Docker Ubuntu Install

docker_ubuntu_setup.md

Docker Ubuntu Setup

N. P. O'Donnell, 2020

Preparing a Ubuntu host for docker. Ensures an nginx image can run on port 80.

Install docker:

sudo apt-get update
sudo apt-get install docker.io

Add yourself to docker group and refresh shell:

sudo usermod -a -G docker $USER
su - $USER

Check if the hello-world container runs:

docker run hello-world

Disable/remove any existing nginx:

sudo systemctl stop nginx
sudo systemctl disable nginx
sudo apt-get remove nginx nginx-common

Ensure port 80 is free:

sudo lsof -P -i :80 | grep LISTEN

Start a demonized nginx which will auto start on boot:

docker run -d --restart unless-stopped --name docker-nginx -p 80:80 nginx

Make sure you can browse to the nginx server:

curl -I localhost

Reboot:

sudo reboot now

When the host has rebooted, check that the nginx container has come back up:

docker ps            # Should see the nginx container
curl -I localhost    # Should get a 200

Cleanup:

for patt in nginx hello-world; do \
  for cid in $(docker ps -a | grep $patt | awk '{print $1}'); do \
    docker stop $cid; \
    docker rm $cid; \
  done; \
  docker rmi $patt; \
done

SSH Setup for docker-compose deployments

1. Add an entry in your ~/.ssh/authorized_keys for the machine you'll be deploying from. Password auth won't work.
2. Add these lines to the sshd config file (/etc/ssh/sshd_config on Ubuntu):

AllowTcpForwarding yes
MaxSessions 1000 # possibly more

Restart sshd:

sudo systemctl restart sshd

Before logging out, ensure you can still SSH to the host.