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Kafka for embedded solutions

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Apache Kafka is an open-source distributed event streaming platform used by many companies for high-performance data pipelines, streaming analytics, data integration and mission-critical applications.

Quick overview of the core concepts of the Kafka architecture:

  1. Kafka is able to scale horizontally
  2. Kafka run as a cluster on one or more servers
  3. Kafka stores a stream of records in categories called topics
  4. Each record consists of a key, value and a timestamp

Just one use case

Tiny and powerless systems like system on a chip (SoC) can produce some important data and just stream them to the Kafka-Broker.
Without any application side logic for data storage, data replication and so on. Any Processing logic is covered by the Kafka broker itself, so the tiny systems can concentrate on the important tasks and sending the results to the Kafka broker.

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Mastering SELinux

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Security–Enhanced Linux (SELinux) is a Linux kernel security module that provides a mechanism for supporting access control security policies, including mandatory access controls (MAC).

Originally the SELinux implementation was done by a three letters organisation, not IBM..

The NSA, the original primary developer of SELinux, released the first version to the open source development community under the GNU GPL. now. By default SELinux is activated on CentOS and RedHat systems.

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Migrate MySQL users

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Following line will query all mysql user with their grants and print the creation statements for them.

By copy pasting or by filling a SQL-file, you can easily migrate all MySQL-user to a new mysql or mariaDB instance. 

mysql -u root -p"YOUR_PW" -Ne "select distinct concat( \"SHOW GRANTS FOR '\",user,\"'@'\",host,\"';\" ) from mysql.user;" mysql | \
mysql -u root -p"YOUR_PW"| \
sed 's/\(GRANT .*\)/\1;/;s/^\(Grants for .*\)/## \1 ##/;/##/{x;p;x;}'