Databases are often the most critical part of an infrastructure. Failure of a database server often leads to a failure of other components because a database server is required for their functionality. Everyone does backups, and it is the first thing you should do if the data stored in your database server is crucial, but backups are run weekly, daily, hourly… And sometimes even a few minutes of outage can cause the loss of a lot of money, that’s when high availability comes to mind.
At first let’s remind ourselves what master-master setup means. Master-master method belongs to Multi-master replication method, in database replications you have 2 types on nodes – master and slave. In master-slave, needed changes identified by a group member must be submitted to the designated “master” of the node. This differs from Master-Master replication in which data can be updated by any authorized contributor of the group. Although it is a bit unusual, it´s sometimes better to have your databases in master-master setup, for example:
What is systemd? Systemd is a fairly recent part of linux operating system – RedHat started developing systemd in 2010 and it was added to version 15 of ubuntu linux back in the year 2015. It is responsible for booting the system correctly and maintaining all its services in its proper state. Basically, systemd is a successor of init scripts used on older linux systems. Why should we use systemd services?
On hot summer days when the heat is in the air, my mind starts to think about vacation and the time passing by, but business never stops and it’s nice to have all things nicely prepared before you leave the office. Especially when you can use OpenStack instrument called Heat. So, let’s take look at it a bit. Heat is a very useful orchestration tool for OpenStack users as it provides a way to automate the process of cloud components creations.
Let’s say you have just finished installing Prometheus, full of enthusiasm you want to take another step, create the structure of exporters and sort out from which exact services you want to harvest metrics. If you use it on a small scale, source code control is not your biggest concern, but when you want to collect metrics from your whole infrastructure, you definitely want to know the binaries you are running.