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What is a replication set?
A ReplicaSet’s purpose is to maintain a stable set of replica Pods running at any given time. As such, it is often used to guarantee the availability of a specified number of identical Pods.
What is the difference between Replicaset and replication controller?
Replica Set and Replication Controller do almost the same thing. Both of them ensure that a specified number of pod replicas are running at any given time. The difference comes with the usage of selectors to replicate pods. Replica Set use Set-Based selectors while replication controllers use Equity-Based selectors.
What are the responsibilities of replication controller?
Replication Controller is one of the key features of Kubernetes, which is responsible for managing the pod lifecycle. It is responsible for making sure that the specified number of pod replicas are running at any point of time.
What is the use of replication controller?
A ReplicationController manages all the pods with labels that match the selector. It does not distinguish between pods that it created or deleted and pods that another person or process created or deleted. This allows the ReplicationController to be replaced without affecting the running pods.
How is replication achieved in a MongoDB instance?
MongoDB achieves replication by the use of replica set. A replica set is a group of mongod instances that host the same data set. In a replica, one node is primary node that receives all write operations. All other instances, such as secondaries, apply operations from the primary so that they have the same data set.
How are mongod instances that host the same data set?
A replica set is a group of mongod instances that host the same data set. In a replica, one node is primary node that receives all write operations. All other instances, such as secondaries, apply operations from the primary so that they have the same data set.
Why do you need replication in a database?
Replication allows you to increase data availability by creating multiple copies of your data across servers. This is especially useful if a server crashes or if you experience service interruptions or hardware failure. If your data only resides in a single database, any of these events would make accessing the data impossible.
How does the heartbeat process work in MongoDB?
The Heartbeat process Heartbeat is the process that identifies the current status of a MongoDB node in a replica set. There, the replica set nodes send pings to each other every two seconds (hence the name). If any node doesn’t ping back within 10 seconds, the other nodes in the replica set mark it as inaccessible.