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World D1: First Containers · Boss challenge

Night shift

You will learn: to find and fix three broken containers on your own.

Checked with Docker Engine 29 on 31 Oct 2026

The problem

Your laptop~

Lunchboxes (containers)

  • webrunning
    from nginx:1.30-alpine 8080→8080
  • timerfailed (exit 127)
    from alpine:3.22
  • dbfailed (exit 1)
    from postgres:18-alpine no name → /var/lib/postgresql

Frozen packs (images)

  • alpine:3.221 layers · 12.9MB · in use
  • nginx:1.30-alpine8 layers · 93.5MB · in use
  • postgres:18-alpine9 layers · 433MB · in use

Lockers (volumes)

  • 1067bd10d611… (no name)0 files · used by db

Boss: night shift! The day cook left three broken lunchboxes. The shop opens at 7. Fix web, timer and db.

Try it

Box 1: web is Up, but curl localhost:8080 fails. Check its hatch, then fix it.

Your laptop~

Lunchboxes (containers)

  • webrunning
    from nginx:1.30-alpine 8080→8080
  • timerfailed (exit 127)
    from alpine:3.22
  • dbfailed (exit 1)
    from postgres:18-alpine no name → /var/lib/postgresql

Frozen packs (images)

  • alpine:3.221 layers · 12.9MB · in use
  • nginx:1.30-alpine8 layers · 93.5MB · in use
  • postgres:18-alpine9 layers · 433MB · in use

Lockers (volumes)

  • 1067bd10d611… (no name)0 files · used by db

Check

curl said Connection reset by peer. Why did -p 8080:8080 fail?

Try it

Box 2: timer stops at once with Exited (127). Find out why, then make it tick for an hour.

Your laptop~

Lunchboxes (containers)

  • webrunning
    from nginx:1.30-alpine 8080→80
  • timerfailed (exit 127)
    from alpine:3.22
  • dbfailed (exit 1)
    from postgres:18-alpine no name → /var/lib/postgresql

Frozen packs (images)

  • alpine:3.221 layers · 12.9MB · in use
  • nginx:1.30-alpine8 layers · 93.5MB · in use
  • postgres:18-alpine9 layers · 433MB · in use

Lockers (volumes)

  • 596e2561bb82… (no name)0 files · used by db

Check

Notes for the next night shift. Where do you look first?

Drag a card into a box. Or tap the card, then tap the box.

      Try it

      Box 3: db stops with Exited (1). Read what it asks for. Then give it that.

      Your laptop~

      Lunchboxes (containers)

      • webrunning
        from nginx:1.30-alpine 8080→80
      • timerrunning
        from alpine:3.22
      • dbfailed (exit 1)
        from postgres:18-alpine no name → /var/lib/postgresql

      Frozen packs (images)

      • alpine:3.221 layers · 12.9MB · in use
      • nginx:1.30-alpine8 layers · 93.5MB · in use
      • postgres:18-alpine9 layers · 433MB · in use

      Lockers (volumes)

      • 24cd65684366… (no name)0 files · used by db

      Check

      Your laptop~

      Lunchboxes (containers)

      • webrunning
        from nginx:1.30-alpine 8080→80
      • timerrunning
        from alpine:3.22
      • dbrunning
        from postgres:18-alpine no name → /var/lib/postgresql

      Frozen packs (images)

      • alpine:3.221 layers · 12.9MB · in use
      • nginx:1.30-alpine8 layers · 93.5MB · in use
      • postgres:18-alpine9 layers · 433MB · in use

      Lockers (volumes)

      • 5308b82d4150… (no name)24 files · used by db

      7 a.m. check: three boxes Up. The hatch answers 200 OK. The shop can open. Night shift done!

      You did it!

      You can now find and fix broken containers on your own.

      Go deeper (optional)

      Your night shift checklist. 1: docker ps -a shows the state. 2: docker logs tells you why it stopped. 3: docker port or docker inspect checks the setup. 4: remove the box, then run it again, right.

      Real rep (optional): break a box on purpose, then fix it.

      Real mission

      1. docker run -d --name db postgres:18-alpine
      2. docker ps -a
      3. docker logs db
      4. docker rm db
      5. docker run -d --name db -e POSTGRES_PASSWORD=secret postgres:18-alpine
      6. docker rm -f db

      0 of 6 steps done · Your ticks are saved.