Docker

Thanks Keith for the intro!

Keith: Alpine is a stripped down linux distro. Need to learn about how to handle persistent volumes, container secrets (don't put in container, but it can prompt for things). Dockerfile -v (volume). Container should output to stdin/out, then host can manage logging. Terraform can build your arch (can use a proxmox template), ansible is great for actual tasks. GCP has managed kubernetes (wait until you understand why you need it). Check out hashicorp vault FOSS version for awesome secret storage that is docker-compatible.

Commands

docker build -t name .            # builds an image from curr dir Dockerfile
docker images                     # lists images
docker run --name cont-name image # to create and start a container from an image, which you can then stop and start
                                  # -it to run in a terminal, then Ctrl-C to stop it; use -d to run detached
docker ps                         # to see what containers are running
docker ps -a                      # to see what containers are running (including recently stopped containers)
docker start|stop name            # to start/stop a container
docker rm name                    # to remove a stopped container
docker container prune            # to remove all stopped containers
docker images                     # lists images
docker rmi REPOSITORY/TAG         # to remove an image
docker image prune                # remove all dangling images

docker push|pull                  # push to / pull from hub.docker.com (for subsequent pull elsewhere!)

• show containers in a nice format (you can also add this as default, in ~/.docker/config.json):

docker ps -a --format 'table Template:.ID\tTemplate:.Status \tTemplate:.Names\tTemplate:.Command'
docker ps -a --format 'table Template:.ID\tTemplate:.Status \tTemplate:.Names\tTemplate:.Command' | grep #mycontainer#

Containers

Find nirvana here.

Debian slim

Debian slim containers are much smaller than standard installs. They are stripped of things like documentation, while still maintaining a full linux kernel and C++ stack.

You can use apt to bake in what you need from there. Nice!

Node

The official node container is huge (1GB), the alpine one is relatively tiny. See the list here.

alpine

Alpine is the best TINY base linux container. But it runs BusyBox and musl so many things (nvm, meteor) won't work (at least without a TON of effort).

Node on alpine

Here's a good starting point for a node app, but remember meteor won't work:

FROM alpine/git
RUN apk --update add curl bash tar sudo npm 
SHELL ["/bin/bash", "-c"]

ENV NEWUSER='m'
RUN adduser -g "$NEWUSER" -D -s /bin/bash $NEWUSER \
&& echo "$NEWUSER ALL=(ALL) ALL" > /etc/sudoers.d/$NEWUSER && chmod 0440 /etc/sudoers.d/$NEWUSER

USER m
WORKDIR /home/m

COPY --chown=m my-code /home/m/my-code

RUN npm install -g whatevah

EXPOSE 3000
CMD [ "my_app", "param1" ]

More examples

• Example dockerfile for nextcloud

Networking

Bridge networking (the default) allows connections between containers running on the same docker host.

docker network create my-nw # defaults to --driver bridge
docker run (...) --network my-nw (...) # to create and start a container on the network
docker network connect my-nw # to attach a container to the network after it is started
docker network inspect my-nw

Install

Install docker

sudo apt-get install apt-transport-https ca-certificates curl gnupg lsb-release
echo   "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \
   $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt update && sudo apt-get install docker-ce docker-ce-cli containerd.io
sudo docker run hello-world
sudo docker container ls -all # to see previous run-and-teardown
sudo usermod -aG docker m # to add m to docker group for complete access, no more need for [sudo docker]

Proxmox CPU config

Some images (like Meteor 5.0) require more-advanced CPU capabilities than Proxmox grants by default. Specifically, Mongo 5.0 requires AVX cpu instructions. To enable them:

Proxmox > VM > Edit > Processor > Type: "host"

Note that my Proxmox docker VM is called matryoshka.