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Re-Add a Computer to a Windows Domain

Re-Add a Computer to a Windows Domain published on

If you e.g. restored a full backup of a client and you could get a similar error to this below:

Then you have to readd the server or computer to a domain with this:

  1. log in as Administrator
  2. Open Powsershell as admin and run this 
    Reset-ComputerMachinePassword -Server domaincontroller.example.com -Credential domainadmin@example.com

Install oracle Java (JDK) on Linux

Install oracle Java (JDK) on Linux published on

If you want to have the original Oracle JDK instead of OpenJDK, follow this:

  1. Download the *.tar.gz file (e.g. jdk-10.0.2_linux-x64_bin.tar.gz) at https://www.oracle.com/technetwork/java/javase/downloads/jdk10-downloads-4416644.html
  2. untar it to /opt
tar xvzf jdk-8u191-linux-x64.tar.gz --directory=/opt
  1. Update the alternatives so the system knows about your Java version (the pathes have to be changed)
update-alternatives --install \
    /usr/bin/java java /opt/jdk1.8.0_191/bin/java 20000 \
    --slave /usr/bin/keytool keytool /opt/jdk1.8.0_191/bin/keytool \
    --slave /usr/bin/orbd orbd /opt/jdk1.8.0_191/bin/orbd \
    --slave /usr/bin/pack200 pack200 /opt/jdk1.8.0_191/bin/pack200 \
    --slave /usr/bin/policytool policytool /opt/jdk1.8.0_191/bin/policytool \
    --slave /usr/bin/rmid rmid /opt/jdk1.8.0_191/bin/rmid \
    --slave /usr/bin/rmiregistry rmiregistry /opt/jdk1.8.0_191/bin/rmiregistry \
    --slave /usr/bin/tnameserv tnameserv /opt/jdk1.8.0_191/bin/tnameserv \
    --slave /usr/bin/unpack200 unpack200 /opt/jdk1.8.0_191/bin/unpack200
  1. change the defualt java:
update-alternatives --config java
  1. check the version
 java -version

remove old java

update-alternatives --remove "java" "/opt/jdk1.8.0_151/bin/java"
rm -r /opt/jdk1.8.0_151/bin/java

Tomcat Logging – logrotate.d for catalina.out

Tomcat Logging – logrotate.d for catalina.out published on

To avoid to have a big catalina.out log file, create a file /etc/logrotate.d/tomcat with this content:

#logrotate for catalina.out
/opt/tomcat/logs/catalina.out {
daily
copytruncate
rotate 4
size 5M
compress
missingok
}

To test logrotate script, use this (without "-d" the rotation run):

/usr/sbin/logrotate -d /etc/logrotate.d/tomcat

Sign vboxdrv for VirtualBox when using Secure Boot

Sign vboxdrv for VirtualBox when using Secure Boot published on

Sign vboxdrv so Secure Boot has no problem with it. (Source AskUbuntu)
Short version:

sudo /usr/src/linux-headers-$(uname -r)/scripts/sign-file sha256 ~/.ssh/MOK.priv .ssh/MOK.der $(modinfo -n vboxdrv)

To create the keys MOK.priv and MOK.der, this steps are required:

# create key pair
openssl req -new -x509 -newkey rsa:2048 -keyout MOK.priv -outform DER -out MOK.der -nodes -days 36500 -subj "/CN=Signing Key for Secure Boot/"

# use mokutil to test, if the key is enrolled (should not, if you just created it)
mokutil --test-key .ssh/MOK.der

# import key
sudo mokutil --import .ssh/MOK.der

# sign vboxdrv
sudo /usr/src/linux-headers-$(uname -r)/scripts/sign-file sha256 .ssh/MOK.priv .ssh/MOK.der $(modinfo -n vboxdrv)

# check vboxdrv and activate
sudo modinfo -n vboxdrv
sudo modprobe vboxdrv

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