Docker Interview Questions and Answer Part – 11

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

Rajesh Kumar

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