Measuring boot performance in Ubunu is fairly simple. Systemd provides a tool for that.
The overall boot time for kernel and userspace is given by:
systemd-analyzeHow much time each boot services takes in descending order is displayed as follows:
systemd-analyze blameThe critical chain for the default target is shown my this:
systemd-analyze critical-chain Those time can also be graphed as svg:
systemd-analyze plot > boot_analysis.svgOn the source system, do the following:
apt-get install apt-clone
apt-clone clone Copy \<systemname>.apt-clone.tar.gz to the new machine and run:
apt-get install apt-clone
apt-clone restore .apt-clone.tar.gz source system:
dpkg --get-selections > ~/Package.listtarget system:
apt-get update
apt-get install dselect
dselect update
dpkg --set-selections < ~/Package.list
apt-get dselect-upgrade -yIn order to let an Ubuntu system access the net via a proxy, edit two files and you're done.
/etc/environment:
http_proxy="http://:/"
https_proxy="http://:/"
ftp_proxy="http://:/"
no_proxy="localhost,127.0.0.1,::1 /etc/apt/apt.conf.d/90_proxy.conf:
Acquire {
HTTP::proxy "http://:";
HTTPS::proxy "http://:";
} This is an update to the article from 2009 regarding quieting down snmpd - this time in recent Ubuntu LTS 18.04. The issue at hand is the intense chattyness of snmpd to syslog.
Due to the complete shift to systemd, files in /etc/default are becoming disregarded. Therefore customisations have to be made to /etc/systemd/system. Two steps are neccessary:
Create a symlink for snmpd in /etc/systemd:
ln -s /lib/systemd/system/snmpd.service /etc/systemd/systemEdit that file and change:
ExecStart=/usr/sbin/snmpd -Lsd -Lf /dev/null -u Debian-snmp -g Debian-snmp -I -smux,mteTrigger,mteTriggerConf -fto
ExecStart=/usr/sbin/snmpd -LS4d -Lf /dev/null -u Debian-snmp -g Debian-snmp -I -smux,mteTrigger,mteTriggerConf -fThen run
systemctl daemon-reload && service snmpd restartNow snmpd should be calmed down.
Lately I ran into some issues using snmp tools, e.g.:
snmpwalk -v2c -c public ${host} testI received errors like:
Unknown Object Identifier (Sub-id not found: (top) -> test)This is because MIBs are not installed in Ubuntu by default. To install them use the follwing line:
apt-get install snmp-mibs-downloaderAlso comment line 4 of /etc/snmp/snmp.conf so it shows:
# mibs:Hope that helps someone.
In El Capitan Apple introduced a feature which opens Mission Cotrol as soon as you drag a window to the top edge of the screen. That is annoying at least to me. Therefore here is a possible fix:
Disable:
defaults write com.apple.dock mcx-expose-disabled -bool TRUE && killall DockEnable:
defaults delete com.apple.dock mcx-expose-disabled && killall DockAfter running virtual machines in KVM for some time, it might come in handy to be able to resize a KVM guest's raw volumes. In order to do so you first have to shutdown your VM for a while:
virsh destroy <guestname>
In order to add an additional 2 gig to your respective machine, you do the following:</guestname>
qemu-img resize <diskname>.img +2G
Now restart the machine:</diskname>
virsh start <guestname>
Then use fdisk inside the guest to make use of the new space:
fdisk /dev/vda
There, you delete the respective partition and immediately recreate it - with more space. Now restart the machine in order to let the kernel make note of the changes:
reboot
After a final resize you're able to make use of the sweet new space:
resize2fs /dev/vda1
Voila!
In order to cleanup docker containers from time to time just fire the following:
docker system prune -a In package center > settings:
Install in this order:
Packages will be installed to /opt.
Command-line tool is opkg.
opkg list-installed
opkg list *gcc*Source /opt/etc/profile at the end of the ~/.profile file for each user that needs
to use packages installed by ipkg.
Many php-based web application are using php's smtp function. Unfortunately, Ubuntu's php default setup disregards the installation of packages necessary for using smtp. The following command line takes care of their installation:
aptitude install php-net-smtp