Docker #

List all docker images/containes #

• docker image list
• “docker ps” SAME AS “docker container list “

Build a new docker image #

• docker build -t myImages/web-server .
  (-t is for tag)

• docker build . -t my-web-app -f subfolder/Dockerfile
  Build using context from another directory

Expose network port on a docker container #

docker run --name local-redis -p 6379:6379 -d redis
Important! the ‘-d redis’ should be at the end of the command
-d stands for detached mode

Start a docker container and keep it running #

docker run -td <image>

Run normally #

docker run -d <image>

Start a docker container and inspect it #

docker run -it --entrypoint=sh test_image

Inspect a running docker container #

docker exec -it <containerIdOrName> bash
OR
docker exec -it <containerIdOrName> sh

View docker container logs #

docker logs fe8a513ec656

Remove all stopped containers #

docker container prune
Docker system prune

Delete docker unused images #

docker system prune -a

Build an image and stop at a specific stage (in a mult-stage build) #

docker build . --target <STAGE> -t <TAG>

Reclaim docker disk size on windows #

Volume: %AppData%\..\Local\Docker\wsl\data\ext4.vhdx

• Stop docker desktop services
• Stop WSU
• wsl –shutdown
• Start powershell with admin rights
• Optimize-VHD -Path ext4.vhdx -Mode Full
• From : https://dev.to/marzelin/how-to-reduce-size-of-docker-data-volume-in-docker-desktop-for-windows-v2-5d38
• If you get an error that Optimize-VHD is not found then
  • wsl –shutdown
  • diskpart
  • select vdisk file=“C:\WSL-Distros\…\ext4.vhdx”
  • attach vdisk readonly
  • compact vdisk
  • detach vdisk
  • exit

View docker storage size #

docker system df

View docker memory usge #

docker stats

Where does docker store its files? #

• Windows c:\ProgramData\DockerDesktop\%AppData%\..\Local\Docker\wsl
• macOS: ~/Library/Containers/com.docker.docker/Data/vms/0/
• Linux: /var/lib/docker/

Using AWS Cloudwatch with docker containers that are running on AWS ECS #

The “ECS, docker, cloudwatch log driver” splits each cloudwatch record on new line.

To keep a single log entry for multiline logs, then use the awslogs-multiline-pattern cloudwatch driver option to specify a string for the multiline statements i.e.
(^access:)|(^info:)|(^debug:)|(^log:)|(^error:)|(^warn:)

Docker is not starting on windows #

Delete %appdata%\Docker\settings.json and let Docker to create a new one