Setup a secured redis-cluster on centos7

Setup a secured redis-cluster on centos7

What is redis exactly?

Redis is an open source (BSD licensed), in-memory data structure store, used as a database, cache and message broker.

Redis Sentinel provides high availability for Redis. In practical terms this means that using Sentinel you can create a Redis deployment that resists without human intervention to certain kind of failures.

⚠️ You need at least three Sentinel instances for a robust deployment.

Sentinel constantly checks if your master and slave instances are working as expected.
Notification.

If a master is not working as expected, Sentinel can start a failover process where a slave is promoted to master, the other additional slaves are reconfigured to use the new master, and the applications using the Redis server informed about the new address to use when connecting.

ℹ️ Sentinel manages the failover, it doesn’t configure Redis for HA. It is an important distinction.

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Ansible – how to collect information about remote hosts with Gathers facts

 Anisble – how to collect information about your remote hosts

In order to do so, we will discuss about ansible modue: Gathers facts

:information_source: Official webpage: https://docs.ansible.com/ansible/setup_module.html

Display facts from all hosts and store them at /tmp/facts indexed by hostname

ansible all -m setup --tree /tmp/facts

➡ now check the file to have a clear view off all variables (facts) collected by ansible for your host like the well known {{ inventory_hostname }}

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Usefulness of an MQ layer in an ELK stack

Usefulness of an MQ layer in an ELK stack

First things first, disambiguation; let’s talk about these strange words.

What does ELK means?

An ELK stack is composed of Elasticsearch, Logstash, and Kibana; these 3 components are owned by the elastic.co company and are particulary useful to handle Data. (ship, enrich, index and search your Data)

What does MQ means?

In computer science, The message queue paradigm is a sibling of the publisher/subscriber pattern.
You can imagine an MQ componant works like several mailboxes; meaning that publisher(s)/subscriber(s) do not interact with the message at the same time, many publishers can post a message for one subsriber and vice versa.

➡ Redis or Kafka or RabbitMQ can be used as buffer in the ELK stack.

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