How to install Apache Cassandra on Ubuntu

In this Ubuntu tutorial we will learn about How to install Apache Cassandra on Ubuntu. Apache Cassandra is a distributed, extremely scalable, highly available and fault tolerant NoSQL database initiated by facebook.

Apache Cassandra is a distributed, extremely scalable, highly available and fault tolerant NoSQL database initiated by facebook, later open sourced as an apache project. Cassandra data model is inspired by Google Bigtable and it's distribution model is inspired by Amazon Dynamo. If you are interested to know more about Cassandra you can refer to the paper written by Facebook.

This post will guide you how to install Cassandra on Ubuntu 12.04.

Install the new updates using following commands

    sudo apt-get update  
    sudo apt-get upgrade

2. open /etc/apt/sources.list using the following command

sudo gedit /etc/apt/sources.list

and add the following lines to it

    deb http://www.apache.org/dist/cassandra/debian 10x main  
    deb-src http://www.apache.org/dist/cassandra/debian 10x main

3. Run update again and you will get the following error. This means you need to add the PUBLIC_KEY. In next step you will understand how to add this PUBLIC_KEY.

    GPG error: http://www.apache.org unstable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 4BD736A82B5C1B00

4. Register and add a PUBLIC_KEY key and update again, note that you may need to change the key accordingly

    gpg --keyserver wwwkeys.pgp.net --recv-keys 4BD736A82B5C1B00  
    sudo apt-key add ~/.gnupg/pubring.gpg  
    sudo apt-get update

5. Install Cassandra using the following command

    sudo apt-get install cassandra

6. Start Cassandra server using the following command

    sudo cassandra -f

After starting the Cassandra server you will see it has started listening for thrift clients.

    ....  
    ....  
    ....  
    INFO 12:18:29,140 Listening for thrift clients...

7. To stop Cassandra server process first find the Process ID for Cassandra and kill it.
To find the process ID use following command

    ps auwx | grep cassandra

Output will be something like this. According to that 3595 is the process ID for cassandra.

    root      3595  0.0  0.0  60048  1908 pts/0    S+   12:18   0:00 sudo cassandra -f

To kill the process use the following command

After killing the process you will see Cassandra server has stopped listening to thrift clients.

INFO 13:04:08,663 Stop listening to thrift clients  
INFO 13:04:08,666 Waiting for messaging service to quiesce  
INFO 13:04:08,667 MessagingService shutting down server thread.

8. Use following command to start Cassandra as a service

    sudo /etc/init.d/cassandra start

9. Use following command to stop Cassandra service

    sudo /etc/init.d/cassandra stop

Installation will create following directories. Uses of them are mentioned within the brackets.

/var/lib/cassandra (data directories)
/var/log/cassandra (log directory)
/var/run/cassandra (runtime files)
/usr/share/cassandra (environment settings)
/usr/share/cassandra/lib (JAR files)
/usr/bin (binary files)
/usr/sbin
/etc/cassandra (configuration files)
/etc/init.d (service startup script)
/etc/security/limits.d (cassandra user limits)
/etc/default

Installing JNA (Java Native Access) on Linux platforms can improve Cassandra memory usage. To install JNA, download jna.jar from here and add it to /usr/share/cassandra/lib directory.

If you get the following error while you try to start a Cassandra server, means that cassandra is already running in the background somewhere. You will need to kill the process that is running in the background first. You can probably use the above mentioned stop command to stop any Cassandra servers running background.

view plainprint?

Error: Exception thrown by the agent : java.rmi.server.ExportException: Port already in use: 7199; nested exception is:
java.net.BindException: Address already in use

Here I have done the packaged installation, alternatively you can install Cassandra binary tarball installation on Ubuntu. Use this link for that.

Original article source at: https://dzone.com

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How to install Apache Cassandra on Ubuntu

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Microsoft Teams is a communication platform used for Chat, Calling, Meetings, and Collaboration. Generally, it is used by companies and individuals working on projects. However, Microsoft Teams is available for macOS, Windows, and Linux operating systems available now.

In this tutorial, we will show you how to install Microsoft Teams on Ubuntu 20.04 machine. By default, Microsoft Teams package is not available in the Ubuntu default repository. However we will show you 2 methods to install Teams by downloading the Debian package from their official website, or by adding the Microsoft repository.

Install Microsoft Teams on Ubuntu 20.04

1./ Install Microsoft Teams using Debian installer file

01- First, navigate to teams app downloads page and grab the Debian binary installer. You can simply obtain the URL and pull the binary using wget;

$ VERSION=1.3.00.5153
$ wget https://packages.microsoft.com/repos/ms-teams/pool/main/t/teams/teams_${VERSION}_amd64.deb

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TeamViewer is a cross-platform, proprietary application that allows a user to remotely connect to a workstation, transfer files, and have online meetings. In this tutorial, we will walk you through how to install TeamViewer on Ubuntu 20.04 Desktop through the command line.

Prerequisites

Before continuing with this tutorial, make sure you are logged in as a user with sudo privileges.

Installing TeamViewer on Ubuntu

01- To install TeamViewer, first, download the TeamViewer .deb package. So, open the Terminal and run the following wget command.

$ wget https://download.teamviewer.com/download/linux/teamviewer_amd64.deb

02- Once you have downloaded the TeamViewer‘s Debian package, execute the following command to install Teamviewer:

$ sudo apt install ./teamviewer_amd64.deb

The system will prompt you with a [Y/n] option. Type ‘Y‘ and hit the enter key in order for to continue the installation.

03- Once the installation is done, you can launch TeamViewer either by typing the command teamviewer in your terminal or by clicking on the TeamViewer icon (Activities -> TeamViewer).

04- A pop-up License Agreement will be displayed. To proceed, click on the Accept License Agreement button.

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How to Install Android Studio on Ubuntu 20.04

1./ Install Android Studio Using APT

Method 1./ Install Android Studio Using APT

1- We need to add official repository to the sources list. Therefore, type the below command to add the Android Studio repository:

$ sudo add-apt-repository ppa:maarten-fonville/android-studio

02- Now let’s install Android studio and all the software dependencies as below.

$ sudo apt update
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Method 2./ Install Android Studio Using snap

We can install using the snap tool. So, use the below command to install Android Studio:

$ sudo snap install android-studio --classic

2./ Starting Android Studio

01- You can start Android Studio either by typing the command android-studio in your terminal or by clicking on the Android Studio icon (Activities -> Android Studio).