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Kafka for embedded solutions

December 31, 2020 by Igor Drobot Leave a Comment

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.

[Read more…]

Filed Under: Linux Tagged With: Debian, Kafka, Streaming

Mastering SELinux

December 26, 2020 by Igor Drobot Leave a Comment

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.

[Read more…]

Filed Under: Linux

Migrate MySQL users

December 24, 2020 by Igor Drobot Leave a Comment

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;}'

Filed Under: Linux Tagged With: MariaDB, Migrate MySQL User, MySQL, SQL

MySQL/MariaDB replication

December 24, 2020 by Igor Drobot Leave a Comment

mysql-replication

MySQL-Replication could be a kind of load balancing for querieng applications or active failover/backup node which has the same data.

Also for common heavy loaded scenarios, where the primary write-queries are going to the master node and all read-queries are running against the slave node.

[Read more…]

Filed Under: Linux, MySQL Tagged With: Debian, MySQL, MySQL replication, MySQL slave

Diff two directories in Linux

December 23, 2020 by Igor Drobot Leave a Comment

For a couple of Linux/Unix systems I run daily backup over rsync.
The filesets are nearly static, so the the backup duration is nearly identical each day. Between 22 and 30 minutes for 21-systems. But there are also days, with a longer backup durations.

[Read more…]

Filed Under: Linux Tagged With: backup, rsync

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