Docker –
Docker is a platform that enables developers to package their applications and dependencies into containers. Containers are isolated, lightweight units that can run consistently across different environments, making it easier to develop, test, and deploy applications.
Docker provides a simple and efficient way to package and distribute applications, as well as a unified way to manage containers, making it easier to scale and manage applications. Docker also integrates well with other tools and services, such as continuous integration and deployment pipelines, making it a popular choice for modern application development.
Docker Image Management –
Docker image management involves creating, storing, retrieving, and distributing Docker images to run containers. It involves using Docker hub or private registry, tagging, pushing and pulling images and automating image build processes. Effective image management helps in efficient application deployment and scaling.
Docker Engine – Security
Docker Engine security involves ensuring the security of the Docker platform and its components, as well as the applications and data that run within containers.
Some key security features of Docker Engine include:
Isolation: Containers are isolated from each other and the host system, providing a high level of security for applications and data.
User Namespaces: Docker Engine allows for the creation of user namespaces, which can be used to map the root user within a container to a non-root user on the host.
Content Trust: Docker Engine supports content trust, which allows for the verification of the source and integrity of images before they are used.
Secure communication: Docker Engine uses secure communication between components and can be configured to use encryption for communication between Docker Engine and Docker registry.
Least Privilege: Docker Engine can be configured to run containers with the least privilege required to perform their intended functions, reducing the risk of security incidents.
Docker Engine – Networking
Docker Engine networking involves configuring the network connections between containers and between containers and the host system.
Docker Engine provides several networking options, including:
Bridge Networking: This is the default networking mode for Docker containers, which creates a virtual network between containers and the host system.
Host Networking: This mode allows containers to share the host's network stack, providing direct access to the host's network interfaces.
Overlay Networking: This mode allows containers to connect across multiple Docker hosts, providing a unified network for containers.
Macvlan Networking: This mode allows containers to have their own unique MAC addresses, providing direct access to the physical network.
Docker Engine also supports the use of custom networks, which can be created and configured to meet specific networking needs.
Docker Engine – Storage
Docker Engine storage involves managing the storage used by containers, including the storage of application data and container images.
Docker Engine provides several storage options, including:
Volumes: Volumes are a way to persist data generated by and used by containers. They can be created and managed independently of the containers and can be shared between containers.
Bind Mounts: Bind mounts allow a file or directory on the host system to be mounted into a container, providing direct access to the host's file system.
tmpfs Mounts: tmpfs mounts allow temporary storage to be created and used within a container, without consuming disk space on the host system.
Docker Engine also supports the use of storage plugins, which can be used to provide access to storage solutions such as network-attached storage (NAS) and storage area networks (SAN).
Docker Compose
Docker Compose is a tool for defining and running multi-container Docker applications. Developers can define application services, networks, and volumes in a single her YAML file called the docker-compose.yml file.
Docker Compose makes managing complex applications easier by providing a simple, uniform way to start, stop, and manage the services and containers that make up your application. Docker Compose allows a developer to define the services that make up an application and how to configure them, and execute them all with her one command.
Docker Swarm
Docker Swarm is a native orchestration solution for Docker that allows you to manage a swarm of Docker nodes as a single virtual system. It provides a centralized management interface for managing a large number of Docker nodes, allowing you to deploy, manage, and scale applications across a large number of nodes.
A Docker Swarm is a group of either physical or virtual machines that are running the Docker application and that have been configured to join together in a cluster.
The activities of the cluster are controlled by a swarm manager, and machines that have joined the cluster are referred to as nodes.
One of the key benefits associated with the operation of a docker swarm is the high level of availability offered for applications.
Docker Swarm lets you connect containers to multiple hosts similar to Kubernetes.
Docker Swarm has two types of services: replicated and global.
Kubernetes
Kubernetes is an open-source platform for automating the deployment, scaling, and management of containerized applications. It provides a unified way to manage containers, across multiple hosts, and automate the processes involved in deploying and scaling applications.
A Kubernetes cluster is a form of Kubernetes deployment architecture. The basic Kubernetes architecture consists of two parts:
The control plane and nodes or computing machines. Each node, either physical or virtual, is its own Linux environment. Each node also runs pods made up of containers.
Kubernetes architectural components (K8s components) consist of the Kubernetes control plane and the nodes in your cluster. Control plane machine components include the Kubernetes API server, Kubernetes scheduler, Kubernetes controller manager, etc. Kubernetes node components include the container runtime engine or Docker, the kubelet service, and the Kubernetes proxy service.
The main components of a Kubernetes cluster include:
Nodes: Nodes are VMs or physical servers that host containerized applications. Each node in a cluster can run one or more application instances. There can be as few as one node, however, a typical Kubernetes cluster will have several nodes (and deployments with hundreds or more nodes are not uncommon).
Image Registry: Container images are kept in the registry and transferred to nodes by the control plane for execution in container pods.
Pods: Pods are where containerized applications run. They can include one or more containers and are the smallest unit of deployment for applications in a Kubernetes cluster.
Scheduling –
Kubernetes Scheduling is the process of assigning Pods to Nodes within a Kubernetes cluster. The Scheduler's responsibility is to ensure that Pods are placed on nodes that have enough resources (such as CPU and memory) to run the Pod, and to balance the distribution of Pods across nodes.
Kubernetes scheduler is a core component of Kubernetes.
When a user or controller creates a pod, the Kubernetes scheduler, which monitors object storage for unassigned pods, assigns pods to nodes. The pod is then run by a kubelet that monitors the object store for the assigned pod.
Logging & Monitoring
Kubernetes logging and monitoring are important components of a robust Kubernetes deployment. Logging refers to the collection and storage of log data generated by the various components of a Kubernetes cluster, while monitoring involves monitoring the health and performance of the cluster and its components in real-time.
Logging and monitoring in Kubernetes are the process of collecting and analyzing data from a Kubernetes cluster to help administrators and developers understand its performance and health. Logging and monitoring provide insight into cluster resource utilization, performance, and availability. It also helps identify and troubleshoot issues with your cluster. Kubernetes provides an integrated logging and monitoring system that can be used to collect and analyze data. The system consists of several components such as the Kubernetes API server, kubelet, and container runtime. Additionally, there are various third-party tools and services that you can use to monitor and analyze data from your cluster.
Application Lifecycle Management
Application lifecycle management (ALM) includes the people, tools, and processes that manage the lifecycle of applications from conception to end of life.
ALM consists of several disciplines that are often isolated as part of the traditional development process. B. Waterfall development methodology including project management, requirements management, software development, testing and quality assurance, deployment and maintenance.
Application Lifecycle Management supports Agile and his DevOps development approach by integrating these disciplines and enabling teams to work together more effectively for the business.
Examples of ALM tools:
Atlassian Jira
IBM ALM solutions
CA Agile Central
Microsoft Azure DevOps Server
Tuleap
Basecamp
Security
Kubernetes security is a critical component of deploying and managing applications in a Kubernetes cluster. There are several key areas of concern when it comes to securing a Kubernetes deployment, including:
Cluster security
Node Security
Kubernetes API Security
Network Security
Pod Security
Data Security
Kubernetes provides several features and tools to help secure a deployment, including secure communication between components, encryption of sensitive data at rest and in transit, and role-based access control. Additionally, there are many third-party tools and services available that can help enhance the security of a Kubernetes deployment.
Storage
Kubernetes storage refers to the storage solutions used in a Kubernetes cluster to persist and manage data generated by applications running in the cluster. In a Kubernetes cluster, storage is typically provided by one or more storage volumes that are attached to pods and containers running in the cluster.
There are several types of storage solutions available in Kubernetes, including:
Local storage: Storage that is located on the same node as the pod, and is therefore tightly coupled with the pod's lifecycle. This type of storage is suitable for ephemeral data that can be regenerated if the pod is deleted or recreated.
Network-attached storage (NAS): Storage that is located on a separate networked device, such as a NAS appliance or a cloud-based storage service. This type of storage is suitable for data that needs to be shared between multiple pods or persist beyond the lifecycle of a single pod.
Persistent volumes (PVs) and persistent volume claims (PVCs): Kubernetes objects that represent physical or network-attached storage resources and the way in which they are consumed by pods. PVs and PVCs allow storage to be abstracted from the underlying infrastructure and managed as a cluster resource.
Kubernetes provides several features and tools to manage storage within a cluster, including the ability to dynamically provision and de-provision storage, the ability to dynamically resize storage, and the ability to manage storage access through PVCs and PVs. Additionally, there are many third-party tools and services available that can help enhance the management and performance of storage in a Kubernetes cluster.
Networking
Kubernetes networking refers to the network infrastructure and communication channels used within a Kubernetes cluster to connect and communicate between the various components and resources in the cluster.
The main components of Kubernetes networking include:
Pods: The smallest deployable units in a Kubernetes cluster, each of which contains one or more containers. Pods are connected to each other and to other resources in the cluster through a shared network namespace.
Services: Kubernetes objects that define network endpoints for pods and provide a stable IP address and DNS name for the pods. Services allow pods to communicate with each other and with external clients.
Network plugins: Software components that provide network connectivity and communication between pods and nodes in the cluster.
Ingress controllers: Kubernetes objects that manage external access to services in a cluster, including load balancing, SSL termination, and name-based virtual hosting.
Kubernetes provides several features and tools to manage networking within a cluster, including automatic IP address allocation, automatic service discovery, and network policy enforcement. Additionally, there are many third-party tools and services available that can help enhance the networking capabilities of a Kubernetes cluster.
Design and install a Kubernetes Cluster
Designing and installing a Kubernetes cluster involves several steps, including:
Determine the hardware and software requirements: This includes the number of nodes, the specifications of the nodes, and the operating system and software components that will be used.
Choose a network architecture: This includes the network topology, subnets, and IP addresses for each node in the cluster.
Plan for security: This includes defining the security policies and protocols that will be used to secure the cluster, including authentication and authorization, network security, and data encryption.
Install Kubernetes components: This includes installing the Kubernetes control plane components, such as the API server, controller manager, and scheduler, as well as the Kubernetes worker nodes.
Configure the cluster: This includes configuring the network and security settings, as well as setting up the network plugins and ingress controllers.
Deploy applications: This involves deploying and managing applications and services on the cluster using Kubernetes objects such as pods, services, and ingress objects.
The exact steps for installing a Kubernetes cluster will vary depending on the operating system and software components being used, as well as the specific requirements of the cluster.
There are several tools and services available that can help simplify the process of installing a Kubernetes cluster, including managed Kubernetes services offered by cloud providers, and automated installation tools such as kubeadm, kops, and minikube.
Question –
What is Docker?
Docker is a platform that enables developers to easily deploy, run, and manage applications in containers.
What are containers in Docker?
Containers in Docker are lightweight, standalone, and executable packages of software that include everything needed to run the application, including the code, runtime, system tools, libraries, and settings.
How does Docker differ from virtualization?
Virtualization creates a virtual machine that runs an operating system, while Docker runs containers on the host machine's operating system. Containers are more lightweight and faster to start than virtual machines.
What is Docker Swarm?
Docker Swarm is a native orchestration technology for Docker that enables you to manage a swarm of Docker nodes as a single virtual system.
What is a Dockerfile?
A Dockerfile is a script that contains instructions for building a Docker image. It specifies the base image to use, the application code to include, and any configuration required to run the application.
What is the difference between Docker image and container?
A Docker image is a pre-built and packaged version of a piece of software, while a Docker container is a running instance of a Docker image. Multiple containers can be created from a single image.
What is Kubernetes?
Kubernetes is an open-source platform for automating deployment, scaling, and management of containerized applications.
What are containers in Kubernetes?
Containers are a lightweight form of virtualization that allow applications to run in isolated environments, providing greater control over the application and its dependencies.
What is a Kubernetes cluster?
A Kubernetes cluster is a group of nodes that run containerized applications managed by Kubernetes. It includes a control plane and multiple worker nodes.
What is a Kubernetes node?
A Kubernetes node is a single machine in a cluster, either a physical machine or a virtual machine, that runs one or more containers.
What is a Kubernetes deployment?
A Kubernetes deployment is an object that describes a desired state for a set of replicas of a pod. It provides declarative updates for pods and ReplicaSets.
What is a Kubernetes service?
A Kubernetes service is a RESTful object that defines a set of pods and a policy for accessing them, typically through a stable IP address or DNS name.
What is Kubernetes scaling?
Kubernetes scaling refers to the process of increasing or decreasing the number of replicas of a pod or deployment to meet changing resource requirements.
What is Kubernetes rolling update?
A Kubernetes rolling update is a deployment strategy in which new updates are gradually rolled out to a set of replicas, with automatic rollback in case of failure.
What are Kubernetes Operators?
Kubernetes Operators are extensions of the Kubernetes API that allow developers to create, configure, and manage complex stateful applications on Kubernetes.