Technology Terms

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Containers

These are terms associated (not strictly) with containers.

Immutable: Immutable means that a container won’t be modified during its life: no updates, no patches, no configuration changes. If there is a change container will be recreated.
Ephemeral: Temporary i.e. The container can be stopped and destroyed, then rebuilt and replaced with an absolute minimum set up and configuration very quickly.
Separation of Concerns: Container shouldn’t contain unique data mixed in with application binaries.
Persistence: Data present on writable-layer(container) gets wiped out when that container no longer exists.
Stateless: A container or application that does not store state within itself. It relies on external services.
Service Discovery: The process of automatically detecting and registering services within a network or infrastructure.
Rolling Updates: A deployment strategy where new versions of containers or applications are gradually rolled out by replacing old instances with new ones avoiding downtime.

These terms are connected with IaC.

Idempotent: Idempotent operation has no additional effect if it is called more than once with the same input parameters
Declarative: Configuration explicitly specified in the code, uses scripting language like JSON, YAML, K8s files etc.
Imperative: Configuration is implicit, you say what you want & rest is filled in. Used with CLI commands in K8s, programming languages like Python, Ruby, JavaScript.
Orchestration: Orchestration is coordinating with multiple systems & services. Orchestrations is a common term when working with microservices, containers & Kubernetes
Configuration Drift: When provisioned infrastructure has unexpected configuration changes.
Mutable Infrastructure: Mutable infrastructure can be updated, configured as per the requirement.
Immutable Infrastructure: Immutable infrastructure is something that can never be modified once it is deployed.
Cloud Agnostic: Cloud agnostic is a process where the company builds systems that aren’t dependent on a specific provider
Execution Plan: A manual review of what will add, change or destroy before you apply changes. Eg: terraform apply
GitOps: Git repositories are used as source of truth for infrastructure provisioning & configuration.

Bastion Host: Typically a hardened server that is used to access private networks.
Bare Metal: When the software/OS is running on the hardware itself rather than some virtualized layer.
Chaos Engineering: Causing intentional failures in a controlled environment to test system resilience.
Canary release: Gradual roll out of a new version of software to a small subset of users.