BhrikutiSoft

Etcd is a distributed key-value store that is an integral part of Kubernetes. It is a highly available and consistent data store used for storing and retrieving configuration data, metadata, and other cluster state information. Kubernetes uses etcd as its primary data store to ensure coordination and consistency across all the nodes in the cluster.

Here are some key features and functionalities of etcd in Kubernetes:

1. Distributed and fault-tolerant: etcd is designed to operate in a distributed manner across multiple nodes, ensuring high availability and fault tolerance. It uses a consensus algorithm to maintain consistency and replication of data across the cluster.

2. Key-value store: etcd provides a simple key-value store where data can be stored and retrieved using simple GET and PUT operations. Each value is associated with a unique key, making it easy to organize and query the data.

3. Strong consistency: etcd guarantees strong consistency semantics, ensuring that all clients see the same view of the data at any given time. It uses a distributed consensus algorithm called Raft to achieve consensus and maintain consistency.

4. Watch functionality: etcd supports a watch mechanism that allows clients to subscribe to changes in the stored data. Clients can receive notifications whenever a key is created, modified, or deleted, enabling reactive programming and event-driven architectures.

5. Secure communication: etcd supports Transport Layer Security (TLS) encryption for secure communication between nodes in the cluster. It also provides authentication and access control mechanisms to ensure secure access to the stored data.

In Kubernetes, etcd is primarily used by the control plane components, such as the API server, controller manager, and scheduler. These components store and retrieve cluster configuration, resource state, and other metadata in etcd. etcd serves as a single source of truth for the cluster, allowing different components to coordinate their actions and maintain a consistent state.

Why ETCD

• It’s a highly replicated resource ensuring that every concerned node is capable of accessing the database completely: with no exceptions.

• It has almost zero downtime and comes with great availability. Under no conditions, it will be unavailable. It’s designed to be highly fault-tolerant and keep on working even when there is hardware or network failure.

• With Kubernetes etcd, it’s possible to have your hands on only updated information as every data reads the information available and delivers the updated information. The great thing is that this updated data is written over any single cluster.

• It’s a speedy resource as it has been observed that it managed to write 10,000 data per second.

• As long as K8s etcd is in use, one doesn’t have to worry about API security. With compatibility with SSL and TLS encryption, it promises to keep data theft under control. Need more data security? Don’t worry as you can easily apply access control.

• etcd is so simple to use that it has become a part of web applications, mobile applications, and container orchestration engines. Whether you’re developing a SPA or using Kubernetes, etcd permits you to read and write data with any standard tool. This simplicity almost meant that developers of all technical competencies could work with it.

While you plan to use it, you must understand one aspect of storage: disk speed has a high influence on etcd performance. Better disk storage speed means high performance. Hence, it’s highly recommended to use an SSD.

The etcd Operator

It is the human operational knowledge used to ease down the etcd usage on Kubernetes. In addition, it works on a container platform. It manages etcd as per the guidelines or instructions of Operator Framework that explains the strategy to remove complexities from etcd management and configurations.With one-command installation, etcd Operator uses a unified declarative configuration. It inherits the below-mentioned features.

• Backup

etcd Operator constantly takes backup in real-time at regular intervals. However, users have to define the backup policies according to their needs and requirements.

• Create/Destroy

etcd Operator allows users to specify the cluster size once and experience uniform configuration settings.

• Resize

Resizing is easy as changing specs in settings is enough to apply new change details in development, destruction, and redesigning.

• Upgrade

Without any downtime, etcd Operator permits etcd upgrades.

Operator in action

The use of the etcd Operator makes etcd usage simpler than ever, as explained above. How does it achieve this? Basically, the process is based on approaches.

The Observation involves close monitoring of the present cluster state with the help of Kubernetes API.

Differentiating means finding differences between past and present cluster states.

Lastly, the Act involves resolving the differences using API of various kinds like k8s API and etcd cluster management API.