Understanding of Server Load balancer/availability/computing Clusters

Understanding of Server Load balancer/availability/computing clusters (analogy)

Since you are so lazy and don't want to collect a pile of information, I can only tell a story to a kindergarten.

Load Balance Cluster

There are a total of four brothers opening tailor shops, a lot of business, a person can not do, always delay the construction period, so the four brothers discuss
The boss received the order and the three brothers came to work. After the customer grows, the boss assigns new tasks based on the workload of the three brothers according to certain principles (policies.

High Availability Cluster

The two brothers opened a breakfast shop with little business, but there were a lot of customers between and every morning and they could not be interrupted. In order to ensure that the breakfast shop can continue to provide services within two hours, the two brothers discuss several methods:

Method 1: In normal times, the boss is doing business. The second child is waiting at home. Once the boss cannot do business, the second child comes out to the top. This is called active/standby.
Method 2
Method 3: at ordinary times, the boss sells steamed buns, and the second child also sells soy milk. The old one has a big problem. The second child sells steamed buns and soy milk, and the second child doesn't work. The boss sells steamed stuffed buns again, sell soy milk again. this is called active/active (dual active)

Steamed Stuffed Bun = application package, which is called heartbeat for mutual reference and Failover/takeover for replacement. if the two brothers suddenly become blind and do not know whether the other party is working now, they all think they want to work for the other party. This is called brain-split, and then they need a third party, for example, their fatherSolutionThis is called tier-breaker, or ask the two of their daughter-in-law to pull one of them. This is called fency.

Hey hey.

High computing Clustering

Ten brothers work together in the handmade furniture business. One customer came to their father to ask for a very complex set of antique furniture which can also be done by one person, but they have to do it for a long time, in order to hand over the set of furniture in a week, the 10 brothers decided to do it together.
The old man handed the different parts of the set of furniture to his sons for work. Then each son was processing the wooden furniture and finally made a fight for the goods.

He is a scheduler Task Scheduler, and his sons are compute nodes. Their jobs are called jobs.