Docker

Concept

VM vs Container

  • VM - Base on OS
  • Container - Base on Application (Linux Kernel: Namespace and Cgroup)

Client to Server

  • Docker daemon - containerd, docker-containerd-shim, docker-runc
  • Docker client - cli command
docker cli -> docker daemon -> containerd -> runc -> namespace & cgroup

Image

  • Snapshots

Container

  • Read-Only processes on image

Hub / Registry

  • Store images

References

Docker commands

Dockerfile

ARG dist="/tmp/password"
ARG projectDir="/password"

FROM golang:1.16-alpine3.14 AS builder
RUN apk add build-base upx
ARG dist
ARG projectDir
WORKDIR ${projectDir}
COPY . .
RUN go build -trimpath -o main cmd/main.go
RUN upx -9 -o ${dist} main

FROM scratch
ARG dist
ENV TZ=Asia/Taipei
COPY --from=builder ${dist} /usr/local/bin/password

Dockerfile1

FROM alpine
CMD ["nc","-l","12345"]

Dockerfile2

FROM alpine
CMD ["echo","DOCKER"]

docker build command

docker build . -t program

docker build . -f Dockerfile -t test_mysql

docker build . -t hello:v1.1 --build-arg dist=/tmp/hello --build-arg projectDir=/hello

docker build

. docker/status
echo -e "${GREEN}Before build${RESET}"
docker image ls
docker build . -f docker/Dockerfile1 -t test1
docker build . -f docker/Dockerfile2 -t test2

docker image

. docker/status
echo -e "${GREEN}After build${RESET}"
docker image ls

docker run AND rm

. docker/status
echo -e "${GREEN}Run container1${RESET}"
docker run -d --name container1 test1
echo -e "${GREEN}Run container2${RESET}"
docker run -d --name container2 test2
echo -e "${GREEN}List alive containers${RESET}"
docker ps
echo -e "${GREEN}List all containers${RESET}"
docker ps -a
echo -e "${GREEN}Remove alive container${RESET}"
docker rm -f container1
echo -e "${GREEN}List all containers${RESET}"
docker ps -a
echo -e "${GREEN}Remove exit container${RESET}"
docker rm container2
echo -e "${GREEN}List all containers${RESET}"
docker ps -a

docker pull AND rmi

. docker/status
echo -e "${GREEN}List all image${RESET}"
docker image ls
echo -e "${GREEN}Pull alpine image${RESET}"
docker pull alpine
echo -e "${GREEN}List all image${RESET}"
docker image ls

docker rmi

. docker/status
echo -e "${GREEN}Remove alpine image${RESET}"
docker rmi alpine
echo -e "${GREEN}List all image${RESET}"
docker image ls

prune

docker system prune -f --volumes

docker history

. docker/status
echo -e "${GREEN}History of test1${RESET}"
docker history test1
echo -e "${GREEN}History of mysql:8${RESET}"
docker history mysql:8

Docker remote

Edit service file

# /lib/systemd/system/docker.service
ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock -H tcp://0.0.0.0:2375

Restart service

systemctl daemon-reload
systemctl restart docker

Specify DOCKER_HOST

. docker/status
echo -e "${GREEN}List images on 192.168.185.9${RESET}"
DOCKER_HOST=192.168.185.9:2375 docker images

Docker-compose

version: "3"

services:
  svn:
    image: zeyanlin/svn
    environment:
      - LDAP_HOSTS=${LDAP_HOSTS}
      - LDAP_BASE_DN=${LDAP_BASE_DN}
      - LDAP_BIND_DN=${LDAP_BIND_DN}
      - LDAP_ADMIN_PASS=${LDAP_ADMIN_PASS}
    ports:
      - 8000:80
      - 3690:3690
    depends_on:
      - ldap
  ldap:
    image: zeyanlin/openldap
    environment:
      - LDAP_DOMAIN=${LDAP_DOMAIN}
      - LDAP_ADMIN_PASS=${LDAP_ADMIN_PASS}
    ports:
      - 389:389
      - 636:636
  php:
    image: zeyanlin/phpldapadmin
    environment:
      - LDAP_HOSTS=${LDAP_HOSTS}
    ports:
      - 80:80
    depends_on:
      - ldap

Env

LDAP_HOSTS=ldap
LDAP_DOMAIN="knowhow.fun"
LDAP_BASE_DN="dc=knowhow,dc=fun"
LDAP_BIND_DN="cn=admin"
LDAP_ADMIN_PASS="123qwe"