cloud engineer
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.
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.
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 $USER # prints docker version =) docker --version |
Here’s how to run docker-compose. I have an Icecast docker-compose.yml file. Icecast is an audio streaming server.
version: "2" services: icecast: image: moul/icecast environment: - ICECAST_SOURCE_PASSWORD=secret - ICECAST_ADMIN_PASSWORD=secret - ICECAST_PASSWORD=secret - ICECAST_RELAY_PASSWORD=secret ports: - "8000:8000" restart: always |
To run Icecast in a container , I run docker-compose in the background.
docker-compose up -d |
Check to see if Icecast is running on your browser.
http://localhost:8000 |
To stop the Icecast container, I simply stop the docker-compose.
docker-compose stop |
Here are the other docker commands you can run.
docker images docker ps docker-compose ps |
Here’s a couple of steps to move a Docker image to the Google Container Registry.
Create a container image.
docker build -t gcr.io/${PROJECT_ID}/my-app:v1 . |
Push image to GCR.
docker push gcr.io/[PROJECT-ID]/[IMAGE] |
Here’s how to run your web application on Google Kubernetes Engine.
Create a Dockerfile. Place your web pages in the public-html directory.
FROM httpd:2.4 COPY ./public-html/ /usr/local/apache2/htdocs/ |
Build a container image for Google Container Registry (GCR).
# set your project export PROJECT_ID=[project_id] # build a container image docker build -t gcr.io/${PROJECT_ID}/your-app:v1 . # verify docker images docker images |
Upload the container image to GCR.
# authenticate gcloud auth configure-docker # upload image docker push gcr.io/${PROJECT_ID}/your-app:v1 |
Create a container GKE cluster.
# create cluster gcloud container clusters create your-app-cluster \ --num-nodes=2 # check clusters gcloud compute instances list |
Deploy your web application.
# create deployment kubectl create deployment your-app \ --image=gcr.io/${PROJECT_ID}/your-app:v1 # see the pods kubectl get pods |
Expose your application to the Internet.
# expose your application kubectl expose deployment your-app \ --type=LoadBalancer \ --port 80 \ --target-port 80 # get the external ip address kubectl get service |
Scale your application.
# scale to 3 replicas kubectl scale deployment your-app --replicas=3 # display the replicas kubectl get deployment your-app |
Cleanup.
kubectl delete service your-app gcloud container clusters delete your-app-cluster |
This Docker image contains Apache (httpd), a web server.
Here’s the Dockerfile.
FROM httpd:2.4 COPY ./public-html/ /usr/local/apache2/htdocs/ |
Build and run your Docker image.
docker build -t my-app . docker run -dit --name my-running-app -p 8080:80 my-app |
Visit http://localhost:8080 to view your app.
Amazon Elastic Container Registry (ECR) is a fully-managed Docker container registry that makes it easy for developers to store, manage, and deploy Docker container images.
Here’s the AWS IAM policy to push and pull images from Docker within ECR.
{ "Version": "2008-10-17", "Statement": [ { "Sid": "AllowPushPull", "Effect": "Allow", "Resource": [ "arn:aws:iam::*:role/your-custom-role" ], "Action": [ "ecr:GetDownloadUrlForLayer", "ecr:BatchGetImage", "ecr:BatchCheckLayerAvailability", "ecr:PutImage", "ecr:InitiateLayerUpload", "ecr:UploadLayerPart", "ecr:CompleteLayerUpload" ] } ] } |
Here’s the installation of Docker for the original Amazon Linux.
# To install docker sudo yum install docker sudo service docker start # Validate it's working docker --version docker run hello-world docker ps -a docker image ls |
Run Icecast2 on a Docker container.
docker run -d \ -p 8000:8000 \ -e ICECAST_SOURCE_PASSWORD=aaaa \ -e ICECAST_ADMIN_PASSWORD=bbbb \ -e ICECAST_PASSWORD=cccc \ -e ICECAST_RELAY_PASSWORD=dddd \ moul/icecast |
Access localhost:8000 on browser. Github.