Docker Context & Multi-Host

#Docker Context & Multi-Host

After this lesson you'll know:

• managing multiple servers with one command
• docker context for staging/production
• monitoring multiple hosts

#Managing Multiple Servers

# Context for Staging
docker context create staging --docker "host=ssh://[email protected]"

# Context for Production
docker context create production --docker "host=ssh://[email protected]"

# Switching
docker use context staging
docker compose up -d

docker use context production
docker compose up -d

#Monitoring Multiple Hosts

# Check status on all hosts
for ctx in staging production; do
  docker use context $ctx
  echo "=== $ctx ==="
  docker ps --format "table {{.Names}}	{{.Status}}"
done

#Avoiding Accidents

# Show the current context
docker context show
# → "default" or "staging" or "production"

# Always check before making changes:
docker ps  # Is this local or remote?

#✋ Try it out

• Create two contexts: dev and prod (even if they point to the same server, just for practice). Switch between them with docker use context
• Write a small script that runs docker ps on all contexts and shows the results

#📌 Summary

• docker context create creates one context per server
• docker use context switches the target server
• docker context show displays the current context — always check!