Docker.md

Docker

• What is docker.io in relation to docker-ce and docker-ee?
• Experimenting with Rootless Docker
• Building Minimal Docker Containers for Go Applications
• Minideb comparison to other popular docker images

Docker feature

Docker is built on top of runC runtime container and uses daemon

Docker installation Debian based.

• install docker from a package
• buster docker repository

sudo groupadd docker
sudo usermod -aG docker $USER
newgrp docker
docker run hello-world

dockerd -log info

Docker troubleshoot

• https://stackoverflow.com/questions/44942790/docker-error-failed-to-register-layer-symlink
• https://stackoverflow.com/questions/35325103/docker-error-when-pulling-java-8-image-failed-to-register-layer/35325477#35325477

Windows Container

• https://blog.mdfranz.com/a-windows-container-guide-for-linux-folks-397785f7675e
• [Simple way to Docker on Windows 10 home with WSL 2] (https://hinty.io/ivictbor/simple-way-to-docker-on-windows-10-home-with-wsl-2/)

Other containercandidates

• https://medium.com/technopanti/docker-vs-podman-c03359fabf77
• https://iximiuz.com/en/posts/journey-from-containerization-to-orchestration-and-beyond/

building

package main
import (
    "fmt"
    "io/ioutil"
    "net/http"
    "os"
)
func main() {
    resp, err := http.Get("https://google.com")
    check(err)
    body, err := ioutil.ReadAll(resp.Body)
    check(err)
    fmt.Println(len(body))
}
func check(err error) {
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
}


FROM golang:onbuild
FROM golang:latest
RUN mkdir /app
ADD . /app/
WORKDIR /app
RUN go build -o main .
CMD ["/app/main"]

go build -o main .
docker build -t example-scratch -f Dockerfile.scratch .


Dockerfile.scratch
FROM scratch
ADD main /
CMD ["/main"]

CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o main .


update 

FROM scratch
ADD ca-certificates.crt /etc/ssl/certs/
ADD main /
CMD ["/main"]

• https://www.cloudbees.com/blog/building-minimal-docker-containers-for-go-applications make small Go app!

Podman

• Redhat market this as the docker replacement
• ability to run rootless
• podman keeps the same commands as docker
• podman run -dt -p 8080:8080/tcp -e
• https://github.com/boot2podman/boot2podman/blob/master/custom_kernel.md using tc linux as a base. see other md files for information.

Podman dependencies

• Podman uses crun instead of runc. They rewrite crun in C, as runc is written in go. They expect there is much lower overhead, and it is a lot faster.
• other podman dependencies include buildah for building images.