Installation + Configuration

Question 1

Installation on multiple platforms

Answer 1

Centos:

1. Install required packages:
2. Add docker ce repo
3. Install the Docker CE packages and containerd.io
4. Start and enable the Docker service:

Ubuntu:

1. install required packages
2. Add the Docker GPG key and repo:
3. Install Docker CE packages:

Question 2

How to configure the default logging driver

Answer 2

sudo vi /etc/docker/daemon.json

{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "15m"
  }
}

Question 3

Overwrite default logging on run

Answer 3

docker run –log-driver json-file –log-opt max-size=50m nginx

Question 4

Describe the use of namespaces

Answer 4

namespaces are a linux tech that allows processes to be isolated in terms of the resources that they see

docker uses namespaces to isolate containers

Question 5

Describe some docker namespaces

Answer 5

• pid: process isolation
• net: network interfaces
• ipc: inter process communication
• mnt: filesystem mounts
• uts: kernel and version identifies
• user namespaces

Question 6

Describe the use of cgroups

Answer 6

limits an application to a specific set of resources

allow docker to share hardware resources to containers and optionally enforce constraints and limits