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The Nature of Split-Brain in Distributed Systems Split-brain occurs when a network partition isolates nodes within a distributed cluster, causing them to form separate, disconnected sub-clusters. In a Redis environment, this often results in multiple nodes simultaneous believing they are the master. This scenario violates data consistency guara ...

Distributed System Fundamentals A distributed system consists of multiple independent computers communicating via a network to accomplish shared objectives. These systems lack a global clock and exhibit non-deterministic behavior among components located across different physical machines. Key System Properties Scalability enables horizontal ex ...

Starting the Service and Enabling Auto-Start On lb01: [root@lb01 nginx]# systemctl start keepalived.service [root@lb01 nginx]# systemctl enable keepalived.service On lb02: [root@lb02 ~]# systemctl start keepalived.service [root@lb02 ~]# systemctl enable keepalived.service Packet Capture Analysis with Wireshark Once the service is running, cap ...

Redis master-slave replication enables data from one Redis server (the master) to be copied to one or more other Redis servers (slaves). Data flows unidirectionallly—from master to slave. By default, every Redis instance starts as a master. A master can have multiple slaves, but each slave can only replicate from a single master. Key Benefits o ...

To configure a highly available SaltStack environment, you must set up a multi-master architecture where minions can communicate with multiple master servers. Additionally, configuration files, state files, and keys must be synchronized between the primary and secondary masters to ensure consistency during a failover. 1. Configuring Salt Minion ...

Initialize a Cluster on the First Host Log into the initial Proxmox instance, referred to here as host-alpha. Use the cluster management tool to form a new group: pvecm create alpha-group This command generates the Corosync authentication material, writes it to /etc/corosync/authkey, and produces an updated /etc/pve/corosync.conf. The cluster ...

Redis Sentinel is a system designed to help manage Redis instances, providing high availability through monitoring, notification, and automatic failover. It oversees master and replica instances, promoting a replica to master if the current master fails. This article explains the core concepts of Redis Sentinel and demonstrates how to integrate ...

Virtual IP Configuration virtual_ipaddress { 10.0.0.3/24 dev eth0 label eth0:1 } track_script { health_check } Failover Testing [root@lb01 ~]# systemctl is-active nginx active [root@lb01 ~]# ip a | grep 0.3 inet 10.0.0.3/24 scope global secondary eth0:1 [root@lb01 ~]# systemctl stop nginx [root@lb01 ~]# ip a | grep 0.3 # VIP migrated after ...

Management High Availability OverviewTo ensure robust administration capabilities, a Ceph cluster requires multiple management nodes. Relying on a single management node creates a single point of failure; if that node goes down, cluster administration becomes impossible. Administrative access is generally divided into two categories: web dashbo ...

What is Redis Redis is a high‑performance, in‑memory key‑value database that also supports optional data persistence. It is open‑source and written in C, widely used both as a cache and as a primary datastore for specialised scenarios. Why Redis Is So Fast In‑memory storage – data is served directly from RAM, avoiding disk I/O for most operati ...