Uly.me

cloud engineer

docker

Docker Exec

by ·

If you want to SSH to a Docker container, use the Docker exec command.

docker exec -it container_name bash

I’m using a Git Bash terminal, so I have to prefix the docker command with winpty.

winpty docker exec -it container_name bash

Result

root@681bbe3f65f1:/var/www/html#

Ctrl-D to exit.

AWS Spot Instances Running Docker

by ·

I have an AMI with docker installed. Here’s how I launch a spot instance using Terraform.

Here’s my Terraform script.

terraform {
  required_providers {
    aws = {
      source = "hashicorp/aws"
    }
  }
}
provider "aws" {
  profile = "default"
  region  = "us-east-1"
}
resource "aws_spot_instance_request" "docker" {
  ami                           = "ami-xxxxxxxxxxxxxxxx"
  spot_price                    = "0.0031"
  wait_for_fulfillment          = "true"
  key_name                      = "servers"
  instance_type                 = "t3.micro"
  subnet_id                     = "subnet-xxxxxxxxxxxxxxxx"
  security_groups               = ["sg-xxxxxxxxxxxxxxxxxx"]
  associate_public_ip_address   = "true"
  user_data = <<-EOF
              #!/bin/bash
              hostnamectl set-hostname docker
              EOF
  tags = {
        Name = "docker-0.1"
  }
}
resource "aws_ec2_tag" "tagging" {
  resource_id                   = aws_spot_instance_request.docker.spot_instance_id
  key                           = "Name"
  value                         = "docker-0.1"
}

I use “aws_ec2_tag” resource to tag the instance properly.

In addition, I use user_data to run a script, to set the hostname.

To launch via Terraform, I run the following commands.

terraform init
terraform apply

When done, I could stop the instance to stop incurring charges. Or just simply destroy it via Terraform.

terraform destroy

It’s not bad deal for an instance that costs only $0.0031 per hour.

Install Docker on Ubuntu 20.04 LTS

by ·

Here’s the script how to install Docker on Ubuntu 20.04 LTS.

#!/bin/bash
sudo apt-get update
# install dependencies
sudo apt-get -y install apt-transport-https ca-certificates curl software-properties-common
# add the gpg key for docker
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
# add the repository in the Linux mint 20
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(. /etc/os-release; echo "$UBUNTU_CODENAME") stable"
sudo apt-get update
# install docker e docker-compose
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(. /etc/os-release; echo "$UBUNTU_CODENAME") stable"
sudo apt-get -y install docker-ce docker-compose
# add the user system to sudo group, no sudo command
sudo usermod -aG docker $USER
# prints docker version =)
docker --version

Run Docker Compose

by ·

Here’s how to run docker-compose. I have an Icecast docker-compose.yml file. Icecast is an audio streaming server.

version: "2"
 
services:
  icecast:
    image: moul/icecast
    environment:
      - ICECAST_SOURCE_PASSWORD=secret
      - ICECAST_ADMIN_PASSWORD=secret
      - ICECAST_PASSWORD=secret
      - ICECAST_RELAY_PASSWORD=secret
    ports:
      - "8000:8000"
    restart: always

To run Icecast in a container , I run docker-compose in the background.

docker-compose up -d

Check to see if Icecast is running on your browser.

http://localhost:8000

To stop the Icecast container, I simply stop the docker-compose.

docker-compose stop

Here are the other docker commands you can run.

docker images
docker ps
docker-compose ps

Docker to GCR

by ·

Here’s a couple of steps to move a Docker image to the Google Container Registry.

Create a container image.

docker build -t gcr.io/${PROJECT_ID}/my-app:v1 .

Push image to GCR.

docker push gcr.io/[PROJECT-ID]/[IMAGE]