Dockerfile Instructions
FROM, base, image, set, karta hai. RUN, BUILD, TIME, par, EK, command, EXECUTE, karta hai, (jaise, package, install, karna) aur, EK, NAYI, LAYER, banata hai. COPY, HOST, machine, se, FILES, ko, IMAGE, ke, ANDAR, LE, jaata hai.
CMD, DEFAULT, command, DEFINE, karta hai, jo, container, START, hone, PAR, chalti hai — agar, "docker run" ke, saath, EXTRA, command, di, jaaye, TO, CMD, OVERRIDE, ho, jaata, hai. EXPOSE, sirf, DOCUMENTATION, ke, liye, hai, ki, container, KAUNSE, PORT, par, LISTEN, karta hai.
FROM node:20-alpine
WORKDIR /app
COPY package.json .
RUN npm install
COPY . .
EXPOSE 3000
CMD ["node", "server.js"]- FROM = base image, RUN = build-time command, COPY = files transfer
- CMD = default startup command, docker run se override ho sakta hai
- EXPOSE sirf documentation hai, actual port publish -p flag se hota hai
"LABEL" instruction, se, image, mein, KEY-VALUE, METADATA, ADD, ki, ja, sakti, hai — jaise, MAINTAINER, naam, VERSION, ya, DESCRIPTION. YE, "docker inspect" se, LATER, dekha, ja, sakta hai.
LABEL maintainer="team@example.com"
LABEL version="1.0"
LABEL description="Production API server""VOLUME" instruction, Dockerfile, ke, ANDAR, EK, PATH, ko, MARK, karta, hai, JISE, HAMESHA, EK, ANONYMOUS, volume, ki, TARAH, TREAT, kiya, jaana, CHAHIYE — YE, ENSURE, karta, hai, ki, US, PATH, ka, DATA, container, REMOVE, hone, ke, BAAD, bhi, KISI, VOLUME, mein, PRESERVE, rahe.