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Question: What security considerations should be taken into account when using Docker?
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Answer: When using Docker, it's important to consider security best practices such as running containers with the
least privileges necessary, using trusted base images, keeping images and containers up to date with security patches,
restricting network access, and using Docker Content Trust to verify image authenticity.
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Question: How does Docker handle container isolation and resource management?
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Answer: Docker provides several mechanisms for container isolation and resource management, including:
• Namespaces: Docker uses Linux namespaces to provide process isolation, network isolation, and filesystem isolation for containers. Each container runs in its namespace, ensuring that it has its view of the system resources.
• Control groups (cgroups): Docker leverages cgroups to limit and manage the resource usage of containers, such as CPU, memory, and I/O. Cgroups allow you to set resource limits, priorities, and quotas for individual containers or groups of containers.
• Container runtime security features: Docker incorporates security features such as seccomp, AppArmor, and SELinux to enforce fine-grained access controls and reduce the attack surface of containers. These features help mitigate security risks and ensure that containers are isolated from each other and the host system.
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Question: What is Docker Swarm, and how does it differ from Kubernetes?
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Answer: The Docker Swarm is Docker's native clustering and orchestration tool, used for managing a cluster of
Docker hosts. It simplifies the deployment and scaling of Docker containers across multiple hosts.
Kubernetes, on the other hand, is a more robust and feature-rich container orchestration platform developed by Google.
It offers advanced features like auto-scaling, rolling updates, and service discovery, making it suitable for large-scale container deployments.
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Question: Can you explain Docker networking modes and when you would use each one?
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Answer: Docker supports various networking modes, including bridge, host, overlay, and macvlan. Details are captured below:
• Bridge mode: Used by default, it creates an internal network for communication between containers on the same host.
• Host mode: Allows containers to use the host network stack, eliminating network isolation but providing better performance.
• Overlay mode: Enables communication between containers running on different hosts in a Docker Swarm cluster.
• Macvlan mode: Assigns each container a MAC address, making it appear as a physical device on the network. Useful for scenarios requiring containers to have their IP addresses.
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Question: What is Docker Hub, and how is it used?
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Answer: The Docker Hub is a cloud-based registry service provided by Docker, Inc., where users can store, share,
and manage Docker images. It serves as a central repository for Docker images, allowing users to pull images from public repositories
or push their custom images. Docker Hub also offers features like automated builds, webhooks, and organization support.
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Question: How do you ensure high availability and fault tolerance in Docker Swarm?
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Answer: To ensure high availability and fault tolerance in Docker Swarm, you can deploy multiple manager nodes across
different availability zones or physical hosts. This helps prevent a single point of failure and ensures that the swarm can continue
to operate even if some nodes fail.
Additionally, you can configure services with multiple replicas and enable automatic
service rescheduling to maintain the desired number of replicas in case of node failures.
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