Will this Linux kernel facility limit a Docker container's access to host resources, such as CPU or memory?Solution: cgroups
Answer(s): A
= (Please check the official Docker site for the comprehensive explanation)
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An application image runs in multiple environments, with each environment using different certificates and ports.Is this a way to provision configuration to containers at runtime?Solution: Provision a Docker config object for each environment.
= Provisioning a Docker config object for each environment is a way to provision configuration to containers at runtime. Docker configs allow services to adapt their behaviour without the need to rebuild a Docker image. Services can only access configs when explicitly granted by a configs attribute within the services top-level element. As with volumes, configs are mounted as files into a service's container's filesystem. Docker configs are supported on both Linux and Windows services.
Docker Documentation, Configs top-level element
During development of an application meant to be orchestrated by Kubernetes, you want to mount the /data directory on your laptop into a container.Will this strategy successfully accomplish this?Solution: Add a volume to the pod that sets hostPath.path: /data, and then mount this volume into the pod's containers as desired.
Answer(s): B
The solution will not work because a hostPath volume mounts a file or directory from the host node's filesystem into the pod, not from the laptop. The host node is the VM or machine where the pod is scheduled to run, not the machine where the kubectl commands are executed. Therefore, the /data directory on the laptop will not be accessible to the pod unless it is also present on the host node. A better solution would be to use a persistent volume that can be accessed from any node in the cluster, such as NFS, AWS EBS, or Azure Disk.
1: Volumes | Kubernetes2: Persistent Volumes | Kubernetes
During development of an application meant to be orchestrated by Kubernetes, you want to mount the /data directory on your laptop into a container.Will this strategy successfully accomplish this?Solution: Create a PersistentVolume with storageciass: "" and hostPath: /data, and a persistentVolumeClaim requesting this PV. Then use that PVC to populate a volume in a pod
= The strategy of creating a PersistentVolume with hostPath and a PersistentVolumeClaim to mount the /data directory on your laptop into a container will not work, because hostPath volumes are only suitable for single node testing or development. They are not portable across nodes and do not support dynamic provisioning. If you want to mount a local directory from your laptop into a Kubernetes pod, you need to use a different type of volume, such as NFS, hostPath CSI, or minikube. Alternatively, you can copy the files from your laptop to the container using kubectl cp command.
Volumes | KubernetesConfigure a Pod to Use a PersistentVolume for Storage | KubernetesMount a local directory to kubernetes pod - Stack OverflowKubernetes share a directory from your local system to kubernetes container - Stack OverflowHow to Mount a Host Directory Into a Docker Container
Is this an advantage of multi-stage builds?Solution: optimizes Images by copying artifacts selectively from previous stages
Multi-stage builds are a feature of Docker that allows you to use multiple FROM statements in your Dockerfile. Each FROM statement creates a new stage of the build, which can use a different base image and run different commands. You can then copy artifacts from one stage to another, leaving behind everything you don't want in the final image. This optimizes the image size and reduces the attack surface by removing unnecessary dependencies and tools. For example, you can use a stage to compile your code, and then copy only the executable file to the final stage, which can use a minimal base image like scratch. This way, you don't need to include the compiler or the source code in the final image.
Multi-stage builds | Docker DocsWhat Are Multi-Stage Docker Builds? - How-To GeekMulti-stage | Docker Docs
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