get install apache2-utils</code>
Sometimes it can be really useful to give a user privileges to run a specific command as root. For example – if you wanted to allow a user to restart a specific service or run a specific program as root without given them access to the whole server. You can configure this using visudo command … Read more
I wanted to monitor the bandwidth usage on my Ubuntu server without a full blown graphic monitoring system but something that I could just check once in a while just to see how things are running. I found an really simple tool called vnstat. It’s good because it’s simple, fast and easy to use and … Read more
The sudo command checks the permission of the /etc/sudoers file and also the contents of /etc/sudoers.d/ before allowing you to use the sudo command. For example you might be warned: or perhaps: Therefore, if you don’t have root login (which is generally good security practise) then you might not be able to change the permission … Read more