Hadoop on demand with Openstack, Cloudinit and Salt

This post will describe the whole process of providing hadoop on demand through Openstack, Cloudinit and Saltstack. We will use Openstack to provision servers on demand, cloudconfig to install salt-master and salt-minion and saltstack to deploy hadoop namenode and datanodes, all fully automated. This makes us able to deploy a ...

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Docker get private ip address of container

In order to access other containers from a container it's needed to get the private IP address of the other containers. The following command is able to get the private ip address of the container.

$ docker inspect --format="{{.NetworkSettings.IPAddress}}" $CONTAINER_ID_OR_NAME
172.17.0.15
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Move first word to end of line (Linux/awk)

Move the first word of a line to the end of line on Linux using AWK. We first store the first column(first word) in the variable t. Then we set the first column to be empty. At last we add a new column after the last column of the ...

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SSH to server behind a firewall via an SSH tunnel

A server behind a firewall was unaccesible from my home, but another server which is on the same local network had public SSH access from my home. So we can create an SSH tunnel via this public server to the server behind a firewall.

For example the public ssh server ...

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Recursive karatsuba multiplication in Python

I'm currently taking the class Algorithm: Design and Analysis of Stanford via Coursera and in the class the Karatsuba algorithm got mentioned. I went ahead and implemented it based on the lecture slides.

The Karatsuba algorithm is a fast multiplication algorithm. It's special because it was the first ...

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