{"id":23599,"date":"2025-07-01T07:07:45","date_gmt":"2025-07-01T07:07:45","guid":{"rendered":"https:\/\/www.devopsschool.com\/blog\/?p=23599"},"modified":"2025-07-12T05:38:38","modified_gmt":"2025-07-12T05:38:38","slug":"docker-lab-excercise-assignment-3-docker-volume","status":"publish","type":"post","link":"https:\/\/www.devopsschool.com\/blog\/docker-lab-excercise-assignment-3-docker-volume\/","title":{"rendered":"Docker Lab, Excercise & Assignment – 3"},"content":{"rendered":"\n

Here\u2019s a practical Lab Guide\/Tutorial<\/strong> for each Docker command you listed, with clear explanations and step-by-step examples<\/strong> using httpd<\/code> (Apache) and ubuntu<\/code> images.
This is designed so a student can follow on their laptop and actually practice each command.<\/p>\n\n\n\n

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Docker Command Lab Guide<\/h1>\n\n\n\n
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1. cp<\/code> \u2014 Copy files\/folders between a container and the local filesystem<\/h2>\n\n\n\n

What it does:<\/strong><\/h3>\n\n\n\n

Copies files\/folders from your computer to a container<\/strong> or from the container to your computer<\/strong>.<\/p>\n\n\n\n

Example:<\/strong><\/h3>\n\n\n\n

a. Copying from local to container:<\/strong><\/p>\n\n\n

# Start an ubuntu container in detached mode<\/span>\ndocker run -dit --name test-ubuntu ubuntu\n\n# Create a test file on your host<\/span>\necho<\/span> \"Hello from your host!\"<\/span> > myfile.txt\n\n# Copy file into the container's \/tmp directory<\/span>\ndocker cp myfile.txt test-ubuntu:\/tmp\/\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
b. Copying from container to local:<\/strong><\/p>\n\n\n
docker cp test-ubuntu:\/tmp\/my<\/span>file.txt .\/copied_from_container.txt\n<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
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2. diff<\/code> \u2014 Inspect changes to files or directories on a container\u2019s filesystem<\/h2>\n\n\n\n
What it does:<\/strong><\/h3>\n\n\n\n
Shows changes (added\/modified\/deleted files) made to the container since it started.<\/p>\n\n\n\n
Example:<\/strong><\/h3>\n\n\n
docker run -dit --name diff-ubuntu ubuntu\ndocker exec diff-ubuntu touch \/root\/newfile.txt\ndocker diff diff-ubuntu\n# Output will show A \/root\/newfile.txt (A = Added)<\/span>\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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3. inspect<\/code> \u2014 Return low-level information on Docker objects<\/h2>\n\n\n\n
What it does:<\/strong><\/h3>\n\n\n\n
Displays detailed JSON info about containers, images, networks, etc.<\/p>\n\n\n\n
Example:<\/strong><\/h3>\n\n\n
docker run -dit --name inspect-httpd httpd\ndocker inspect inspect-httpd\n# Look for \"IPAddress\", \"Mounts\", \"Config\" in the output<\/span>\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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4. port<\/code> \u2014 List port mappings or a specific mapping for the container<\/h2>\n\n\n\n
What it does:<\/strong><\/h3>\n\n\n\n
Shows how the container\u2019s ports are mapped to your host.<\/p>\n\n\n\n
Example:<\/strong><\/h3>\n\n\n
docker run -d -p 8080<\/span>:80<\/span> --name httpd-port httpd\ndocker port httpd-port\n# Output: 80\/tcp -> 0.0.0.0:8080<\/span>\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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5. update<\/code> \u2014 Update configuration of one or more containers<\/h2>\n\n\n\n
What it does:<\/strong><\/h3>\n\n\n\n
Change resource limits (like CPU, memory) for running containers.<\/p>\n\n\n\n
Example:<\/strong><\/h3>\n\n\n
docker run -dit --name update-ubuntu ubuntu\n# Update CPU shares to 512 (default is 1024)<\/span>\ndocker update --cpu-shares 512<\/span> update-ubuntu\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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6. wait<\/code> \u2014 Block until one or more containers stop, then print their exit codes<\/h2>\n\n\n\n
What it does:<\/strong><\/h3>\n\n\n\n
Waits for a container to stop and prints its exit code.<\/p>\n\n\n\n
Example:<\/strong><\/h3>\n\n\n
docker run --name wait-ubuntu ubuntu sleep 5<\/span>\ndocker wait wait-ubuntu\n# Output: 0 (means sleep exited successfully)<\/span>\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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7. logs<\/code> \u2014 Fetch the logs of a container<\/h2>\n\n\n\n
What it does:<\/strong><\/h3>\n\n\n\n
Shows the output (stdout\/stderr) of the main process (PID 1) in a container.<\/p>\n\n\n\n
Example:<\/strong><\/h3>\n\n\n
docker run -d --name logs-httpd httpd\ndocker logs logs-httpd\n<\/code><\/span><\/pre>\n\n
docker run --name logs-ubuntu ubuntu echo<\/span> \"Hello from Ubuntu\"<\/span>\ndocker logs logs-ubuntu\n# Output: Hello from Ubuntu<\/span>\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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8. ps<\/code> \u2014 List containers<\/h2>\n\n\n\n
What it does:<\/strong><\/h3>\n\n\n\n
Shows all running containers.<\/p>\n\n\n\n
Example:<\/strong><\/h3>\n\n\n
docker ps                 # Running containers only<\/span>\ndocker ps -a              # All containers, including stopped<\/span>\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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9. stats<\/code> \u2014 Display a live stream of container(s) resource usage statistics<\/h2>\n\n\n\n
What it does:<\/strong><\/h3>\n\n\n\n
Shows CPU, memory, network, and disk stats live.<\/p>\n\n\n\n
Example:<\/strong><\/h3>\n\n\n
docker run -dit --name stats-httpd httpd\ndocker stats stats-httpd\n# Press Ctrl+C to stop viewing stats<\/span>\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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10. top<\/code> \u2014 Display the running processes of a container<\/h2>\n\n\n\n
What it does:<\/strong><\/h3>\n\n\n\n
Lists the active processes inside a container.<\/p>\n\n\n\n
Example:<\/strong><\/h3>\n\n\n
docker run -dit --name top-ubuntu ubuntu bash\ndocker top top-ubuntu\n<\/code><\/span><\/pre>\n\n\n
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11. events<\/code> \u2014 Get real time events from the server<\/h2>\n\n\n\n
What it does:<\/strong><\/h3>\n\n\n\n
Shows real-time Docker events (container start\/stop, image pull, etc).<\/p>\n\n\n\n
Example:<\/strong><\/h3>\n\n\n
docker events\n# In another terminal, start\/stop containers to see events in real time<\/span>\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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12. Detach from container without stopping it:<\/strong><\/h2>\n\n\n\n
When you\u2019re attached to a container (e.g., after docker attach<\/code>), use:<\/p>\n\n\n
CTRL + P + Q\n<\/code><\/span><\/pre>\n\n\n
(This detaches your terminal from the container, but leaves the container running!)<\/strong><\/p>\n\n\n\n
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Lab Flow Example (httpd & ubuntu)<\/strong><\/h1>\n\n\n
# 1. Start containers<\/span>\ndocker run -dit --name myubuntu ubuntu\ndocker run -d -p 8080<\/span>:80<\/span> --name myhttpd httpd\n\n# 2. Practice each command:<\/span>\ndocker cp myfile.txt myubuntu:\/tmp\/\ndocker diff myubuntu\ndocker inspect myhttpd\ndocker port myhttpd\ndocker update --cpu-shares 512<\/span> myhttpd\ndocker wait myubuntu\ndocker logs myhttpd\ndocker ps\ndocker ps -a\ndocker stats myhttpd\ndocker top myubuntu\ndocker events\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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Summary Table<\/strong><\/h2>\n\n\n\n
Command<\/th>What it Does<\/th>Example<\/th><\/tr><\/thead>
cp<\/td>Copy files to\/from container<\/td>docker cp foo.txt cont:\/tmp\/<\/code><\/td><\/tr>
diff<\/td>Show filesystem changes<\/td>docker diff cont<\/code><\/td><\/tr>
inspect<\/td>Show low-level object info<\/td>docker inspect cont<\/code><\/td><\/tr>
port<\/td>Show port mappings<\/td>docker port cont<\/code><\/td><\/tr>
update<\/td>Change container resources<\/td>docker update --cpu-shares 512<\/code><\/td><\/tr>
wait<\/td>Wait for container exit<\/td>docker wait cont<\/code><\/td><\/tr>
logs<\/td>Show container logs (PID 1 output)<\/td>docker logs cont<\/code><\/td><\/tr>
ps<\/td>List containers<\/td>docker ps -a<\/code><\/td><\/tr>
stats<\/td>Live resource stats<\/td>docker stats cont<\/code><\/td><\/tr>
top<\/td>Show processes in container<\/td>docker top cont<\/code><\/td><\/tr>
events<\/td>Real-time Docker events<\/td>docker events<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
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<\/h3>\n\n\n\n