Från fysiska servrar till containers

Owned by Ulf Sälg
Last updated: Mar 17, 2022
2 min read

 

Traditional deployment

Fysiska servrar med egen hårdvara, OS och en eller flera applikationer

Virtualized deployment

Virtuella servrar som delar på fysisk hårdvara men har eget OS och en eller flera applikationer

Container deployment

Oberoende av OS

 

Containers are similar to VMs, but they have relaxed isolation properties to share the Operating System (OS) among the applications. Therefore, containers are considered lightweight. Similar to a VM, a container has its own filesystem, share of CPU, memory, process space, and more. As they are decoupled from the underlying infrastructure, they are portable across clouds and OS distributions.

 

  • Agile application creation and deployment: increased ease and efficiency of container image creation compared to VM image use.

  • Continuous development, integration, and deployment: provides for reliable and frequent container image build and deployment with quick and efficient rollbacks (due to image immutability).

  • Dev and Ops separation of concerns: create application container images at build/release time rather than deployment time, thereby decoupling applications from infrastructure.

  • Observability: not only surfaces OS-level information and metrics, but also application health and other signals.

  • Environmental consistency across development, testing, and production: Runs the same on a laptop as it does in the cloud.

  • Cloud and OS distribution portability: Runs on Ubuntu, RHEL, CoreOS, on-premises, on major public clouds, and anywhere else.

  • Application-centric management: Raises the level of abstraction from running an OS on virtual hardware to running an application on an OS using logical resources.

  • Loosely coupled, distributed, elastic, liberated micro-services: applications are broken into smaller, independent pieces and can be deployed and managed dynamically – not a monolithic stack running on one big single-purpose machine.

  • Resource isolation: predictable application performance.

  • Resource utilization: high efficiency and density.

 

Containerisering ger dig:

  • Service discovery and load balancing Kubernetes can expose a container using the DNS name or using their own IP address. If traffic to a container is high, Kubernetes is able to load balance and distribute the network traffic so that the deployment is stable.

    Storage orchestration Kubernetes allows you to automatically mount a storage system of your choice, such as local storages, public cloud providers, and more.

    Automated rollouts and rollbacks You can describe the desired state for your deployed containers using Kubernetes, and it can change the actual state to the desired state at a controlled rate. For example, you can automate Kubernetes to create new containers for your deployment, remove existing containers and adopt all their resources to the new container.

    Automatic bin packing You provide Kubernetes with a cluster of nodes that it can use to run containerized tasks. You tell Kubernetes how much CPU and memory (RAM) each container needs. Kubernetes can fit containers onto your nodes to make the best use of your resources.

    Self-healing Kubernetes restarts containers that fail, replaces containers, kills containers that don't respond to your user-defined health check, and doesn't advertise them to clients until they are ready to serve.

    Secret and configuration management Kubernetes lets you store and manage sensitive information, such as passwords, OAuth tokens, and SSH keys. You can deploy and update secrets and application configuration without rebuilding your container images, and without exposing secrets in your stack configuration.