Docker

Docker Interview Questions and Answer Part – 11

January 18, 2020 comments off

Which of the following are the standard secured and unsecured Docker engine daemon ports?

  • 2375 (unsecured), 2376 (secured) (Ans)
  • 4000 (unsecured), 4001 (secured)
  • 3375 (unsecured), 3376 (secured)
  • 80 (unsecured), 443 (secured)

Which of the following arguments gets passed to the swarm command to join a node to the Swarm cluster?

  • raft-join
  • join (Ans)
  • swarm-join
  • cluster-join

Which of the following describes what occurs when the primary Swarm Manager that is part of a highly available set of Swarm Managers fails?

  • A leader election occurs and an administrator selects which of the secondary managers is promoated to primary.
  • The Swarm cluster enters a split brain configuration.
  • A leader election occus and a secondary Swarm Manager seamlessly takes over the role of primary. (Ans)
  • The remaining secondary Swarm Managers combine to fill the role of primary.

Which of the following technologies allows Docker Swarm to leverage a pluggable discovery service backend?

  • libnetwork
  • libkv (Ans)
  • Consul
  • godep

Which two resources can containers reserve on the nodes they will run on?

  • CPU and RAM (Ans)
  • CPU and TCP ports
  • CPU and IOPS
  • IOPS and RAM

Which of the following is not a standard constraint?

  • storagedriver
  • networkdriver (Ans)
  • executiondriver
  • operatingsystem

Which of the following is the preferred way to get TLS certificates into a Swarm manager container?

  • Start the Swarm manager container and copy the keys in via SCP.
  • Mount them in via a data volume. (Ans)
  • Rebuild the swarm image with the certificates baked in via a Dockerfile.

Which environment variable can be used to automatically enable TLS for Docker Engine client commands?

  • DOCKER_TLS_AUTHENTICATE
  • DOCKER_TLS
  • DOCKER_TLS_VERITY (Ans)
  • DOCKER_TLS_ENABLE

Which of the following filter types allows you to launch new containers on the same node as another container?

  • Affinity (Ans)
  • Resource
  • Custom
  • Node

How is the Swarm Discovery Service implemented in a production-grade Swarm cluster?

  • As a distributed key-value store (Ans)
  • A flat text file stored on every node in the cluster
  • As a high-speed relational database
  • Using Docker Hub as the hosted discovery service

Which of the following would be a good design for a Swarm cluster?

  • Three Swarm managers on separate VMs and separate physical hosts (Ans)
  • Three Swarm managers on separate VMs on a single physical host
  • Three Swarm managers all on the same VM
  • Five Swarm managers on separate VMs on a single physical host

Which of the following is passed to the swarm command to start a new Swarm Manager process?

  • manager
  • master
  • manage (Ans)
  • leader

Which of the following allows Swarm related components to trust a CA?

  • The presence of the Swarm component’s own public key
  • The presence of the Swarm component’s own private key
  • The presence of the CA’s public key on the Swarm component (Ans)
  • The presence of the CA’s private key on the Swarm component

Which of the following shows the way Docker prefers keys to be named?

  • ca-cert.pem, swarm-cert.pem, swarm-key.pem
  • ca-cert.pem, node-cert.pem, node-key.pem
  • ca.pem, cert.pem, key.pem (Ans)

By default, how does Swarm enforce affinity filters?

  • Best effort. If the affinity cannot be met the container is still started
  • Strictly. If an affinity cannot be met the container is not started (Ans)

Which of the following is true of configuring the Docker Engine daemon for TLS?

  • The Engine daemon dynamically picks up TLS options.
  • The Engine daemon must be restarted to pick up TLS options. (Ans)
  • The Engine daemon must be re-installed and compiled with the TLS configuration.

Which of the following discovery service backends are supported by Swarm?

  • MongaDB, CouchDB, MySQL
  • MySQL, PostgreSQL, etcd
  • Consul, etcd, Zookeeper (Ans)
  • Consul, etcd, MySQL

Which of the following describes the Swarm manager high availability model?

  • The Swarm manager service does not support high availability.
  • Point in time (PiT) copies that can be quickly be promoted to live in the event of failure
  • A single primary manager with n secondary managers (Ans)
  • Multiple primary managers that are all active

Which of the following filter types works with labels/tags that are applied to Docker engine daemons?

  • Affinity filters
  • Standard constraints
  • Custom constraints (Ans)
  • Resource filters

How do Consul agents learn about other agents etc?

  • Using libkv
  • Using the Serf gossip protocl (Ans)
  • Using libnetwork
  • Leveraging the Consul key-value store

Which of the following Consul commands allows you to see the status of agents in the Consul cluster?

  • consul agent status
  • consul members (Ans)
  • consul list members
  • consul status
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