Tag: ubuntu

Join domain on Ubuntu

It took me a while to find out how to join a domain (Microsoft Active Directory) on Ubuntu (16.04). I’ve adapted this guide to the following:

sudo apt update
sudo apt install ssh -y
wget https://github.com/BeyondTrust/pbis-open/releases/download/8.5.2/pbis-open-8.5.2.265.linux.x86_64.deb.sh
sudo chmod +x pbis-open-8.5.2.265.linux.x86_64.deb.sh
sudo ./pbis-open-8.5.2.265.linux.x86_64.deb.sh
sudo domainjoin-cli join <domain> <username>
sudo reboot #if necessary

This is not an universal solution. There are chances you’ll need extra steps depending on your network’s configuration.

Converting seconds from float to int

Another small one on time precision that I’ve noticed.

package main

import (
	"fmt"
	"math"
	"time"
)

func main() {
	now := time.Now().Add(time.Hour)
	seconds = time.Now().Sub(now).Seconds()
	fmt.Println(int(seconds))
	fmt.Println(int(math.Floor(seconds)))
}

Line 12 will print -3599, line 13 will print -3600 (tested on Ubuntu). So watch out when converting the number of seconds to an integer, you might not always get what you need.

A fresh bug on Libvirt Python

If you’re using Libvirt Python library on Ubuntu, watch out for the 4.1.0 version. When trying to install, you’re gonna have this beauty:

Command "/usr/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-6nHyGT/libvirt-python/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-v9fxvX-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /tmp/pip-build-6nHyGT/libvirt-python/

It’a fresh known bug: https://bugs.launchpad.net/openstack-requirements/+bug/1753539

Until the patch is released, you can use an older stable version:

pip install libvirt-python==4.0.0

 

Docker container with internet connection but no working DNS server

I’ve met a network setup where common DNS servers like 8.8.8.8 were not working and domain names could not be resolved inside Docker containers.

Find out the DNS servers on your system (I was using Ubuntu 16.04):

# Get the name of the interface you're using to connect to your network
ifconfig

# Then get DNS servers associated to it (I've used the first one in this list)
nmcli device show <interfacename> | grep IP4.DNS | awk '{print $2}'

 

Now you have two options (“x.x.x.x” will be the DNS you chose from above):

  • You can run containers with the dns flag: 
    docker run -tid --dns x.x.x.x ubuntu:16.04 bash
  • Or, as I did, you can configure the DNS to be used automatically by all future containers:
    • open /etc/network/interfaces
    • add “dns-nameservers x.x.x.x” after “iface lo inet loopback”
    • restart interfaces: sudo ifdown -a && sudo ifup -a 
      sudo sed -i '/iface lo inet loopback/a dns-nameservers x.x.x.x' /etc/network/interfaces
sudo ifdown -a && sudo ifup -a

Compile Libvirt for Python on Ubuntu

Installing Libvirt on Ubuntu for Python is as easy as:

sudo apt install -y python python-pip libvirt-dev
pip install libvirt-python

 

With the default installation, you could miss some of the Libvirt API bindings exposed to the Python package, although you have the latest version.  So if you ever need to compile the library yourself, here you go (my setup was Libvirt 4.0.0 on Ubuntu 16.04 with Python 2.7):

#!/usr/bin/env bash

WORK_DIR="/tmp/libvirt"

sudo apt update
sudo apt install -y git

# LIBVIRT

WORK_DIR_LIBVIRT="$WORK_DIR/libvirt"
mkdir -p $WORK_DIR_LIBVIRT
cd $WORK_DIR_LIBVIRT

LIBVIRT_VERSION="v4.0.0"
git clone -b $LIBVIRT_VERSION --single-branch --depth 1 https://github.com/libvirt/libvirt.git .
git checkout $LIBVIRT_VERSION

sudo apt install -y \
	gettext \
	libtool \
	autoconf \
	autopoint \
	pkg-config \
	xsltproc \
	libxml2-utils
./bootstrap

sudo apt install -y \
	libnl-3-dev \
	libnl-route-3-dev \
	libxml2-dev \
	libdevmapper-dev \
	libpciaccess-dev \
	python
./configure

sudo apt install -y intltool
aclocal

make
sudo make install


# LIBVIRT PYTHON

WORK_DIR_LIBVIRT_PYTHON="$WORK_DIR/python"
mkdir -p $WORK_DIR_LIBVIRT_PYTHON
cd $WORK_DIR_LIBVIRT_PYTHON

LIBVIRT_PYTHON_VERSION="v4.0.0"
git clone -b $LIBVIRT_PYTHON_VERSION --single-branch --depth 1 https://github.com/libvirt/libvirt-python .
git checkout $LIBVIRT_PYTHON_VERSION

sudo apt install -y python-dev

python setup.py build
python setup.py install


# CLEANUP

rm -r $WORK_DIR
sudo apt purge -y \
	gettext \
	libtool \
	autoconf \
	autopoint \
	pkg-config \
	xsltproc \
	libxml2-utils \
	libnl-3-dev \
	libnl-route-3-dev \
	libxml2-dev \
	libdevmapper-dev \
	libpciaccess-dev \
	intltool \
	python-dev

The above may vary depending on your Ubuntu setup. Just pay attention to errors regarding missing tools.

Now check for the symbols you needed:

sudo apt install -y binutils
nm -g /usr/local/lib/libvirt.so

 

I recommend compilation attempts inside an isolated environment.