Rubric

• https://review.udacity.com/#!/rubrics/2804/view

Docker

Docker Cheat Sheet

Environment variables

• --env-file <file> provides all environment variables which are contained in <file>
• However, the file content differs from that of a bash script which can be launched with source <file.sh>:

$ cat env.list
# This is a comment
VAR1=value1
VAR2=value2
USER

This file should use the syntax <variable\>=value (which sets the variable to the given value) or <variable\> (which takes the value from the local environment), and # for comments.

NOTE: see https://docs.docker.com/engine/reference/commandline/run/

Port access

• Use --net host if the following applies
  • container is running locally
  • container shall be reachable via its IP address
• Access with localhost:8081/api/v0/feed for udagram-feed

Inspecting the container

• login to a running container
  • docker exec -it <container name> /bin/bash to get a bash shell in the container
• log into a NOT running container
  • docker run -it --rm --entrypoint sh udagram-feed

NOTE: see https://thorsten-hans.com/how-to-run-commands-in-stopped-docker-containers

docker run --env-file ../env.list --net host udagram-feed

Dockerfile

• Either (XOR)
  • Configure container with EXPOSE 8080 in its Dockerfile
  • Run the container with docker run -p 8100:80 <container name>

All useful commands

• docker build -t <container name> . will run the Dockerfile to create an image
• docker run <IMAGE_ID> will run a container with the image
• docker images will print all the available images
• docker ps will print all the running containers
• docker kill <CONTAINER_ID> will terminate the container
• docker exec -it <container name> /bin/bash to get a bash shell in the running container
• docker run --env-file ../env.list --net host udagram-feed to get a shell in the NOT running container
• docker container inspect [OPTIONS] <container id> [CONTAINER...] get metadata about mentioned container(s)

Step by step

# installing node's package dependencies
npm install

# doing a test drive
npm run dev

# build the project for the container, output is in www folder
npm run build

# build the container
docker build -t udagram-feed .

# run it by configuring environment variables and using hosts IP address
docker run --env-file ../env.list --net host udagram-feed

The Frontend

• https://knowledge.udacity.com/questions/217758
• https://knowledge.udacity.com/questions/397631
• https://knowledge.udacity.com/questions/192623

AWS

S3

• aws s3 ls momi-303817241937-dev to list the content of given bucket
• aws s3 rm s3://momi-303817241937-dev/tea.jpg to remove given file

Kubernetes

• Pairing local cli with EKS: aws eks --region eu-central-1 update-kubeconfig --name DemoCB

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NOTE

• https://knowledge.udacity.com/questions/326491

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DockerHub

Tag and Push

docker tag <container name> <repo name> docker login --username=finfalter docker push finfalter/udagram-feed

Kubernetes

Information

kubectl get pods

Debugging

kubectl logs ${POD_NAME} -p kubectl describe pod ${POD_SHORT_NAME}

Get a Shell to a Running Container

https://kubernetes.io/docs/tasks/debug-application-cluster/get-shell-running-container/ kubectl exec <ID> --stdin --tty /bin/bash

Cleanup

kubectl delete -n NAMESPACE deployment DEPLOYMENT e.g. kubectl delete -n default deployment udagram-feed kubectl delete --all pods --namespace=default

Configuration

echo "changing location"
cd ~/dev/udacity/cloud-developer/03-microservices/src/project/udagram-microservices

kubectl delete all --all -n default

# create a secret
# https://kubernetes.io/docs/tasks/configmap-secret/managing-secret-using-config-file/
kubectl apply -f ../../aws-secret.yml

# create a configuration map
# https://kubernetes.io/docs/tasks/configure-pod-container/configure-pod-configmap/
kubectl create configmap udagram-env --from-env-file=./env.list

kubectl apply -f udagram-feed/deploy/deployment.yml
kubectl apply -f udagram-feed/deploy/service.yml

kubectl apply -f udagram-user/deploy/deployment.yml
kubectl apply -f udagram-user/deploy/service.yml

kubectl apply -f udagram-frontend/deploy/deployment.yml
kubectl apply -f udagram-frontend/deploy/service.yml

kubectl apply -f udagram-reverse-proxy/deploy/deployment.yml
kubectl apply -f udagram-reverse-proxy/deploy/service.yml

kubectl get secret aws-secret -o yaml

kubectl get configmap udagram-env -o yaml

kubectl get pods

Autoscaling

kubectl autoscale deployment <NAME> --cpu-percent=<CPU_PERCENTAGE> --min=<MIN_REPLICAS> --max=<MAX_REPLICAS> kubectl get hpa

Minikube

External IP

# https://stackoverflow.com/questions/44110876/kubernetes-service-external-ip-pending
minikube service --url udagram-frontend

Port Forwarding

kubectl port-forward udagram-reverse-proxy-64f66fd9d6-v4f8v 8080:8080

kubectl port-forward udagram-frontend-64f66fd9d6-v4f8v 8100:80

ConfigMap

replace: kubectl create configmap udagram-env --from-file ./env.list -o yaml --dry-run | kubectl replace -f -

echo -n 'hallo' | base64 echo -n 'bWF6ZGEzMjMK' | base64 --decode